The development of an abnormal isotactic polypropylene spherulite: Morphology and kinetics. Issue 5 (2nd October 2020)

• Record Type: Journal Article
• Authors: Hou, Chunyue; Wan, Ruru; Sun, Xiaoli; Ren, Zhongjie; Li, Huihui; Yan, Shouke
• Is Part Of: Polymer crystallization. Volume 3:Issue 5(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-02
• Subjects: abnormal spherulites -- growth kinetics -- isotactic polypropylene -- morphology -- spherulites; Crystalline polymers -- Periodicals; Crystallization -- Periodicals; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pcr2.10157
• Languages: English
• ISSNs: 2573-7619

Abstract

Abstract: A kind of abnormal iPP spherulites were revealed by scanning electron microscopy. Different from the radial growth of lamellae in normal polymer spherulites, the arrangement of lamellae within abnormal iPP spherulites are not uniform. The lamellae in abnormal spherulites seems disordered, growing along all directions, but the spherical symmetry can be kept. These abnormal iPP spherulites cannot, however, be distinguished clearly by polarized optical microscopy. In addition to the morphology difference, the abnormal iPP spherulite presents higher radial growth rate than the normal ones, and its growth rate cannot keep constant at constant supercooling. Because the growth mode of the lamellae in the abnormal iPP spherulites can transform to that of the normal ones, that is, present growth along radial direction gradually, and its growth rate also decreases accordingly. Consequently, the lamellae growth in the abnormal iPP spherulites is approaching that of the normal ones with increasing crystallization time, and the average radial growth rate also decreases. Moreover, the transition is rather later at higher crystallization temperatures. Abstract : The abnormal(Ab‐) and normal(N‐) isotactic polypropylene (iPP) spherulites are presented in the film. Different from the normal spherulites, the lamellae growth in the abnormal spherulites is not along the radial direction evidently, but the spherical symmetry can be kept.