Improvement of the Low-Temperature Property of Aliphatic Polycarbonate Glycols-Based Polyurethane Elastomers

Structure-property relationship of polyurethane elastomers (PUEs) based on aliphatic carbonate glycols (PC-glycols) with various molecular weights (HO-[(CH2)(m)OC(=O)O](n)-(CH2)(m)-OH, m = 3 and 6, M-n = 1000-3000) were investigated to improve their low-temperature property. Differential scanning calorimetry (DSC) measurement revealed that the glass transition temperature (T-g) of the soft segment in the PUEs decreased ca. 10-25 degrees C and crystallized hard segment exhibited larger heat of fusion with increasing molecular weight of the PC-glycol. This trend clearly implies that the degree of microphase separation of the PUEs became stronger with an increase in molecular weight of the PC-glycol. In the tensile testing, Young's modulus and tensile strength increased with increase in the degree of microphase separation. In other words, an increase in molecular weight of the PC-glycol gives the PUEs bearing lower T-g and superior mechanical properties.