Effect of Stretching on β -Phase Content of Isotactic Polypropylene Melt Containing β -Nucleating Agent.

Autor:	Li, Songwei, Zheng, Guoqiang, Jia, Zhenhua, Zhang, Zhenfang, Liu, Chuntai, Chen, Jingbo, Li, Qian, Shen, Changyu, Peng, Xiangfang
Předmět:	POLYPROPYLENE STRETCHING of materials MELTING points NUCLEATION DIFFERENTIAL scanning calorimetry X-ray diffraction CRYSTALLIZATION
Zdroj:	Journal of Macromolecular Science: Physics; May2012, Vol. 51 Issue 5, p828-838, 11p, 2 Color Photographs, 1 Diagram, 6 Graphs
Abstrakt:	Pure isotactic polypropylene (iPP) and that containing 0.2 wt% of a β-nucleating agent (β-NA) were extruded through a slit die. Simultaneously, the extruded melt was stretched at the die exit with different stretching rates (SR). The change of β-phase content with different SR was investigated by differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The results indicate that, for pure iPP, the content of β-phase first increases with increasing SR till it reaches a maximum and then it gradually decreases. However, for the case of β-nucleated iPP, it decreases monotonously with increasing SR. The spatial confinement is considered as the best explanation for the suppression of β-phase in the nucleated iPP melt upon stretching. [ABSTRACT FROM PUBLISHER]
Databáze:	Complementary Index
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