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"The traditional fiber reinforced composite (FRC) contains bishpenol A glycidyl methacrylate (bis-GMA) in the resin matrix, which is thought to have some disadvantages. This research aimed at replacing bis-GMA with another monomer-urethane dimethacrylate (UED-MA), with the desired properties for dental use still retained. Four groups were prepared with light-curing (n = 30), one Control group with a bis-GMA-based resin matrix and three experimental groups with UEDMA-based matrices (Exper 1, Exper 2 and Exper 3 with a varying UEDMA weight percentage). Specimens were stored in dry conditions for 24 h or in deionized water for 1, 3, 6 or 12 months prior to the tests. Water sorption (n = 6), Vicker's hardness (n = 6) and flexural properties (n = 6) after each storage time were investigated.Scanning electron microscopy (SEM) images were taken at the fracture sites after 3-point bending. All the results were statistically analyzed (α = 0.05). The Exper 1 group exhibited the lowest weight increase after water storage among the experimental groups. As for dry conditions, 1- and 6-month storage, different resin matrix compositions made no significant difference to hardness, while for 3- and 12- month storage, "Control" possessed the highest hardness. The Control group's strength and modulus, Exper 1 and Exper 2's modulus were stable during water storage. Compared to other experimental groups, Exper 1 had the highest strength and modulus values with most of the storage times. SEM images showed relatively good adhesion between the fiber and the matrix. With all the tested properties considered, the Exper 1 group had superior performance among all the three experimental groups."

"Dewasa ini, penggunaan material komposit polimer berpenguat serat karbon (carbon fiber reinforced polymer, CFRP) dalam berbagai bidang semakin populer dan berkembang. Hal ini dikarenakan nilai ekonomis serta sifat mekanik yang baik yang mampu dihasilkan oleh material komposit tersebut. Ada banyak faktor yang dapat mempengaruhi sifat/ karakteristik material komposit CFRP, diantaranya adalah arah orientasi serat karbon serta perlakuan panas. Penelitian ini membahas mengenai pengaruh orientasi serat anyam karbon dan temperatur perlakuan panas terhadap sifat mekanik material komposit laminate bermatrik polimer. Komposit CFRP dimanufaktur dengan menggunakan metode hand lay-up dengan variasi orientasi [00 or 900]s, [00 or 900]/[±450] dan [±450]s. Spesimen komposit selanjutnya dilakukan pemanasan pada variasi temperatur lalu dilakukan pengujian berupa pengujian tarik, tekuk, impak, dan FTIR. Kekuatan tarik tertinggi diperoleh pada orientasi [0o or 90o]s dengan pemanasan 200 oC selama 3 jam, kekuatan tekuk tertinggi diperoleh pada orientasi [0o or 90o]s dengan pemanasan 100 oC selama 3 jam, serta energi impak tertinggi diperoleh pada orientasi [0o or 90o]s dengan pemanasan 100 oC selama 3 jam. Hasil pengujian FTIR menunujukkan gugus fungsi polimer yang dihasilkan dari Unsaturated Polyester Resin setelah pemanasan pada temperature curing adalah ikatan C=O (ester) dan ikatan ikatan C=C (cincin aromatik).

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Nowadays, the use of carbon fiber reinforced polymer (CFRP) composite in various fields is getting more popular and fast growing. This is due to the economic value and good mechanical properties of the composite materials can produce. There are many factors that affect the characteristics of CFRP composite materials, including orientation of the carbon fiber and heat treatment. This study discusses the effect of the orientation of carbon woven fibers and the temperature of heat treatment on the mechanical properties of polymer matrix composite laminates. CFRP composites were manufactured using the hand lay-up method with various orientations [0 or 90o]s, [0 or 90o] / [± 45o] and [± 45o]s. The composite specimens were then heating at various temperatures. Characteristics of the composites were examined in the form of tensile test, bending test, impact test and FTIR analysis. The highest tensile strength was obtained at orientation [0o or 90o]s followed by heating at 200 oC for 3 hours. The highest bending strength was obtained at orientation [0o or 90o]s followed by heating at 100 oC for 3 hours, whereas the highest impact energy was obtained at orientation [0o or 90o]s followed by heating at 100 oC for 3 hours. FTIR test showed that the polymer functional groups from unsaturated polyester resin after heating at curing temperature are C=O bonds (ester) and C=C bonds (aromatic rings)."

