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Study of reaction injection molding of polyurethane microcellular foam
Author(s) -
Park Hyeog,
Youn Jae R.
Publication year - 1995
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.760352310
Subject(s) - nucleation , polyurethane , materials science , supersaturation , polyol , isocyanate , composite material , saturation (graph theory) , blowing agent , chemical engineering , organic chemistry , chemistry , mathematics , combinatorics , engineering
Processing of microcellular foam was investigated for the feasibility of production of tough and lightweight polyurethanes. To increase the nucleation rate in a gas‐supersaturated resin, ultrasonic excitation was applied to the mixture of polyol(polyether‐based polyol) and isocyanate(diphenyl methane diisocyanate). A microcellular structure was produced by two sequential steps, i.e., supersaturationof the polyol resin with nitrogen gas at elevated pressure and ultrasonic bubble nucleation right after the impingement mixing of two components of the polyurethane system. Theoretical analyses based on nucleation theories were employed to predict the rate of nucleation in the gas‐supersaturated polyurethane. The rate of nucleatio in the resin was predicted by classical nucleation and cluster theories. In the experimental investigation, ultrasonic excitation was applied to increase the nucleation rate in the resin that had been saturated by nitrogen at a saturation pressure < 2.0 MPa.