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"The electronic industry’s need for semiconductor material is increasing each year due to technology’s rapid development. Semiconductor material has an electric conductivity of approximately 10-8-103 S/cm, and it is used as an important component in electronic devices. Semiconductor material is generally made of plastic modified with conductive filler. The problem with using semiconductor material is that the discarded components can be plastic waste that requires significant time to degrade; therefore, the synthesis of semiconductor material from natural substances must be observed. One of these natural substances is nata de coco fiber modified with a conductive filler. The impregnation method is used in the synthesis of the nata de coco fiber composite. The fillers used in this study are ZnO and silica, and the size of the filler particle and the concentration of the filler suspension are used as variations. From the SEM-EDX results, it can be seen that the filler is successfully deposited on the nata de coco fiber. Silica filler gives a higher conductivity than ZnO filler because of its lower energy band gap. The highest conductivity result is obtained from the composite impregnated in a 0.3-0.4 mm particle diameter of filler with 3% w/v suspension concentration for three days, producing the conductivity result of 6.95×10-6 S/cm for ZnO filler and 10.1×10-6 S/cm for silica filler, or about 16 times higher than the conductivity of nata de coco fiber."

"Kebutuhan material semikonduktor untuk industri elektronika di Indonesia semakin meningkat ditandai dengan tren sumbangan dari industri elektronika terhadap ekspor industri yang terus meningkat setiap tahunnya. Namun demikian, ternyata Indonesia masih mengimpor bahan baku material semikonduktor. Permasalahan lain dari penggunaan material semikonduktor adalah komponen semikonduktor yang tidak dipergunakan lagi akan dibuang menjadi sampah plastik yang sulit diuraikan. Oleh karena itu pembuatan material semikonduktor yang berasal dari bahan alam dapat menjadi solusi dari permasalahan tersebut. Salah satu material yang dapat digunakan untuk material semikonduktor adalah komposit serat nata de coco dengan filler silika. Metode yang digunakan untuk membuat komposit serat nata de coco dengan filler silika adalah metode perendaman dengan variasi ukuran partikel silika, konsentrasi suspensi silika, dan lama perendaman. Dari hasil SEM-EDX dapat diketahui bahwa silika telah terdeposisi pada serat. Hasil uji konduktivitas listrik menunjukkan bahwa semua komposit yang dihasilkan bersifat semikonduktor. Nilai konduktivitas tertinggi sebesar 1,21 x 10-5 S/cm atau kurang lebih 48 kali konduktivitas serat nata de coco polos dihasilkan dari komposit serat nata de coco/silika dengan ukuran partikel 370 nm, konsentrasi suspensi 6%w/v, dan lama perendaman 3 hari.

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The needs of semiconductor material for the electronic industry in Indonesia is increasing each year according to the postive trend of export from electronic industry in Indonesia. In contrast, the fact that Indonesia actually still import the raw material for the semiconductor material that is used in electronic industry is ironic. Another problem comes from the use of semiconductor material is that the unused semiconductor component can be a plastic waste that needs a long time to be degraded. As a solution for this condition, the making of semiconductor material from natural substances is needed. One of the natural substances that can be used as the semiconductor material is nata de coco fiber composite with silica filler. The submerged method is used in the production of nata de coco fiber composite with silica filler by using the immersion time, concentration of nanosilica suspension, and the size of silica particle as the variations. From the SEM-EDX results, it can be seen that silica particle is deposited on the nata de coco fiber. From the conductivity characterization, it is known that all of the composite can be categorized as semiconductor material. The highest electric conductivity, 1,21 x 10-5 S/cm or about 48 times higher than the conductivity of nata de coco fiber, is reached from the nata de coco fiber composite with silica filler that has a particle diameter of 370 nm, and submerged in silica suspension with concentration 6% w/v for 3 days."

"ABSTRAKDewasa ini, material komposit banyak digunakan dalam berbagai aplikasi karena memiliki sifat mekanik yang lebih bagus dari pada logam, memiliki kekuatan pembentukan yang tinggi, memiliki ketahanan yang baik, memiliki kekuatan jenis dan kekakuan jenis (modulus Young) yang lebih tinggi daripada logam. Namun demikian, material komposit rentan terhadap degradasi termal pada temperatur tinggi. Oleh karena itu, penelitian dalam tesis ini bertujuan untuk meningkatkan ketahan termal dan sifat mampu bakar material komposit dengan mencampurkan zat tahan api berbasis halogen jenis brominated bisphenol A ke dalam material komposit serat karbon dengan dua variasi densitas serat, yaitu 200 dan 240 gr/m2. Penelitian yang dilakukan berbasis pada eksperimen skala laboratorium menggunakan kalorimeter kerucut. Fenomena pembakaran yang terjadi adalah piloted ignition dengan fluks kalor pembakaran dibatasi sampai dengan 25 kW/m2. Hasil penelitian menunjukkan bahwa sampel komposit serat karbon terbakar karena vaporisasi dari resinnya, sedangkan serat karbonnya sendiri hanya mengalami pengarangan (charring). Eksperimen pada fluks kalor 21,12 kW/m2, menunjukkan bahwa kebeadaan kandungan brominated bisphenol A di dalam sampel komposit serat karbon mampu menekan puncak laju produksi kalor dari sekitar 125 kW/m2 menjadi hanya sekitar 80 kW/m2. Hasil penelitian juga menunjukkan bahwa kandungan zat tahan api (fire retardant) mampu menunda waktu penyalaan api pembakaran dan memberikan ketahana termal yang lebih baik kepada material komposit

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ABSTRACTNowadays, carbon fiber reinforced epoxy-acrylate composite (CFRE) is used in various applications such as in aircraft and industrial applications including pressure vessels, civil engineering/construction-related uses, ship manufacturing, and automobile. That is because of its characteristics such as lightweight and high-strength. Nevertheless CFRE is very easy to be burned after preheating in a low heat flux, moreover with the presence of an external energy source. Hence, this study aimed to find out the effects of brominated bisphenol A as fire retardant agent on fire retardancy of CFRE using cone calorimeter with a spark igniter as a trigger to represent an amount of external energy source. Carbon fibers used in this study have density of 200 gr/m2 and 240 gr/m2. The parameter studied in this research includes density of carbon fiber, time to ignition, heat release rate and density of smoke production. In this initial work, the heat flux was limited up to 25 kW/m2 with piloted ignition. The measured temperatures of CFRE’s ignition range from 450oC to 575oC at atmospheric pressure. The initial result shows that the ignition of CFRE is strongly depend on the density of carbon fiber, the existing of an external energy source and the condition of gas mixture. For the density of of 200 gr/m2, CFRE starts to ignite under heat flux of 14.2 kW/m2 with peak heat release rate of 163.4 kW/m2. While for the density of of 240 gr/m2, CFRE starts to ignite under heat flux of 16.7 kW/m2 with peak heat release rate of 98 kW/m2. Combustion mechanism of CFRE started when a spark igniter is turned on after preheating at a certain sufficient heat flux, causing a flaming condition on the surface of CFRE. Next, vaporization of its resin causing a sustain flaming condition until reaching a decay period. When it burned, the resin vapor is forced out of the fiber pores, causing the material to swell and increased its volume. The effects of brominated bisphenol A as fire retardant agent in the CFRE give a significant impact to fire retardancy of the CFRE, especially in time to ignition and heat release rate aspect."