Pulse NMR methods have been employed to investigate the phase state and the process of phase separation in segmented PUs based on 1,4-butanediol and 4,4′-diphenylmethane diisocyanate with crystallizable (polybutylene glycol adipate) and non-crystallizable as part of PU (polybutylene ethylene glycol adipate) polyesters. For both samples the same Tg of flexible blocks (-20°C) and temperature of the disappearance of the microphase of the rigid blocks (110°C) are observed. The segregation process was found to have two stages with acceleration as the temperature rises in a certain interval. The crystallization processes of the flexible blocks were found to influence the rate of segregation of the rigid blocks.
|Original language||English (US)|
|Number of pages||6|
|Journal||Polymer Science U.S.S.R.|
|State||Published - 1989|