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Title:	Production and characterization of regenerated cellulose membrane, hydrogel and aerogel from hydrolysed and carbamated celluloses
Authors:	Gan Sin Yee (P68039)
Supervisor:	Sarani Zakaria, Prof
Keywords:	Cellulose membrane Hydrogel Aerogel Oil bath Autohydrolysis Carbamated celluloses Dissertations, Academic -- Malaysia
Issue Date:	20-Aug-2015
Description:	Pretreatment of cellulose is the dominant method to modify the functions as well as to increase the properties and the overall use of natural biopolymers. This study was conducted using two types of cellulose pretreatments which were cellulose autohydrolysis under hydrothermal condition and carbamate syntesis under microwave irradiation and hydrothermal condition, respectively. The autohydrolysis on cellulose was carried out via hydrothermal condition using autoclave in an oil bath. Cellulose carbamate (CC) was produced using two methods which were carbamate synthesis in microwave oven and carbamate synthesis in autoclave immersed in oil bath under hydrothermal condition. Besides that, the CC was reinforced with graphene oxide (GO) to fabricate homogeneous CC-GO membranes using a simple solution-mixing method. The study of autohydrolysis on cotton linter was to examine the effect of autohydrolysis and the amount of cellulose (4-7 wt%) used in dissolution toward the solubility of cellulose in LiOH/urea and NaOH/urea aqueous solution, respectively. On the other hand, the study of autohydrolysis on kenaf pulp was to investigate the effect of autohydrolysis reaction time (0.5-5h) and temperature (100-140 oC) on solubility of cellulose in LiOH/urea aqueous solution. The cotton linter dissolved in LiOH/urea aqueous solution possessed higher solubility than in NaOH/urea aqueous solution. The autohydrolysis has improved the solubility of cotton linter in LiOH/urea aqueous solution up to 19.15 %. The solubility and autohydrolysis of cotton linter decreased when the amount of cellulose being dissolved increased. As the reaction time and temperature of autohydrolysis on kenaf pulp increased, molecular weight of cellulose decreased, hence the cellulose solubility increased. The 5 h autohydrolysis has improved the solubility of kenaf as high as 11.3 %. The improvement on cellulose solubility was due to the reduction in molecular weight and crystallinity index of cellulose through autohydrolysis. CC produced from microwave irradiation and hydrothermal condition was proven by characterization of nitrogen content and functional group (C = O) through FTIR, where the urea concentration, reaction time and temperature are crucial in the formation of CC. As each of urea concentration, reaction time and temperature increased, the nitrogen yield in CC increased. The CC with higher nitrogen content obtained higher solubility in LiOH/urea aqueous solution. The CC prepared via microwave irradiation can attained solubility up to 94.3 %, while CC produced from hydrothermal condition can achieved 99.2 % solubility in LiOH/urea aqueous solution. The crystallinity index and the presence of cellulose II in all regenerated cellulose membranes and hydrogels were determined by XRD. Morphology of cellulose, cellulose membrane and aerogel were viewed under SEM. The effect of GO content (with GO/cellulose ratio 1-4 wt%) on properties of CC-GO membranes via NaOH/urea aqueous solution was investigated. The CC-GO membranes were characterized with AFM, TEM, XRD, TGA, FTIR, FESEM and mechanical testing. The cross section of all the CC-GO membrane samples displays a 3D homogeneous porous structure. The membrane containing 4 wt% GO/CC increased tensile modulus and strength of around 525 % and 93 %, respectively, as compared to the neat CC. As increasing the GO/CC ratio from 1 to 4 wt%, the tensile strength of membranes increases from 40.8 to 50.9 MPa. The CC-GO membrane has enhanced the thermal stability compare to neat cellulose membrane. The CC-GO membrane showed better morphology, mechanical and thermal properties compare to cellulose membrane.,Certification of Master's/Doctoral Thesis" is not available
Pages:	182
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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