文献类型：期刊文献

英文题名：Improved kinetic model of crystallization for isotactic polypropylene induced by supercritical CO2: Introducing pressure and temperature dependence into the Avrami equation

作者：Zhang, Ren-Han[1]; Li, Xue-Kun[1]; Cao, Gui-Ping[1]; Shi, Yun-Hai[1]; Liu, Hong-Lai[1]; Yuan, Wei-Kang[1]; Roberts, George W.[2]

机构：[1] UNILAB, State Key Lab of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; [2] Department of Chemical and Biomolecular Engineering, North Carolina State University, Box 7905, Raleigh, NC 27695-7905, United States

年份：2011

卷号：50

期号：18

起止页码：10509

外文期刊名：Industrial and Engineering Chemistry Research

收录：EI(收录号：20113814345749)

语种：英文

外文关键词：Polypropylenes - Carbon dioxide - Kinetic parameters - Kinetic theory - Supercritical fluid extraction - Temperature distribution - Differential scanning calorimetry

摘要：Supercritical carbon dioxide (SC-CO2) provides a highly tunable technique to induce changes in morphology and crystallization kinetics of various polymers. In this study, the effect of SC-CO2 treatment on the crystallinity of isotactic polypropylene (i-PP) was analyzed by differential scanning calorimetry (DSC). The Avrami equation is suitable for describing crystallization kinetics of various solids. However, the assumption that the crystallinity approaches 1.0 as the time approaches infinity is not valid for semicrystalline polymers, especially in the atmosphere of SC-CO2. An improved kinetic model for the CO2-induced crystallization of i-PP was purposed by introducing equilibrium crystallinity, as well as temperature- and pressure-dependent terms into the Avrami equation. The parameters of the crystallization kinetics model were obtained by least-squares fitting of the DSC data. The results show that the improved kinetic model provides a reasonable description of the crystallization behavior of i-PP induced by SC-CO 2. The successful application of the improved kinetic model to the CO2-induced crystallization of i-PP suggests that this model may be adopted to other SC-CO2-semicrystalline polymer systems. ? 2011 American Chemical Society.