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"Penelitian mengenai pengaruh penambahan bahan pengisi atau filler berupa bahan pati dan bahan kaolin terhadap peningkatan kekuatan rekat Polivinil Asetat (PVAc) telah dilakukan. Penambahan filler dilakukan dengan dua kondisi yang berbeda yakni filler tanpa pemanasan dan filler yang melibatkan pemanasan. Pada setiap kondisi, dilakukan variasi komposisi filler yang ditambahkan ke PVAc antara lain 1%, 3% dan 5%. Terkhusus untuk kondisi filler dengan pemanasan, filler dilarutkan dengan akuades dengan temperatur 70-80 °C serta kecepatan pengadukan 300 rpm selama 60 menit. Pencampuran PVAc dengan berbagai variasi komposisi filler pati dan kaolin dilakukan dengan kecepatan agitasi 300 rpm selama 60 menit. Pengujian kekuatan rekat sampel dilakukan berdasarkan ASTM D905-03 tentang uji kuat geser dan diperoleh hasil kekuatan rekat PVAc meningkat seiring penambahan filler pati dan kaolin hingga batas komposisi 3%, lalu untuk komposisi filler sebanyak 5% kekatan rekat yang dihasilkan menurun. Evaluasi beberapa parameter juga dilakukan dalam penelitian ini yang meliputi, pengukuran pH, densitas, viskositas, dan kandungan padatan (solid content). Beberapa metode karakterisasi juga dilakukan yakni FTIR, SEM dan PSA. Spektrum FTIR menunjukkan adanya kemiripan antara PVAc murni dan PVAc yang dilakukan penambahan filler, dengan adanya sedikit pergesaran serta penambahan spektrum dan intensitas puncak. Hasil SEM menunjukkan morfologi partikel filler pati dan kaolin yang tersebar dan mengisi pori matriks PVAc. Seiring penambahan komposisi filler, hasil PSA menunjukkan peningkatan ukuran rata-rata diameter partikel dari 2,12 μm hingga 6,29 μm.

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Polyvinyl Acetate (PVAc) has been studied to find out what happens when fillers like starch and kaolin are added to make the glue stronger. Filler were added in two different ways: with or without heat. In each condition, different amounts of filler were mixed into the PVAc, such as 1%, 3%, and 5%. For the filler condition with heating, the filler was mixed with distilled water at 70–80°C and 300 rpm for 60 minutes. The PVAc was mixed with different combinations of starch and kaolin filler at a speed of 300 rpm for 60 minutes. The shear strength test of the samples was carried out according to ASTM D905-03, and the results showed that adding starch and kaolin fillers increased the adhesive strength of PVAc up to a composition limit of 3%. After that, the adhesive strength actually went down at a composition limit of 5%. Several parameters, such as pH, density, viscosity, and solid content, were also measured as part of this study. FTIR, SEM, and PSA were also used to figure out what the material was like. With a small shift and spectrum addition, the FTIR spectrum shows that pure PVAc and PVAc with filler added are generally similar. The SEM results showed the shape of the starch and kaolin filler particles, which were scattered and filled the holes in the PVAc matrix. When more filler is added to PVAc, the PSA results show that the average particle size was increased from 2,12 µm to 6,29 µm. "

"Telah dilakukan penelitian untuk melihat pengaruh dari penambahan agen ikatan silang terhadap ketahanan air perekat Polivinil Asetat (PVAc). Proses pencampuran agen ikatan silang dengan perekat Polivinil Asetat dilakukan dalam jangka waktu 30 menit hingga 1 jam pada suhu ruang (25-30°C). Agen ikatan silang yang ditambahkan dalam proses ini antara lain aluminium klorida, glioksal, dan boraks dengan konsentrasi sebanyak 1, 3, dan 5 wt%. Melalui uji ketahanan terhadap air, diperoleh jenis agen ikatan silang glioksal dengan komposisi 5 wt% yang paling tahan terhadap air dengan kuat tarik perekat sebesar 98.000 N/m2 setelah direndam selama 8 jam. Selain itu, didukung dengan penambahan densitas dan viskositas yaitu 1,45 gr/cc dan 17,78 mPa.s. Nilai pH yang diperoleh dari pencampuran glioksal dengan perekat polivinil asetat tidak mengalami perubahan signifikan karena kedua bahan sama-sama memiliki pH asam. Selain itu, tidak terjadi perubahan yang signifikan pada hasil FTIR karena ikatan silang terbentuk secara fisik, namun keberadaan glioksal dapat dilihat dengan adanya penurunan gugus fungsi C-O pada PVAc yang sudah ditambahkan glioksal. Selain itu, PVAc murni yang digunakan pada pencampuran dengan agen ikatan silang sudah melewati reaksi polimerisasi yang sempurna dengan nilai kandungan padatan 50,66%.

