Interlocking shish-kebab morphology in polybutene-1

The aim of this research was to explore the effect of shear-controlled orientation injection molding (SCORIM) on polybutene-1 (PB-1). This article describes the methods and processing conditions used for injection molding and discusses the properties of the moldings. Both conventional and SCORIM have been used for the production of moldings. SCORIM is based on the application of specific macroscopic shears to a solidifying melt that facilitates enhanced molecular alignment. The effect of the process was investigated by performing mechanical tests, X-ray studies, differential scanning calorimetric studies, polarized light microscopy, and atomic force microscopy (AFM). Moldings exhibited an improved mechanical performance as compared with conventional moldings. Young's modulus was increased over twofold, and the impact energy was enhanced by 60%. The improvement in mechanical performance was combined with an increase in crystallinity and enhanced molecular orientation. The application of SCORIM also favored the formation of the stable Form I' in PB-1. The formation of interlocking shish-kebab morphology following the application of SCORIM was observed in the AFM studies. Relationships between the mechanical properties of PB-1 and the micromorphologies formed during processing are demonstrated.