The addition of a filler to the poly(vinyl chloride) matrix causes a significant improvement of its thermal stability, which is approximately three times higher compared to a polymer without a filler. Furthermore, the prepared composites are additionally characterized by advantageous mechanical properties, especially higher Young’s modulus. A 10% increase in the oxygen index of PVC composites upon addition of 10 wt % hybrid fillers has also been observed, which contributes to an extended range of their application under conditions that require notable fire resistance.A functional magnesium hydroxide/lignin hybrid system was prepared by grinding and mixing the pure precursors using a planetary ball mill. In addition, the thermal stability was assessed based on the total mass loss of the hybrid system within the temperature range of 30–1000 °C, which amounted to 38%. Moreover, the average particle size was at 4.9 μm as determined by the laser diffraction method. The effect of addition of the prepared and characterized Mg(OH) Composite materials with the addition of functional fillers, including hybrid materials, are used in almost all areas of everyday life. They have well-defined, enhanced mechanical, thermal and physicochemical properties; low specific gravity; and considerable chemical resistance ,3,4,5,6.2 an agent commonly used to reduce the combustibility of polymer materials [Magnesium hydroxide belongs to a group of unique inorganic compounds, which exhibit numerous advantageous properties and practical applications. It is distinguished primarily by its antibacterial activity, nontoxic nature and high thermal stability. All of the above features make Mg(OH)aterials ,12,13,142/vinyl acetate nanocomposite as a material with advantageous mechanical, reinforcing and non-combustible properties. Based on the obtained TEM images, a very high dispersion degree of the inorganic filler in the inorganic modifier was observed. The improvement of non-combustible properties of the formed composite was confirmed by comparing the determined Limiting Oxygen Index (LOI) values for both micro-Mg(OH)2/EVA as well as nano-Mg(OH)2/EVA. Based on the results, an increase in the oxygen number from 24.0 to 38.3 was noted for the material with nanometric refinement. The improvement of the non-combustible properties occurred due to the good dispersion of Mg(OH)2 in the EVA matrix and the formation of compact, charred structures during the combustion of the material, which showed similarity to the structure of ceramic materials.Qiu et al.  proposed2 modified using zinc titanate and stearate, as a potential HFFR -type filler applied to polypropylene (PP). The observations of the fillers microstructure using SEM images showed a better distribution of Mg(OH)2 particles after introduction of the titanate and stearate, in contrast to Mg(OH)2 with no modifier. The inclusion of the modifying compounds also favorably influenced the adhesion of the PP and Mg(OH)2 components, directly contributing to the improvement of their compatibility, and thus the mechanical properties of the formed PP/Mg(OH)2 composite. The obtained tensile strength value for PP/Mg(OH)2/zinc titanate and PP/Mg(OH)2/zinc stearate was higher by approximately 6–8 MPa compared to PP/Mg(OH)2 . In turn, the results of composite flame retardancy tests showed that an increase in the oxygen index value occurred as a result of increased modifier content.In other studies, Chen et al.  carried 2 as a fire retardant was also reported in study [2 and the modification of its surface with silanes on the thermal and mechanical properties of EP components. Both the nano- and micro-particles of Mg(OH)2 used in the experiment were modified using 3-aminopropyltriethoxysilane in a water solution, and were used as fillers introduced to the epoxy matrix. The obtained test results confirmed that nano-Mg(OH)2 introduced improved mechanical properties to EP, compared to its counterpart on the micrometric scale. In his study, Wang demonstrated that modified Mg(OH)2/siloxane nanocomposites obtained using the hydrothermal and hypergravity method also had potential flame retarding properties [2 particles obtained by other methods, and the agglomeration was significantly reduced. The surface area of the composite particles was reduced, and the affinity and thermal stability were effectively improved. As a type of filler for polymers, the Mg(OH)2/siloxane nanocomposite may improve the reinforcement of the polymer and the heat resistance and flame retardancy, which provide the foundation for further application of this nanocomposite as a flame retardant. Ma et al. used magnesium hydroxide by applying it onto the surface of cotton fibers with the aim of reducing the combustibility and improving the thermal stability of cotton/magnesium hydroxide composite [2 crystals) as a result of modification with urea and a citric acid solution. On the other hand, the composite combustibility tests showed that introduction of sodium chloride to the cotton/magnesium hydroxide composite considerably increased the fire resistance of the fabric. These results may also be applied for development of new polymer/inorganic material composites.Using Mg(OH)in study , which cin study . The stuoperties . The resomposite . ExcelleWithin the framework of the conducted research, it seems reasonable to also use poly(vinyl chloride) (PVC), which is one of the most important engineering polymers. Its production is constantly increasing due to numerous applications. Among other thermoplastic polymer materials, PVC is distinguished by the possibility to modify its properties over a wide range by using many additives, including fillers ,14. ThisOne of the reasons for the widespread use of PVC in the building industry is the fact that this polymer is classified as the only non-combustible material among general-purpose polymeric materials, due to its chloride content (above 56%). Furthermore, PVC is characterized by the lowest value of heat of combustion ,18 compaAlthough many common applications of rigid PVC do not require the use of flame retardants, investigations are undertaken to additionally enhance its fire resistance and reduce its smoke generation ability. This results from increasingly stringent requirements which are imposed on engineering materials. Aluminum hydroxide and magnesium hydroxide are most often used flame retardants for this purpose. The latter is used more often in the processing of unplasticized PVC due to its higher decomposition temperature . MagnesiPoly(vinyl chloride) is sensitive to heat and under processing conditions may undergo mechano-thermal destruction processes. These processes primarily involve progressive dehydrochlorination and may proceed following different mechanisms, which depend on the used thermal stabilizers . DiffereAside from standard stabilizers, the literature also describes an advantageous effect of other additives, including fillers used in PVC compounds, which can simultaneously enhance their dynamic thermal stability ,25. FolaThe literature contains numerous examples of the use lignin and lignin-based materials as a filler of a polymer matrix, e.g., polyethylene, polypropylene, polystyrene, poly or poly(ethylene oxide), in which lignin can act as a stabilizer against UV degradation or thermo-oxidation ,29. It iRecently, much interest has been directed in the possibility of preparing functional fillers of silica combined with natural polymers, including lignin ,38. SiliThe results of our previous research regarding the use of silica/lignin fillers showed a favorable effect of lignin as one of the hybrid filler components on the thermal stability of PVC during processing by the method of kneading in a Brabender plastographometer . It can Mw ~10.000—both supplied also by Sigma Aldrich , were used for the production of the hybrid filler. Reagent-grade magnesium hydroxide (CAS number 1309-42-8)  and kraft lignin (CAS number 8068-05-1)—average 2/lignin hybrid material produced using the above-mentioned components was then used as the filler of composites on the matrix of unplasticized poly(vinyl chloride) (PVC) blend. In order to minimize the influence of processing additives, the stabilizer and the paraffin wax were the only additional components used in the PVC dry blend. The PVC dry blend was composed of: suspension PVC S-61 Neralit  100 phr, organotin stabilizer Patstab 2310  4 phr, and 1 phr Naftolube FTP paraffin wax .The Mg(OH)2, namely 2.5 wt % (M1), 5 wt % (M2), 7.5 wt % (M3) and 10 wt % (M4).The content of the hybrid filler (HM) in the PVC matrix amounted to 2.5 wt % (HM1), 5 wt % (HM2), 7.5 wt % (HM3) and 10 wt % (HM4), respectively. The obtained PVC composites contained the same percentage contents of Mg(OH)2:lignin mass ratio equal to 1:1) was placed eccentrically on the rotary base of the planetary ball mill. The base rotation direction was opposite to the vessel rotation direction, with a speed ratio of 1:−2. The movement of agate balls within the vessel is the result of the action of the Coriolis force. The speed difference between the balls and the vessel results in the interaction of friction and impact forces, which generate high dynamic energy. The interaction of these two phenomena leads to a very high degree of size reduction of the ground/homogenized material. The mill operated with a change in rotation occurring every 5 min. To achieve the appropriate homogeneity of the final material, the grinding process was continued for 2 h. To prevent a possible overheating of the material due to continuous grinding, the mill automatically shut down every 30 min for 5 min, after which it resumed operation. Upon appropriate grinding, the hybrid material was separated through a 40 μm-mesh sieve.In order to combine magnesium hydroxide and lignin, the process of mechanical grinding of pure precursors with their simultaneous mixing was employed using a Pulverisette 6 Classic Line planetary ball mill . The vessel with the materials subjected to homogenization (Mg(OH)The morphology and microstructure of the examined systems were assessed using an EVO40 scanning electron microscope manufactured by Zeiss . Before testing, the samples were coated with Au for a time of 5 s using a Balzers PV205P coater .The dispersion properties were determined by measuring the particle size in the range of 0.6–6000 nm, using a Zetasizer Nano ZS analyzer supplied by Malvern Instruments Ltd. . The operation of the analyzer is based on the Non-Invasive Back Scatter (NIBS) technique. The measurement of the size of particles suspended in a dispersing medium is possible owing to the fact that the particles are suspended in the liquid and are in constant motion due to the Brownian movements occurring as a result of their accidental collisions with the particles of the surrounding medium.In addition, to determine the dispersive properties, a Mastersizer 2000 analyzer supplied by Malvern Instruments Ltd.  was used. The measurement relies on the technique of laser diffraction in the particle size range of 0.2–2000 μm. An important element of the apparatus is the Hydro 2000 G attachment, to which distilled water is poured to play the role of a dispersing medium for the measurement of the electric and optic backgrounds and also for minimizing the