THE EFFECT OF VARIATION PERCENTAGE ALKALIZATION (NAOH) ON THE MECHANICAL PROPERTIES ANALYSIS AND WATER ABSORPTION BEHAVIOUR IN BIOCOMPOSITE WITH CASSAVA RUBBER STARCH

Abstract

Maluku as one of the provinces in Indonesia has a lot of potential sago plants, which is the basis for conducting research using sago fiber and rubber cassava starch as a base material for making composites that have good mechanical value and are environmentally friendly. Composites are made using natural ingredients namely sago fiber and cassava rubber starch as the matrix. The making of composites is expected to get good bending strength, impact strength, and water absorption rate. Composites are made using the hand lay-up method with a variation of the matrix. The variation of the volume fraction of sago pith fibers is 1:1 and 7:3 using NaOH liquid and distilled water in the alkali process with a percentage ratio of 0%, 5%, 10%, 15%, and 20% soaking time in NaOH liquid for 120 minutes. The results of this study were found to be the best impact value on composites with 1:1 fiber volume variation with 15% alkaline NaOH liquid process. The highest value of the energy absorbed by the composite was 7.5479 J with an impact strength of 0.0755 J·mm^-2. At a variation of 7:3 the highest absorption energy is 5.7430 J, while the impact strength is 0.0574 J·mm^-2 at 15% of NaOH liquid percentage. The highest bending strength is 226.035 MPa at 1:1 volume fraction variation with 15% NaOH liquid percentage. In 7:3 fiber volume fraction variation, the highest value reaches 206.199 MPa at 15% NaOH liquid percentage. The best water absorption rate is at 8.82% that occurs in 1:1 fiber volume fraction variation, with 15% percentage of the NaOH alkaline process. In the other side, water absorption rate is 9.16% in the 7:3 fiber volume fraction variation with 15% NaOH liquid in the alkalization process.

Keynote : sago pith fiber, cassava rubber starch, NaOH, hand lay up method, bending strength, impact strength and water absorption rate