N,O-羧甲基壳聚糖的制备及表征

Preparation and characterization of water-soluble N,O-carboxymethylchitosan

以壳聚糖为原料,成功地制备了水溶性良好的N,O-羧甲基壳聚糖,并采用傅立叶红外、X射线衍射、热失重分析、元素分析以及激光光散射等方法对所制备的产物进行了表征。红外谱图中在1620cm-1及1429cm-1处分别出现了—COO-的反对称及对称伸缩振动吸收峰,表明了羧甲基取代的发生。取代的结果极大地降低了产物的结晶度,表现为X-ray曲线中2θ=20°和2θ=10°与结晶有关的峰极大削弱。热失重的结果表明N,O-羧甲基壳聚糖中含有缔合水,故将此结论用于元素分析的结果处理中,可得到取代度为1.01。通过激光光散射Zimm作图法,得到产物的Mw=2.44×105。

N,O-carboxyrmthylchitosan was prepared and characterized by using FTIR, X-ray diffraction, TGA, elemental analysis and laser light-scattering methods in the present paper. New peaks at 1620 cm^-1 and 1429 cm^-1 in VFIR spectrum assigned to asymmetric and symmetric stretching vibration of COO^- group appeared, which indicated that the substitution reaction took place. The carboxyrmthylafion reduced the modified chitosan greatly, which was manifested by X-ray diffracti＇on result. Studies of TGA when compared with chitosan showed that there existed a small amount of bound water in the product. The TGA result was then combined with elemental analysis to obtain substitution degree of the product. The calculated value is equal to 1.01. The weight average molecular weight determined by Zimm plot was about 2. 44× 10^5.