Pengaruh Penambahan Serat Purun Tikus (Eleocharis Dulcis) Pada Komposit Poliester Terhadap Sifat Fisika

Abstract

Serat purun tikus (Eleocharis dulcis) yang selama ini digunakan sebagai bahan baku kerajinan tangan dapat dimanfaatkan sebagai bahan untuk pembuatan komposit. Tetapi pemanfaatan komposit masih memerlukan pengembangan agar mendapatkan sifat fisika yang baik. Dalam penelitian ini, metode yang digunakan untuk membuat material komposit adalah metode pengepresan cetakan (mold pressing) dengan ukuran 20x20x0,5 cm. Variabel penelitian yang dipelajari adalah perbedaan komposisi serat purun (5%, 10%, dan 15%) terhadap berat resin poliester dan susunan serat sejajar, acak, dan anyaman. Komposisi serat purun dianalisa terhadap gugus fungsi dan sifat fisika. Analisa gugus fungsi dilakukan dengan fourier transform infra-red (FTIR), analisa komposisi dan ukuran kristal menggunakan X-Ray diffraction (XRD), Analisa sifat fisika meliputi densitas, daya serap air dan thickness swelling dari komposit. Berdasarkan hasil analisa gugus fungsi serat purun sebelum dan sesudah treatment yang diberikan kepada serat purun mampu mengurangi kadar lignin dan hemiselulosa serta bisa menambah gugus fungsi baru yaitu Si-O-C. Hasil dari derajat serat purun sebelum dan sesudah treatment memiliki karakteristik peak pada 2θ = 12,6^o (selulosa I), 22,8^o (selulosa II), karakteristik peak pada 2θ = 12, 6^o, sedangkan untuk amorph peak pada 2θ = 21, 94^o. Hasil tertinggi dari sifat fisik komposit diantaranya ialah densitas, water absorption, dan thickness swelling berturut-turut sebesar 0,9577 g/cm³, 10.07977%, dan 24.57x10^-3%.

Kata Kunci: Serat purun tikus (Eleocharis dulcis), komposit, poliester, sifat fisika.

Purun Tikus (Eleocharis dulcis) fiber, which has been used as a raw material for handicrafts, can be used as a material for making composites. However, the use of composites still requires development to obtain good physical properties. In this research, the method used to make composite materials is the mold pressing method with a size of 20x20x0.5 cm. The research variables studied were differences in purun fiber composition (5%, 10%, and 15%) on the weight of polyester resin and parallel, random, and woven fiber arrangements. The composition of purun fiber was analyzed for functional groups and physical properties. Functional group analysis was carried out using Fourier transform infra-red (FTIR), composition and crystal size analysis using X-Ray diffraction (XRD), analysis of physical properties including density, water absorption and swelling thickness of the composite. Based on the results of analysis of the functional groups of purun fiber before and after the treatment given to purun fiber, it can reduce lignin and hemicellulose levels and can add new functional groups, namely Si-O-C. The results of the degree of purun fiber before and after treatment have a characteristic peak at 2θ = 12.6o (cellulose I), 22.8o (cellulose II), a characteristic peak at 2θ = 12.6o while for amorph peak at 2θ = 21.94o. The highest results from the physical properties of the composite include density, water absorption, and thickness swelling of 0.9577 g/cm3, 10.07977%, and 24.57x10-3%, respectively.

Keywords: Rat purun (Eleocharis dulcis) fiber, composite, polyester, physical properties.