An @entity74 analysis of lignin as a potential antioxidant for XXXX .

@entity1568 @entity9436 @entity7294 @entity74 @entity505 @entity599 @entity285 @entity44516
UNASSIGNED: @entity44516 are complex phenolic polymers with limited industrial uses. To identify new applications of @entity44516 , this study aims to evaluate the conifer @entity285 lignin as a potential antioxidant for @entity9436 , using the petroleum asphalt as an example. Using the @entity74 ( @entity74 ) method, the evaluation is accomplished by tracking the generation of critical species in a lignin-asphalt mixture under a simulated oxidative condition. The generation of new species was detected using nuclear magnetic resonance and four analytical methods including density of states analysis, highest occupied molecular orbital and lowest unoccupied molecular orbital analyses, bonding and energy level analysis, and electrostatic potential energy analysis. Results of the analyses show that the chemical radicals of @entity505 , @entity1568 and @entity599 generated in the oxidation process could enhance the agglomeration and/or decomposition tendency of asphalt. The effectiveness of @entity44516 as an antioxidant depends on their chemical compositions. @entity44516 with a HOMO-LUMO gap larger than the HOMO-LUMO gap of the @entity7294 system to be protected, such as the conifer @entity285 lignin to protect petroleum asphalt as was studied in this work, do not demonstrate beneficial anti-oxidation capacity. @entity44516 , however, may be effective oxidants for @entity7294 systems with a larger HOMO-LUMO gap. In addition, @entity44516 may contain more polar sites than the @entity9436 to be protected; thus the @entity44516 ' hydrophobicity and compatibility with the host @entity9436 need to be well evaluated. The developed @entity74 model provides a useful tool for developing antioxidants for generic @entity9436 .
