Pengaruh Penambahan Molase Pada Resin Dan Lamanya Perendaman Larutan NaOH Terhadap Kekuatan Bending Pada Komposit Serat Waru

Abstract

 Composites are engineered materials resulting from the combination of two or more different materials, each possessing its own advantages. Waru tree bark fibers (Hibiscus tiliaceus) have significant potential as natural reinforcement in composites, especially after undergoing alkali treatment. Furthermore, molasses possesses good adhesive characteristics to enhance the mechanical and thermal properties of composites when applied as an additive in the resin matrix. However, the combined use of waru fiber and molasses in polyester resin is still rarely studied. This research aims to investigate the effect of molasses addition to BTQN 157 polyester resin in three variations (3%, 5%, and 7%), as well as the effect of fiber immersion duration in 6% NaOH solution (for 1 hour, 2 hours, and 3 hours) on the bending strength of the composite. Specimen preparation utilized the ASTM D790 standard with dimensions of 120mm in length, 12mm in width, and 4mm in height. The results showed that the highest bending strength reached 67.7 MPa at a composition of 15% fiber, 80% resin, and 5% molasses after 2 hours of immersion. This indicates that the addition of molasses and the immersion time significantly affect the mechanical strength of the composite.