A study of the dilation of the unit cell of metallocene isotactic poly(propylenes): The monoclinic form

✍ Scribed by J. R. Isasi; R. G. Alamo; L. Mandelkern

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 199 KB
• Volume: 35
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19971115)35:15<2511::aid-polb13>3.0.co;2-8

✦ Synopsis

The lattice parameters of a series of monoclinic metallocene poly(propylenes) of constant molecular weight are measured as a function of defect content, that vary between 0.3 and 2.35 total defects per 100 monomeric units. The parameters are also measured as a function of molecular weight for a fixed defect content and as a function of the crystallization temperature. The b axis is found to increase with decreasing isothermal crystallization temperature whereas only small changes are found for samples rapidly crystallized. The a and c axis showed basically no variation with crystallization temperature. The parameters of the unit cell were essentially constant with varying defect content in the poly(propylene) chain. Lack of observed effect on the dilation of the unit cell by increasing defects is a consequence of the rapid crystallization required to ensure formation of monoclinic crystals. The unit cell parameters increased as a mild function of the molecular weight.