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The orientation of carbon nanotubes in poly(ethylene‐ co ‐octene) microcellular foaming and its suppression effect on cell coalescence
Author(s) -
Zhai Wentao,
Wang Jing,
Chen Nan,
Naguib Hani E.,
Park Chul B.
Publication year - 2012
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.23157
Subject(s) - materials science , nanocomposite , coalescence (physics) , carbon nanotube , composite material , blowing agent , supercritical fluid , octene , ethylene , chemical engineering , copolymer , polymer , polyurethane , chemistry , physics , organic chemistry , astrobiology , engineering , biochemistry , catalysis
Poly(ethylene‐ co ‐octene)/multiwall carbon nanotube (PEOc/MWNT) nanocomposites were prepared by a melt blending process. The MWNT's solubility and the transmission electron microscopy (TEM) observation indicated that the MWNT bonded well with a PEOc matrix. This facilitated the orientation of the MWNT when shear and extensional forces were applied to the nanocomposite melts. Microcellular PEOc/MWNT nanocomposite foams were prepared by a rising temperature process using supercritical CO 2 as the blowing agent. Various foaming times were selected to reveal the cell‐structure evolution during the cell growth stage. The obvious cell opening, resulting from cell coalescence, was observed in the cell wall in the neat PEOc foams. When the MWNT was introduced, however, the MWNT tended to orient in the cell wall. Here, as a result of the strain hardening, it acted as a self‐reinforcing element, protecting the cells from destruction during cell growth. Consequently, a dramatic decrease in the open cell content and a still high cell density at long foaming times were obtained in the PEOc/MWNT nanocomposite foams. The present study provides experimental evidence of the vital effects of nanoparticle orientation on cell coalescence. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers