AI SearchChitosan solution behavior during storage
Call Number: AIT Thesis no. BP-01-06 Material type:
SeriesSeries: Asian Institute of Technology. Thesis ; no. BP-01-06Publication details: Bangkok : Asian Institute of Technology, 2001Description: 74 leavesSubject(s): Online resources: Dissertation note: Thesis (M.Sc.) - Asian Institute of Technology, 2001 Summary: In 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.
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A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development
Thesis (M.Sc.) - Asian Institute of Technology, 2001
In 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.
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