measurement errors caused by impurities. Before measurements the ultrasonic treatment was additionally applied.The thermal stability analysis was made using a Jupiter STA 449F3 analyzer supplied by Netzsch GmbH, , which utilizes the thermogravimetry (TGA) method. The measurement involved heating a sample of an appropriate mass at the temperature range of 30–1000 °C with a step of 10 °C/min, in a nitrogen atmosphere. The analysis was performed by using the TGA-DTA attachment.The examination of the properties of the porous structure was made using an ASAP 2020 apparatus supplied by Micromeritics Instrument Co. . The determination of the porous structure parameters was conducted using low-temperature nitrogen sorption. In the final examination phase, using suitable software, the most important parameters of the porous structure were determined, including the BET surface area (determined by the Brunauer–Emmett–Teller method) and the total volume and size distribution of pores  algorithm).2 as well as an unfilled PVC dry blend, used as the reference materials, were processed under identical conditions.At the first stage of preparing composites in the Brabender mixer, compounds of the hybrid filler, previously dried for 3 h at the temperature of 105 °C, were prepared with a PVC dry blend. The homogeneous mixtures were processed in the chamber of a Brabender plastographometer  at the temperature of 180 °C and a rotor speed of 30 rpm; the charge mass was 62 g. Kneading was conducted up to the point of establishing torque equilibrium, i.e., for about 10 min. The PVC mixtures with Mg(OH)After cooling down, the processed material was ground and pressed using a hydraulic press which was constructed in the UTP Department of Technology of Polymer and Protective Coatings  at the temperature of 180 °C, under a pressure of 10 MPa for a duration of 5 min into 10 × 10 × 4 mm and 10 × 10 × 2 mm plates, which were used for the preparation of samples for mechanical testing and softening temperature determination by the Vicat method as well as for flammability test by the oxygen index method. The residue was ground and the obtained milling was used for thermal stability examination by the TGA and Congo red methods and for the determination of the mass flow rate.MX), the value of the actual temperature of kneaded mixture (TX) associated with the maximum torque and the time of its attainment (tX), as well as the torque in the equilibrium state (ME) and the temperature of the mixture in the equilibrium state (TE).During kneading of the compounds, the torque of the rotors was recorded, as a function of time; simultaneously, the actual charge mass temperature was registered. Based on the obtained plastograms, the values characterizing the processing properties were determined, namely: the maximum value of the torque (Examinations of the mass flow rate (MFR) of the produced composites were also carried out using a D4004DE apparatus . The measurements were taken under the following conditions: cylinder temperature, 190 °C; piston load, 211.8 N; and length and diameter of the nozzle, 8.000 ± 0.025 mm and 2.095 ± 0.005 mm, respectively.The mechanical properties were determined in accordance with ISO 527-1 using a Zwick Roell Z010 testing machine manufactured by Zwick GmbH & Co. KG, Ulm, Germany. The test was conducted using 1B-type 2 mm-thick specimens; 10 specimens from each material series were used for the determination.Thermogravimetric analysis and Congo red test were used to investigate the thermal stability of the samples. The TGA measurements of all samples were performed using a thermogravimetric analyzer Netzsch TG 209F3 , at a scanning rate of 10 °C/min under nitrogen atmosphere at the temperature range 20–900 °C.Congo red thermal stability was determined at the temperature of 200 °C, according to ISO 182-1:1990.3. The measurements for one type of sample were carried out for 3 times, in accordance with the requirements of the standard.The tests of Vicat softening temperature were performed in accordance with ISO 306:2014, using specimens 10 × 10 × 4 mmThe flammability test was performed by the oxygen index method at room temperature in accordance with Standard ISO 4589-2:2006. The determination of the lowest concentration of oxygen in its mixture with nitrogen, at which the burning of vertically positioned test specimens is maintained, was performed using 4 mm-thick specimens.The structure of the PVC composites and the homogeneity of dispersion of the fillers was assessed by the optical microscopy method using a Nikon Eclipse 400 polarization microscope  at a magnification of 10 times. Approximately 0.1 mm-thick polymer films, obtained by the pressing method, were used for observations. Additionally, the microstructure was observed by scanning electron microscopy EVO40 . The samples were broken in liquid nitrogen, and coated with gold for 5 s using a Balzers PV205P coater  before placing in the chamber of the microscope.2/lignin hybrid system, obtained based on the precursors used, contains particles in the size range of 342–615 and 955–5560 nm in its microstructure (the data from the Zetasizer Nano ZS apparatus). The data obtained with the Mastersizer 2000 analyzer and the SEM microphotograph  filler. In terature ,42,43. Lterature ,31. The terature ,44,45. Tterature .2/g and an overall pore volume and a pore size of 0.06 cm3/g and 4.2 nm, respectively. The precursors used, in turn, were characterized by a BET surface area of 108 m2/g (magnesium hydroxide) and 1 m2/g (lignin), which is consistent with the data previously determined and reported by other researchers [In order to obtain an in-depth assessment of the physicochemical properties of the obtained hybrid and the precursors used for its fabrication, the characterization of porous structure parameters was carried out see . The hybearchers ,41.2/lignin (PVC/HM2) with marked characteristic values, which were the subject of further analysis. The values of torque (MX and ME), temperature (TX and TE) and time (tX), determined from the plastograms, are summarized in The behavior of the dependency of the torque and the actual charge temperature on kneading time for all produced PVC composites are essentially similar and typical for unplasticized PVC blends see . The couX), associated with PVC gelation, is higher and slightly increases along with the increase of the concentration of the hybrid filler in the kneaded blends  was noted for mixtures containing 10 wt % of the filler.The time of attaining the maximum torque value is significantly shortened with increasing hybrid filler concentration. The shortest gelation time (shorter by approximately 55% compared to PVC) was found in case of mixture containing 10 wt % of the lignin hybrid filler. A lower reduction of the gelation time with increasing filler content of the matrix was observed during kneading of PVC mixtures with Mg(OH)X temperature. The shortening of the gelation time and the decrease of the TX temperature by 3–5 °C along with increasing hybrid filler content in the PVC matrix is advantageous from the economical point of view and the potential manufacturing of such composites in industrial practice. The analysis plastograms  directly related to their viscosity is observed.Similar effects observed during kneading of PVC containing lignin modified with polyacrylate ,50 as werams see  also sho2 are approximately the same as the MFR values of the composites with hybrid fillers. A similar tendency of lowering the MFR value of the composites with PVC was found when lignin was used as a filler [The analysis of data in a filler .ME values during kneading in the plastograph chamber are relatively negligible.The reduction of the MFR value with the increase in the filler content of the PVC matrix is most likely caused by hindering the free movement of PVC macromolecules in the capillary of the plastometer due to the effect of the applied piston pressure. Such a possibility is confirmed by the relationship of the torque in the equilibrium state as a function of the increasing filler content (regardless of its type) shown in t value for unfilled PVC. During mechanical testing at static tension, it was found that specimens of all materials, i.e., PVC, PVC/M and the PVC/HM composites, indicated a distinct yield point. Regardless of the filler content, the value of the yield stress (σY) in each case corresponded to the tensile strength (σM).The analysis of test results of mechanical properties summarized in M of unmodified PVC and PVC/M composites, and its value decreases with increasing hybrid filler concentration. Furthermore, the modification of PVC with the hybrid magnesium hydroxide/lignin filler leads to a slight decrease of the mechanical strength of the composites, which was also observed in our previous studies, in which both silica/lignin hybrid fillers and a single component in the form of lignin were used [M value compared to PVC.The tensile strength of the PVC/HM composites is lower than the σere used ,40. Thisere used ,52,53. TεB value of the PVC/HM composites is slightly lower in comparison to the composites modified only with magnesium hydroxide.Regardless of their filler content, all PVC/HM and PVC/M composites showed a much lower elongation at break, compared to unfilled PVC, moreover the T5 and T50 associated with the mass loss 5% and 50%, respectively, and the value of the temperature TDTG, at which the decomposition rate is maximal, similar to Blanco et al. [o et al. . Figure The behavior of the TGA curves for the PVC/HM composites a and PVC2/lignin filler slightly increases this temperature to a maximum value of 260 °C upon introducing 10 wt % of the hybrid to the matrix. In contrast, the value of temperature of the 5% decomposition for PVC/M is higher than for the unmodified PVC and the PVC/HM composites, which is associated with the higher thermal stability of Mg(OH)2 compared to lignin . Compared to PVC composites containing a single component of the hybrid, i.e., Mg(OH) T50 see . It can TDTG temperature, at which the dehydrochlorination process takes place with the highest intensity. This temperature was approximately 276 °C for pure PVC, and with the increase of the Mg(OH)2/lignin filler content in the matrix, it shifts towards higher values, as shown in In the DTG curve b, two seCompared to PVC composites modified with magnesium hydroxide, PVC/HM composites are characterized by a higher DTG peak temperature b by appr2 content in the PVC matrix. The maximum PVC decomposition rate is approximately 37%/min, introduction of 10 wt % of the magnesium hydroxide reduces this value to 28%/min. Introduction of 10 wt % of the Mg(OH)2/lignin hybrid filler reduces this value to 23%/min. Thus, the Mg(OH)2/lignin hybrid material proposed in this work has an advantageous contribution to reducing the intensity of HCl emission during the decomposition of PVC used as the matrix of PVC/HM composites.Moreover, the height of the dehydrochlorination peak on the DTG curve, which indicates the intensity of HCl emission, decreases with the increase of both hybrid filler and Mg(OH)3 as a filler in PVC composites produced by the solution casting method [3 particles can bind the HCl gas, whereby the self-accelerating effect is avoided when CaCO3 is used as a filler. Scavenging