Interfacial interaction enhancement by shear-induced β-cylindrite in isotactic polypropylene/glass fiber composites

Isotactic polypropylene (iPP)/glass fiber (GF) composites with different specific interfacial features (viz., alpha-spherulite, alpha-cylindrite and beta-cylindrite) were prepared via shear-induced interfacial crystallization. alpha-spherulite, alpha-cylindrite and beta-cylindrite were successively encouraged at the interface between iPP matrix and GF with increasing the fiber-pulling speed. Moreover, the composite specimens containing beta-cylindrite exhibited remarkably higher interfacial shear strength (IFSS) than those containing alpha-spherulite or alpha-cylindrite, as demonstrated by the single fiber fragmentation test (SFFT). More interestingly, simultaneously improved tensile strength and toughness were observed in the presence of beta-cylindrite. This study offers a new insight that beta-cylindrite produced by shear is an alternative approach to achieve comprehensive mechanical properties for the iPP/fiber composite systems. (C) 2016 Elsevier Ltd. All rights reserved.