Studi Eksperimental Pengaruh Variasi Komposisi Serat Kelapa Terhadap Sifat Penyusutan Pada Biokomposit Berdasarkan Standar ASTM D955

Triatmaja, Ryan Rachmadi (2026) Studi Eksperimental Pengaruh Variasi Komposisi Serat Kelapa Terhadap Sifat Penyusutan Pada Biokomposit Berdasarkan Standar ASTM D955. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Penelitian ini bertujuan untuk mengkaji pengaruh variasi komposisi serat kelapa terhadap nilai penyusutan pada biokomposit Polypropylene (PP) berdasarkan standar ASTM D955. Tingginya potensi serat kelapa di Indonesia memberikan peluang pengembangan biokomposit PP untuk komponen berbahan plastik. Tiga variasi komposisi diuji meliputi 90% PP–10% serat, 80% PP–20% serat, dan 70% PP–30% serat, dengan penambahan maleic anhydride polypropylene sebesar 5%. Serat kelapa diproses melalui perlakuan alkalisasi menggunakan larutan NaOH 5% selama 2 jam, dihaluskan hingga ukuran ≤125 µm, dan dikeringkan pada suhu 110 °C selama 24 jam. Pelet biokomposit dibuat menggunakan ekstruder sekrup tunggal, kemudian dicetak dengan mesin injection molding sesuai parameter yang telah ditetapkan. Sebelum spesimen diukur, dilakukan pengukuran kelengkungan menggunakan metode kisi dibantu dengan dial indicator. Penyusutan spesimen (ASTM D955) diukur 24 serta 48 jam pasca-cetak menggunakan jangka sorong digital. Signifikansi pengaruh komposisi serat dianalisis secara statistik menggunakan ANOVA satu arah, uji Tukey, dan analisis regresi dengan signifikansi statistik p < 0,05. Karakterisasi struktur mikro serta distribusi serat dievaluasi melalui pengamatan SEM (Scanning Electron Microscopy). Hasil penelitian menunjukkan komposisi serat berpengaruh signifikan terhadap penyusutan pada kedua arah pengukuran, dengan pengaruh lebih dominan pada arah tegak lurus aliran dibandingkan arah searah. Komposisi 20% serat menghasilkan nilai penyusutan terendah pada kedua arah (1,591% searah; 1,901% tegak lurus), sementara komposisi 10% menghasilkan penyusutan tertinggi (2,013% searah; 2,323% tegak lurus), dan komposisi 30% menunjukkan peningkatan penyusutan kembali yang dikaitkan dengan meningkatnya stress interfacial dan aglomerasi serat, sebagaimana diindikasikan oleh hasil pengamatan SEM. Hubungan antara komposisi serat dan stabilitas dimensi bersifat curvilinear, menunjukkan titik optimasi pada konsentrasi 20% serat di mana laju penurunan penyusutan melambat seiring peningkatan komposisi.
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This research aims to investigate the effect of coconut fiber composition variations on the shrinkage behavior of polypropylene (PP) biocomposites in accordance with ASTM D955. The abundant availability of coconut fiber in Indonesia provides significant potential for the development of PP-based biocomposites for plastic components. Three fiber compositions were examined: 90% PP–10% fiber, 80% PP–20% fiber, and 70% PP–30% fiber, with the addition of 5% maleic anhydride polypropylene as a coupling agent. The coconut fibers were subjected to alkalization using a 5% NaOH solution for 2 hours, ground to a particle size of ≤125 µm, and dried at 110 °C for 24 hours. Biocomposite pellets were produced using a single-screw extruder and subsequently formed into specimens through injection molding under predetermined processing parameters. Prior to shrinkage measurement, specimen flatness was evaluated using the grid method assisted by a dial indicator. Shrinkage measurements (ASTM D955) were conducted at 24 and 48 hours after molding using a digital caliper. The significance of fiber composition on shrinkage behavior was statistically analyzed using one-way ANOVA, Tukey’s post-hoc test, and regression analysis at a significance level of p < 0.05. Microstructural characteristics and fiber distribution were examined using Scanning Electron Microscopy (SEM). The results indicate that fiber composition significantly affects shrinkage in both measurement directions, with a more pronounced influence observed in the direction perpendicular to the melt flow. The 20% fiber composition exhibited the lowest shrinkage values in both directions (1.591% parallel to flow; 1.901% perpendicular), while the 10% fiber composition resulted in the highest shrinkage (2.013% parallel; 2.323% perpendicular). urthermore, the 30% composition exhibited a subsequent increase in shrinkage, attributed to heightened interfacial stress and fiber agglomeration, as evidenced by SEM observations. The relationship between fiber composition and dimensional stability follows a curvilinear trend, indicating an optimal fiber content at 20%, beyond which the reduction in shrinkage becomes less effective.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Serat kelapa; Biokomposit Polypropylene; Penyusutan; ASTM D955, Coconut fiber; Polypropylene biocomposite; Shrinkage; ASTM D955
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TS Manufactures T Technology > TS Manufactures > TS170 New products. Product Development
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Ryan Rachmadi Triatmaja
Date Deposited:	04 Feb 2026 07:00
Last Modified:	04 Feb 2026 07:00
URI:	http://repository.its.ac.id/id/eprint/132052

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