of HCl does not lead to a complete stop of the decomposition process, though it can significantly reduce the rate of degradation. The stabilizing effect of magnesium hydroxide due to the absorption of hydrogen chloride released during PVC degradation, which has a direct effect of extending the duration of thermal stability, as measured by the Congo red method, is also described [Similar absorption properties of HCl and thus stabilization properties were found in the case of using micrometer and nanometer CaCOg method . The TGAescribed . The effescribed ,57,58,59A potential application of lignocellulose materials as the absorbers of hydrogen chloride released during destruction of polymer medical wastes including PVC was proposed in study . The mec2 and lignin, hence it can be presumed that the mechanism of the stabilizing effect of this filler on PVC is complex and may result from the simultaneous interactions of both hybrid components with polymer macromolecules.The filler used in this study contains both of the components described in the literature cited above, i.e., Mg(OH)2/lignin filler to the matrix in the amount of 5 wt % and more significantly extends the time after which the change in the indicator’s color is observed, which confirms the destruction of PVC. PVC composites containing 7.5 and 10 wt % are characterized by higher temperature stability compared to unfilled PVC by 29 and 41 min, respectively. The time of the thermal stability of PVC/M composites increases with increasing Mg(OH)2 content of the matrix, though the stability improvement is not as considerable as in the case of the hybrid filler. It can therefore be inferred that the significantly increased thermal stability of PVC/HM is associated with the presence of the lignin component, as has also been found in work [The favorable effect of the used filler on the static thermal stability is also confirmed by the results of the Congo red method. The analysis of the data presented in 2 component reinforces this effect, the HCl released at the initial stage of destruction may be a substrate for the reaction of synthesis from Mg(OH)2, resulting in MgCl2 [It can be presumed that the presence of lignin in the hybrid filler is an important factor preventing the chain reactions of PVC dehydrochlorination, probably due to attaching HCl molecules initiating the chain reactions of decomposition to metoxy groups in phenolic rings, which leads to the formation of chloromethane . In addiin MgCl2 ,20,62.The PVC/HM composites are distinguished by a higher softening temperature compared to unfilled PVC and PVC/M composites see ; introdu2/lignin hybrid filler [A similar effect of improving the functional properties of PVC matrix-based composite materials in terms of widening their temperature applicability range is described for the use of the wood flour filler  and the d filler .2/lignin filler as an agent enhancing the fire resistance, as determined by the LOI method. The value of the LOI index of unfilled PVC sample is 45.1%, which allows it to be ranked among self-extinguishing materials. It has been found that the PVC/HM composites are characterized by LOI values ranging from 45.8% to 49.6%, which may suggest a potential for using the Mg(OH)2/lignin hybrid as an agent which additionally increases the fire resistance of PVC.Within the present study, a preliminary investigation was also carried out to determine the usefulness of the Mg(OH)2 is higher by approximately 20% compared to pristine PVC and by approximately 11% compared to a PVC sample containing the identical hybrid filler fraction.As expected, the LOI value of PVC composites containing 10 wt % of Mg(OH)Within this study, the examination of the LOI of PVC composites with a lignin addition was also carried out. The LOI values of composites are similar and range from 43.6% to 44.0% regardless of the lignin content up to 10 wt %. Thus, the increase in the oxygen index of PVC-based composites is associated with the presence of an inorganic component in the hybrid filler.SEM images see  confirm 2/lignin hybrid system has been produced by a mechanical method using a planetary ball mill and described. The obtained material is distinguished by an average particle size of 4.9 μm and a BET surface area of 73 m2/g. In addition, the potential for using the inorganic–organic hybrid as a possible PVC filler has been confirmed by thermal stability analysis, which allowed determining that the total mass loss at the temperature range up to 1000 °C amounts to 38%.Within the study, a novel, functional Mg(OH)2/lignin hybrid filler has a favorable effect on the processing properties of composites on the unplasticized PVC blend by shortening of the gelation time. In contrast, no significant increase in the mechanical and thermal loads of the processed compounds is observed. The same applies to the effect of the employed filler on the resistance of kneading the composites in a melted state, associated with their viscosity. In addition, introduction of the HM filler to the PVC causes a significant improvement of its thermal stability. The PVC composites with the Mg(OH)2/lignin filler are also characterized by good mechanical properties. The increase of the oxygen index of PVC composites due to the introduction of hybrid fillers with the proposed composition, which was observed in the study, may contribute to an extended range of their application under conditions that require special fire resistance.The addition of the Mg(OH)In summary, the obtained results indicate the possibility of using the magnesium hydroxide/lignin filler as an additional component of PVC dry blends to improve the essential properties of composites produced from them. However, further studies are purposeful to determine the smoke generation of the PVC/HM composites and their other parameters, such as the quantity of heat released during combustion.


Background and aims: Primary immunodeficiencies (PID) are characterized by recurrent infections and increased risk of malignancies because of the reduced immunological surveillance against cancer cells and oncogenic viruses.Methods: We report the incidence of tumors among 690 patients with PID, diagnosed from 1990 until 2017 in Brescia.Results: Out of 690 patients, 25 patients (3.6%) developed 33 tumors. Of the 25 affected patients, 8 patients suffered from common variable immunodeficiency (CVID), 5 from combined immunodeficiency (CID), 3 from Ataxia-telangectasia (AT), 2 from Hermanksy-Pudlak type 2 (HSP2), 2 from gammaglobulinemia X-linked (XLA), 2 from Wiskott-Aldrich syndrome (WAS), 2 from Hyper IgE syndrome (HIES), 1 from severe combined immunodeficiency (SCID). The age at diagnosis ranged from 1 to 52 years, with a median age of 19.6 years. The time between the diagnosis of PID and onset of tumor was short, often <1 year between diagnosis and the appearance of cancer in the case of CID. Moreover, in two cases of CID, the diagnosis of cancer was made before the diagnosis of PID, so cancer was the onset clinical manifestation. Hematological malignancies were prevalent  with a minority of solid tumors . In particular Non-Hodgkin lymphomas were the most frequent . In total 13 patients survived (52%) and tumor was the main cause of death (7 cases). Two patients underwent BMT once the disease was in remission.Conclusions: Therefore, the correct management of tumors that arise in patients with primitive immunodeficiency still represents a challenge in the pediatric field. For this reason now it is mandatory to collect in a unique international registry the cases of malignancies in PID that could lead to a better understanding of the etiopathogenesis and of the biological and clinical characteristics of these tumors, with the aim of defining adequate preventive measures and guaranteeing an early diagnosis which also creating a shared and specific therapeutic strategy, with the prospect of obtaining a better prognosis for these patients. Primary immunodeficiencies (PID) represent a heterogeneous group of congenital diseases characterized by an alteration of the functionality of the immune system. These diseases are considered rare, in fact in Italy the incidence of these forms is variable, ranging from 1:500 for the most frequent forms to 1:500 000 for other rare forms. The overall incidence of PID can be calculated around 1:2000These diseases are characterized by an increased susceptibility to infections, by the frequent development of autoimmune diseases and by a predisposition toward the onset of neoplasia. This particular case became even more evident in recent years since the development of drugs for the prophylaxis and the treatment of opportunistic infections made it possible to have an increase of the life expectancy of these patients, providing the necessary time for neoplastic development. Indeed, tumors are currently the second leading cause of death for patients with PID after infections.The high incidence of tumors is primarily evident in the combined immunodeficiencies in which there is a defect of cell-mediated immunity that plays a fundamental role in the control of birth and neoplastic growth, a mechanism that it is called Tumor Immunosurveillance –3. In fapresence of defects in DNA damage repair (Ataxia-telangectasia) presence of defects of apoptosis that, causing cellular immortalization, allow cells to survive even in the presence of irreversible damage to the genome (Autoimmune Lymphoproliferative Syndrome) presence of deficiencies in the cell cycle check-points for which the cell cycle, fundamental to allow a correct repair of the damage, is missing (Cartilage-hair hypoplasia) defects in the cytokinesis which, by hindering cell division, lead to the formation of genetically unstable tetraploid cells (Neutropenia X linked and Wiskott-Aldrich syndrome) .de novo, reactivated or chronic, can play a decisive role in the genesis of both blood tumors and solid tumors  the prefections ], througfections  lymphomafections .Instead, as regards the mechanism of chronic antigenic stimulation, an example is represented by Helicobacter pylori (HP) infections, which is implicated in the genesis of gastric carcinoma and gastric MALT lymphoma. The increased risk of infections from this microorganism in patients with PID  suggests a genesis due to a reduction in the production of gastric IgA and hydrochloric acid, which facilitates the colonization of HP. This microorganism promotes carcinogenesis by establishing chronic inflammation by stimulating the local production of cytokines, which alter the adhesive properties of the surface of the gastric mucosa and promote ectopic proliferation of lymphoid tissue . FinallyFurthermore, in some immunodeficiencies the acquisition of mutations is favored by the presence of defects in the cell cycle check-points . These mechanisms are normally able to detect possible DNA damage and stop the cell cycle for the time necessary to guarantee a correct repair , which, We decided to carry out a retrospective analysis at the Brescia Children's Hospital  reporting the incidence of tumors among 690 patients with a diagnosis of PID, diagnosed between 1990 and 2017 in Brescia. The study was approved by the Ethical Committee of the Spedali Civili of Brescia, president Aldo Maria Roccaro.The study has the main