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Microcellular silicone rubber foams: The influence of reinforcing agent on cellular morphology and nucleation
Author(s) -
Xiang Bin,
Deng Zhaoping,
Zhang Fengshun,
Wen Na,
Lei Yajie,
Liu Tao,
Luo Shikai
Publication year - 2019
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.24857
Subject(s) - nucleation , materials science , silicone rubber , composite material , supercritical fluid , supercritical carbon dioxide , silicone , morphology (biology) , natural rubber , rheology , blowing agent , surface tension , chemical engineering , chemistry , organic chemistry , physics , quantum mechanics , biology , polyurethane , genetics , engineering
A series of microcellular silicone rubber foams were prepared by supercritical carbon dioxide (scCO 2 ). The effect of reinforcing agent (silica) on the rheological behavior, cellular morphology and nucleation of silicone rubber composites was investigated. The results show that the silica not only acts as reinforcing agent but also plays an important role in the cellular nucleation. When the content of silica increases from 40 phr to 70 phr, the range of the calculated surface tension of silicon rubber composites/scCO 2 ( γ mix ) and radius of the critical nucleus ( r* ) are 158.95∼1,092.74 nN/m and 14.45–99.34 nm, respectively. Meanwhile, aggregated silica has good heterogeneous nucleation as the diameter of aggregated silica particles is approximate to twice r* . The smallest cell diameter and the highest cell density of the silicone rubber foam can reach to 708 nm and 1.02 × 10 11 cells/cm 3 , which indicate that the silicone rubber nanofoams can be obtained by means of the supercritical foaming technology. POLYM. ENG. SCI., 59:5–14, 2019. © 2018 Society of Plastics Engineers