Self-Assembly β Nucleating Agent Induced Polymorphic Transition from α-Form Shish Kebab to β-Form Highly Ordered Lamella under Intense Shear Field

Abstract

In this study, a kind of self-assembly β nucleating agent (TMB-5) and intense shear field provided by a microinjection machine were simultaneously employed to address the long-standing question about the possibility to cultivate highly oriented β-crystals. The experimental results were cheerful. For dotlike TMB-5, it preferred to tumble and rotate following Jeffery orbits. In this case, the flow-induced α-nuclei in bulk materials were prevailing and only few β-crystals were generated on the surface of β nucleating agent or the oriented α-crystals. When it came to fibrous TMB-5, it was difficult for slender particles to rotate freely. The stretched polymer chains generated by flow continually deposited on the surface of TMB-5 and became β-precursors, which further induced adjacent molecules to crystallize into β-crystals. That is, with the applied flow, the well-aligned fibrous β nucleating agent replaced the stretched molecules to trigger the oriented epitaxial growth of lamellas, into hybrid shish-kebab ...