Thermal and mechanical properties of blends and composites from HDPE and date pits particles

The date pits flour was used as a filling material in composition with high density polyethylene (HDPE). The blending proportions were: (1) 10% date pits, 90% HDPE; (2) 20% date pits, 80% HDPE; (3) 30% date pits, 70% HDPE; and (4) 40% date pits, 60% HDPE. Thermal conductivities, specific heat, and melt flow index of the blends were determined. The thermal conductivities ranged from 0.460 to 0.720 W/(m degrees C) and specific heats ranged from 1.10 to 5.30 kJ/(kg degrees C). The tensile and flexural tests on composite plates, fabricated by compress molding, indicated that strength and strain values decreased with increase in the percentage of date pits. There was no significant difference between flexural moduli of elasticity of the composites, but tensile modulus had the highest value at 30% blend. Moduli of elasticity of the composites were lower than the plates prepared from virgin HDPE at 180 degrees C. It was presumed that high temperature processing of pure HDPE altered its original properties and consequently increased its modulus of elasticity.