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Morphology and electrical properties of short carbon fiber‐filled polymer blends: High‐density polyethylene/poly(methyl methacrylate)
Author(s) -
Zhang Cheng,
Yi XiaoSu,
Yui Hiroshi,
Asai Shigeo,
Sumita Masao
Publication year - 1998
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/(sici)1097-4628(19980829)69:9<1813::aid-app16>3.0.co;2-m
Subject(s) - materials science , high density polyethylene , percolation threshold , composite material , percolation (cognitive psychology) , polyethylene , molding (decorative) , polymer blend , polymer , phase (matter) , compression molding , morphology (biology) , linear low density polyethylene , methyl methacrylate , fiber , electrical resistivity and conductivity , copolymer , chemistry , mold , engineering , organic chemistry , neuroscience , electrical engineering , biology , genetics
Morphology and electrical properties of short carbon fiber‐filled high‐density polyethylene (HDPE)/poly(methyl methacrylate)(PMMA) polymer blends have been studied. The percolation threshold of HDPE50/PMMA50 blends filled with vapor‐grown carbon fiber (VGCF), 1.25 phr VGCF content, is much lower than those of the individual polymers. The SEM micrographs verified that the enhancement of conductivity could be attributed to the selective location of VGCF in the HDPE phase. A double percolation is the basic requirement for the conductivity of the composites, i.e., the percolation of carbon fibers in the HDPE phase and the continuity of this phase in the blends, which hereby are defined as the first percolation and the second percolation, respectively. The SEM micrographs also showed that the short carbon fibers could affect the morphology of the blends. With the increase of VGCF content, the HDPE domains are elongated from spherical into strip shape, finally develop to a continuous structure. As a result, the second percolation threshold of the blends filled with 2.5 phr VGCF, 20 wt % HDPE, is lower than that of the blends filled with 1.5 phr VGCF, 30 wt % HDPE. The influence of molding temperature and time on the second percolation threshold has also been investigated. For the composites molded at a lower temperature, the second percolation threshold is shifted to a higher VGCF content, but there is little influence of molding time on the second percolation threshold. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1813–1819, 1998