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Effect of polytetrafluoroethylene on the foaming behaviors of linear polypropylene in continuous extrusion
Author(s) -
Wang Kun,
Wu Fei,
Zhai Wentao,
Zheng Wenge
Publication year - 2013
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.38959
Subject(s) - extrusion , polypropylene , materials science , polytetrafluoroethylene , composite material , supercritical fluid , reactive extrusion , blowing agent , morphology (biology) , plastics extrusion , extensional viscosity , rheology , shear viscosity , chemistry , organic chemistry , biology , polyurethane , genetics
Linear polypropylene (PP) foams, blown in the continuous extrusion process using supercritical CO 2 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