Nonisothermal crystallization kinetics and melting behaviors of isotactic polypropylene/N,N ',N ''-tris-tert.butyl-1,3,5-benzene-tricarboxamide

摘要

The nonisothermal crystallization and melting behavior of an additive-free (blank) iPP(BPP) and iPP (isotactic polypropylene) containing 0.3wt% of N,N',N''-tris-tert.butyl-1,3,5-benzene-tricarboxamide (NA) was investigated by the differential scanning calorimetry (DSC). The results showed that adding NA and increasing the cooling rate led to an increased crystallization rate. he BPP presented multiple melting behavior, while the NPP (nucleated iPP) showed a single melting peak with a slightly increased melting peak temperature, and the increased cooing rate had limited influence on the melting peak temperature. Friedman's isoconversion method was used to estimate the activation energy of the nonisothermal process. It was found that the NA led to a more negative value of activation energy, and the magnitude of activation energy increased almost linearly with increased relative degree of crystallinity. The nucleation activity of NA for iPP was calculated according to Dobreva's model, and the result showed that it was a effective nucleating agent for iPP.