Shish–kebab of polyolefin by “melt manipulation” strategy in injection-molding: A convenience pathway from fundament to application

Abstract

Due to both theoretical and practical importance, the formation mechanism of shear-induced shish–kebab and the precise microstructure and molecular composition in shish–kebab have been extensively investigated for many years. However, a systematic review on the manipulation of shish–kebab superstructure in the injection-molded specimens, taken account of combining theoretical understanding, preparation processing, structural/morphological control and macroscopic properties, has rarely seen in the open publication by far. In this article, we will discuss mainly the topic of formation of fine polyolefin shish–kebab superstructure facilitated by “melt manipulation” strategy in injection-molding process. The main body of this review is governed by a logical sequence of (fundamental research)–(injection molding of melt manipulation)–(manipulation of shish–kebab)–(macroscopic mechanical properties). The fundamental understandings of the early stage of shish–kebab crystallization, transition process from random entangled chains network to stable shish–kebab cylindrulite, and the role of long polymer chains on shish–kebab formation, are very helpful for in-depth comprehension of shear-induced shish–kebab in realistic processing. Various highly oriented morphologies with fine shish–kebab superstructure in injection-molded bars of polyolefin melts, including single component polyolefin melt, biphase melts of blend and heterogeneous melts of polyolefin/inorganic filler composites, could be achieved via “melt manipulation” strategy, as demonstrated by the work mainly from our group.