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Physical aging of syndiotactic polypropylene

✍ Scribed by L. Guadagno; C. Fontanella; V. Vittoria; P. Longo

Publisher: John Wiley and Sons
Year: 1999
Tongue: English
Weight: 163 KB
Volume: 37
Category: Article
ISSN: 0887-6266
DOI: 10.1002/(sici)1099-0488(19990115)37:2<173::aid-polb6>3.0.co;2-w

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✦ Synopsis

Syndiotactic polypropylene (sPP) was quenched from the melt in an icewater bath, and changes in the structural organization, during the aging time, were followed by X-rays, differential scanning calorimetry, and transport properties of dichloromethane at low activities. After 1 month, an increase of crystallinity from 19 to 26% was observed. In addition, the results of sorption and diffusion indicated a consistent increase of an intermediate phase not crystalline, yet impermeable to the vapors. The study of the mechanical properties showed that there is a remarkable increase of all the mechanical parameters with the aging time, and this effect was associated to the increase of the intermediate phase. The elastic modulus increased three times in the first hours of aging.

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