purpose of reporting the experience of an Italian Pediatric Children's Hospital with patients suffering from PID who developed an oncological pathology during their lifetime, trying to report their characterizing elements.Out of 690 patients, 25 patients (3.6%) developed 33 tumors. They were treated differently depending on the tumor and the immunodeficiency: in particular, for solid tumors surgery was performed, with or without chemotherapy, while for hematological tumors, the treatment was based on National or International therapeutic protocols , 2.In the literature it is reported that 4–25% of patients with PID develop a neoplasm , but we We discovered that tumors appeared only in some of the primitive immunodeficiencies present in our Center . Indeed Another interesting finding is about the two patients with HSP2, who are two siblings, who both developed Hodgkin's lymphoma, a neoplasm that had never previously been identified in this immunodeficiency. In fact, before now, this syndrome was known only to determine a predisposition to the development of skin tumors (in our case a Dermatofibroma was detected) .Among the cases we analyzed, patients who developed cancer were mostly male: 17 males (68%) and 8 females (32%). These data appear to be discordant with what emerges from the major studies in the literature. In fact, in two of these a distribution of cases of similar cancer was found in males and females , 17, whiThe age at diagnosis ranged from 1 to 52 years, with a median age of 19.6 years. These data are similar to those derived from the ICR (Immunodeficiency Cancer Registry), where the average age was 20 years , 2. We hWe also evaluated the latency time between the diagnosis of PID and the appearance of the first tumor, which was very different from case to case (from 1 month to 29 years). For example, there was a short latency (in 5 patients <1 year) between the diagnosis of SCID/CID and the subsequent appearance of cancer. Indeed, in two cases of CID the tumor was diagnosed even before the underlying immunodeficiency, constituting the clinical manifestation of onset.This finding has already been reported in the literature, in particular in those PIDs that present a delayed onset and/or a mild clinical manifestation . TherefoThe presence of a marked predisposition to the development of neoplasms is suggested in our study by the number of tumors: 25 patients showed 33 tumors, of which 26 were early tumors, of which two were synchronous and one bilateral, 6 were second tumors, and 1 a third tumor.in situ).Most of the tumors were malignant , only 3 cases (9.1%) were non-invasive tumors : 21 cases of lymphomas (5 cases of Hodgkin's lymphomas and 16 cases of Non-Hodking's lymphomas), 1 case of Acute Linfoblastic Leukemia.Non-Hodgkin's lymphomas were the most frequent tumors . We identified the different subtypes: 8 diffuse large cell lymphomas, 2 Burkitt lymphomas, 1 gastric MALT lymphoma, 1 lymphoblastic T cell lymphoma, 1 plasmablastic B cell lymphoma, 1 folliculotropic mycosis fungoides, 1 anaplastic large cells lymphoma, and 1 non-determined subtype.These lymphomas presented peculiar characteristics: (1) frequent extranodal onset 12/15 cases); (2) Prevalence of B phenotype (12/15); (3) Majority of diffuse large cell Lymphoma B (8/15). These results also appeared to be aligned with those present in the literature and this is fundamental, since it is thanks to the knowledge of the common characteristics of these tumors that it is possible to make a diagnostic plan aimed at their early identification , 2 cases of thyroid tumors (papillary thyroid carcinoma), 2 gastric tumors , 1 case of surrenalic tumor (leiomyosarcoma), 1 case of duodenal tumor , 1 case of breast cancer (lobular breast cancer), and 1 case of renal tumor .There was a minority of solid tumors , which appeared to be very heterogeneous both by histotype and by localization: 3 cases of skin tumors  in total and the tumor was the leading cause of death (7 cases). In particular, in our experience among patients who developed cancer at pediatric age, 7/11 patients (63.6%) survived 5 years after diagnosis, a number that appears lower than the general population of patients with cancer of the same age, in which the 5-year survival is 82% . This diOur descriptive study certainly has the advantage of a very large number of cases (690) for a single Center considering the rarity of these diseases, a very long observation period (27 years) and good expertise in PID. The limits are instead represented by the difficulty of finding all the blood tests of older patients, above all because in many cases some immunological tests were not yet carried out. Furthermore, such a long observation time helps to highlight the importance of monitoring patients with PID in order to recognize and treat tumors early.Therefore, the correct management of tumors that arise in patients with PID still represents a challenge in the pediatric field. For this reason now it is mandatory to collect in a unique international registry the cases of malignancies in PID that could lead to a better understanding of the etiopathogenesis and of the biological and clinical characteristics of these tumors, with the aim of defining adequate preventive measures and guaranteeing an early diagnosis which also creating a shared and specific therapeutic strategy, with the prospect of obtaining a better prognosis for these patients.The datasets generated for this study are available on request to the corresponding author.FP, RS, ES, and LN contributed conception and design of the study. AS organized the database. AL was involved in the manipulation of stem cells of transplant patients and has coordinated the activities of the stem cell laboratory. MM performed the statistical analysis, wrote the first draft of the manuscript and sections of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The atmospheric corrosion of epoxy prime coated aluminum alloy 7075-T6 exposed for 7, 12 and 20 years was investigated. The remaining thicknesses of epoxy prime coatings for macroscopically intact coating areas followed a normal distribution and decreased linearly. EIS results demonstrated that the corrosion resistance of the coating decreased with exposure time. After 20 years of exposure, the epoxy coating had lost its protection as cracks existed within the coating and exfoliation corrosion had occurred on the substrate. The substrate was sensitive to exfoliation corrosion through metallographic and TEM analysis. The corrosion products were mainly hydroxides of aluminum. The morphology and chemical compositions of the coating bubbling area and propagation characterizations of exfoliation corrosion were analyzed by SEM, EPMA and EDS. Cracks between the lumps of corrosion products provided the channels for the transmission of corrosion mediums. Furthermore, the mechanical model was proposed to analyze the propagation characterization of exfoliation corrosion. Because of its high strength and low density, the aluminum alloy 7075-T6 is widely used in aircraft structures; however, the service of aircraft structures in the outdoor atmosphere exposes them to the influence of atmospheric corrosion . To imprGenerally, aircrafts utilize a three-layer coating system including a conversion coating, primer and topcoat . CurrentThe corrosion of coated metals, organic coatings, and aluminum alloys has been extensively investigated through accelerated tests or electrochemical methods ,12,13,14This paper presents the surface appearance and corrosion products of epoxy primer coated aluminum alloy 7075-T6 exposed for 7, 12 and 20 years in the Wanning test site in China. We also estimated the atmospheric corrosion properties of epoxy coatings using a statistical method and electrochemical impedance measurements. The exfoliation corrosion resistance of the aluminum alloy substrate was analyzed by metallographic and TEM analysis. Finally, we analyzed the morphology and chemical compositions of coating bubbling area and propagation characterizations of exfoliation corrosion by SEM, EPMA and EDS.http://data.ecorr.org/edata/01/0103/010301/01030101/index.html. All the specimens were placed on the test racks facing south at an angle of 45° in a ventilated room to simulate the environment in which the internal structures of an aircraft were located. The analyses were then carried out on the upper surface, facing the sky, since it had endured more pronounced aging and corrosion. Five specimens were withdrawn from the test sites after 7, 12 and 20 years of exposure for each time period and then kept in a desiccator.The exposure tests were performed in the Wanning test site in China. The upper surface appearance of the test section , a platinum wire as counter electrode (CE) and a saturated calomel electrode (SCE) as reference electrode (RE). The electrolyte employed in this measurement was a 3.5% NaCl solution. The impedance data was taken after measuring the open circuit potential for several tens of seconds. The impedances were characterized over frequencies ranging from 100 kHz to 10 mHz, using a 20 mV perturbation signal. Equivalent circuit modeling was performed using ZSimpWin software .Electrochemical impedance spectroscopy (EIS) measurements were performed using a PARSTAT 2273 electrochemical workstation . The electrochemical impedance test samples with a coating area of 1 cmThe remaining thickness of the epoxy coating in the macroscopically intact coating area on the test section of the specimens after different exposure times was estimated using a statistical method. Slices of coating cross-section from a macroscopically intact area within the test section were ground with a 1000 grit SiC paper. The remaining thickness of the upper surface coating was measured by RH-8800 digital video microscope  and TSview-7 software. 