Effects of hydrostatic extrusion on the mechanical and thermal properties of polypropylene

✍ Scribed by T. Ariyama

• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 630 KB
• Volume: 31
• Category: Article
• ISSN: 0022-2461
• DOI: 10.1007/bf00352796

✦ Synopsis

The structure change in spherulites for hydrostatically extruded polypropylene (PP) was studied bythe use of internal friction measurements and thermophotometrytests. The onset temperature of the 13-loss peak of the PP sample decreases with increasing reduction in area, R. For the extrudates below R=50%, the peak temperature of s-loss shifts to lower temperature. The ~ and 13 absorptions for the extrudates up to R=50% become broad and overlap with each other. The intensity of the 13-loss peak, Amax, is maximum for the extrudate with R= 50%. The results of tan 5, damping, and the intensity of the 13-loss peak indicate that the mechanism of molecular chain deformation is divided into two stages, below and above R=50%. The results are due to spherulitic changes, i.e. the shape of spherulites changed from spherical to elliptical in the extrudates above R=50% and the spherulite with R=50% changed from coarse structure to a finer one by the imposition of hydrostatic pressure.