Review: Auto-oxidation of aliphatic polyamides

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• 作者：Emmanuel Richaud ; Octavie Okamba Diogo ; Bruno Fayolle ; Jacques Verdu ; Jean Guilment ; Fran?ois Fernagut
• 关键词：Aliphatic polyamides ; Oxidation ; Mechanisms ; Kinetics ; Oxidation products
• 刊名：Polymer Degradation and Stability
• 出版年：2013
• 出版时间：September, 2013
• 年：2013
• 卷：98
• 期：9
• 页码：1929-1939
• 全文大小：1667 K

文摘

The literature on oxidation kinetics of polyamides and model compounds has been reviewed in order to try to extract suitable information for non-empirical kinetic modeling. Polyamide characteristics are systematically compared to polyolefin ones, these latter being more extensively studied. From kinetic analysis point of view, it is shown that oxidation attacks predominantly ¦Á amino methylenes of which C-H bond is considerably weaker than the other methylenes. As a result, propagation by H abstraction is considerably faster in polyamides than in polyethylene for instance. Termination by radical combination is also very fast. Another cause of PA oxidizability is the instability of ¦Á amino hydroperoxides linked to the inductive effect of nitrogen. This instability is responsible for many key features of oxidation kinetics especially the absence of induction period.<p>The main stable oxidation products are imides resulting from disproportionation processes meanwhile chain scissions resulting from rearrangements of ¦Á amino alkyls by ¦Â-scission are also significant process although their yield appears lower than in polyolefins.