The Effects of Calcium Carbonate Filler on HDPE Pipe

The objective of this work is the preparation and the characterization of high density polyethylene /calcium carbonate (HDPE/CaCO3) composites. Polyethylene composites, containing 10-35 wt. % of CaCO3 and HDPE with MFI (Melt Flow index) (0.550 g/10mn) were prepared with co-extrusion process using extruder type Cincinati 90D. Thermal and mechanical studies were made in order to determine the parameters for obtaining a material (corrugated pipe) with optimal properties. The composite viscosity increased with filler content, suggesting the formation of filler agglomerates. Thermal analysis shows that addition of 30 % CaCO3 increased the thermal stability of HDPE around 32°C, decreasing the processing temperature of composites in 15°C. Regarding to the mechanical tests, the ring stiffness of the composites decreased with the addition of CaCO3. According to the obtained results, we suggest that HDPE/CaCO3 composites could be used in the pipe production where tensile strengths higher than 25 MPa are not required and for service temperatures between 30°C and 70°C.