Studi Eksperimental Pengaruh Variasi Komposisi Serat Sabut Kelapa Tanpa Alkalisasi pada Biokomposit Berbasis Polypropylene terhadap Kekuatan Tarik dan Impak dengan Proses Cetakan Injeksi

Rahayu, Risma (2026) Studi Eksperimental Pengaruh Variasi Komposisi Serat Sabut Kelapa Tanpa Alkalisasi pada Biokomposit Berbasis Polypropylene terhadap Kekuatan Tarik dan Impak dengan Proses Cetakan Injeksi. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Perkembangan teknologi material menuntut inovasi yang tidak hanya unggul secara mekanik, tetapi juga ramah lingkungan dan berkelanjutan. Biokomposit berbasis serat sabut kelapa dengan matriks polypropylene (PP salah satu alternatif material yang berpotensi menggantikan komposit berbasis serat sintetis maupun logam konvensional, terutama untuk aplikasi komponen otomotif dan produk teknik.Penelitian ini menganalisis pengaruh fraksi volume serat (10%, 20%, dan 30%) terhadap kekuatan tarik (ASTM D638-03) dan impak (ASTM D256) biokomposit hasil injection molding. Karakterisasi sifat mekanik diuji melalui standarisasi ASTM D638-03 untuk kekuatan tarik, serta ASTM D256 untuk kekuatan impak. Evaluasi ANOVA (α=0,05) mengonfirmasi variasi fraksi serat berpengaruh signifikan terhadap kedua sifat mekanik dengan tren bertolak belakang.Hasil penelitian mengonfirmasi bahwa variasi fraksi massa serat berpengaruh signifikan terhadap kedua sifat mekanik dengan tren fisis yang saling bertolak belakang.Kekuatan tarik tertinggi dicapai oleh variasi fraksi 10% sebesar 39,948 MPa dan secara konsisten menurun hingga nilai 37,376 MPa pada fraksi 30%, dimana seluruh nilai tersebut belum mampu melampaui kekuatan polypropylene murni. Sebaliknya, ketangguhan impak tertinggi berhasil diraih pada fraksi maksimum 30% sebesar 2,431 kJ/m² dan mampu melampaui performa polypropylene murni. Karakterisasi SEM (100x) menunjukkan korelasi positif antara peningkatan fraksi serat dan void. Penurunan kekuatan tarik dipicu kenaikan void penampang patahan sebesar 11,288% akibat aglomerasi serat (fiber agglomeration) yang mereduksi penampang efektif dan memicu retak matriks (matrix cracking). Sebaliknya, kenaikan kekuatan impak didukung oleh void penampang sebesar 15,581% dimana porositas tersebut bertindak sebagai peredam mikro untuk memecah konsentrasi tegangan kejut bersamaan dengan mekanisme serat tercabut (fiber pull-out).
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Developments in material technology demand innovations that are not only mechanically superior, but also environmentally friendly and sustainable. Coconut fiber-based biocomposites with a polypropylene (PP) matrix serve as a potential material alternative to replace synthetic fiber-based composites and conventional metals, particularly for automotive components and engineering product applications. This study analyzes the effect of fiber volume fractions (10%, 20%, and 30%) on the tensile strength (ASTM D638-03) and impact strength (ASTM D256) of injection-molded biocomposites. Mechanical properties characterization was evaluated through standardized testing protocols using ASTM D638-03 for tensile strength and ASTM D256 for impact strength. ANOVA evaluation (α=0.05) confirmed that variations in fiber volume fraction significantly affect both mechanical properties, displaying opposing physical trends. The highest tensile strength was achieved by the 10% volume fraction variation at 39.948 MPa, consistently decreasing to 37.376 MPa at the 30% volume fraction, where none of these values surpassed the strength of pure polypropylene. Conversely, the highest impact toughness was successfully obtained at the maximum 30% volume fraction at 2.431 kJ/m², surpassing the performance of pure polypropylene. SEM characterization (100x) demonstrated a positive correlation between increasing fiber fraction and void formation. The reduction in tensile strength was triggered by an increase in fracture cross-sectional void area to 11.288%, resulting from fiber agglomeration which reduced the effective cross-sectional area and induced matrix cracking. On the other hand, the increase in impact strength was supported by a cross-sectional void area of 15.581% ,wherein such fine porosity effectively acted as a micro-damper to disperse shock stress concentrations in conjunction with the fiber pull-out mechanism.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	ASTM D256, ASTM D638-03, Biokomposit, Fraksi volume, Injection Molding, Impak, Polypropylene, Serat sabut kelapa, Tensile, ASTM D256, ASTM D638-03, Biocomposite, Volume fraction, Injection Molding, Impact, Polypropylene, Coconut coir fiber, Tensile
Subjects:	T Technology > T Technology (General) > TA404 Materials--Biodegradation T Technology > TS Manufactures > TS176 Manufacturing engineering. Process engineering (Including manufacturing planning, production planning)
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Risma Rahayu
Date Deposited:	04 Aug 2026 04:27
Last Modified:	04 Aug 2026 04:27
URI:	http://repository.its.ac.id/id/eprint/143042

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