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Polybenzoxazine, poly(B-a), was hybridized with polysiloxanes by synchronizing two reactions1 ring-opening polymerization of benzoxazine (B-a) and the sol-gel process of diethoxysilanes. As diethoxysilanes, mixtures of diethoxydimethylsilane and diethoxydiphenylsilane in various ratios were used to prepare polysiloxane copolymers, poly(dimethylsiloxane-co-diphenylsiloxane), P(DMS/DPS). The effect of diphenylsiloxane (DPS) content of polysiloxane copolymer on the optical, mechanical, and thermal properties of the hybrids was studied. The progress of the sol-gel process was confirmed by IR, 1 H-NMR and size exclusion chromatography. Opaque poly(B-a)-P(DMS/DPS) hybrid films were obtained at high dimethylsiloxane (DMS) content corresponding to the phase separation. The domain size of the polysiloxane was evaluated from the scanning electron microscope. Meanwhile, transparent hybrid films were obtained at high DPS content, corresponding to the homogeneous phase as observed from the scanning electron microscope. The hybrid films revealed higher tensile strength and elongation at break than pristine poly(B-a) as a function of DPS content. Dynamic viscoelastic analyses of the hybrids at high DMS content revealed two glass transition temperatures (T g ) corresponding to polysiloxane and poly(B-a) components, while one T g was observed at high DPS content. Thermogravimetric analysis of the hybrids revealed that the thermal stability of the poly(B-a)-polysiloxane hybrids was higher than pristine poly(B-a) depending on the DPS content.

Aspect ratio which is the ratio between the length and diameter of the fiber affects the sound absorption performance of the polymer reinforced natural fiber (ramie or bamboo fiber). The aim of this study is to choose the specific frequency –which is important for industrial application- to obtain an optimal sound absorption coefficient (α) by designing a certain aspect ratio.The acoustic was measured using impedance tube of The ASTM E- 1050=98 standard. Fiber length was 10 mm, while the diameter of the fiber was measured by using a digital optical microscope measurement with an average diameter of 110.4 microns. The morphology of the material was observed by using scanning electron microscope (SEM). Fourier Transform Infrared (FTIR) spectroscopy was used to identify the presence of certain functional groups in a molecule. The results indicated that the average of the sound absorption coefficient of the polymer reinforced ramie fiber reached 0,836 at low frequency of 125 Hz and 0,537 at medium frequency of 1000 Hz, and aspect ratio of 90, while the sound absorption coefficient of the polyester material reinforced bamboo fiber reached 0.973 at medium frequency of 1000 Hz.

Influence of weathering effect in natural environment on thermal properties hybrid kenaf blast/glass fibre and unsaturated polyester composite M Mohammed, A R Rozyanty, B O Beta et al. (10, 20, 30, 40,and 80 wt.%) using mechanical blending method. The blends were cured at room temperature using methyl ethyl ketone peroxide (MEKP) (4 wt.%) as catalyst initiator without the presence of catalystaccelerator. The effect of vinyl ester composition on theenhancement of mechanical and thermal properties of unsaturated polyester/vinyl ester blends was investigated.The polymer blends were characterized by Fourier Transform Infra Red (FTIR)spectroscopy, tensile testing, hardness testing, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). IR spectra showed UP and VE peaks. The curing copolymerization reactionoccurred at vinyl (C=C) bonds. The addition of vinyl esters enhanced mechanical and thermal properties. The UP/VE blends showed homogeneous morphology, transparent and copolymer thermoset blend.Keywords: unsaturated polyester, vinyl ester, polymer blend, thermal properties IntroductionUnsaturated polyester is a widely used thermosetting resin. Unsaturated polyester has a reactive vinyl (carbon-carbon double) bond. Styrene is added to unsaturated polyester as asolvent and acrosslinking agent for curing reaction. The organic peroxide is used to initiatethe reaction. Organic salt isadded to accelerate the reaction. The polymer is achieved as a result of random condensation copolymerization reaction between styrene and unsaturated vinyl double bonds by free radical mechanismforming crosslinked network structure [1,2]. Unsaturated polyester is a resin (prepolymer) with low price, light weight, easy processing and water resistance. Unsaturated polyester commonly used in laminating resin, composites, coating, adhesive, microelectronic, aerospace, building, automotive, and shipbuilding. However, unsaturated polyester shows limited mechanical and thermal properties. It is necessary to enhance the properties of unsaturated polyester.The properties of unsaturated polyester have been enhanced by theadditionof carbon fiber , fly ash, carbon nanotube, and polyamide [3][4][5][6]. Vinyl ester is an attractivehigh-performance thermoset polymer. Vinylester has reactive double bonds with rigid epoxy structure. Vinyl ester is synthesized by the reaction of epoxy with methacrylic

Komposit merupakan salah satu material yang dikembangkan sebagai material penyerap suara. Sebelumnya sudah diteliti mengenai penguat dalam komposit penyerap suara menggunakan serat tandan kosong kelapa sawit. Akan tetapi, penelitian sebelumnya masih dilakukan penelitian untuk prosesnya dan belum diaplikasikan untuk penguat komposit penyerap suara. Sehingga dibuatlah penelitian yang bertujuan untuk mengetahui pengaruh proses alkalisasi pada serat tandan kosong kelapa sawit terutama pada pemisahan selulosa dari lignin serat tersebut. Penelitian ini menggunakan NaOH 2% sebagai pelarut pada proses alkalisasi serat tandan kosong kelapa sawit. Pengujian yang dilakukan yaitu uji FTIR pada serat tandan kosong kelapa sawit tanpa perlakuan dan dengan perlakuan alkalisasi. hasil uji FTIR menunjukkan serat tandan kosong kelapa sawit dialkalisasi secara kurang optimal dengan masih menyisakan sebagian kadar lignin yang ditunjukkan dengan masih terdapatnya peak gugus aromatik C=C pada rentang 1200-1300 cm-1 .

Abstrak-Komposit berpenguat nanofiller merupakan salah satu material yang sedang dikembangkan. Salah satu aplikasinya dapat digunakan sebagai bahan akustik. Penggunaan serat alam sebagai penguat pada komposit mendukung regulasi tentang persyaratan habis pakai produk untuk komponen otomotif dengan mengurangi konsumsi polimer. Indonesia merupakan salah satu negara yang membudidayakan kelapa sawit terbesar di dunia. Kelapa sawit mengandung selulosa yang cukup tinggi sehingga dapat dimanfaatkan sebagai penguat pada komposit polimer. Tujuan dari penelitian ini adalah menganalisis ikatan kimia serat setelah diberi perlakuan kimia. Pengujian yang dilakukan dalam penelitian yaitu FTIR. Pembuatan nanoselulosa dengan menggunakan tiga tahap perlakuan kimia yaitu alkalisasi, bleaching dan hidrolisis asam. Setelah dilakukan tiga tahap perlakuan kimia pada serat tandan kosong kelapa sawit, hasil FTIR menunjukkan tiga daerah serapan utama yaitu 3288.08 cm -1 , 1636.43 cm -1 dan 1089.92 cm -1 yang menunjukkan ikatan O-H stretching, O-H deformasi dan C-C stretching. Daerah serapan yang muncul menunjukkan bahwa telah dihasilkan selulosa dan kandungan lignin menghilang.