关键词: 4,4'/2,4'-二苯基甲烷二异氰酸酯, 热塑性聚氨酯, 转矩流变仪, 流变动力学, 平均分子量

Abstract: Bulk polymerizations of 4,4'/2,4'-diphenylmethane diisocyanate/polytetramethylene ether glycol/1,4-butylene glycol without and with the addition of Bi/Zn composite catalyst were carried out to synthesize thermoplastic polyurethane (TPU) in a torque rheometry to simulate twin-screw extruder conditions, and the rheokinetics of polymerization process was investigated.The relations between torque and weight average molecular weight (M_W) of TPU were corrected based on two-dimensional flow simplification, correction between melt viscosity and molecular weight, and Arrhenius equation.The rheokinetics model was used to fit the variation of M_W of TPU during polymerization.The fitted M_W of TPU showed good agreement with that determined by gel permeation chromatography.The rheokinetic model could quickly provide real-time fitting results of M_W of TPU from the torque for the whole synthesis process.

Key words: 4,4'/2,4'-diphenylmethane diisocyanate, thermoplastic polyurethane, torque rheometer, rheokinetics, average molecular weight