Study of Mechanical Properties of Alkali Treated Smilax Zeylanica Fiber/Sisal Fiber/Vinyl Ester Hybrid Composites under Wet Condition

Mechanical properties of vinyl ester hybrid composites reinforced with alkali treated Smilax zeylanica and sisal fibers were studied at wet condition in the present communication. Hybrid composites were fabricated by using a simple hand lay up technique based on three different fiber loading of 25, 35, and 45 wt.% with alkali treated fibers. Hybrid composite specimens were then subjected to the water absorption test to observe the behaviours of composite specimens at wet condition under mechanical loads such as tensile, flexural and impact. The water absorption test was carried out in two ways in the distilled water environment at room temperature. The first way test was conducted for 10 days to observe the percentage of water particle absorption of hybrid composites. The second way test was performed for 5 days to determine the mechanical properties of hybrid composites at wet condition to observe its durability when they are used in outdoor applications. Mechanical properties of hybrid composite specimens at wet conditions were compared with the dry composite specimens. Experimental results showed that the percentage of the water particle absorption in the alkali treated hybrid fiber composites is lower as compared to the untreated hybrid fiber composites. Mechanical properties of alkali treated hybrid fiber composites at wet condition are slightly reduced as compared to the treated hybrid fiber composite at dry condition. As a result, it is observed that the resistance to the penetration of the water particles is higher for the alkali treated smilax zeylanica and sisal fibers reinforced vinyl ester hybrid composites. The fracture surfaces of the hybrid composite specimens were examined by scanning electron microscope to understand the effects of water absorption on the mechanical properties.