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Title:	Effect of dissolution parameter and properties of regenerated cellulose hydrogel and membrane prepared from kenaf core cellulose
Authors:	Hatika Kaco (P62846)
Supervisor:	Sarani Zakaria, Prof. Dr.
Keywords:	Regenerated cellulose hydrogel Kenaf cellulose Cellulose
Issue Date:	12-Jan-2014
Description:	Selulosa telah diekstrak daripada serbuk teras kenaf (TK) melalui satu siri proses pelunturan. Selulosa terekstrak dilarutkan menggunakan pelarut alkali/urea (NaOH/urea dan LiOH/urea) secara kaedah pra-penyejukan untuk menghasilkan larutan selulosa. Parameter optimum untuk pelarutan boleh diperoleh menggunakan nisbah NaOH:urea: air suling adalah 6:4:80. Kesan suhu ke atas pelarutan selulosa menggunakan pelarut LiOH/urea menunjukkan bahawa keterlarutan yang tertinggi boleh dicapai pada suhu −13 °C selepas 60 min proses pelarutan. Tambahan pula, selulosa TK dengan purata kelikatan berat molekul (Mŋ) yang berbeza disediakan melalui proses hidrolisis asid pada masa hidrolisis yang berbeza. Index penghabluran (CrI) selulosa TK meningkat dengan masa hidrolisis dengan penurunan Mŋ selulosa. Penurunan Mŋ bagi selulosa TK meningkatkan darjah keterlarutan dalam larutan LiOH/urea. Larutan selulosa yang terhasil daripada selulosa TK dengan Mŋ yang and kandungan selulosa berbeza telah dijana semula untuk mengahsilkan hidrogel selulosa terjana semula. Hidrogel yang terhasil daripada selulosa dengan Mŋ yang lebih rendah mempunyai keliangan yang lebih tinggi di mana telah meningkatkan ketelusan dan pembengkakan air ke atas hidrogel. Larutan selulosa telah dicampurkan dengan polivinil alkohol (PVA) dengan peratus PVA yang berbeza untuk menghasilkan membran terjana semula yang telus. Penambahan 10 % PVA telah meningkatkan keliangan dan ketelusan membran terjana semula. Walau bagaimanapun, indeks regangan membran dilihat mengalami sedikit penurunan sebanyak 7 % apabila 10 % PVA ditambah. Membran terjana semula selulosa/PVA telah dicetak warna menggunakan pencetak laser dan membran tersebut boleh digunakan semula di mana dakwat yang dicetak telah disingkirkan menggunakan air suling dan dicetak semula untuk beberapa kali. Taut silang selulosa TK oleh penaut silang berasaskan aldehid (glioksal dan glutaraldehid (GA)) dikaji menggunakan peratus aldehid yang berbeza. Spektrum spektroskopi inframerah transformasi fourier (FTIR) menunjukkan taut-silang telah berlaku disebabkan kehadiran kumpulan berfungsi aldehid. Tambahan pula, corak belauan sinar-X (XRD) juga menunjukkan nilai CrI berkurang dengan peningkatan penaut silang bagi kedua-dua membran tertaut silang glioksal dan GA. Kekuatan regangan membran meningkat dengan peningkatan peratus penaut silang. Penambahan glioksal dan GA sebanyak 20 % telah meningkatkan kekuatan regangan bagi kedua-dua membran sebanyak 15 dan 20 %. Walau bagaimanapun, ketelusan dan keliangan telah berkurang disebabkan oleh struktur selulosa tertaut silang.,Cellulose was prepared from kenaf core (KC) powder by a series of bleaching and alkali treatment processes. The extracted cellulose was dissolved using different the alkali/urea solvents (NaOH/urea and LiOH/urea) via pre-cooled method to form cellulose solution. The optimum parameter for dissolution of KC can be obtained using ratio NaOH:urea: distilled water is 6:4:80. The effect of temperature on cellulose dissolution using LiOH/urea solvent shows that −13 °C give the highest cellulose solubility after 60 min of dissolution process. In addition, KC cellulose at different average viscosity molecular weight (Mŋ) was prepared by acid hydrolysis process using sulphuric acid at different hydrolysis times. Crystallinity index (CrI) for the KC cellulose increased with the hydrolysis time with decreased of the cellulose Mŋ. The decrease in Mŋ of the KC cellulose has enhanced its degree of solubility in the LiOH/urea solution. Cellulose solution produced from KC cellulose at different Mŋ and cellulose content was regenerated to form cellulose hydrogel. Hydrogel produced from cellulose with lower Mŋ possessed higher porosity, hence increased the light transparency and water swelling of the hydrogel. Cellulose solution also was mixed at different percentage of polyvinyl alcohol (PVA) to produce regenerated transparent membranes. The addition of 10 % of PVA has increased the porosity and transparency of the regenerated membrane. However, slight reduction (7 %) on the tensile index of the membrane was observed when 10 % of PVA was added. The regenerated cellulose/PVA membranes were color-printed using a laser printer and the membranes were recycled, in which the printed ink was removed using distilled water and printed repeatedly for several times. Crosslinking of the KC cellulose solution with aldehyde based crosslinker (glyoxal and glutaraldehyde (GA)) were studied using different percentages of the aldehyde. Fourier transform infrared spectroscopy (FTIR) spectras revealed that the crosslinking occured due to the existance of aldehyde functional group in both glyoxal and GA crosslinked membranes. In addition, X-ray dffraction (XRD) patterns also showed that CrI value has decreased as the amount of crosslinker increased for both gyoxal and GA crosslinked membranes. Tensile strength of the membranes increased with increasing crosslinker percentages. The addition of 20 % glyoxal and GA has increased the tensile strength for both membranes by 15 and 20 %. However, the transparency and porosity decreased due to the crosslinked cellulose structure.,PhD
Pages:	126
Call Number:	QK898.C42H347 2014 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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