Structure and properties comparison of poly(ether-urethane)s based on nonpetrochemical and petrochemical polyols obtained by solvent free two-step method

Abstract

The application of thermoplastic polyurethanes (TPU) is becoming more and more extensive, and the decreasing of used petrochemical monomers and reduction of energy for the polymerization and processing processes is getting increasingly important. In this paper, we confirmed the positive influence of high bio-based monomers contents (by replacing petrochemical polyol and glycol by bio-based counterparts) on processing and properties of obtained materials. A series of partially bio-based thermoplastic poly(ether-urethane)s (bio-based TPU) were obtained from bio- and petrochemical-based polyols, bio-based 1,4-butanediol, and 4,4′-diphenylmethane diisocyanate by the two-step method without using any solvents. Both the monomers’ origin and polyurethane prepolymer processing parameters were taken into account in characterization of the obtained materials. The TPUs' chemical structure was analyzed by FTIR spectroscopy and 1H NMR and the number average molecular weight was examined by 1H NMR and GPC. The measurements of dynamic mechanical thermal analysis, tensile test, hardness, density method, and rheological behavior provided useful information about the properties of prepolymers and TPUs. The processing properties and an activation energy of prepared materials was examined using the melt-flow index. It has been confirmed that despite the origin of polyols obtained thermoplastic poly(ether-urethanes) exhibited comparably good mechanical and thermo-mechanical properties, and an appropriate melt flow index facilitates their processing. Nevertheless, the use of high amount of bio-based monomers resulted in obtaining more eco-friendly materials.