Linear segmented polyurethanes: mathematical model of the two step polymerization

ESTENOZ, D.; POLO, M. L.; MEIRA, G. R.; SPONTÓN, M. E.

Simposio; XVI Simposio Latinoaméricano de Polímeros; 2018

Linear Segmented Thermoplastic Polyurethanes (STPUs) are multi-block copolymers typically obtained in two-stage polymerizations. The thermomechanical properties of STPUs are determined by the molecular characteristics acquired during their synthesis, such as the molar mass distribution (MMD). The understanding and control of molar mass is crucial in the synthesis and development of STPUs. Thus, mathematical models for these processes are valuable tools for simulating the effects of varying polymerization parameters on the molecular structure. Several stochastic mathematical models have been reported for the synthesis of STPUs. The model in Ref. 3 estimates the mass concentration of the oligomers containing 1 and 2 sequences of macrodiol in each chain, but without estimating the MMD. The model in Ref. 4 estimates the MMD of high molar mass polymers only at high conversions. None of the mentioned articles calculates the evolution of the complete MMD along both polymerization stages. In this work, a deterministic mathematical model is presented that estimates the detailed molecular structure of the evolving reaction mixture.