Abstract

The influence of chemical composition on microphase segregation in segmented polyurethanes based on 2,4 and 2,6 toluene diisocyanate (TDI) was investigated earlier by Schneider, Sung and co-workers (1-3). In these studies, polymers of varying degrees of phase segregation were prepared from the two types of TDI coupled to polyether or polyester soft segments and chain extended with butanediol. The extent of phase mixing was judged from infared estimates of interurethane hydrogen bonding as well as from thermal properties, particularly the soft segment glass transition temperature Tg· In general, for 2,4TDT-butanediol, which forms an amorphous hard segment structure, phase segregation was weak in samples with a 1000 molecular weight soft segment, but enhanced with increasing soft segment molecular weight, for the polyether as compared to the polyester soft segment, and with the use of 2,6TDI which forms a crystalline hard segment structure.

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