Nano-structuring of isotactic polypropylene in presence of a self-assembling nucleating agent under defined flow conditions

摘要

Additives play an important role in physical properties of polymers. One of the most frequently used additives for isotactic polypropylene (iPP) is Bis 3,4-dimethylbenzylidene sorbitol (DMDBS). iPP and DMDBS together form a binary mixture with a monotectic phase diagram. Homogeneous dissolution of DMDBS in iPP at reasonable temperatures is possible only in a limited range of low concentrations. Upon cooling, the nucleating agent first crystallizes forming nano-fibrils which are an excellent substrate for heterogeneous crystallization of iPP. Consequence to it, nucleation density is very high thus forming crystals smaller than wavelength of light resulting into a translucent material. In this paper we explore structural development during crystallization of the binary system iPP-DMDBS under defined flow conditions.