Study on the crystallization process of isotactic polypropylene in mixed diluents

摘要

Since thermally induced phase separation (TIPS) method was first introduced by Castro in the late 1970s and early 1980s, it has offered a new approach to prepare semi-crystalline microporous materials with high void volume and favorable strength. As a kind of semi-crystalline polymer, the crystallization of isotactic polypropylene (iPP) significantly influenced the morphologies and strength of iPP microporous materials via TIPS to a great extent, therefore, non-isothermal crystallization of iPP from solution was widely investigated in terms of polymer concentration, cooling rate and diluent mobility. W.Y.Chiu and co-workers[l] analyzed non-isothermal kinetics of polypropylene on the basis of the Avrami equation. C.T.Chung and co-workers[2] proposed for measuring spherulite growth rates using temperature programs to expand the temperature range where spherulite growth rates can be measured. D.R.Lloyd and co-worker[3,4] investigated the structure variation of membrane formed via TIPS in terms of iPP crystallization kinetics and diluent mobility. However few works on crystallization of iPP in mixed diluents were reported.