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Decomposition mechanisms of cured epoxy resins in near‐critical water
Author(s) -
Gong Xianyun,
Liu Yuyan,
Wu Songquan,
Ding Daowei,
Wei Huige,
Guo Zhanhu
Publication year - 2015
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.41648
Subject(s) - epoxy , homolysis , polymer , thermosetting polymer , bond cleavage , monomer , polymer chemistry , hydrogen atom abstraction , reaction mechanism , radical , decomposition , materials science , chemistry , degradation (telecommunications) , depolymerization , ether , organic chemistry , catalysis , telecommunications , computer science
ABSTRACT A reaction mechanism based on the near‐critical water homolysis of bonds in the cured epoxy followed by the saturation of the resulting radicals by hydrogen abstraction from the donor was discussed. The compounds evolved during degradation were identified by gas chromatography and mass spectrometer. The materials prepared possess the characteristics of thermosets, due to the presence of ether groups in the polymer chains, which were broken at the beginning of degradation. The degradability increased when the reaction time and reaction temperature increased. Based on the experimental results, a probable macroscopic mechanism was proposed. The near‐critical water degradation mechanisms of polymers consist of three categories: random scission, unzipping, and side group elimination, which simultaneously occurs in the reactor. The first random scission of links caused a molecular weight reduction of the raw polymer, the second side‐group elimination caused the generation of the volatile product, and the last unzipping produced either fragmentation to smaller oligomeric units or unzipping all the way to monomers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41648.