Improvement of Tensile Properties of Recycled Low-Density Polyethylene by Incorporation of Calcium Carbonate Particles

Plastics are used in versatile applications including automobile, packaging, piping and house goods, these huge uses attribute in the consumption of the oil reserves and the emerged waste harm the environment when it disposed irregularly. Recycling of plastics is one of the realistic solutions to the aforementioned problems and to reduce production cost. However, the reduction in mechanical properties of recycled plastics limit their use and thus reinforced plastics become popular because of their high mechanical, physical and thermal properties. The effects of calcium carbonate content from 0 to 15 wt.% on the tensile properties of recycled low-density polyethylene (RLDPE) were tested, the addition of calcium carbonate particles up to 15 wt.% was found to enhance the tensile strength and modulus of elasticity of RLDPE samples. Three calcium carbonate particle sizes (80, 200 and 500 µm) were mixed with RLDPE to investigate the effect of particles size on the tensile properties of RLDPE, it was found that the addition of small filler particles resulted in a noticeable improvement of tensile strength and modulus of elasticity of RLDPE compared with large filler particles. It was also observed that the addition of stearic acid slightly improves tensile properties of RLDPE which may be related to improvement of the interfacial adhesion between the filler and RLDPE. The crystallization temperature and the degree of crystallinity of RLDPE were increased by the addition of 7.5 wt.% calcium carbonate particles because they act as nucleating agents.