title: Formation of various crystalline structures in a polypropylene/polycarbonate in situ microfibrillar blend during the melt second flow.
abstract: A strong shear flow was imposed on the melt of polycarbonate (PC) microfibrils with β-nucleation agent reinforced isotactic polypropylene (iPP) during the melt second flow process, i.e. gas-assisted injection molding (GAIM). A special shell-core structure was formed in the iPP/PC microfibrils with β-nucleation agent (PP/PC/β-NA) composites. A lot of β-transcrystalline and α-transcrystalline superstructures were observed in the skin and sub-skin regions, whereas β-spherulite structures were formed in the gas channel region. There is no doubt that the distinct hierarchical structure has great potential to significantly improve the mechanical performance of the composites, and the experimental results verify this. The results of the mechanical performance testing show that the yield strength of the PP/PC/β-NA composites reached 61.9 MPa, which is 19.7 MPa higher than that of the iPP parts molded by GAIM (G-iPP) (42.2 MPa). The tensile modulus of the PP/PC/β-NA composites (3.3 GPa) increased by 135%, compared to that of G-iPP (1.4 GPa). The high content of β-crystals improved the elongation at break of the composites compared to the iPP/PC microfibril (PP/PC) composites; the elongation at break of the PP/PC/β-NA composites (13%) is over 3 times greater than that of the PP/PC composites (4%).
authors.affiliation: College of Polymer Science & Engineering, and the State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, Sichuan, PR China. yangmb@scu.edu.cn.
authors.forename: Xiao-Chao
authors.initials: XC
authors.lastname: Xia
authors.affiliation: College of Polymer Science & Engineering, and the State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, Sichuan, PR China. yangmb@scu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.affiliation: College of Polymer Science & Engineering, and the State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, Sichuan, PR China. yangmb@scu.edu.cn.
authors.forename: Shan
authors.initials: S
authors.lastname: He
authors.affiliation: College of Polymer Science & Engineering, and the State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, Sichuan, PR China. yangmb@scu.edu.cn.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Xie
authors.affiliation: College of Polymer Science & Engineering, and the State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, Sichuan, PR China. yangmb@scu.edu.cn.
authors.forename: Rui-Yan
authors.initials: RY
authors.lastname: Zhang
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 2012204, China. tianfeng@sinap.ac.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Tian
authors.affiliation: College of Polymer Science & Engineering, and the State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, Sichuan, PR China. yangmb@scu.edu.cn.
authors.forename: Ming-Bo
authors.initials: MB
authors.lastname: Yang