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A study has been achieved to see the effect of the addition of a cross-linking agent on the water resistance of polyvinyl acetate (PVAc) adhesives. The mixing process of crosslinking agent with Polyvinyl Acetate adhesive is carried out within a period of 30 minutes to 1 hour at room temperature (25-30°C). Crosslinking agents added in this process include aluminium chloride, glyoxal, and borax with concentrations of 1, 3, and 5 wt%. Through the water resistance test, it was found that the type of glyoxal crosslinking agent with a composition of 5 wt% was the most resistant to water with a strong adhesive pull of 98,000 N/𝑚2 after being soaked for 8 hours. It is supported by the addition of density and viscosity, namely 1,45 gr/cc and 17.78 mPa.s. The pH value does not change significantly because both materials have an acidic pH. There was no significant change in FTIR results because crosslinking was formed physically, but the presence of glyoxal can be seen by a decrease in the C-O functional group in PVAc that has been added glyoxal. The pure PVAc used with cross-linked agents has gone through a complete polymerization reaction with a solids content value of 50.66%."

"Polivinil alkohol (PVA) sudah menjadi perekat esensial pada kehidupan sehari-hari. Penilitian ini berfokus pada derajat hidrolisis PVA dengan mengeksplorasi variasi yang memiliki ketahanan terhadap air paling baik sebagai koloid pelindung untuk polivinil asetat (PVAc) sebagai perekat. Sintesis dilakukan dengan penambahan PVA menggunakan 2 jenis PVA yang terhidrolisis Sebagian dan terhidrolisis Sempurna. Reaksi berlangsung berada pada temperatur 70-800C, menggunakan kecepatan agitator 300 rpm, dan teknik polimerisasi semi-continuous selama 5 jam. Beberapa karakterisasi PVAc yang terukur sebagai parameter antara lain pH antara 4,5-1, kandungan padatan yang memiliki rentang nilai 10,52-19,7 %, viskositas antara 0.58-9,43 mPa.s. Sintesis PVAc menunjukkan gugus O–H yang gelombang 3224 cm-1 variasi tanpa PVA, 3245 cm-1 variasi dengan PVA derajat hidrolisis Sebagian, dan 3353 cm-1 derajat hidrolisis sempurna pada hasil FTIR yang menunjukkan polimer PVAc. Derajat hidrolisis sempurna juga memiliki ketahanan pada air lebih baik dibandingkan dengan PVAc tanpa PVA maupun dengan PVA yang derajat hidrolisisnya parsial. Pada pengujian ketahanan pada air PVAc menggunakan PVA derajat hirolisis sempurna memiliki kekuatan rekat lebih tinggi setelah direndam air selama 5 jam (9906,25 N/m2) dibandingan dengan PVA derajat hidrolisis parsial tanpa direndam air (4093,75 N/m2).

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Polyvinyl alcohol is a essential adhesive in our daily life. This research focuses on the degree of hydrolysis of polyvinyl alcohol (PVA) by exploring which variation has the best water resistance as a protective colloid for polyvinyl acetate (PVAc) as an adhesive. Synthesis was carried out by adding PVA using 2 types of partially hydrolyzed and fully hydrolyzed PVA. The reaction took place at a temperature of 70-800C, using an agitator speed of 300 rpm, and a semi-continuous polymerization technique for 5 hours. Some of the PVAc characterizations measured as parameters include pH between 4.5-1, solids content which has a value range of 10.52-19.7 %, viscosity between 0.58-9.43 mPa.s. The PVAc synthesis showed O–H groups with a wave variation of 3224 cm-1 without PVA, 3245 cm-1 for the variation with partially hydrolyzed PVA, and 3353 cm-1 for the fully hydrolyzed in the FTIR results showing PVAc polymer. The variation which uses fully hyrolyzed also has better water resistance compared to PVAc without PVA or PVA which has a degree of partial hydrolysis. In the PVAc water resistance test using PVA degree of complete hydrolysis had higher adhesive strength after being soaked in water for 5 hours (9906.25 N/m2) compared to PVA degree of partial hydrolysis without being immersed in water (4093.75 N/m2)."

