Role of dicumyl peroxide on the morphology and mechanical performance of polypropylene random copolymer in microinjection molding. (27th June 2017)

• Record Type: Journal Article
• Authors: Li, Mengjue; Yang, Qi; Kong, Miqiu; Huang, Yajiang; Liao, Xia; Niu, Yanhua; Zhao, Zhongguo
• Is Part Of: Polymers for advanced technologies. Volume 29:Number 1(2018)
• Page Start: 171
• Page End: 181
• Publication Date: 2017-06-27
• Subjects: flow‐induced crystallization -- hierarchical structure -- microinjection molding -- wall slip; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pat.4099
• Languages: English
• ISSNs: 1042-7147

Abstract

Abstract : The purpose of this work is to systematically investigate the effects of dicumyl peroxide (DCP) on the microstructural evolution and mechanical properties of polypropylene random copolymers (PPRs) during the microinjection process. Polarized light microscopy, differential scanning calorimetry, X‐ray diffraction, and scanning electronic microscopy measurements were employed to characterize the morphology evolution of the PPR microparts with DCP. A hierarchical structure was found in the PPR microparts with DCP. Specifically, with the individual addition of organic peroxide, the orientation parameter of the PPR microparts decreased pronouncedly and the formation of skin layer was suppressed, while the formation of core layer was promoted. This was ascribed to the distribution of shear rate in the microchannel, which was determined by the wall ship effect in the filling stage and the relaxation behavior in the cooling stage. A mechanism was proposed to explain the distinctive filling behavior and molding characteristics of PPR with DCP in microinjection molding.