Effect of Hard Segment Molecular Weight on Concentrated Solution and Bulk Properties of Ether Based Thermoplastic Polyurethanes

摘要

A systematic study was conducted to investigate the effect of hard segment molecular weight on concentrated solution and bulk properties of thermoplastic ether based polyurethanes (TPUs). The molar feed was used to determine the molecular weight of the hard segment. Then the weight fraction of the hard segment is determined by calculating the ratio of the molecular weight of the hard segment to the number average molecular weight of the TPU determined by GPC. Similar to the study of dilution solution properties, it was found that thermal and mechanical properties in the bulk were significantly affected at low weight fractions of the hard segment. The critical weight fraction of the hard segment was found at about 0.4. above critical weight fraction of hard segment there is a diminishing effect on the thermal properties and dynamical/ mechanical properties in bulk.