Supramolecular self‐assembly of compound β nucleating agent and effect on polypropylene microporous membrane. Issue 5 (18th June 2019)

• Record Type: Journal Article
• Authors: Ding, Chao; Wu, Gao‐Gao; Zhang, Ya; Chen, Wen‐Bo; Yin, Bo; Yang, Ming‐Bo
• Is Part Of: Polymer crystallization. Volume 2:Issue 5(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-06-18
• Subjects: compound nucleating agent -- microporous membranes -- supramolecular self‐assembly; Crystalline polymers -- Periodicals; Crystallization -- Periodicals; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pcr2.10080
• Languages: English
• ISSNs: 2573-7619

Abstract

ABSTRACT: In this work, the β crystalline morphology of polypropylene membranes and dual nucleating ability of compound nucleating agent (NA) are systematically invested. A kind of aryl amide‐based compound TMB‐5 and another kind of commercial rare earth‐based β‐NA WBG‐II were chosen. It is intriguing that the supramolecular self‐assembly aggregations of WBG‐II changed from flower‐like to needle‐like frameworks with a lower supercooling temperature for recrystallization after the introduction of TMB‐5. Considering that it is more difficult for TMB‐5 to dissolve in polypropylene melt, the remaining undissolved TMB‐5 aggregations serve as the heterogeneous nucleation sites, which can accelerate the recrystallization of WBG‐II. Such a process prevents the WBG‐II microfibers self‐assembled into big flower‐like frameworks. The needle‐like aggregations of the compound NA are smaller and more uniform in size, which is helpful in obtaining cast films with more uniform crystal morphology. Thus, microporous membranes with high porosity could be obtained after biaxial stretching of oriented cast films. This work leads to a new understanding of the relationship between "NA framework size uniformity"‐ "crystallization uniformity"‐ "micropore uniformity, " which is helpful to find an appropriate crystalline morphology for high‐performance microporous membranes of PP by biaxial stretching. Abstract : Compound β‐nucleating agents can self‐assemble into oriented uniform and fine needle‐like frameworks in polypropylene cast films. After biaxial stretching of the cast films containing oriented β‐transcrystals, microporous membranes with more uniform micropore distribution were obtained. This work provides a new understanding of the relationship between nucleating agent framework size uniformity, crystallization uniformity, and micropore uniformity.