Studies on Bamboo/Glass Fiber Reinforced USP and VE Resin

The effects of weight fraction and length of short bamboo and glass fibers on flexural strength and inter-laminar shear strength (ILSS) of vinyl ester resin and unsaturated polyester (USP) resins were investigated. The bamboo fibers were isolated from the bamboo plant by treating them with dilute solution of sodium hydroxide (0.1 and 1N NaOH) for 72 h and then boiling them in a pressure cooker for 30 min. The fibers were separated, dried, and cut into 5 or 10mm lengths. Composites were fabricated using vinyl ester resin or USP resin as binders. The flexural properties of glass/bamboo fiber reinforced vinyl ester resins were higher than those based on USP resins. This may be due to better wetting of the fibers by VE resins due to their low viscosity and possibility of hydrogen bond formation with hydroxyl group on bamboo fibers. Hybrid composites were fabricated using 50wt% of fibers. The wt% of bamboo fibers in these hybrid composites was varied as 25, 50, and 75wt% of chopped glass fibers (5 mm). Replacement of 25wt% of glass fibers did not affect the flexural modulus and a marginal increase in ILSS was observed. However, replacement of 75% glass fibers by bamboo fibers resulted in a significant decrease in flexural strength, modulus and ILSS.