3 + 1.5 mL HCl + 95 mL H2O) for 15 s. The microstructure of the S-L section was then observed by metalloscopy.The S-L section of the extruded 7075 aluminum alloy substrate exposed for 20 years was ground with a 1000 grit SiC paper, polished with 2.5 μm diamond paste, and chemically etched with Keller’s reagent  was obtained. Thinning and perforation were carried out on 695 PIPS COOL ion beam thinner , thus completing the preparation of TEM samples. The grain boundary structure of the aluminum alloy was observed on a FEI Talos F200X high resolution transmission electron microscope .The S-L sections of the coating bubbling area and of the junction area between the corroded and un-corroded substrate of a specimen exposed for 20 years were ground with a 1000 grit SiC paper and polished with 2.5 μm diamond paste. The sectional morphology and chemical compositions of the corrosion products were analyzed through SEM and EDS. In addition, the elemental distribution of the coating bubbling section was obtained by EPMA.The surface appearance of coated specimens exposed for 7, 12 and 20 years in the Wanning test site are shown in 3. The volume of this component is larger than that of the parent material, thus forcing the sheets apart. In addition, the more elongated the grains are, the greater the generated wedging force [The XRD pattern of the white corrosion products in substrate corrosion area of a specimen exposed for 20 years is shown in ng force ,22,23,24(1)Normal distribution:(2)Log-normal distribution:(3)Gumbel distribution:(4)Logistic distribution:(5)Weibull distribution: where x is the remaining thickness variable; μ is the location parameter which determines the range of abscissa value of the distribution function and indicates the location of the centralized distribution of measured data; σ is the scale parameter which determines the scale of the distribution function and indicates the discreteness of measured data; β is the shape parameter which determines the shape of the distribution function and directly changes the property of the distribution function. Changes of σ only compress or expand the distribution function without changing its basic shape. After the logarithmic linearization of these five distributions, the different parameter values were obtained by the least square fitting [r). From  fitting  and the t-distribution, the critical correlation coefficient (cr) that satisfies distribution assumption can be calculated by [According to the relationship between the correlation coefficient and the lated by :(6)rc=tαn) is 60 and the significance level α is 0.01, the cr is 0.330. It can be seen in When the sample size (sp) and confidence level (γ). For fixed values of sp and γ, the remaining thickness (t) can be calculated by:The remaining thickness to be considered for the practical application of the coating was then determined by defining a reliability , eviously .n is 60, and k is −3.237 corresponding to the general reliability of 99.9% and confidence level of 95%. The estimated thickness of the epoxy coating exposed for 7 years is 39.5 μm, as calculated by Equation (7). This means there is a 95% probability that the coating thickness will be over 39.5 μm in more than 99.9% of the regions after 7 years of exposure [In this paper, exposure . Figure It can be seen that the remaining thicknesses of epoxy coatings decrease linearly as the exposure time increases . As thosf=0.01, decreased significantly from 70.8 MΩ cm2 to 0.075 MΩ cm2. After 12 years of exposure, the impedance of the coating still had a higher value, and the epoxy zinc chromate coating had a protective effect on substrate. On the contrary, after 20 years of exposure, the phase angle was less than zero at the low frequency region 2 and Zn2(OH)2CrO4. A large number of zinc chromate pigments and their hydrolysis products contribute to increase the transport resistance, making it more difficult for the electrolyte to seep into the coating and slowing down the transmission of reaction particles to the corrosion interface, thus causing the diffusion impedance [The Bode log |Z| plots in mpedance .The Bode phase angle plots of coated samples exposed for 12 and 20 years showed the existence of three time constants. When the electrolyte reached the anodic oxide film surface through the coating, the chlorine ions accelerated the dissolution of the anodic oxide film, and the corrosion of the aluminum alloy substrate occurred at the site of the destruction of anodic oxide film . TherefoRs is the solution resistance, Rc and Qc are the coating resistance and coating capacitance, respectively, and W represents the Warburg diffusion impedance of the coating. The parameter groups Qf and Rf represent the interface double layer capacitance and the charge transfer resistance of anodic oxide film corrosion reaction, respectively. The parameter groups Cdl and Rt represent the charge-transfer reaction at the electrolyte/substrate aluminum alloy. L and RL respectively represent the inductance and inductive resistance produced by substrate corrosion. The inductive loop is usually obtained by the corrosion products deposited or adsorbed on the sample surface [Although the compositions of the coated samples after exposure for 7, 12, 20 of years were basically the same, since the EIS results of samples exposed for 20 years showed inductance characteristics it became necessary to add inductance and inductive resistance in the equivalent electrical circuit selection of samples exposed for 20 years . The equ surface ,33.Q (CPE) to compensate for non-ideal capacitance [Q is given by the following equation [In this work, the frequency response characteristics of the coating and anodic oxide film were not consistent with the pure capacitance; therefore, the capacitance elements were fitted by constant phase elements acitance . The impequation ,34.(8)ZY0 is the CPE-constant, j is the imaginary number unit, ω is the angular frequency , and n is the CPE-power. When n = 1, the CPE represents a pure capacitive.In Equation (8), Rc, Rf and Rt decreased with the exposure time. With the aging and corrosion of the coating, chlorine ions and other aggressive ions were more prone to invade the anodic oxide film. The long-term action of aggressive ions led to the local dissolution and destruction of the anodic oxide film, which made the corrosion of the substrate easier, and thus the Rt decreased. The series inductive resistance, Rl, of the coated samples exposed for 20 years was 6.99 × 104 Ω cm2, which indicated that the corrosion products deposited on substrate surface had a certain protective effect on the aluminum alloy substrate.(1)Cathodic disbondment: Under the conditions of atmospheric corrosion, the anodic oxide film or aluminum alloy substrate under the coating endures electrochemical corrosion. The oxygen reduction reaction (Equation (9)) occurs on the cathode and the pH in the cathode reign increases significantly. The strong basic environment damages the metal oxide or polymer-coating of the interface, which affects the bonding of the coating to the anodic oxide film, and then causes the cracking ,36,37.((2)Photoaging of coatings: Small molecules such as ketones, alcohols and acids can be washed away by water during photoaging (ultraviolet irradiation), continuously changing the composition of the coating, which therefore contracts and is subject to a decrease in thickness. This causes and embrittlement of the coating . In addi(3)Temperature alterations: The seasonal and daily alternations of atmospheric temperature cause the expansion and contraction of the coating, and the change of coating tension and internal stress, which leads to the decrease of adhesion, cracking and destruction of coating .(4)2 air pollutant: The air pollutant SO2 can significantly reduce the adhesion of the coating, resulting in cracking between the coating and anodic oxide film. When SO2 and H2O are simultaneously present, the destruction of the coating is more obvious [Effect of SO obvious .2. The presence of SO2 significantly reduced the bonding force between the coating and the substrate, and also reduced the corrosion resistance of the coating [The S-L sectional SEM morphology and EDS spectrum of the corrosion products and the elemental distribution in the coating bubbling area of coated specimen exposed for 20 years are shown in  coating . The pre coating .In 2), T(AlZnMgCu), S(CuMgAl2) and β(Al7Cu2Fe). The main strengthening phases of 7××× aluminum alloy after T6 aging are the G. P. zone and a small amount of transitional phase 2). A continuous chain of precipitates is distributed at the grain boundary (α solid solution (Area 2#) and of the precipitates at the grain boundaries (Area 1#), a higher Mg and Zn content is noticed in the grain boundary precipitates, and thus it can be inferred that the grain boundary precipitates consisted mainly of the η phase.The metallurgical structure of the S-L section and the grain boundary microstructure of 7075-T6 aluminum alloy substrate exposed for 20 years are shown in boundary b. From tThe η phase in the pitting process acts as an anode and will be dissolved preferentially . As the The junction area between the corroded and un-corroded substrate can be used to study the propagation of exfoliation corrosion. 2 was indirectly involved in intergranular corrosion through conversion to acid in the moist environment. The annual average of NO2 in the Wanning test site was far less than the annual average of SO2, as shown in x was not involved in the exfoliation corrosion of the aluminum alloy substrate.Due to the ventilation and daily temperature alternations on the test site, the surface of the specimens underwent dry and wet alternation, which made the products of intergranular corrosion harden c. From tThe EDS analysis results of the cracking area d showed 1 area, structures of aluminum alloy on the upper side (part 1) exfoliated outwardly, and the intergranular corrosion of structures under the lower side (part 2) also occurred along the L direction. Compared to the area of un-corroded substrate, the exfoliation of the structures on both the upper and lower sides of the A1 area can be considered as the bending of the cantilever beam under load. For the equilibrium of part 1, the wedging force of corrosion products, F1, and the bending moment, M1, produced at the cantilever beam base, C1, must be in balance. Similarly, for the equilibrium of part 2, the wedging forces of corrosion products, F2 and F3, and the bending moment, M1, produced at the cantilever beam base, C2, must be in balance. It was obvious that before the part 1 had been completely exfoliated outwardly, if part 2 appeared the same degree of wedge exfoliation as part 1, it would require a greater wedging force of the corrosion products in the B area. However, due to the fact that the intergranular corrosion in the B area was not deep enough to provide enough wedge force, part 2 does not form the obvious wedge exfoliation as shown in the A1 area.The analysis of wedge exfoliation that occurred near the A area in (1)After exposure for 20 years in the Wanning test sites, the epoxy coating had been partially destroyed, and the exfoliation corrosion had occurred on the extruded 7075-T6 aluminum alloy substrate. The remaining thicknesses of epoxy coatings for macroscopically intact coating areas followed a normal distribution and decreased linearly.(2)The corrosion resistance of epoxy coatings decreased with the increase of exposure time. After 12 years of exposure, the coating still had a protective effect. After 20 years, although the coating was apparently intact, it had lost its protective characteristics and EIS results showed the occurrence of inductive characteristics. The reason was the formation of cracks between the local coating and the anodic oxide film and of cracks within the coating, which reduced the resistance of the coating to aggressive mediums.(3)The anodic oxide film under the epoxy coating bubbling area had been destroyed and the aluminum alloy substrate had also been corroded. The corrosion products in the interior of the coating bubbling area were mainly hydroxides of aluminum.(4)As the continuous chain of η phase was distributed at the grain boundary, the extruded 7075-T6 aluminum alloy was sensitive to exfoliation corrosion. The propagation of exfoliation corrosion in the S-L section was along the direction of extrusion. Cracks between the lumps of corrosion products provided the channels for the transmission of corrosion mediums, which created conditions for the further propagation of corrosion. Moreover, the structures of the aluminum alloy on the upper side of the corrosion product area displayed a more evident exfoliation than the lower side.


