Structural changes in solvent-induced crystallization of quenched isotactic polypropylene

Abstract

Solvent-induced crystallization of quenched isotactic polypropylene (iPP) films in dichloromethane, cyclohexane, carbon tetrachloride, and chloroform has been investigated.

WAXD, density, and DSC measurements indicate that smectic iPP films undergo a complex rearrangement of the structure in these liquids, leading to a process of crystallization.

Transport properties of the dried samples, after the solvent treatment, show that the first stage of crystallization involves, in addition to the smectic phase, a fraction of amorphous phase, while further crystallization regards only the smectic phase.

The morphology of the crystallized samples has been investigated by transmission electron microscopy following permanganic etching. No change in the basic morphology is found, although local organization showing splaying and branching appears clearer in the solvent crystallized samples than in the starting smectic sample.