Non-isothermal crystallization kinetics of calcium carbonate-filled β-crystalline phase polypropylene composites

✍ Scribed by Tjong, Sie Chin; Xu, Shi Ai

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 381 KB
• Volume: 44
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199709)44:1<95::aid-pi821>3.0.co;2-l

✦ Synopsis

The non-isothermal crystallization behaviour of high purity b-phase and a-phase polypropylene (PP) and their calcium carbonate-Ðlled composites was investigated by means of di †erential scanning calorimetry. High purity b-PP polymer was prepared by adding an e †ective b-nucleator consisting of equal amounts of pimelic acid and calcium stearate. The crystallization temperature and crystallization rate coefficient of pure b-PP polymer were considerably higher than those of the a-PP polymer. This was due to the b-PP polymer containing nucleating agents, which act as nuclei for b-spherulites. The calcium carbonate content had little or no e †ect on the crystallization rate coefficient and Ozawa exponent of the b-phase PP in the composites. On the other hand, the crystallization temperature, crystallization rate coefficient and Ozawa exponent of the a-phase PP composites depended on the calcium carbonate loading. The e †ect of calcium carbonate additions on the crystallization of a-PP and b-PP is discussed.