A relatively high permeability is also observed for carbon dioxide. At the same time, the content of POE blocks has a small effect on the permeability for all studied gases. The diffusion coefficient increases with an increase in the POE block content in PPEG for all studied gases.Nowadays, block copolymers hold great promise for the design of novel membranes to be applied for the membrane gas separation. In this regard, microporous block copolymers based on a macroinitiator with an anionic nature, such as potassium-substituted block copolymers of propylene oxide and ethylene oxide (PPEG) and 2,4-toluene diisocyanate (TDI), were obtained and investigated as effective gas separation membranes. The key element of the macromolecular structure that determines the supramolecular organization of the studied polymers is the coplanar blocks of polyisocyanates with an acetal nature (O-polyisocyanate). In the present research, the influence of the content of peripheral polyoxyethylene (POE) blocks in PPEG on the supramolecular structure processes and gas transport characteristics of the obtained polymers based on PPEG and TDI was investigated. According to the study of polymers if the POE block content is 15 wt %, the polyoxypropylene segments are located in the internal cavity of voids formed by O-polyisocyanate blocks. When the POE block content is 30 wt %, the flexible chain component forms its own microphase outside the segregation zone of the rigid O-polyisocyanate blocks. The permeability for polar molecules, such as ammonia or hydrogen sulfide, significantly exceeds the permeability values obtained for non-polar molecules He, N Due to the constantly growing requirements for the characteristics of substances, such as quality (purity) and environmental friendliness, the design and development of energy-efficient methods and purification technologies have become increasingly popular ,2,3,4. IBlock copolymers can potentially be used to obtain new membrane materials that can be applied for the selective separation of gases. Poly(styrene-butadiene-styrene) block copolymers were the most studied in this series ,13,14,152 were studied in n[CH2(CH3)CH2O]m[CH2CH2O]nK and molecular weight of 4200 g/mol, containing 15, 20, 30 and 40 wt % of peripheral POE blocks, were synthesized in the laboratory of Scientific and Research Center, PJSC Nizhnekamskneftekhim , which also had a content of potassium alcholate groups that was 10.9% of the total number of functional groups. The 2,4-toluene diisocyanate 98% (TDI) was purchased from Sigma-Aldrich . PPEG was additionally dried at a reduced pressure and at an elevated temperature of 353 K to reduce the moisture concentration to 0.01%.The block copolymer of propylene oxide with ethylene oxide (PPEG) with the formula of HO:[TDI] = 1:15 was introduced. Five minutes after being mixing with TDI, the reaction system was loaded with triethylamine (0.0072 g) and water (0.001 g). Ten minutes after the reaction mass was dispensed to Petri dish, it was cured at room temperature for 72 h.Tensile stress–strain measurements were obtained from the film samples with dimensions of 40 mm × 15 mm using Universal Testing Machine Inspekt mini  at 293 ± 2 K and 1 kN. The crosshead speed was set at 50 mm/min and the test continued until sample failure. A minimum of five tests was analyzed for each sample and the average values were reported.−1. The spectral resolution was 2 cm−1 and the number of scans was 10.The FTIR spectra were recorded on an InfraLUM FT 08 Fourier transform spectrometer  using the attenuated total reflection technique in the spectral range of 3800–400 cmThe thermomechanical curves of polymer samples were obtained using TMA 402 F  thermomechanical analyzer in the compression mode. The thickness of the sample was 2 mm, the rate of heating was 3 K/min from room temperature to 540 K in the static mode and the load was 2 N.Thermal gravimetric analysis (TGA) was performed using STA-600 TGA–DTA combined thermal analyzer . The samples (0.1 g) were loaded in alumina pans and heated from 297 to 870 K at a rate of 5 K/min in a nitrogen atmosphere.The atomic force microscopy (AFM) was used to reveal the surface morphology of samples. All AFM measurements were obtained using an atomic force microscope  and silicon vibration cantilevers  with a typical tip curvature radius of no greater than 8 nm. The lateral scan area was of up to 5 μm × 5 μm. The microscopic images were obtained at a resolution of 256 × 256. Membrane samples were attached to the metal sample discs using adhesive carbon tabs . The AFM images were obtained for three samples of each material. The measurements were all carried out under ambient conditions using the tapping mode of imaging.s is the mass of the sample after the test. The arithmetic average of the results of the five tests was determined as the main result.Water adsorption was determined by the gravimetric method. A sample of a certain size was cut out from the obtained polymer. The resulting sample was weighed on an analytical balance. The measuring cup loaded with distilled water before the sample was placed in water and fixed. After a specified amount of time, the samples were removed, the remaining water from the surface was removed using filter paper and the sample was weighed. Water adsorption (B) is calculated as a percentage using the following formula:Single gas permeances tests through the obtained membranes (polymeric films) were performed according to the Daynes-Barrer technique in a constant-volume variable-pressure apparatus for gas permeability measurements at the initial transmembrane pressure difference of 110 kPa and at ambient temperature (25 °C).−5 Pa. The membrane area was 2.54 cm2. The feed- and permeate-side pressures were monitored by high precision pressure sensors PT 5000  at an accuracy of 0.5% of the span (for the feed side) and MKS Baratron 750B 0–100 torr pressure transducer  with an accuracy of 1% of the reading (for the permeate side). The constant feed pressure was maintained at 110 kPa and the permeate pressure evolution was recorded with a sampling rate of 10 ms. Each single gas test was repeated at least three times. A radial membrane permeation cell .It was determined that when the peripheral polyoxyethylene blocks  were not found in MI, the reaction was accompanied by the formation of a glassy polymer product, regardless of the cocatalysts used, and lower temperatures. In that case, polyisocyanurates (PIR) were exclusively formed , accordiWhen MI containing 100% of POE blocks  is used, the polymer products formed exhibit significant hydrophilicity, low strength characteristics and high plastic deformation. In that case, the formation of O-polyisocyanate structural elements does not occur according to FTIR spectroscopy.Previous studies ,40 exami−1 corresponding to the stretching vibrations of the C=O bond are practically absent but a band appeared in the region of 1670 cm−1 that corresponds to the stretching vibrations of N=C bonds in O-polyisocyanates (−1 indicated the formation of urea.Therefore, the PPEGs with a molecular weight of 4200 g/mol were used to study the effect of the content of peripheral POE blocks on the opening of NCO groups along the C=O link. According to FTIR spectroscopic studies, a change in the content of POE blocks in PPEG from 15 to 30% does not affect the character of the spectra. The bands in the region of 1710 and 1410 cmcyanates . A shoulThus, the presence of terminal POE is a prerequisite for the activation of isocyanate groups under the influence of MI on TDI with their subsequent opening by the carbonyl component. In this regard, the next studies were carried out for polymers obtained on the basis of TDI and PPEG, which contain 15, 20, 30 and 40 wt % of POE blocks.According to the measurements of the thermogravimetric analysis curves , a decreThe curves of thermomechanical analysis  reflect In addition, the findings indicate that O-polyisocyanate blocks are the main element of the supramolecular organization of the studied polymers. The domains formed with their participation are distinguished by their stability in high temperatures. Thus, for the polymer obtained at 15 wt % of POE content, the deformation values of 20% are achieved only at 250 °C.ortho-position TDI, which are included into adjacent O-polyisocyanate blocks.The deformation of the samples, which accompanies the temperature rise from 250 °C, is connected with the processes of thermal destruction of polymers. The run of TMA analysis curves reflects the fact that the segregation of O-polyisocyanate blocks is not due to the intermolecular interactions of physical nature but is instead due to the fact that urea is formed as a result of the involvement in its formation of NCO groups of A change in the content of POE blocks leads to noticeable changes in the mechanical behavior of polymers . In thisIt is suggested that during the formation of the cellular supramolecular structure of the synthesized microporous block copolymers, the internal component of the pore depends on the content of POE blocks in the initial macroinitiator. Thus, when the content of POE blocks in PPEG is 15–20 wt %, part of the pore cavity is filled with polyoxypropylene segments. When the content of POE blocks in PPEG is 30 wt %, the surface of the pores is composed of O-polyisocyanate blocks. In these cases, the obtained microporous polymers adsorb water without changing their geometric dimensions. An increase in the content of POE to 40 wt % leads to the swelling of polymer samples in water and the destruction of the cellular supramolecular structure due to the hydrophilicity of the polyoxyethylene segments .According to the AFM data , the con2 and CH4. A relatively high permeability is also observed for carbon dioxide. The fact that CO2 exhibits higher permeability compared to He, N2 and CH4 is associated with the higher solubility of CO2 in polyoxyethylene and polyoxypropylene blocks compared to other gases. This hypothesis is also confirmed by the higher sorption coefficients for CO2 in comparison with He, N2 and CH4 (According to the studies of gas transport characteristics  of the o and CH4 . At the It is important to note the high values of ideal selectivity for pairs of gases, including polar and non-polar molecules.The diffusion coefficient increases with an increase in the POE block content in PPEG for all studied gases. These regularities are consistent with the stated assumption that the voids of polymers obtained with a low content of POE blocks are filled with a polyoxypropylene component. As a result, the space inside the pores is reduced. Therein, for non-polar gases, an obstacle appears due to the imperfection of the channel formation between the pores.In the case of polar gases, these penetrate as a result of their sorption by chemical substances and subsequently fill the surface of the pores. At the same time, the values of the sorption coefficients for polar gases enormously exceed those for non-polar gases .3/CH4, H2S/CH4, CO2/CH4, NH3/N2, H2S/He, H2S/N2, CO2/He, NH3/He and CO2/N2 pairs at a POE block content of 15–20 and relatively high ideal selectivity for NH3/CO2 and H2S/CO2 pairs. Moreover, the obtained results for CO2/N2 hold promise in comparison with the data presented on the revised upper bond of Robeson plot [2/CH4, the best results are obtained with 15% POE but this is slightly lower than the upper bond.The established differences in the permeability values turned out to be the cause of the high ideal selectivity for NHson plot , especiaThe ability to select the necessary ideal selectivity of the resulting polymer membranes by changing the POE block content in PPEG is important from a practical perspective.In this present work, the influence of the content of peripheral POE blocks in PPEG on supramolecular structure processes and gas transport characteristics of polymers obtained on the basis of PPEG and TDI was investigated. The presence of peripheral POE blocks in PPEG is a prerequisite for the activation of isocyanate groups under the influence of MI on TDI, with their subsequent opening by the carbonyl component and formation of O-polyisocyanate blocks.Several relaxation processes are observed on TMA curves, which are significantly influenced by the content of POE blocks in PPEG. With an increase in the weight percentage of POE blocks, a shift in the onset of deformation to lower temperatures is observed. The observed changes in TMA curves confirm the conclusion that a decrease in the content of POE blocks leads to more rigid packaging of O-polyisocyanate blocks.From the results obtained in this work, it can be inferred that if the POE block content is 15 wt %, the polyoxypropylene segments are located in the internal cavity of voids formed by O-polyisocyanate blocks. When the POE block content is 30 wt %, the flexible chain component forms its own microphase outside the segregation zone of the rigid O-polyisocyanate blocks.2 and CH4. A relatively high permeability is also observed for carbon dioxide. At the same time, the content of POE blocks has a small effect on the permeability for all studied gases. The diffusion coefficient increases with an increase in the POE block content in PPEG for all studied gases.The permeability for the polar molecules of ammonia and hydrogen sulfide significantly exceeds the permeability values obtained for non-polar molecules of He, N


