Effect of Carbon and Glass Fillers on Tensile and Impact Strength, Water Absorption, and Degradation Properties of Sisal/Polyester Composites

The inferior mechanical and water absorption properties of natural fibers are massive challenges to utilizing them for industrial applications. The study aims to enhance tensile strength, impact strength, water absorption, and degradation of sisal/polyester composites using glass and carbon fillers. Four fillers proportions (2.5 wt.%, 5 wt.%, 7.5 wt.%, 10 wt.%) and two sisal fiber proportions (20 wt.% and 30 wt.%) were taken to fabricate the composites. Experimentations were performed according to the ASTM standards. The fillers improved tensile and impact strength, water absorption, and degradation of the composites. Carbon-filled composites displayed better results than the corresponding glass-filled composites. Carbon fillers showed a maximum increment of 24.2% in tensile and 78.5% in impact strength for the dry 20/80 composites, and 14.7% in tensile and 57.3% in impact strength for the dry 30/70 composites. Moreover, carbon fillers reduced water absorption by 55.4% for the 20/80 composites and by 53.6% for the 30/70 composites. The highest values of tensile and impact strengths were obtained for the 5 wt.% carbon-filled 30/70 composite; whereas, the lowest water absorption was for the 10 wt.% carbon-filled 20/80 composite. The lowest degradation of 2% in tensile and impact strengths was exhibited for the 7.5 wt.% carbon-filled 20/80 composites.