Isotactic polypropylene crystallization: Analysis and modeling

The relevance of crystallization phenomena during the processing of semi-crystalline polymers is well known. Despite the huge investigation work done in the field, a full description of the crystallization kinetics under non-isothermal conditions still lacks. In this work, a commercial semi-crystalline polymer, an isotactic polypropylene, was studied in term of isothermal crystallization and of crystallization during cooling in a large range of cooling rate. The entire experimental behavior – solidification at high cooling rates, alpha-phase crystallization kinetics at intermediate cooling rates, and secondary crystallization at low cooling rates – was carefully quantified. Finally, a model able to reproduce all the observed features was proposed and tuned, to build a tool useful for the transformation processes simulation codes.