Relatively high‐molecular‐weight segmented polyurethanes based on methylene bis(4‐phenyl‐iso‐cyanate), poly(propylene glycol), butane‐1,4 diol, and cis‐2‐butene‐1,4 diol have been synthesized and characterized. These unsaturated polyurethanes were successfully grafted using N‐vinyl pyrrolidone as monomer and 2,2′‐azobisisobutyronitrile as free‐radical initiator. However, grafting experiments involving benzoyl peroxide as initiator were unsuccessful. The graft copolymers were isolated from the ungrafted polyurethane and poly(N‐vinyl pyrrolidone) by selective solvent extraction. Elemental microanalysis, IR, NMR, thermogravimetric analysis, and equilibrium water sorption measurements were used to characterize the graft copolymers.
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Egboh et al. (1982) studied this question.
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