Light Scattering Study of Chitosan in Propionic Acid Aqueous Solutions

• Main Authors: Hou-Fei Guo, 郭豪飛
• Other Authors: Tzyy-Lung Yu
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/74286203599690496976

碩士 === 元智大學 === 化學工程研究所 === 89 === In this study,we inverstigated the chain conformation of chitosan in propionic aqueous solutions at various pH values. The intrinsic viscosity [η] were measured using Ubbelohde viscometer. The second virial coefficient (A2), radius of gyration <Rg>, and weight average molecular weight (Mw) can be obtained from static light scattering and hydrodynamic radius <Rh> from dynamic light scattering. The experiments results revealed that [η], (A2), <Rg> and <Rh> decreased with increasing pH value. Increasing [H+] concentration resulted in an increase in the positive charge [-NH3+] group of chitosan. The charge repulsion of chitosan leads to increases both in molecular size and solubility of chitosan in water as pH decreases. The study of fractal dimesion also revealed that the molecular chain dimesion becomes more compact as pH increased. We also compared experimental data of chitosan in acetic aqueous solution with those in propionic aqueous solution. In the same pH value, we found that molecular size of chitosan in propionic aqueous solution was larger than that in acetic aqueous solution.