Analysis of the effect of polyester resin composite on tensile strength reinforced with oil palm bunch fiber

Abstract

Oil palm empty fruit bunch (OPEFB) fiber is one of the agricultural wastes that has great potential to be used as a natural reinforcement in the manufacture of environmentally friendly composite materials and has economic value. The use of this fiber is expected to be an effective alternative in replacing the use of synthetic fibers which are generally more expensive and less environmentally friendly. This study aims to determine the effect of variations in fiber volume fraction and alkali immersion time using NaOH solution on the tensile strength of polyester resin-based composites. The study was conducted experimentally with the hand lay-up method according to the ASTM D638 standard for the manufacture of tensile test specimens. The variations used were fiber volume fractions of 20% and 25% with fiber immersion time in 5% NaOH solution for 2 hours and 3 hours. Tensile tests were conducted using a Universal Testing Machine (UTM) Zwick Roell Z020 with three repetitions for each variation. The test results showed that the highest tensile strength value of 44.8 MPa was obtained in specimens with a volume fraction of 20% and a 3-hour immersion, while the lowest value of 41.9 MPa was obtained in a 25% volume fraction with a 2-hour immersion. This proves that increasing the fiber volume fraction is not always directly proportional to increasing tensile strength, because too high a fiber concentration can cause agglomeration and voids. Conversely, a longer immersion time tends to increase the fiber-resin interfacial bonding, resulting in better mechanical properties. Thus, the use of OPEFB fibers with a simple alkali treatment can be a potential solution in the development of environmentally friendly composite materials with competitive tensile properties