Micropore formation process during stretching of polypropylene casting precursor film

作者：Xu, R J; Lei, C^*; Cai, Q; Hu, B; Shi, W; Mo, H; Chen, C

来源：Plastics Rubber and Composites, 2014, 43(8): 257-263.

DOI：10.1179/1743289814Y.0000000100

• Polypropylene
• Microporous membrane
• Stretching
• Melt stretching mechanism
• Pore formation

The micropore formation process during stretching of polypropylene casting precursor film was followed by DSC, SEM, AFM, SAXS and WAXD. DSC and SAXS results prove that annealing improves the lamellae periodicity and new crystals are formed. The increase of lamellae thickness is also observed by SEM and AFM. Preferentially oriented crystalline grain is along the direction perpendicular to the MD. After cold stretching, the newly formed crystals between the lamellae disappear and the voids appear in SEM and AFM. The hot stretching makes the lamellae separated step by step and many connecting bridge crystals appear between the adjacent lamellae, at the same time pores are formed. Their crystallisation behaviour is proved by the higher temperature shoulder in DSC curves and the broadening of second order peak in SAXS curves. During stretching, the long period decreases and the lamellae become twisted. More crystal grains are preferentially oriented along the direction of (110) plane.

• 出版日期2014-10
• 单位广东工业大学