Polyurethane/ground tire rubber composite foams based on polyglycerol: Processing, mechanical and thermal properties

During the synthesis of rigid polyurethane foams, petrochemical polyol was substituted with polyglycerol, the product of thermo-catalytic polycondensation of waste glycerol, resulting from biodiesel production. Two types of ground tire rubbers, untreated and thermo-mechanically reclaimed, were used to obtain green polyurethane-polyglycerol composite foams. Samples were prepared by a single-step method for the ratio of NCO/OH groups equal to 2. Foams containing different types of fillers showed noticeably various appearances, which suggested significant differences in the matrix-filler interactions between materials modified with untreated and reclaimed ground tire rubber. Addition of rubber particles shortened the processing time by more than 20s and reduced the temperature during synthesis. Incorporation of ground tire rubber increased the size of the cells in comparison to unmodified foam. Modifications of rigid polyurethane foams resulted in the increase of apparent density and compressive strength even by 40% compared to neat foam. Enhancement was stronger for samples containing thermo-mechanically reclaimed ground tire rubber as a result of better developed surface of filler particles and their interfacial interactions with polyurethane matrix. Prepared polyurethane foams filled with untreated rubber particles also showed slightly enhanced thermal stability compared to neat foam.