The Synthesis, Functionalisation And Characterisation Of Carbon Nanotubes Alumina Hybrid Compound And Its Nanocomposites

Nosbi, Norlin (2017) The Synthesis, Functionalisation And Characterisation Of Carbon Nanotubes Alumina Hybrid Compound And Its Nanocomposites. PhD thesis, Universiti Sains Malaysia.

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Abstract

Dalam kajian ini, karbon nanotiub (CNT) dan alumina hybrid telah disintesis menggunakan proses pemendapan wap kimia (CVD). Sebatian hibrid CNT-alumina ini diteruskan penghasilannya dengan polydimethylsiloxane (PDMS) untuk menghasilkan komposit. Pada mulanya, analisis yang dilakukan semasa sintesis hibrid CNT-alumina adalah secara fizikal dan kimia untuk mengenalpasti penghasilan mana yang lebih baik dengan mengggunakan kepelbagaian pemangkin sokongan seperti nikel nitrat, ferik nitrat dan kobalt nitrat. Didapati nikel nitrat mempamerkan ciri-ciri yang dikehendaki dengan tahap pertumbuhan CNT yang lebih tinggi dan sifat-sifat yang agak baik berbanding pemangkin sokongan yang lain. Kemudian, kajian ke atas masa kitaran (0, 5, 10 dan 15 jam) mendakan pemangkin untuk menghasilkan hybrid CNT-alumina telah dikaji. Ia adalah untuk mengetahui kesan pengaktifan mekanokimika terhadap sifat-sifat bahan semasa sintesis hibrid CNT-alumina. Didapati pemilihan masa kisaran 15 jam adalah yang paling sesuai serta lebih baik untuk pertumbuhan CNT dari segi sifat-sifat fizikal, kimia dan terma. Seterusnya, hibrid CNT-alumina telah difungsikan dengan asid H2SO4: HNO3 (50 °C / 24 jam dan 100 °C / 2 jam) dan reagen asli (minyak zaitun dan minyak sawit) untuk pengubahsuaian dan pembaikan permukaan hybrid tersebut. Kefungsiaan ini ditunjukkan untuk membandingkan ciri dan sifat mana yang lebih baik daripada interaksi ikatan kimia yang terbentuk di permukaan hybrid CNT-alumina. Didapati permukaan hybrid CNT-alumina menunjukkan ikatan kimia telah dibentuk, tetapi didapati bahawa rawatan asid reagen pada suhu 50 °C selama 24 jamadalah lebih sesuai dengan ketetapan kumpulan ikatan yang baik. Terdapat lebih kumpulan karboksil berfungsi di dinding sisi hibrid CNT-alumina. Pada akhirnya, penghasilan hibrid CNT-alumina / PDMS komposit telah dicapai melalui pemprosesan ultrasonik. Kesan daripada ikatan hibrid CNT-alumina dalam pelbagai peratusan berat (0, 0.5, 1.0 dan 1.5 wt%) di PDMS telah dikaji. Jelas dilihat melalui keputusan kajian bahawa komposit 1.5 wt% hibrid CNT-alumina / PDMS telah menunjukkan lebih keberkesanan di mana ianya memiliki kekuatan tekanan yang lebih tinggi dengan daya terikan yang lebih rendah dan kekonduksian terma yang tinggi tetapi pengembangan haba serta kehilangan komposisi berat yang rendah. Secara kajiannya, pembuatan hibrid CNT-alumina / PDMS komposit ini telah menunjukkan sifat kefungsian dalam keadaan baik dengan ciri-ciri yang lebih baik serta boleh digunakan mengikut aplikasi yang diperlukan. __________________________________________________________________________________ In this study, CNT and alumina hybrid compound were synthesised using the chemical vapour deposition (CVD) process. The CNT-alumina hybrid compound was synthesised with polydimethylsiloxane (PDMS) to produce composites. Initially, the synthesised CNT-alumina hybrid was analysed physically and chemically to identify the best production route by using nickel nitrate, ferric nitrite and cobalt nitrate as the supported catalysts. Throughout the synthesis, nickel nitrate was verified as having the most desirable characteristics with a high level of CNT growth compared to the other supported catalysts. Then, investigations were carried out on the milling time (0, 5, 10 and 15 hours) of the precipitate catalyst in producing the CNT-alumina hybrid. The effects of mechanochemical activation by milling on the particular characteristics of the synthesised CNT-alumina hybrid were also studied. It was found that 15 hours of milling time of the catalyst produced the best physical, chemical and thermal properties for CNT growth. Thereupon the milled, CNT-alumina hybrid compound was functionalised with acids, namely H2SO4: HNO3 (50 °C for 24 hours and 100 °C for 2 hours), and natural reagents (olive oil and palm oil) for surface modifications. These functionalisations were exhibited to compare the possible characteristics and all the improved properties of interactions at the CNT-alumina hybrid surface in the form of the attached chemicals. The entire CNT-alumina hybrid functionalisation showed that chemical surface attachments had been formed, but it was found that most of the chemical attachments were specifically applicable to treatment with acid reagents at a temperature of 50°C for 24 hours. Thus, more carboxyl groups were found to be attached to the CNT-alumina hybrid on the sidewalls. Finally, CNT-alumina hybrid/ PDMS composites were fabricated using an ultrasonic processor. Furthermore, the effects of interactions of the various weight percentages (0, 0.5, 1.0 and 1.5 wt%) of CNT-alumina on PDMS were investigated. It was clearly seen that 1.5 wt% of the CNT-alumina hybrid/ PDMS composite presented effective results with higher strength and lower strain, high thermal properties but low thermal expansion and low weight loss. Experimentally, these CNT-alumina hybrid/ PDMS composites were fabricated and functionalised in good condition with better properties and can be applied in suitable applications.

Item Type: Thesis (PhD)
Subjects: T Technology
T Technology > TA Engineering (General). Civil engineering (General) > TA401-492 Materials of engineering and construction. Mechanics of materials
Divisions: Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Bahan & Sumber Mineral (School of Material & Mineral Resource Engineering) > Thesis
Depositing User: Mr Mohamed Yunus Mat Yusof
Date Deposited: 18 Nov 2019 08:29
Last Modified: 20 Nov 2020 07:17
URI: http://eprints.usm.my/id/eprint/45781

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