"Limbah pertanian di negara agraris seperti Indonesia sangatlah potensial. Pengolahan limbah pertanian seperti jerami padi akan memberikan nilai tambah ekonomis bagi para petani di Indonesia. Salah satu caranya adalah dengan pembuatan biokomposit perupa papan serat jerami dan serat gelas dengan polimer PVAc. Papan serat ini berpotensi menjadi material struktur yang murah dan mudah di dapat dikarenakan jumlahnya yang melimpah dan murah. Untuk meningkatkan kekuatan jerami dalam pembuatan papan serat dilakukan proses awal berupa perendaman jerami dalam cairan NaOH. Hal ini dilakukan untuk memperbaiki sifat mekanis jerami. Untuk mendapatkan komposisi yang terbaik maka dibuat beberapa komposisi serat papan jerami mulai dari 20% berat serat hingga 70% berat serat. Komposisi optimal papan serat jerami padi berada pada 30% berat serat dengan kekuatan tarik sebesar 4.5 MPa. Variasi subtitusi serat gelas pada komposisi optimal papan jerami padi menghasilkan kekuatan optimal pada komposisi 50% jerami padi, 50% serat gelas dan 70% PVAc yaitu sebesar 4.26 MPa. Rata- rata kadar air 10% atau dibawah 13% menunjukkan papan serat ini sesuai dengan SNI 01-4449-2006.

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Agricultural waste in an agricultural country like Indonesia is very potential . Processing of agricultural wastes such as rice straw provides economic value for farmers in Indonesia. One way of agricultural processing is to manufacture biocomposites such as rice straw fiber and glass fiber hybrid boards with PVAc polymer. This fiberboard material could potentially as structural materials and can an inexpensive because the fiber source is abundant and cheap. To increase the strength of the fiberboard made an initial process of soaking hay in an NaOH solution was conducted.

From this research it was found that the optimal composition of the rice straw board was at 30 % by weight of rice straw with a tensile strength of 4.5 Mpa, increased BLA % compared to tensile strength of the pristine PVAc. Moreover, the optimal composition of the hybrid board was 50 % rice straw, 50 % glass fiber and 70 % PVAC and this composition resulted a tensile strength of 4:26 MPa . The tensile strength of the hybrid board was smaller than that of the straw board becuase of the presence of big voids in between the straw and the glass fibers. Average moisture content of 10 % met the SNI 01-4449-2006 criteria , which was below 13 %."

"Penelitian telah dilakukan untuk mengetahui pengaruh konsentrasi koloid pelindung Polivinil Alkohol (PVA) terhadap kekuatan daya rekat polimer emulsi Polivinil Asetat (PVAc). Sintesis polimerisasi emulsi dilakukan dengan teknik semi-kontinyu dengan komponen polimerisasi terdiri dari air, larutan PVA terhirolisis sebagian medium viscosity, dan surfaktan SDS. Sementara monomer Vinil Asetat (VAM) dan inisiator APS diberikan secara kontinyu selama proses sintesis berlangsung dengan temperature reaksi 70°C, kecepatan agitasi 300 rpm, dan waktu reaksi 5 jam dengan variasi konsentrasi larutan koloid pelindung PVA 2 wt%, 5 wt% dan 10 wt%. Kekuatan rekat polimer PVAc dilakukan dengan uji kuat geser terhadap kayu triplek mengikuti standar ASTM D905-03 dan diperoleh nilai shear strength PVAc meningkat seiring bertambahnya konsentrasi PVA sebesar 96, 225, 277, dan 421 kiloPascal. Parameter lain hasil akhir polimer juga dievaluasi dalam penelitian ini, meliputi temperatur reaksi, kandungan padatan, viskositas, nilai pH, dan densitas. Uji gugus fungsi pembentukan PVAc telah dilakukan dengan Spektrometer FTIR dan diketahui adanya gugus carbonyl C=O stretching & C=C stretching, dan gugus hydroxy O-H stretching. Ukuran partikel diuji dengan Dynamic Light Scattering PSA dan diperoleh ukuran 216 nm untuk PVAc tanpa koloid pelindung, sedangkan pada PVAc dengan koloid pelindung PVA berkisar antara 35-68,5 nm.

