The effect of varying chemical group structure on the properties of polyurethane elastomers has been investigated. The introduction of urea and biuret groups into polyester and polyether urethanes by the use of 4,4,-methylene bis-(2-chloroaniline), MOCA, yielded elastomers with superior physical properties to elastomers which contained predominantly urethane groups and were chain extended and/or crosslinked with diols and triols. MOCA cured polyester urethanes gave higher tensile strengths with better resistance to dry air and STF (petrol) than polyether urethanes cured in the same way; while MOCA cured polyether urethanes were harder and had superior hydrolytic stability compared to polyester urethanes. (Author)
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