Thermal decomposition of amide and imide derivatives of maleated polyethylene

The thermal decomposition behavior of six derivatives of maleated polyethyl ene was investigated by high-resolution pyrolysis gas chromatography-mass s pectrometry. The results revealed that substituents attached to maleated po lyethylene as amides formed from secondary amines were significantly less s table than imides formed from primary amines. Morpholine amide and N-methyl aniline amide derivatives of maleated polyethylene underwent significant de composition at 160 degrees C and substantial decomposition at 200 degrees C . In contrast, the imide derivatives of maleated polyethylene were stable f or long periods of time at elevated temperatures. Following 2 min of heatin g, the first traces of decomposition were detected at 200 degrees C for the 2-aminoanthrancene imide derivative, at 255 degrees C for the 2-phenethyla mine imide, and at 280 degrees C for the 9-aminomethylphenanthrene imide. W ith the exception of the 9-aminomethylphenanthrene imide, all other derivat ives decomposed to form the corresponding amine as the single most signific ant volatile product. The most likely explanation for this result is that t he polymer contained small amounts of succinamic acid that did not close to form the imide. We concluded that the imide was stable even to 315 degrees C and that the amine was lost from beta-carboxyamide groups present in the sample. In the 9-aminomethylphenanthrene imide derivative, we observed no loss of amine. Instead, we observed an alternative fragmentation process yi elding 9-methyl phenanthrene. The dependence of the thermal stability of th ese various derivatives of maleated polyethylene has important implications for the design of reactive-blending strategies for polyolefins with other functional polymers. (C) 2000 John Wiley & Sons, Inc.