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Research has been conducted to determine the effect of the concentration of protective colloid Polyvinyl Alcohol (PVA) on the adhesive strength of Polyvinyl Acetate (PVAc) emulsion polymer. The synthesis of emulsion polymerization was carried out using a semi-continuous technique with polymerization components consisting of water, partially hydrolyzed PVA solution with medium viscosity, SDS surfactant. Meanwhile, Vinyl Acetate (VAM) monomer and APS initiator were administered continuously during the synthesis process with a reaction temperature of 70°C, agitation speed of 300 rpm, and a reaction time of 5 hours with variations in the concentration of the protective colloid PVA solution 2, 5 and 10% by weight. The adhesive strength of the PVAc polymer was carried out by a shear strength test against plywood following the ASTM D905-03 standard and the value of the shear strength of PVAc increased with the increase in PVA concentration of 96, 225, 277, and 421 kiloPascal. Other parameters of the final polymer yield were also investigated in this study, including reaction temperature, solids content, viscosity, pH value, and density. Function group test for PVAc formation has been carried out with an FTIR Spectrometer and it is known that there are carbonyl groups C=O stretching & C=C stretching, and hydroxy groups O-H stretching. The particle size was tested with Dynamic Light Scattering PSA and obtained a size of 216 nm for PVAc without a protective colloid, while for PVAc with a PVA protective colloid it ranged from 35-68.5 nm."

"Boron karbida merupakan material yang sulit terbentuk yang memiliki struktur dan aplikasi elektronik yang menarik. Beberapa kelebihan yang dimiliki oleh boron karbida antara lain stabil pada temperatur tinggi, memiliki tingkat kekerasan yang tinggi, berkemampuan tinggi dalam menyerap neutron pada pusat reaktor nuklir, dan memiliki sifat-sifat termoelektrik yang sangat baik. Kombinasi dari sifat-sifat tersebut memungkinkan boron karbida digunakan dalam berbagai aplikasi, termasuk material yang tahan abrasi, persenjataan militer, moderator neutron pada reaktor nuklir, dan berpotensial diaplikasikan pada pembangkit daya penerbangan angkasa luar.Penelitian ini berhasil mensintesis boron karbida dengan fasa B4C yang memiliki sistem kristal rhombohedral, space grup m 3 R , dan parameter kisi a = b = 5,600, c = 12,08, α = β = γ = 90o dengan menggunakan bahan-bahan awal berupa asam borat (H3BO3), karbon aktif, dan asam sitrat (C6H8O7) yang ditambahkan dengan magnesium sebagai koreduktor.

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Boron carbide is highly refractory material that is of great interest for both its structural and electronic properties. Of particular importance are its high-temperature stability, high hardness, high cross-section for neutron capture, and excellent high-temperature thermoelectric properties. This combination of properties gives rise to numerous applications, including uses as an abrasive wear-resistant material, ceramic armor, a neutron moderator in nuclear reactors, and potentially, for power generating deep space flight applications.

This experimental succesfull to synthesis B4C boron carbide that has rhombohedral crystal system, space grup m 3 R, and lattice constant a = b = 5,600, c = 12,08, α = β = γ = 90o by using raw materials i.e. boric acid (H3BO3), activated carbon, dan citric acid (C6H8O7) and magnesium as co-reductant."

"Biocomposite fiberboards using thermoplastic adhesive polymer white glue polyvinyl acetate and two types of natural fibers, rice straw and coir fibers, were made by vacuum bag moulding. The influences of fiber loading on the biocomposite?s tensile and behavior to water properties were investigated. Prior to the fabrication of the biocomposite the natural fibers were treated using the the alkali process by soaking the fibers in NaOH 5%. Three kind of fiber board were fabricated, a biocomposite with a variation of rice straw fiber loading, a biocomposite with a mixture of 50% rice straw and 50% coir whose fiber loading was also varied, and last a biocompsite with a 30% fiber loading mixture with a variation of coir fiber loading. The biocomposites fabricated had a gradual increase of tensile strength to an optimum fiber loading which after drops with the increase of fiber loading. Rice straw based composites had an optimum fiber loading of 30% percent and the the composite with a mixture of 50% rice straw and 50% coir dah an optimum fiber loading of 35%. The increase of fiber loading also increase the water content and the water absorption for all biocomposites fabricated. The study showed that rice straw and coir fibers may not work well with PVAc as reinforcing filler but showed similar trends when varying the fiber loading with other using natural fibers."