"The aim of this study was to examine defect depths and volumes at the resin composite-dentin (R/D) interface after air polishing with different particles and spray angles. Samples were 54 dentin specimens that were formed in saucer-shaped cavities filled with resin composite. Each specimen was air polished with either sodium bicarbonate (NaHCO3) or one of two glycine (Gly) powders. The air polisher was set at angles of 90° to the interface and at 45° to the interface from both the dentin and resin composite sides. Air polishing with Gly powder produced defects with less depth and volume than NaHCO3 powder (p < 0.05). Air polishing with a spray angle of 45° to the interface from the resin composite side produced fewer defects (p < 0.05) than polishing from the dentin side. Air polishing to the R/D interface from the resin composite side produced fewer defects to the interface because the hardness of the resin composite was higher than that of dentin. "

"Serat tandan kosong kelapa sawit (TKKS) merupakan limbah tanaman kelapa sawit yang berlimpah di Indonesia. Serat ini merupakan serat alam yang dapat digunakan sebagai penguat di dalam komposit polimer, namun masalah utama dari serat alam adalah hidrofilik sedangkan polimer propilena sebagai matriks adalah hidrofobik. Perlakuan kimia alkalinisasi merupakan perlakuan kimia yang dapat meningkatkan kompatibilitas serat dan sifat mekanis yang dihasilkan pada pembentukan komposit. Metode pengujian yang dilakukan untuk mengetahui bentuk serat di dalam struktur komposit menggunakan Scanning Electron Microscope (SEM) dan kemudian diolah menggunakan perangkat lunak ImageJ. Alkalinisasi dapat meningkatkan distribusi serat di dalam komposit dinyatakan dalam bentuk rasio distribusi hingga 0,42 pada serat 50 mesh dan 0,40 pada serat 100 mesh. Selain itu, kompatibilitas serat juga meningkat ditunjukkan oleh selisih tegangan permukaan yang menurun hingga 1.60 mN/m. Hasil pengujian dibentuk dalam purwa-rupa aplikasi sebagai contoh manfaat mengetahui pengaruh secara kuantitatif yaitu dapat memprediksi sifat-sifat yang dihasilkan.

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Oil Palm Empty Fruit Bunch (OPEFB) Fiber is an abundant waste in Indonesia. This fiber is a natural fiber that can be used for reinforcement in polymer-based composites, but natural fiber is hydrophilic while polypropylene as a matrix are hydrophobic. Alkalinization is a type of chemical treatment that can improve fiber compatibility and mechanical properties resulting in the formation of composites. Testing methods conducted to determine the shape of the fibers in the composite structure are using Scanning Electron Microscope (SEM) and then processed using ImageJ software. Alkalinization can increase fiber distribution in composites expressed in the form of distribution ratio up to 0,42 for 50 mesh and 0,40 for 100 mesh. In addition, the compatibility of the fiber also increases, indicated by the differences in surface tension decreased to 1,60 mN/m. The test results are formed in the prototype of application that can be used for an example of the benefits of knowing the influence quantitatively so that can be able to predict the resulting properties.

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"The purpose of this study was to investigate the effect of different staining solutions on the color coordinates of indirect light-cured resin composites. 112 discs were made using four indirect composites, Signum+/ Haraeus-Kulzer, Sinfony/3M-Espe, GC Gradia/GC, Ena HRi/Micerium, and divided into four groups which immersed in tea, coffee, chocolate and distilled water, at 37°C, for 4 weeks, was measured according to CIELAB system and AL*, Aa*, Ab and AE* values were calculated for all immersion periods. The effect of time, solution and material on primary and secondary color coordinates was estimated using two-way repeated ANOV As and pairwise comparisons, at a = 0.05. The results showed that coffee strongly affected all the materials (p < 0.05), followed by tea and chocolate. Sinfony presented the highest color change (p < 0.05), due to changes in b* and L* coordinates. Color coordinates were affected differently by material type and solution. In conclusion, this study showed that the color of indirect resin composites was affected by all three examined factors (immersion time, staining solution and material type), in a clinically appreciable level (AE* > 2.7 U) even from the first week, and in an unacceptable level (AE* > 5.5 U) in the second, third and fourth week, depending on the staining solution and the material. "

