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Semi‐ and fully interpenetrating polymer networks based on polyurethane–polyacrylate systems. II. Polyurethane–poly(methyl acrylate) semi‐1‐interpenetrating polymer networks
Author(s) -
Hourston D. J.,
Zia Y.
Publication year - 1983
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.1983.070281215
Subject(s) - polyurethane , materials science , acrylate , polymer , dynamic mechanical analysis , polymer chemistry , interpenetrating polymer network , isocyanate , phase (matter) , methyl acrylate , composite material , chemistry , copolymer , organic chemistry
A series of semi‐1‐IPNs based on polyurethane networks and poly(methyl acrylate) were prepared, and their properties and morphologies investigated. All the materials showed substantial phase separation, but the phase sizes were orders of magnitude smaller than those observed for blends of the same linear polymers. The effects of the isocyanate/hydroxyl ratio used in the preparation of the polyurethane, of the molecular weight of the linear polymethyl acrylate component, of the overall composition, and of the molecular weight between crosslinks in the polyurethane networks were investigated. Stress‐relaxation experiments were conducted over a range of temperatures and master curves were produced for both components of the semi‐1‐IPNs and for a semi‐1‐IPN containing 40 wt% polyurethane. It was found that both the components obeyed a WLF type of equation, but that the semi‐1‐IPN only showed this type of behavior over a limited temperature range. Several reinforcement theories were applied to experimental dynamic storage modulus data. The closest fit was given by the Davies equation and by the logarithmic rule of mixing. By changing the exponent in the Davies equation to 1/10, a close fit was found. Application of a modified Takayanagi model indicated that these semi‐1‐IPNs showed some dual phase continuity when the poly(methyl acrylate) composition was relatively high.