Respondents who rated their workconditions the highest expressed a vision of their work in terms ofautonomy, achievement and well-being, while those who rated their workconditions the lowest talked mostly of exhaustion, depersonalization andnegative climate. A correspondence analysis showed a close relationshipbetween the quantitative assessments of working conditions and the verbalcodes of the meaning of work. the meanings given to work were not only consistent with the numericalevaluations of the working conditions but also made them moreunderstandable. The information obtained poses challenges for reflection andindicates ways to promote the positive aspects and prevent the negativeconditions of nursing work. The scientific literature has analyzed the impact of workingconditions on well-being and professional performance, as well as their multipleside effects on occupational health and the quality of the service provided. Theseeffects appear as a negative spiral of care pressure, staff shortage, task overload,time deficit to execute everything and to do so well, distress and burnout,absenteeism and presentism, rotation and abandonment of the workplace andprofession-the meaning ofworking argue that the meanings that people ascribe to their work donot derive only from immediate situations, contexts and conjunctures but also from acomplex construction process involving values, ideals, goals, norms, rhetoric,strategies, beliefs, aspirations and sociocultural and personal expectations aboutwork, profession and career. Another important topic of contemporary research in this field is the dynamics bywhich people give meaning and significance to their work in different socioculturaland organizational contexts and the role these cognitive processes play not only inshaping work experience but also in how professional practice is carried outTechnical Medical Assistant (1953-1979), through theDiploma in Nursing (1977-2012) to the Graduate degreein Nursing (begun in 2009), which opened the way for the second- andthird-cycle training (Master’s and Doctorate) of nursing as an autonomous disciplineand the development of the profession in the areas of assistance, teaching, researchand managementIn recent decades, the development of the nursing profession has followed aparadoxical development at both the global and local levels: on the one hand,training in skills and material and technological resources for professionalperformance has improved, while on the other, the conditions of work have becomemore hard, complex and difficult. This is precisely what happened in the environmentof Barcelona, where, over the last half-century, the profession went from basictraining as a Questionnaire on Working Conditions) ,composed of sets of closed items with a Likert-type format with ranges from 0 to 10and an open question regarding the meaning of the work that invited respondents tosummarize the actual work experience itself in 5 “keywords.” The lexical formsobtained from the answers were later categorized and codified. Finally, therespondents filled out a section of sociodemographic and work data.Through the website of the Official College of Nurses of Barcelona (COIB) and somesocial networks of sector associations, 1,760 people, from a finite population of32,463 nursing professionals, were accessed through simple random sampling. Theseindividuals were working nurses in the province of Barcelona in June 2014. The sizeof this sample provided a confidence level of 99% and a confidence interval of 3%.The characteristic profile of the participants (which reproduced with remarkableprecision that of the reference population) was that of women (85.9%), 41.9 yearsold (standard deviation SD = 10.4), with 18.3 years (SD = 10.8) of seniority sincegraduation and 13.5 years (SD= 10.0) in the workplace, with a general education(95.5%), stable or permanent contract (73.0%), full-time employment (76.1%), dayshift (80.5%), in the health care industry (81.0%), hospital or clinic (53.3%),public (32.7%) or mixed ownership (57.7%). All of them voluntarily answered a surveythat collected information on the central variables of the study by including thefigure 1, the mean,standard deviation and Cronbach’s alpha of the entire questionnaire are specified,and each of the factors and scales are included.The cCT is based on a theoretical model according to which the working conditions arestructured around a triple relationship of the organization with the method, theenvironment and the person. The questionnaire evaluates the psychosocial componentsof working conditions (WC) that, depending on their form of presence and level ofintensity, can function as protectors and promoters of health, well-being andquality of work life or as psychosocial risk factors. The cCT includes 44 closeditems, presented in a Likert-type format of 11 ranks ranging from 0 to 10 . The obtained psychometric data adequately reproduced theproposed theoretical model structure and showed a high internal consistency, withalpha values ranging from 0.852 to 0.983. In The mixed design of the research combined the qualitative technique of the analysisof textual content for the study of meanings expressed by keywords and thequantitative techniques of descriptive statistical analysis of the WCs and offactorial analysis of correspondences between WC and meaning of work (MW). For thecorrespondence analysis, the WC-related scores were divided into four categories:“very bad” WC (X = 0-2.5), “bad” WC (X = 2.5-5), “good” WC (X = 5- 7.5) and “verygood” WC (X = 7.5-10). In the descriptive statistical analysis, the quantitativevariables were presented in terms of mean (X) and standard deviation (SD), while thequalitative variables were in the form of frequencies and percentages. In thefactorial analysis of correspondences, the chi square (χ²) was used to determine therelationships between the WC and MW variables from the data in the contingencytable.The project of this research was approved by the Bioethics Commission of theUniversity of Barcelona. In its development, the international rules regardinginformed consent, confidentiality of data of participants and institutions,safeguarding the anonymity of the answers, commitment of return of results andscientific and responsible use of the information were applied. burnout, such asphysical and emotional exhaustion, depersonalization, cynicism and inefficacy. Onthe other side are positive work meanings associated with well-being andsatisfaction, realization and efficacy, as well as the components of thework engagement model -All the lexical forms were categorized and codified according to a dictionaryconstructed from a theoretical model according to which the meanings of the work aredistributed along a bipolar semantic continuum. One of these slopes containsnegative connotations of the work experience, such as malaise and dissatisfaction,as well as various aspects covered by the model of The mean valuation of WC, in scales ranging from 0-10, was 5.77 (SD=1.555), as shownin 2 = 1434.01, p <0.001 and degrees of freedom =93), as shown in A correspondence analysis showed a close and statistically significant relationshipbetween the quantitative assessments of working conditions and the verbal codes ofmeaning of the work .The vision provided by the participants is also consistent with what the literaturereports regarding the dark side of the characteristics and tendencies of workingconditions in general, both for their psychosocial risk factors--,-,-,-The moderately positive assessment of the conditions for the realization of one’s ownwork experience is in line with what has been gathered by current reports on thequality of work life within the general context of contemporary workingconditionsWhile the numbers presented indicate the relative levels of satisfaction for theconditions of nursing work in the social and organizational environment studied, thecodes of meaning associated with them give names to the aspects of those conditionsthat need to be strengthened and those that need to be modified.Overall, the study contains some notable weaknesses and strengths. Among itsmethodological limitations is the use of self-report measures within the frameworkof a cross-sectional design, which in turn did not allow for causal inferences.However, none of these characteristics hampered the achievement of the research goalconcerning the relationship between numerical scores and verbal responses referringto the same phenomena of experience of working conditions. However, the fact thatfieldwork was developed in the context of a crisis in the Spanish health system’sfinancing, which had a significant impact on working conditions in nursing inBarcelona, raises reasonable doubts as to whether the results presented would havebeen different if they had been obtained before or after this critical period. Amongthe strengths of the research, we highlight the breadth of the thematic fieldcovered and its mixed design, which combined the use of numerous scales composed ofa series of closed items for the collection of quantitative data, with an openquestion as a source of the qualitative data. This allowed the implementation ofvarious techniques for studying the information obtained, such as statisticalanalysis, thematic content and correspondences. The agenda for future studies linkedto the present includes the challenge of improving understanding of the mechanismsinvolved in an observed paradox: the nursing professionals who participated in theresearch were generally highly affected by a life care practice experienced as verystressful, exhausting and fatiguing while they maintained a positive vision of it, ahigh professional self-esteem and a strong involvement in the work.The eight thousand key words with which the respondents summarized their workexperience in their current organizational context agreed with their numericalassessments of the conditions of their professional practice, giving such scores amore precise meaning. In this respect, the contribution of this study has a twofoldaspect: on the one hand, it ratifies in the current Barcelona environmentquantitative aspects already known regarding the real conditions of the contemporarypractice of health care. On the other, it involves progress in and deepening of thequalitative knowledge of the investigated reality by specifying the positive andnegative nuances of current nursing work experience with words, categories andsemantic codes.By showing the image of an ambivalent work experience characterized by the tensionbetween the vocation to care and the imposition of a chronic task overload,professionals have noted challenges for reflection and paths for policies committedto a double mission: strengthening the positive aspects and correcting the negativeaspects of the nursing staff’s work conditions, with a view to improving theiroccupational health and well-being while optimizing the quality of the service theyprovide to their patients and their community.


