Biobased Ultralow-Density Polyurethane Foams with Enhanced Recyclability

Polyurethane (PUR) foams are widely used in many engineering applications, but their efficient recycling has remained a major challenge for many years. This study presents a novel strategy of incorporating hydrolyzable ester units into the PUR structure to enhance PUR foam recyclability. The present eco-design concept of PUR materials enables fully the replacement of petrochemical polyols with biobased alternatives and production of ultralow-density (16 kg center dot m(-3)) PUR foams. To reach this target, a series of low-function polyols based on succinic acid (SA) were first synthesized. Their subsequent use in combination with a high-functional biobased tall oil-derived polyol led to the production of highly homogenous semirigid, partly open-cell PUR foams with outstanding structural, thermal, and mechanical properties. Additionally, the study shows that the incorporation of SA-polyols with hydrolyzable ester linkages into the PUR foams significantly enhances their recyclability via glycolysis, proving their potential in contributing to a circular economy and addressing plastic waste concerns.