Authors Chang, B. ; Schneider, K. ; Vogel, R. ; Heinrich, G.
Title Influence of nucleating agent self-assembly on structural evolution of isotactic polypropylene during uniaxial stretching
Date 28.02.2018
Number 55076
Abstract Dotlike, needlelike, and treelike morphologies of N,N´-dicyclohexyl-2,6-naphthalene dicarboxamide (NJS) are induced via self-assembly. Isotactic-polypropylene (iPP)/NJS composite with treelike NJS shows the highest ß-iPP relative crystallinity (Kß). During uniaxial stretching, a higher Kß could increase the number of voids. However, the size of voids is similar regardless of the NJS morphology. The ß-a phase transition takes place after void formation. During intralamellar and interlamellar slip, no obvious polymer chains orientation can be found for a-iPP. In the strain range of 0.1–0.6, the c-axis of the ß-iPP crystal tends to orient perpendicular to the stretching direction. This is caused by lamellae twisting, a unique deformation mode of ß-iPP lamellae. The lamellae twisting is proposed to be responsible for the intense voids formation of the composite with higher Kß. At a strain larger than 0.6, the drastic increase of orientation is mainly caused by the rotation of the residual fragmented lamellae and the orientation of the newly formed crystals.
Publisher Polymer
Citation Polymer 138 (2018) 329-342
Tags self-assembly isotactic-polypropylene void phase transition orientation

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