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Semi‐ and fully interpentrating polymer networks based on polyurethane–polyacrylate systems. IV. Grafted semi‐1‐interpenetrating polymer networks
Author(s) -
Hourston D. J.,
Zia Y.
Publication year - 1984
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.1984.070290218
Subject(s) - polyurethane , materials science , acrylate , monomer , polymer chemistry , diol , polybutadiene , polymerization , grafting , polymer , composite material , glass transition , copolymer
A series of semi‐1‐IPNs containing 40% polyurethane and 60% polymethyl acrylate was synthesized using Adiprene L‐100, trimethylol propane, and polybutadiene diol. This diol was chosen to yield polyurethanes with a large number of potential graft sites for the methyl acrylate which was polymerized after the polyurethane network had been formed. A series of linear polyurethane–polymethyl acrylate blends, covering a range of compositions, was also prepared. The polyurethane for these polyblends was synthesized from Adiprene L‐100 and butane‐1,4‐diol. Both sets of materials were investigated by dynamic mechanical analysis. On the basis of a comparison of solubility parameters, the polyurethanes and polymethyl acrylate would be expected to be incompatible. In the dynamic loss modulus‐temperature plots of the polyblends there was a significant shift of the polyurethane T g to higher temperature, but the polymethyl acrylate transition did not shift. The polyurethane transitions of the semi‐1‐IPNs were also shifted, but considerably more than in the case of the polyblends. For both systems, it was postulated that grafting had occured to a significant extent. With the semi‐1‐IPNs, it was found that as M̄ c decreased the extent of grafting apparently increased. This was rationalized on the grounds that as the network chain lengths decrease, a higher proportion of the methyl acrylate monomer, prior to polymerization, was close to polyurethane segments and that this is a situation likely to lead to more grafting.