Recycled Polyurethane as a Second Phase in Thermoset Blends and Its Effect on Thermal Degradation Kinetics Studies

A new approach is introduced in the modification of thermosetting polymer by using different amount of polyurethane of waste origin. The post consumer polyurethane foam coatings are degraded using glycolysis process and the recycled product is further converted into new polyurethane. The blending of recycled polyurethane with epoxy exhibits transparency and produces nanostructures. The effective interaction between two polymers is confirmed with dynamic mechanical analysis at 10 Hz. Selected relaxations are also noticed by the inclusion of the flexible PU chains at low temperature regions. The glass transition temperature shows a shift in value from neat epoxy indicating effective miscibility of the flexible domains. The initial degradation temperatures of the blends are increased by the polyurethane inclusion, which is confirmed by thermogravimetric analysis. The increase is more than 25 °C for the 20 phr inclusion. The thermal degradation kinetics is correlated with different theosetical equations like Cord-Redfern, Horowitz-Metzger, and Broido.