Estimating the feasibility of using industrial solid wastes as raw material for polyurethane composites with low fire hazards

Abstract

Solid wastes including phosphate tailings (PT) and fly ash (FA) are by-products with large quantities and deposited in surface impoundment without treatment, which can easily trigger environment issues. The comprehensive utilization of industrial solid wastes has received intensive attention. In present work, the recycling of industrial solid wastes was studied to explore the probability of utilizing PT and FA as fillers for fabrication of polymer materials with low fire hazards. The micro-sized PT and FA powders were firstly treated with silane coupling agents and then introduced into thermoplastic polyurethane (TPU) through solvent blending method. The influences of solid wastes on the thermal degradation behavior, as well as the fire hazards of TPU were explored. The thermogravimetric analysis results illustrated that due to the introduction of PT and FA, the thermal degradation rate was reduced while the thermal degradation temperature and char yields were increased, in contrast to pristine TPU. The cone calorimetry test results demonstrated the introduction of PT and FA obviously reduced the heat release rate (HRR), total heat release (THR), smoke production rate (SPR), total smoke release (TSR), carbon monoxide (CO) and carbon dioxide (CO2) emission rate of TPU composites. Therefore, the PT and FA might be promising fillers for fabrication of polymeric materials with controllable properties and provide a novel solution for effective recycling of industrial solid wastes.