Electronic Theses and Dissertation

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, morfologi, mekanik serta termal 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, sifat fisika, sifat morfologi, sifat mekanika dan sifat termal. analisa gugus fungsi dilakukan dengan fourier transform infra-red (ftir), analisa morfologi menggunakan scanning electron microscope (sem), analisa komposisi dan ukuran kristal menggunakan x-ray diffraction (xrd), analisa sifat termal dilakukan dengan thermogravimetric analysis (tga) dan differential scanning calorimeter (dsc). analisa sifat fisika meliputi densitas, daya serap air dan thickness swelling dari komposit. sedangkan analisa sifat mekanik meliputi tensile test dan flexural test. 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 purun sebelum dan sesudah treatment memiliki karakteristik peak pada 2θ = 12,6o (selulosa i), 22,8o (selulosa ii), karakteristik peak pada 2θ = 12, 6o sedangkan untuk amorph peak pada 2θ = 21, 94o. 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%. hasil gugus fungsi treated serat purun adanya serapan yang cukup tajam pada panjang gelombang 1735, 1452 dan 1267 cm-1 yang menunjukan adanya vibrasi dari c=c pada cincin aromatik. struktur komposit terbaik diperoleh dengan penambahan serat purun 10% untuk semua susunan serat. hasil tertinggi sifat mekanik komposit diantaranya ialah tensile strength, tensile modulus, elongation, dan flexural strength berturut-turut sebesar 813.9519 mpa, 9345.737 mpa, 14.06 mpa dan 58.8399 mpa. sedangkan hasil sifat termal yang dapat dilihat dari persen weight loss komposit yang diperoleh dari hasil terbaik yaitu pada sampel acak dengan variasi 10%, dan untuk pengaruh rasio filer serat purun terhadap heat flow komposit yang diperoleh dari hasil terbaik yaitu pada sampel sejajar 5% dengan suhu 500.87oc. kata kunci: serat purun tikus (eleocharis dulcis), komposit, polyester, sifat fisika, morfologi, mekanika dan termal.

Rat purun fiber (Eleocharis dulcis), which has been used as raw material for handicrafts, can be used as a material for making composites. However, the utilization of composites still requires development in order to obtain good physical, morphological, mechanical and thermal properties. In this research, the method used to make composite materials is the mold pressing method with a size of 20x20x0.3 cm. The research variables studied were the different composition of purun fibers (5%, 10%, and 15%) to the weight of polyester resin and the arrangement of parallel, random, and woven fibers. The serat fiber composition was analyzed for functional groups, physical properties, morphological properties, mechanical properties and thermal properties. Analysis of functional groups was carried out with fourier transform infra-red (FTIR), morphological analysis using a scanning electron microscope (SEM), analysis of composition and crystal size using X-Ray diffraction (XRD), analysis of thermal properties was carried out with thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC). Analysis of physical properties includes density, water absorption and thickness swelling of the composite. While the analysis of mechanical properties includes tensile tests and flexural tests. Based on the results of the analysis of purun fiber functional groups before and after treatment given to purun fibers can reduce lignin and hemicellulose levels and can add new functional groups, namely Si-O-C. The results of the degree of purun purun fiber before and after treatment have a characteristic peak at 2θ = 12.6o (cellulose I), 22.8o (cellulose II), characteristic peak at 2θ = 12, 6o while for amorph peak at 2θ = 21, 94o. The highest results of 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. The results of functional groups treated with purun fiber showed a sharp absorption at wavelengths of 1735, 1452 and 1267 cm-1 which indicated the vibration of C = C on the aromatic ring. The best composite structure was obtained with the addition of 10% purun fiber for all fiber arrangements. The highest results of composite mechanical properties include tensile strength, tensile modulus, elongation, and flexural strength of 813.9519 MPa, 9345.737 MPa, 14.06 MPa and 58.8399 MPa respectively. While the results of thermal properties that can be seen from the percent weight loss of composites obtained from the best results are in random samples with a variation of 10%, and for the effect of purun fiber filer ratio on composite heat flow obtained from the best results are in samples aligned 5% with a temperature of 500.87oC. Keywords: Rat purun fiber (Eleocharis dulcis), composite, polyester, physical, morphological, mechanical and thermal properties.