Glycolysis of waste flexible polyurethane foam

Abstract

Glycolysis of flexible polyurethane (PU) was investigated to provide useful data for the recycling of waste cars. The glycolysis experiments were performed under atmospheric pressure and isothermal condition (220 °C). Diethylene glycol (DEG) and potassium acetate (KAc) were used as solvent and catalyst, respectively. The properties of glycolysis products were determined by analyzing the hydroxyl value, weight average molecular weight ( M w), viscosity, and the conversion (X) of the –NCOO– functional group in PU. The results indicate that the adequate concentrations of DEG and KAc are about 150 and 1% of the mass of the PU and an adequate reaction time is 90 min. Purification experiments on the glycolysis products were carried out in a stirred flask with a shell and tube condenser. The distilled materials were collected at the gas-phase temperature ranges of <245, 245–260, 260–275, 275–290, and >290 °C. The polyol-containing products are mostly in the temperature range of 245–260 °C. The recovery of polyol-containing products can be achieved by the distillation of glycolysis products.