Thermomechanical evaluation of expanded ethylene-propylene diene monomers rubber mixed with recycled polyvinyl chloride foams

The hazardous practice of landfilling at the end of life (EoL) of large amounts of rigid crosslinked interpene- trated network polyvinyl chloride (PVC) foams urgently requires development of effective recycling methods. In this work, PVC foam waste obtained from an industrial process was mixed with ethylene‐propylene diene monomers (EPDM) rubber. The waste PVC foam naturally contained water (up to 35%) which was exploited for the expansion of EPDM rubber. For this, various amounts of recycled polyvinyl chloride (PVC) (20%, 30%, 40% by weight) were melt compounded with ethylene‐propylene diene monomer rubber (EPDM) at 60 °C for 15 min. The obtained rubber mixtures were vulcanized at 160 °C for 20 min under varied compression time to create square sheets of expanded EPDM/PVC blends. The insertion of the humid PVC foam promoted the foam- ing of EPDM rubber up to a total porosity of 40% meanwhile geometrical density was decreased by 33% by the expansion of the rubber. Tensile tests revealed that, despite the presence of rigid PVC foams, the expanded EPDM/PVC blends manifested appreciable elongation at break values (up to 700%). Both compression set and shore A values of rubber increased with the addition of the rigid PVC foam. Moreover, all expanded blends showed low thermal conductivity values with a minimum of 0.07 W/m K.