幾丁聚醣之溶解特性及溶解處理對其性質之影響

Dissolving characteristics of chitosan and the effect of dissolving treatment on its properties

本研究以一般幾丁聚醣（Chitosan；CS）及水溶性幾丁聚醣（Water soluble chitosan；WCS）為原料，以去離子水、濃度1%、2%、3%之冰醋酸水溶液（Glacial acetic acid aqueous solution；GAA （aq））及重量混合比95/5、50/50之二甲基乙醯胺/GAA （aq）為溶解試劑，探討幾丁聚之溶解特性，並進一步以FTIR、DSC、TGA分析GAA （aq）溶解處理對幾丁聚醣性質之影響。由結果可知，GAA （aq）對CS及 WCS均具備良好的溶解能力。幾丁聚醣GAA （aq）溶液之性質主要受幾丁聚醣種類所影響，提高GAA （aq）濃度可降低CS溶液之黏度，然對WCS溶液則無明顯影響。FTIR分析結果顯示CS之分子結構中仍存在部分乙醯胺基，DSC及TGA分析結果則顯示，GAA （aq）溶解處理將造成幾丁聚醣結構之降解，經溶解處理之幾丁聚醣其熱活動性提高，熱抵抗性則降低。 In this study, normal chitosan (CS) and water soluble chitosan (WCS) were used as raw materials. Deionized water, glacial acetic acid aqueous solution (GAA (aq)) with 1%, 2% and 3% concentration, and dimethyl acetamide/GAA (aq) mixed with the weight ratio of 95/5 and 50/50 were used as the dissolving reagents. The dissolving characteristics of chitosan were investigated. In addition, the effect of GAA (aq) dissolved on the properties of chitosan were also detected with FTIR, DSC and TGA analysis. The results showed that GAA (aq) had good dissolving capability for both CS and WCS. The properties of chitosan/GAA (aq) solutions were mainly depended on the kind of chitosan. Increasing the concentration of GAA (aq) would decrease the viscosity of CS solution, but had no effect on WCS solution. The results of FTIR analysis indicated that some acetamido-groups were still existed in the molecular structure of CS. The results of DSC and TGA analysis showed that GAA (aq) dissolving treatment caused a degradation of the molecular structure of chitosan. After dissolving treated, the heat activity of the chitosan increased and the thermal resistance decreased.