Effect of polytetrafluoroethylene on the foaming behaviors of linear polypropylene in continuous extrusion |
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| Authors: | Kun Wang Fei Wu Wentao Zhai Wenge Zheng |
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| Affiliation: | Ningbo Key Lab of Polymer Materials, Division of Polymers and Composites, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China |
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| Abstract: | Linear polypropylene (PP) foams, blown in the continuous extrusion process using supercritical CO2 as the blowing agent, exhibited poor cell morphology and narrow foaming window, because of their low melt strength. In this study, polytetrafluoroethylene (PTFE) was blended with PP resin with the aim of improving the foaming behavior of PP. It was found that the PTFE particles were deformed into fine fibers under shear or extensional flows during the extrusion process, which significantly increased the melt strength of PP from 0.005 N to 0.03 N (PP/PTFE with PTFE content of 4.0 wt %) at 230°C. The experimental results indicated that the presence of PTFE improved the cell morphology of PP foams and broadened the foaming window of PP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 |
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| Keywords: | polyolefins foams extrusion fibers |
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