Isothermal Crystallization Behaviors of Isotactic Polypropylene Nucleated with Nucleating Agent Bicyclic [2,2,1] heptane di-carboxylate

摘要

Bicyclic [2,2,1 ] heptane di-carboxylate (commercial product name: HPN-68) is a novel nucleating agent with high nucleation efficiency for α-iPP. In this article, differential scanning calorimetry (DSC) was adopted to investigate the isothermal crystallization kinetics of isotactic polypropylene (iPP) nucleated with HPN-68. The Avrami equation well described the isothermal crystallization kinetics of iPP nucleated with HPN-68. The results showed that addition of HPN-68 could shorten half crystallization time (t112) and increase the crystallization rate of iPP significantly. The Avrami exponents of both virgin iPP and iPP nucleated with HPN-68 were close to 3.0, which indicated that the addition of nucleating agent HPN-68 didn't change the crystallization growth patterns of iPP under isothermal conditions and the crystal growth was heterogeneously nucleated three-dimensional spherulitic growth. In addition, incorporation of nucleating agent HPN-68 obviously decreased the crystallization activation energy AE of iPP, from 368 kJ/mol for virgin iPP to 306 kJ/mol.