Effects of Chemical Treatment, Hybridization, and Hybrid Fiber Stacking Sequence and Orientation on Tensile and Impact Strength of Continuous Sisal Fiber Reinforced Polyester Composites

Abstract

This paper has presented the enhancement of tensile and impact strength of continuously aligned sisal fiber reinforced polyester composites through chemical treatment and hybridization. Sodium hydroxide (NaOH) and baking soda (NaHCO3) were used for sisal fiber treatment. Comparisons on the effect of sodium hydroxide and baking soda treatments on tensile and impact strength of the composites were performed. Unidirectional glass and carbon fibers were selected as hybrid fibers. Nineteen laminates were prepared as per the standards. The laminates were made of pure sisal fiber and hybridized with glass or carbon fibers at different stacking sequence, orientation, and volume fraction. The effects of glass and carbon fibers hybridization on tensile and impact strength of the composites were studied and compared. Further enhancements on the tensile and impact strength of the composites were investigated through alterations on the stacking sequence, orientation, and volume fraction of the hybrid fibers. Symmetric hybrid composites which avoided sisal/sisal plies interface have shown more than 95% and 130% rise in their tensile strength by adding about 8% volume of glass and carbon fibers respectively. Moreover, with only about 8% carbon fiber inclusion in the laminates, almost 60% improvements in the impact strength were discovered.

Keywords

• sisal fiber
• alkali treatment
• hybridization
• stacking sequence
• fiber orientation
• continuous alignment