"Kebutuhan akan peralatan-peralatan kepolisian selalu dibutuhkan dalam jumlah anggaran yang besar. Kebutuhan tersebut meliputi berbagai macam peralatan seperti peralatan defensif yaitu helm anti peluru. Oleh karena itu dibutuhkan pengembangan helm anti peluru dalam negeri yang memiliki kekuatan serupa dengan produk impor tetapi tetap ringan dan baik untuk mobilitas pemakainya. Untuk itu dilakukan penelitian ini menggunakan komposit yang terdiri dari multi reinforcement. Multi reinforcement yang digunakan pada penelitian ini adalah serat kenaf sebagai serat alam dan serat karbon sebagai serat sintetis. Penggunaan serat kenaf dilakukan karena serat kenaf selain mudah ditemukan dan murah, ternyata juga memiliki sifat mekanik yang baik. Metode pembuatan dilakukan dengan metode cetakan terbuka yaitu metode hand layup. Jumlah lembaran kenaf sudah ditentukan sementara jumlah lembaran serat karbon akan divariasikan. Serat kenaf akan digunakan 4 lembar pada setiap produknya. Variasi lembaran serat karbon dibagi menjadi tiga variasi yaitu, 3 lembar serat karbon, 6 lembar serat karbon, dan 9 lembar serat karbon. Pengujian yang dilakukan adalah uji balistik tipe I sesuai standar National Institute of Justice 0101.3. Pengujian kekerasan dan flexural strength akan dilakukan untuk mengetahui sifat mekanik produk komposit serta efek penambahan serat karbon. Pengujian menggunakan SEM digunakan untuk mengetahui morfologi patahan dan mekanisme yang terjadi pada produk komposit. Produk komposit yang terdiri dari 9 lembar serat karbon dan 4 lembar serat kenaf mampu menahan laju peluru. Terjadi kerusakan serat tetapi hanya berada di bagian luar produk komposit.

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The needs of police gears are always needed in large scale budget. That needs cover many gears start from the offensive ones until the defensive ones like ballistic helmet. Hence Indonesia need the development of ballistic helmet that has the mechanical properties as good as the imported ones but also lightweight and comfort to use. This research uses multi reinforcement composite. Kenaf fiber used as a natural fiber based reinforcement, meanwhile carbon fiber used as a synthetic fiber based reinforcement. Those two reinforcements will be combined to create a composite. Kenaf fiber will be used because of its availability in Indonesia, and surprisingly has good mechanical properties. The method of fabrication used in this research is by using open mold and hand layup technique. The number of kenaf fiber ply will be fixed by 4 plies. The number of carbon fiber will be varied as is 3 plies, 6 plies, and 9 plies. Test used in this research is Level I ballistic testing National Institute of Justice 0101.3. Hardness and flexural strength will be conducted to find out the mechanical properties and also effect of addition of carbon fiber plies. Another test using SEM also done in this research to examine the morphology of the area of impact. In the end the product constructed by 9 plies of carbon fiber and 4 plies of kenaf fiber is capable to hold the bullet. That product is still damaged but only at the outside and the bullet does not penetrate through the product.

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"ABSTRAKNatural fiber reinforced polymer composites are widely developed because of their relative low price and eco-friendly. One of natural fiber sourches is pandanus tectorius leaf. This study aimed to determine the effect of variations in fiber volume fraction on tensile strength, impact strength, bending strength and morphological on sea pandanus fibers- polypropylene composites.Tensile test spesimen refer to ASTMD 638, impact test spesimen refes to ASTMD 5942-96, bending test spesimen refer to ASTMD 790 -02. The increasing of the volume fraction increased the tensile strength and impact strength. The tensile test results showed the highest tensile strength results for composites with a volume fraction of 35% was 25.82 MPa. The impact test results showed that the highest impact strength was obtained in the 35 % volume fraction of 0.0062 Joule/mm2. The bending test results showed that the highest bending strength was obtained in the 20% volume fraction of 24.96 MPa. Based on SEM test results, there were voids, cracks, fibers pull out on the composite."

