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005			20260817172703.0
008			020215s2001 th uzm rtt 00| a1eng d
035			_a.b11845958
099		9	_aAIT Thesis no. BP-01-06
100	0		_aNguyen Thi Thanh Binh
245	1	0	_aChitosan solution behavior during storage
260			_aBangkok : _bAsian Institute of Technology, _c2001
300			_a74 leaves
490	1		_aThesis ; _vno. BP-01-06
500			_aA thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development
502			_aThesis (M.Sc.) - Asian Institute of Technology, 2001
520			_aIn this study, the degradation of chitosan in organic acids has been examined. Two methods of Capillary Viscometry and Gel Permeation Chromatography (GPC) have been applied to evaluate the change of intrinsic viscosity and molecular weight of shrimp chitosan with a degree of deacetylation of 81.5% and 88%DD respectively. Storage of chitosan in 0.2M acetic acid was examined during 60 days at three different temperatures: 5, 28 and 60°C. It was found that the higher the storage temperature, the faster the rate of degradation. The viscosity of 8 l .5%DD chitosan was reduced to less than 10% of the original value after 60 days of incubation at 60°C. The chitosan of higher degree of deacetylation has a better resistance to acid hydrolysis. Minor changes on the intrinsic viscosity and molecular weight were observed after the treatment at 28°C and nearly no change after treatment at 5°C. The intrinsic viscosity and molecular weights of chitosan in three concentrations of acetic acid of 0.1, 0.2 and 0.8M before and after precipitation was compared. No significant difference has been found. The effect of formic acid and acetic acid in various concentrations on degradation of chitosan was studied. After incubation the chitosan was precipitated with alkali and redissolved in acetic acid. It was found that chitosan is more resistant to degradation in foimic acid than in acetic acid. However, between three concentrations of 0.1, 0.2 and 0.8M of individual acid, only minor differences in the rate of degradation were observed. The results in viscosity-average molecular weight obtained from viscometry method were very consistent with the results in weight-average molecular weight obtained by GPC method. This illustrates the accuracy of these analytical methods and suggests that viscometry method can be widely used for determining the molecular weight of chitosan in routine laboratory.
650	1	0	_aChitosan _xStorage
700	1		_aStevens, Willem Frans, _eChairperson
700	1		_aSuwalee Chandrkrach, _eExamination committee
700	1		_aTrankler, Josef, _eExamination Committee
700	1		_aSuwabun Chirachanchai, _eExamination committee
710	2		_aSwedish International Development Cooperation Agency (Sida), _eScholarship donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. BP-01-06
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B07828
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902			_a240329
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