On enhanced impact strength of calcium carbonate-reinforced high-density polyethylene composites

The micromechanism of plastic deformation during impact loading of 20% calcium carbonate-reinforced polyethylene micrometric composite is investigated through scanning electron microscopy and atomic force microscopy and the behavior compared with the un-reinforced polyethylene under identical conditions of processing. The impact strength of composites is linked to structural studies by X-ray diffraction and atomic force microscopy observations. The adoption of calcium carbonate in polyethylene has two primary effects: the reinforcement and the nucleating effect. The reinforcement effect increases the bulk crystallinity and modulus, while the nucleating effect decreases the spherulite size. The addition of calcium carbonate to polyethylene increases impact strength in the investigated temperature range of −40 to +70 °C and alters the primary micromechanism of plastic deformation from crazing-tearing and brittle behavior in neat polyethylene to particle-induced cavitation and fibrillation in the composite.