Dynamic vulcanization of recycled milk pouches (LDPE-LLDPE) and EPDM blends using dicumyl peroxide

The viability of thermomechanical recycling of post-consumer milk pouches (blend of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE)) and its scope for suitable engineering applications were investigated. The effects of blending with ethylene-propylene-diene monomer (EPDM) rubber and subsequent curing using dicumyl peroxide (DCP) on the macromolecular structure and properties of recycled polyethylene (PE) blends were studied. The crosslinking efficiency of recycled PE/EPDM blends and possible thermooxidative degradation of recycled polymer upon peroxide curing was assessed using torque and gel content measurements along with infrared spectroscopic analysis. Both the torque and gel content of the blends varied with DCP crosslinking reactions and also were affected by oxidative degradation. In view of the electrical application area of this recycled blend material, the dielectric breakdown strength and volume resistivity were measured. The mechanical performance and thermal stability of recycled PE/EPDM blends improved with progressive crosslinking by DCP but deteriorated somewhat at higher DCP dose. Scanning electron microscopy showed good interface bonding between recycled polymer and dispersed EPDM phase in the cured blends compared to the non-cured blends. (c) 2007 Society of Chemical Industry