多嵌段聚氨酯分子化学组成不均一性的GPC研究

本文用带有示差和紫外双检测器的GPC对不同软段,不同聚合方式,不同链段分子量和含量的多嵌段聚氨酯的组成分布进行了研究.计算公式中,因不涉及具有明显分子量依赖性的硬段示差响应系数,而使得问题简化.结果表明,多嵌段聚氨酯的化学组成分布受软硬段相容性和聚合方式的影响.聚合过程中发生相分离导致组成不均一.本文研究结果为测定多嵌段共聚物化学组成分布提供了简单快速的近似方法.

GPC STUDEIS ON THE CHEMICALLY COMPOSITIONAL HETEROGENEITY IN SEGMENTED POLYURETHANES

The method of GPC equipped with RI and UV detectors was employed to investigate the chemically compositional heterogeneity ( CCH ) in segmented polyurethanes.The disappearance of RI proportionality contant of the hard segment in the equations made the calculation available. The studies showed that the CCH in segmented poly-urethanes was dependent on many factors such as segment compatibility, preparation method, soft segment length and hard segment content. The CCH in the samples pre-pared by bulk method was more serious thanthat by solution method. As the soft segmene telength increased, the CCH increased sharply. Poor segment compatibility or incre ased hard segment content also caused serious CCH. The origin of CCH was the segment incompatibility which resulted in phase separation during the polymerizations.