"ABSTRAKPada penelitian ini telah disintesis material komposit berbasis logam atau metal matrix composite MMC . Komposisi Al/SiC, dan AlCu/SiC sebagai material komposit hasil peleburan dan pemadatan solidifikasi dilakukan proses lebih lanjut dengan menggunakan penekanan panas 5 ton hot press pada temperatur 300o C. Analisis data XRD merupakan fasa tunggal Al dengan sistem kristal FCC yang memiliki kontanta kisi 4.0560 dengan bidang kristal pada intensitas terbesar 111 , 002 , 022 , 113 , 222 dan telah terjadi perubahan arah bidang kristal secara signifikan akibat penekanan panas hot press dan pendinginan cepat arah sejajar yaitu pada bidang 111 dan 002 dan arah tegak lurus atau melintang pada bidang kristal 022 . Hasil foto SEM pada permukaan morfologi padatan Al, Al/SiC 4 berat, dan AlCu/SiC 4 , permukaan pada arah sejajar tampak lebih merata dan lebih homogen secara bentuk struktur. Sedangkan permukaan pada arah tegak lurus atau penampang melintang sampel memiliki bentuk struktur yang berbeda dan membentuk arah memanjang tegak lurus terhadap arah penekanan pada proses penekanan panas. Nilai kekerasan Vickers HV secara keseluruhan sampel komposit AlCu/SiC hasil penekanan panas hot press lebih besar dibandingkan dengan Al/SiC untuk pendinginan lambat dan cepat. Juga termasuk dimana posisi permukaan melintang atau tegak lurus perpendicular memiliki nilai HV yang lebih besar dibandingkan dengan permukaan sejajar in-plan . Laju korosi mulai dari yang terbesar sampai terkecil adalah Al 1,8986. 10-3 , Al/SiC 1,2509. 10-3 mm/tahun , AlCu 1,1716. 10-3 mm/tahun , AlCu/SiC 1,1144. 10-3 mm/tahun , dan Al2024 1,0648. 10-3 mm/tahun . Hal ini menunjukkan bahwa ketahanan korosi diperoleh pada sampel AlCu dan AlCu/SiC.

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ABSTRACT Hybrid aluminum metal or metal matrix composite MMC have been synthesized and characterized. The composition of Al SiC, and AlCu SiC as a composite material melting and solidification solidification process is carried further by using heat suppression 5 tons hot press at a temperature of 300oC. Analysis of x ray Diffraction XRD show that the spectrum indicates a single phase Al with crystal system face center cubic FCC which constants lattice 4.0560 and the crystal orientations are 111 , 002 , 022 , 113 , and 222 . The direction of the crystal orientations were influenced by compression heat hot press and fast cooling. It can be seen from the direction 111 and 002 . The SEM images on the surface morphology of solids Al, Al SiC 4 by weight, and AlCu SiC 4 , the surface in a direction parallel seems more equitable and more homogen in the form of the structure. While, the surface in the direction perpendicular or cross sectional sample has a form different structures and forming a longitudinal direction perpendicular to the direction of the emphasis on hot press process. The Hardness Vickers value HV overall composite sample AlCu SiC heat suppression results hot press is greater than the Al SiC for slow and fast cooling. Also included where the surface position of transverse or perpendicular perpendicular has a HV value greater than the surface parallel in plan . The corrosion rate starting from the largest to smallest is Al 1.8986 x10 3 mm y , Al SiC 1.2509 x 10 3 mm y , AlCu 1.1716 x 10 3 mm y , AlCu SiC 1.1144 x 10 3 mm y , and Al2024 1.0648 x 10 3 mm y . These indicated that the corrosion resistance obtained on the sample AlCu and AlCu SiC."

"Keramik merupakan material yang memiliki kekerasan yang sangat tinggi dan getas (getas). Untuk meningkatkan ketangguhan keramik,maka dikembangkan CMCs (Ceramic Matix Composite). Salah satu metode untuk memproduksi CMCs adalah dengan melalui proses DIMOX, yaitu cara mengoksida leburan logam dalam atmosfer dapur. Karakteristik produk CMCs yang dihasilkan melalui metode ini dipengaruhi oleh variabel waktu tahan, temperatur, dopant serta atmosfer tempat berlangsungnya proses pembentukan komposit.Penelitian ini bertujuan untuk mempelajari proses pembuatan CMCs C/Al melalui proses DIMOX dan pengaruh waktu tahan terhadap karakteristik produk CMCs yang dihasilkan. Pada penelitian ini dilakukan variasi waktu tahan, dimana digunakan waktu tahan 8, 10, 15, 20, 24 jam pada temperatur 1100 °C. Karakterisasi terhadap produk komposit yang dihasilkan dilakukan melalui pengujian densitas dan porositas, pengujian kekerasan mikro, pengamatan struktur mikro dengan menggunakan mikroskop optik dan SEM serta pegujian komposisi kimia.Infiltrasi prabentuk C oleh leburan Al dapat terjadi secara optimum pada waktu tahan 24 jam. Produk CMCs dengan densitas yang tertinggi, sebesar 3,17 gram/cm3, diperoleh pada waktu tahan 24 jam. Porositas produk CMCs cenderung meningkat seiring dengan penambahan waktu tahan. Produk CMCs dengan kekerasan mikro tertinggi, sebesar 14300 Mpa pada waktu tahan 24 jam. Laju keausan produk CMCs tertinggi, sebesar 2.03x10^-6 m3/mm terdapat pada waktu tahan 24 jam. Partikel C terdistribusi cukup merata pada produk CMC C/Al. Pada produk CMCs pada daerah sekitar partikel C dapat ditemui adanya Al, spinel (MgAl2O4), Al2O3.

