Improvement of adhesion between poly(ethylene terephthalate) and polyethylene

Three-layer films were prepared with polyethylene (PE) and poly(ethylene terephthalate) (PET) films as the outer layers and a film of high-density polyethylene (HDPE)/ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) terpolymer blend as the inner layer using compression molding. E-MA-GMA, an elastomer containing an epoxy functional group, was used as the adhesion promoting agent in the multilayer films. The effects of processing temperature, pressure application time and elastomer concentration on adhesion were investigated. The adhesion strength between PE and PET films increased with increasing bonding temperature, bonding time and elastomer concentration. From contact angle measurements, it was observed that the work of adhesion between the polymers increased with increasing amount of elastomer. Improved adhesion between PET and HDPE with 30% clastomer films was confirmed by SEM analyses of the film layers. Using FT-IR analysis of PE/HDPE-30% elastomer/PET delaminated film, the decrease in peak intensity of the epoxy groups tends to indicate reaction of epoxy functionality with functional groups in PET.