After fabricating the composites by in-situ casting, the composites were processed using the ECAP process up to two passes at room temperature. Microstructural studies have been carried out using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer. Mechanical properties were also documented using Vickers microhardness and shear punch tests. In the hypereutectic composites, a decrease in the average size of pro-eutectic Mg2Si (Mg2Sip) particles, breakages in eutectic networks, and lengthening of the Al (α) phase in direction of shear bands were observed after the ECAP process. For instance, the average size of Mg2Sip Particles in Al-20%Mg2Si composite reduced from 40 to 17 μm after 2 passes of ECAP. Furthermore, a uniform distribution of Mg2Sip particles was developed in the matrix. In hypoeutectic composite, the ECAP process caused a uniform distribution of eutectic Mg2Si (Mg2SiE) in the matrix that considered a favorable microstructure. Microhardness measurements and shear punch results showed an ascending trend after each pass of ECAP for all specimens. For example, microhardness and shear strength of Al-20%Mg2Si increased from 88 HV and 109 MPa to 119 HV and 249 MPa after two passes indicating 35% and 34% increments, respectively. Density and porosity calculations by Archimedes principle revealed that the density of the composites increased after two passes of ECAP due to the reduction of porosity.In this paper, the effect of equal channel angular pressing (ECAP) on microstructure and mechanical properties of hypereutectic Al-20%Mg The test was repeated at least 10 times for each specimen and the averages values were reported along with their standard deviation.P is the shear punch force in Newtons, t is the sample thickness in millimeters, and d is the mean diameter of the punch and mold in millimeters. The shear punch test graphs were obtained by plotting shear stress in terms of normal displacement. Normal displacement was obtained from the following equation  direction is limited by the thickening of the aluminum-rich blanket. This phenomenon usually occurs at the later stages of solidification, in which the melt becomes more viscous and melt movement is limited [FESEM images of the Al-20%Mg limited . 2Si composite are presented in 2Si precipitated in two different modes. The first one is Mg2Sip particles, which exists as an initial phase in hyper-eutectic Al-Mg2Si composites. The second one is the Mg2SiE layers, which is present in all Al-Mg2Si composites studied in current research as a two-phase eutectic with two types of morphology (layer and rod-like morphology).EDS results and three-dimensional images of observed particles in Al-20%Mg2Si particles and a portion of the binary eutectic were broken and elongated along the shear bands. The Al(α) phase was also elongated in the direction of shear bands  phases were elongated in the direction of shear bands, and some portions of the binary eutectic phase located in the direction of shear bands were broken. After the second ECAP pass, the refinement of the microstructure was developed in the composite, and due to movement of the broken arms of dendrites in the direction of the shear bands, a more uniform distribution of Mg2SiP particles in the matrix of the composite was developed. 2SiP particles. The average sizes of the Mg2SiP particles in the cast Al-20%Mg2Si and Al-15%Mg2Si composites were about 40 and 27 μm, respectively. The average sizes of the Mg2SiP particles in the Al-20%Mg2Si composite has already been measured by Emamy et al. [2SiP particles. They have found that by decreasing the sample size, the cooling rate increases. Accordingly, Mg2SiP particles would not have enough time to grow and consequently the average size decreases. Influence of casting mold type has been studied by Qin et al. [2SiP particles due to the higher chilling capacity. Therefore, it can be concluded that difference in the calculated average size of the Mg2SiP particles in current research with previous works lies in the differences in the diameter of the casting sample and type of the molds. After the first ECAP pass, the average size of Mg2SiP particles in the Al-15%Mg2Si composite was reduced by 47% to 21 μm, and after the second pass, it was reduced by 22% to about 17 μm. In the Al-20%Mg2Si composite, after the first and second ECAP passes, the average size of Mg2SiP particles was decreased by 21 and 17% to about 22 and 18 μm, respectively.y et al.  studied n et al. . Results2Si composite are presented in 2SiP particles do not exist in the matrix, and the microstructure consists of the Al(α) as the primary phase with round morphology (non-faceted interface) and binary eutectic (Al(α) + Mg2SiE) with layered morphology . Some impurity of iron (white phase) is also present in the microstructure which is from the raw materials or the tool used in the casting process. A noteworthy point about the eutectic phase is the difference between the spaces of eutectic layers in different parts of the composite, as a result of the various freezing temperature [2SiE phase was more uniformly distributed in the matrix.FESEM images of initial and ECAP-processed Al-10%Mgperature . After t2Si composites with different amount of Mg2Si, as a function of ECAP pass number. The theoretical densities of composites containing 10, 15, and 20% Mg2Si calculated by rule of mixtures were 2.62, 2.558, and 2.55 gr/cm3, respectively. As can be seen, after the first ECAP pass, the density of all three composites was increased significantly, which is due to the decrease in porosity amount and reduction in the size of the voids in the composites. On the other hand, there was no significant change in the density of the composites after subsequent passes [2Si amount in the composites led to an increment in porosity amount owing to the presence of more Mg2SiP particles in the matrix. 2Si composites with different amount of Mg2Si, as a function of ECAP pass number. As shown, increasing ECAP passes causes an enhancement in hardness value of all composites. After the final pass of ECAP, the hardness values of composites containing 10, 15, and 20% Mg2Si were about 61, 57, and 51 HV, respectively. According to hardness diagrams, this increment in the first pass is more profound in comparison with that of the subsequent passes. The hardness increment after the second pass in all three composites was less than 10%. The improvement of microhardness during ECAP is attributed to various mechanisms such as reduction of porosity and microstructural defects, the interaction between dislocations (work hardening), grain refinement of the matrix and modification of Mg2SiP particles and binary eutectic morphology. The high strain imposed to the composites in the first pass of ECAP cause considerable work hardening, and accordingly, the hardness increases notably in the first pass, while by increasing the number of ECAP passes, the work hardening capability of the composites reduces, and consequently the hardness increases slightly. 2Si content, which is very hard reinforcement. On the other hand, the highest hardness increment after ECAP process occurred in Al-10%Mg2Si composites (42%). This can be attributed to the possibility of micro-cracks formation during ECAP process of composites containing Mg2SiP particles, as well as greater effect of ECAP process on modification of eutectic and primary Al(α) phase in the Al-10%Mg2Si composite.It is also clear from 2Si were increased by about 34, 29 and 25%, respectively; the shear yield strength was also enhanced by about 38, 34 and 49%, respectively. According to diagrams, the most considerable part of the strength increment occurred after the first pass, and the strength increment after the second pass of ECAP was negligible. This issue has also been observed in previous investigations after ECAP process of various materials [2Si) compared to hypereutectic composites (containing 15 and 20% Mg2Si). This is due to the presence of Mg2SiP particles, and also increasing their volume fraction. Therefore, because of the brittle nature of these particles, the probability of cracking and breaking during the shear punch test is greater and affects the mentioned properties.The shear stress-normalized displacement curves and the corresponding ultimate shear strength (USS) and shear yield strength (SYS) of all three composites before and after ECAP process are presented in aterials ,34,35. Iaterials . Another2Si composites during ECAP process is related to the effect of three different strengthening mechanisms. The first mechanism is work hardening caused by increment of dislocations as well as considerable grain refining during ECAP process, which improve the strength of the composites in accordance with Taylor and Hall-Petch equations, respectively [2SiP particle size and modification of Mg2SiP and eutectic phase during ECAP process. As already mentioned, during ECAP process, Mg2SiP particles were broken up and their morphology was modified and distributed more uniformly. Likewise, the morphology of the Mg2SiE Phase was changed from a layer-like structure into a point-like and flake-like structure and distributed uniformly in the matrix. Morphological modification of the intermetallic phases makes them more difficult barriers against dislocations movement, and thus improves the strength. In addition, in brittle fracture of metal matrix composites, cracks, and local stress concentrations along the interface of particles and matrix cause failure at extremely lower stress than their intrinsic yield strength. The Mg2SiP particles with local stress concentrations such as sharp corners and internal holes which have been mentioned in microstructure section can act as crack initiation point and encourage their growth and propagation. Therefore, it is expected that morphological modification of the Mg2SiP particles and producing a finer microstructure leads to more fracture energy toleration and higher strength in composites [Principally, increasing the strength of Al-Mgectively ,36,37,38mposites . The thi2Si composites has investigated. In this study, the composite’s ultimate tensile strength (UTS) has increased to about 210–217 MPa after four passes of ECAP in various routes. In another research by Emamy et al. [2Si and Al-20%Mg2Si composites has reached to 225 and 221 MPa, respectively. Considering that in accordance with Tresca criterion, the tensile to shear strength ratio of metals is 2 [2Si composites containing different amounts of Mg2Si, the tensile to shear strength ratio is higher than 2. Therefore, it can be concluded that the strength obtained after 2 passes of the ECAP process in the current study is significantly better than the values obtained in previous studies. This shows a great ability of the ECAP process for improving the mechanical properties of Al-Mg2Si composites.In previous research by Bian et al. , the effy et al. , after hals is 2 ,32, and als is 2  has foun2Si and Al-15% Mg2Si) and hypoeutectic composite (Al-10%Mg2Si) have been studied. Microstructure was characterized by FESEM, and mechanical properties were studied using Vicker’s microhardness and shear punch tests. The density and porosity of composites were also calculated in accordance with the Archimedes principle. The main conclusions of current research are as follows:In the present study, the effects of severe plastic deformation by the ECAP process on microstructure and mechanical properties of hypereutectic composites  phase was oriented along shear bands in both hypereutectic and hypoeutectic composites, and accordingly, a uniform distribution of Mg2SiE was made in the matrix.(1) The results obtained from FESEM study showed that in the hypereutectic composites, after each pass of ECAP process, Mg2Si composite was increased by about 42% (from 76 HV to 108 HV), and 10% (from 108 HV to 119 HV) after the first and second pass of ECAP, respectively.(2) The hardness measurement results showed an increment in all composites after each pass of ECAP. The hardness increment after the first pass was more than subsequent passes. For example, the hardness of the Al-10%Mg(3) The shear punch test results indicated that shear yield strength and ultimate shear strength of all composites enhanced after each pass of ECAP. After the first pass, the highest increment was recorded, and in subsequent passes, the increasing trend was continued with a slight slope. The difference between USS and SYS after the first pass was decreased sharply, indicating a reduction in formability after the ECAP process. (4) The results of density and porosity calculations in accordance with Archimedes principle showed high porosity content and low density of the cast composites compared to that of the theoretical density. After the ECAP process, the porosity of the composites decreased, and consequently, the density increased. The highest increment in density and reduction of porosity was after the first pass, which could be due to the decrease in the diameter of porosities and voids to a critical radius under pressure, while their sizes cannot be lowered by continuing the pressing process during subsequent passes.