Stress-induced crystallization of biaxially oriented polypropylene

✍ Scribed by Wei Yang; Zhong-Ming Li; Bang-Hu Xie; Jian-Min Feng; Wei Shi; Ming-Bo Yang

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 82 KB
• Volume: 89
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.12150

✦ Synopsis

Abstract

The hot stretching of thick, extruded sheets at high temperatures is a very important process in the production of finished biaxially oriented polypropylene (BOPP) films with special inner structures. Through a simulation of hot stretching in the machine direction (MD) of the processing of BOPP films, it was found that at high temperatures, the stretching ratio greatly influenced the obtained crystalline structure, as observed by differential scanning calorimetry (DSC). Also, in MD hot stretching, the crystallinity increased by an average of 20%. Wide‐angle X‐ray diffraction patterns of extruded sheet samples with and without stretching confirmed the structural changes shown by DSC, and the results proved that β‐crystal modification did not occur during the MD hot‐stretching process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 686–690, 2003