Polyurethane (PU) foams were recovered from European and U.S. shredder residues, which typically come from automobiles and other sources of durable goods, such as appliances, furniture, construction, etc. PU foams were characterized and glycolyzed. Glycolysis products were successfully treated for the removal of select substances of concern, heavy metals, and bromine-containing compounds and propoxylated into polyols for polyurethanes with 171 and 355 average equivalent weights.
Properties of the glycolysis product and corresponding propoxylated polyols were evaluated, including their molecular weight distribution via gel permeation chromatography (GPC). The polydispersity index decreased from 5.8 to 2.1 by reaction of glycolysis product with 50 wt% of propylene oxide based on a total amount of the initiator.
The recycled polyol of an average equivalent weight of 171 was evaluated in rigid polyurethane and urethane-modified isocyanurate foam formulations. This recycled polyol exhibited self-catalytic properties, as no catalyst was needed in preparation of water-blown rigid polyurethane foams. Foams based on the recycled polyol exhibited significantly better resistance to combustion than the foams prepared from the conventional sucrose-based polyol; physical and mechanical properties of foams were similar.