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Ceramic is material which possed a very high hardness and brittle. To increase its toughness, then CMCs is developed. One of method to produce CMCs is DIMOX process. DIMOX involved oxidized molten metal in furnace atmosphere. The charateristic of CMCs product is effected by variables processes such as : holding time, temperature, dopant and the atmosphere where the process is held.

The aim of this research is to study the making process of CMCs C/Al itself through DIMOX process and the effect of holding time with variable : 8, 10, 15, 20, 24 hours at 1100 °C. The characterizations of CMCs are examined by density, porosity, hardness, wear and microstructure analysis.

It is found that Infiltration preform graphite by molten Al is optimal at the holding time of 24 hours. This variable produced highest density at 3,17 gr/cm3. The porosity of CMCs product tends to increase with increment of holding time. The highest porosity that obtained at holding time of 24 hours is 6.15 %. The highest hardness that can be obtained at holding time of 24 hours is 14300 MPa. This variable also produced the lowest wear rate, it is 2.03x10^-6 mm3/mm. Distribution of graphite particles spread over C / Al composite product and around graphite particles can be found Al, spinel ( MgAl2O4 ), and Al2O3. Based on EDS analysis, there are three phase in systems of CMCs product, they are C/Al, Al2O3/Al, and C/Al2O3."

"Komposit hijau merupakan komposit yang salah satu bahan penyusunnya terdiri dari bahan ramah lingkungan. Salah satunya menggunakan serat alam sebagai penguat. Salah satu jenis serat alam yang sering digunakan adalah kenaf. Penelitian ini bertujuan untuk mendapatkan pemodelan sifat elastis komposit berpenguat serat kenaf Sumberejo dengan berbagai variasi matriks polimer. Variasi matriks polimer yang digunakan adalah polipropilena, poli asam laktat, epoksi dan poliester. Pemodelan komposit ini menggunakan teori Rule of mixture dan teori lamina yaitu specially orthotropic. Hasil penelitian menunjukkan bahwa komposit epoksi/ serat kenaf Sumberejo memiliki regangan yang lebih rendah dibandingkan dengan tiga matriks polimer lainnya yaitu sebesar 0,61% untuk longitudinal dan 0,90% untuk transversal. Namun, komposit epoksi/ serat kenaf Sumberejo memiliki modulus elastisitas yang lebih tinggi dibandingkan dengan tiga matriks polimer lainnya yaitu sebesar 9174 MPa untuk longitudinal dan 6639 MPa untuk transversal. Pemodelan sifat elastis komposit pada penelitian ini menunjukkan bahwa komposit epoksi/ serat kenaf Sumberejo memliki sifat mekanik terbaik dibandingkan komposit berpenguat serat kenaf dengan matriks tiga polimer lainnya.

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Green composite is a composite of which one of the constituent materials consists of environmentally friendly materials. One of them uses natural fiber as a reinforcement. One type of natural fiber that is often used is kenaf. This study aimed to obtain an elastic property model of Sumberejo kenaf fiber reinforced composites with a variety of polymer matrix variations. Polymer matrix variations used were polypropylene, polylactic acid, epoxy, and polyester. Rule of mixture and specially orthotropic lamina theories were applied to these composite models. The results of the study indicated that the epoxy/ Sumberejo kenaf fiber composite had lower strain compared to other three polymer matrices with the result of 0,61% for the longitudinal and 0,90% for the transverse. However, the epoxy/ Sumberejo kenaf fiber composite had higher elasticity modulus compared to the other three polymer matrices with the result of 9174 MPa and 6639 MPa for longitudinal and transverse directions respectively. The elastic property modeling from this study indicated that epoxy reinforced Sumberejo kenaf fiber composites had the best mechanical properties compared to the other three polymers reinforced Sumberejo kenaf fiber composites."