Thermal degradation behaviors of nylon 4 homopolymer, a polymer which the chain end of nylon 4 was modified with diamine, and a copolymer containing nylon 4 were investigated by thermal gravimetric analysis at various heating rates. The copolymer (content of nylon 4, 23.5 mole-%) was prepared by anionic copolymerization of α-pyrrolidone and ε-caprolactam.
Nylon 4 became more decomposable with a process of degradation reaction. The activation energy of thermal degradation of the polymer was 28-31 kcal/mole, which was smaller than that of nylon 6. The activation energy in the initial stage of degradation depends on the temperature at which degradation of the polymers starts.
Thermal stability of the nylon 4 which chain end was modified with bis (p-aminocyclohexyl)-methane increased with rising the temperature of treatment, but its molecular weight remarkably decreased.
Thermal stability of the copolymer was considerably superior to that of nylon 4, and in contrast with nylon 4 the copolymer became more non-decomposable with a process of degradation reaction. The degradation reaction proceeded even over the range of nylon 4 contained in the copolymer, indicating occurrence of the degradation reaction of nylon 6 in the main chain of the copolymer.
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