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Title:	Extraction of nanocelluloses from kenaf core and its applications
Authors:	Chan Chi Hoong (P62852)
Keywords:	Cellulose Kenaf Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	25-Mar-2015
Description:	In Malaysia, a bio-based economy is still in its infancy and offers a vast opportunity due to our active agricultural activity. Developing new bio-based materials from local agricultural products are crucial to generate new industries and to boost the economy. Natural fibers such as kenaf have been studied extensively as a reinforcing agent and received major attention recently due to their renewability, biodegradability, and high strength comparable to other synthetic fibers. This study aims to extract and evaluate nanocellulose from kenaf core so as to provide a set of preliminary data for nanocellulose produced from kenaf core. In this study, two types of nanocellulose were extracted and characterized from kenaf core, namely, cellulose nanocrystals (CNC) and cellulose nanofibrils (CNF). CNC from kenaf core were extracted via hydrolysis with 64 wt.% H2SO4 after alkaline treatment and bleaching. On the other hand, CNF from kenaf core were extracted after bleaching and defibrillation. Both types of nanocellulose were characterized using compositional analysis, Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). Compositional and FTIR analysis of CNC found that alkaline treatment and bleaching effectively remove all lignin in kenaf core. The diameters of CNC obtained from kenaf core were found to be in the range of 8.5 to 25.5 nm with an average aspect ratio of 27.8 with approximately 15.7 % of yield. The crystallinity index (CrI) were found to be as high as 80 %. Whereas for CNF, after bleaching, hemicellulose was retained while insoluble lignin were found to be negligible. TEM showed that hemicellulose content is crucial for defibrillation as higher hemicellulose content shows a higher degree of fibrillation. No cellulose macrofibrils were observed after 30 minutes of defibrillation time for CNF with 30.6 wt.% of hemicellulose content. The CrI were found to be only 52 % due to significant amorphous hemicellulose present (> 30 %). Variable content of CNC were incorporated into PLA to investigate its reinforcing capability. Low filler content composites films of CNC (0.1 - 0.4 wt.%) in PLA films were prepared separately using solution casting method. From tensile test (ASTM - D882), it was found that optimum modulus value were obtained for 0.2 wt.% CNCs in PLA, which gave an increment of 125 %. From microscopic observations of PLA composites, CNC agglomerates served as void nucleating agent during plastic deformation. The improvement of mechanical properties were not due to increment of crystallinity in PLA but reinforcement properties of the fillers. The adsorption of methylene blue towards CNF equilibrates after 1 min. It was found that hemicellulose plays an important role in adsorption as reducing hemicellulose content in CNF renders it less likely to adsorb dye. The maximum adsorption capacity for MB adsorption by CNF is determined to be 122.2 mg/g. CNF can be regenerated by desorption at low pH, in which, 70 % of dye can be desorbed after six cycles of adsorption-desorption cycle.,Ph.D.
Pages:	140
Call Number:	QK898.C42C484 2015 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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