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Title:	Penyediaan komposit getah asli / polietilena berketumpatan tinggi / sekampadi (Nr / Hdpe/ Sp) terawat getah asli terepoksida cecair (Lenr)
Authors:	Rahmadini Syafri (P41565)
Supervisor:	Ibrahim Abdullah, Prof Dr.
Keywords:	komposit getah Polymeric composites
Issue Date:	2-Aug-2010
Description:	Komposit getah asli termoplastik (TPNR) berpengisi sekam padi (SP) telah dihasilkan dengan kaedah pengadunan leburan menggunakan mesin pencampuran dalaman Brabender Plasticorder. Adunan matriks TPNR disediakan daripada getah asli (NR) dan polietilena berketumpatan tinggi (HDPE) pada nisbah 60/40. Parameter pemprosesan yang optimum untuk matrik NR/HDPE diperolehi pada suhu 135oC, kadar pencampuran 50 rpm dan masa pengadunan 12 minit, sedangkan bagi komposit NR/HDPE/SP diperolehi pada suhu 135oC, kadar pencampuran 45 rpm dan masa pengadunan 12 minit. Pemilihan pengisi sekam padi bertujuan sebagai pengisi penguat dalam komposit yang disediakan oleh kerana sekam padi memiliki kandungan silika yang cukup tinggi dan berpotensi sebagai pengukuh fasa komposit TPNR. Sekam padi sebagai pengisi juga memiliki beberapa kelemahan antaranya, sifat hidrofilik permukaan sekam padi yang menyebabkan ketidakserasian dan ikatan antara muka yang lemah antara pengisi dan matriks polimer yang bersifat hidrofobik. Rawatan kimia ke atas permukaan sekam padi tanpa rawatan (SPi) dijalankan dengan kaedah pengalkalian (NaOH) sebagai pra-rawatan dan seterusnya penyalutan dengan getah asli terepoksida cecair (LENR). Beberapa kepekatan larutan NaOH digunakan dalam kaedah pra-rawatan sekam padi, dan kepekatan berkesan diperolehi ialah 5% larutan (SPiNa). Penyalutan SPi dengan LENR juga dilakukan pada beberapa kepekatan berbeza iaitu 5% hingga 20% (SPiNaLE) dalam larutan toluena. Pencirian sekam padi dijalankan melalui analisis FTIR, mikroskop optik dan mikrograf SEM. Penilaian sifat mekanik ke atas komposit terisi SP menunjukkan nilai yang optimum adalah pada sekam padi terawat alkali serta rawatan 10% LENR (SPiNaLE 2) dengan nilai tegasan dan hentaman masing-masing 6.9 MPa dan 24.6 kJ/m2. Kesan pengisian SPiNaLE 2 ke dalam matrik NR/HDPE pada peratusan kandungan pengisi daripada 10% hingga 30% juga turut dikaji dan didapati nilai tegasan dan hentaman mengalami penurunan pada pembebanan pengisi yang tinggi akibat daripada pembentukan aglomerat, akan tetapi modulus regangan dan kekerasan komposit meningkat. Analisis terma mekanik dinamik juga menunjukkan interaksi yang wujud antara SPiNaLE 2- Matriks adalah lebih berkesan berbanding SPi-Matriks berdasarkan puncak tan delta (Tg) yang semakin beranjak ke suhu yang lebih tinggi. Dapat disimpulkan bahawa kaedah rawatan NaOH-LENR ke atas pengisi sekam padi telah berjaya mengurangkan sifat hidrofilik sekam padi seterusnya meningkatkan interaksi antara muka SPi- Matriks yang membawa kepada peningkatan sifat mekanik komposit.,Thermoplastic natural rubber (TPNR) composites with rice husk (RH) as filler were prepared via melt blending using an internal mixer Brabender Plasticorder. TPNR matrix was prepared from natural rubber (NR) and high density polyethylene (HDPE) with a composition ratio of 60:40. The optimum processing parameters for NR/HDPE matrix was obtained at 135 oC, at mixing rate of 50 rpm and blending time of 12 minutes, while the parameters for the NR/HDPE/RH composite was at 135 oC mixing rate of 45 rpm and blending time of 12 minute. Addition of rice husk into the NR/HDPE matrix was aimed to reinforce the composites with the filler. The high silica content of rice husk has made rice husk to be used as potential reinforcement filler for composites. However, the application of rice husk as filler is limited due to the hydrophilic nature of rice husk surface causing incompatibility and weak interfacial adhesion between rice husk and the hydrophobic polymer matrix. Hence, the cellulose surface of rice husk has to be modified. The rice husk was treated with sodium hydroxide (NaOH) as pre-treatment and later coated with liquid epoxidized natural rubber (LENR). Several concentrations of NaOH solution were used for alkali treatment of untreated rice husk (RHi) and the most effective was at 5% NaOH in aqueous solution (RHiNa). LENR coating was also carried out at several concentrations from 5% to 20% LENR in toluene. Characterizations of rice husk surfaces were analyzed by FTIR, optical microscope and SEM micrograph. The mechanical properties of rice husk filled composites observed, showed that the maximum value obtained were for composites reinforced with alkali treated and coated with 10% of LENR (RHiNaLE 2). The tensile and impact strength obtained were 6.9 MPa and 24.6 kJ/m2 respectively. Effects of RHiNaLE 2 loading on tensile and impact strengths of composites showed that the properties decreased at higher loadings due to agglomeration of filler particles. However the tensile modulus and hardness were found to increase with filler loading. The dynamic mechanical thermal analysis also showed that composites prepared exhibited a shift in the tan delta peak (Tg) to a higher temperature due to the increased RHiNaLE 2-Matrix interaction. In conclusion, modification of rice husk surface via NaOH treatment and coating with LENR was successful in reducing the hydrophilic nature of rice husk powder. The RHi-Matrix interfacial adhesion had improved which lead to higher mechanical properties of the composites prepared.,Master/Sarjana
Pages:	118
Call Number:	TA418.9.C6R336 2011 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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