The effect of gamma irradiation and particle size of CaCO3 on the properties of HDPE/EPDM blends

Mechanical blends formed of 50 wt% of high-density polyethylene (HDPE) and 50 wt% of ethylene–propylene–diene-monomer (EPDM) elastomer have been loaded with 50 wt% of three different particle size of CaCO3, namely CaCO3 300, CaCO3 700, and CaCO3 2000 whereby the latter has the smallest particle size of ∼311, 82 μm. Mechanical, physico-chemical and thermal properties were followed up as a function of irradiation dose for loaded and unloaded blends. The results obtained indicated that the values of tensile strength, tensile modulus at 50% elongation, gel fraction and decomposition temperature increase with increasing irradiation dose. On the other hand elongation at break, permanent set and swelling number were found to decrease with increasing irradiation dose. Moreover, the effect of particle size of CaCO3 was observed in a limited but apparent upgrading of mechanical, physico-chemical, and thermal properties. The order of semi-reinforcing capacity of three different types of CaCO3 is as follow: CaCO3 2000 > CaCO3 700 > CaCO3 300 > unloaded blend. Whereby CaCO3 2000 has the smallest particle size.