Compatibilization of recycled and virgin PET with radiation-oxidized HDPE

Blends of high-density polyethylene (HDPE), which cross-links on radiation, and both, recycled and pristine polyethylene terephtalate (PET), one of the most radiation-stable polymers, that contain aromatic groups, which are effective at dissipation of the energy of the ionizing radiation, were irradiated with gamma rays, in order to form a copolymer capable of improving the compatibility of the blend HDPE/PET. Due to the low content of the PET in the resulting copolymer, blends PET and radiation-oxidized HDPE, were also studied. The tensile and flexural properties were improved when the PET content was increased and when the HDPE was pre-irradiated; the largest increase in the mechanical properties was observed for PET contents between 10% and 20% (w/w). The improvement in the properties is believed to occur because of a percolation effect of the PET in the HDPE matrix and the radiation-improved compatibility by means of polar groups formed in the polyethylene. However, impact properties were observed to decrease when the PET content increased in spite of the irradiation. (C) 2002 Elsevier Science Ltd. All rights reserved.