Surfactant-assisted β-NA supramolecular self-assembly in mini injection molding PP composite

Abstract

The introduction of surfactant (polyoxyethylene sorbitan monoisostearic acid ester, Tween-60) conduces to the dispersion of β-NA (N,N′-dicyclohexylterephthalamide, TMB-5) and regulation of its self-assembly morphologies. In this work, surfactant-assisted β-NA was firstly utilized in a strong flow field when processing β-iPP by mini-jet injection molding. The polymorphism morphologies and crystalline structure in isotactic polypropylene (iPP)/surfactant-assisted β-NA self-assembly were explored. The SEM results indicated that hierarchical structures containing shish-kebab and cylindrites in the skin and mid layer, inter-locked β-transcrystals and spherulites structure in the core layer were obtained. The strong shear drove the surfactant-assisted β-NA self-assembly needles to align in a dense orientation along machine direction which induced the formation of inter-locked β-transcrystals. The crystalline structure and orientation of different layers were further investigated via small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) characterization. The variation of surfactant-assisted β-NA supramolecular self-assembly and crystalline structure in mini injection molding PP composites were systematically discussed. This paper would have referential significance for the β-NA self-assembly.