Miscibility of poly(urethane-urea) elastomers with chlorinated poly(vinyl chloride)

Abstract

Effect of a chemical structure of poly(ether-urethane-urea) (PUU) elastomers on a miscibility of their blends with chlorinated poly(vinyl chloride) (cPVC) has been studied by FTIR and DSC. The segmented PUU were synthesized by prepolymer approach in N,N-dimethylformamide (DMF) solution. PUU-1 was synthesized using poly(propylene glycol) (PPG) of Mn = 1000, mixture of 2,4- and 2,6-isomers of tolylenediisocyanate (TDI) in a ratio of 65:35 (by weight) and 4,4´-methylenedianiline as a chain extender at a molar ratio of 1:2:1. PUU-2 was prepared based on poly(tetramethylene glycol) (PTMG) of Mn = 1000, TDI and cyanoethylated ethylene diamine at a molar ratio of 2:3:1. The polymer-polymer blends were obtained via solution casting technique using DMF as a solvent. It was found a miscibility of the polymers enhances due to a formation of hydrogen or donor-acceptor bonding between polar NH urethane-urea or nitrile groups of hard PUU segments and chlorine of cPVC. According to DSC results the polymer-polymer systems stabilized by stronger donor-acceptor bonding are characterized by single glass transition temperature, Tg, a position of which is higher than that of the theoretical one, TFg, calculated in full composition range via Fox’s equation. When stabilization of polymer-polymer blend with 30 % (by weight) of cPVC performs by weaker hydrogen bonding we observed a formation of mixed phase and the composite is characterized by appearance of three relaxation transitions. Increasing cPVC content reduces a miscibility of the components and biphasic structure of the composites forms. Comparative analysis of experimental and theoretical (additive) tensile strength vs composition dependencies demonstrates an impact of donor-acceptor interface interactions on strength of the polymer composites obtained.