羧甲基壳聚糖结构与性质研究

Studies on the Structure and the Properties of Carboxymethylchitosans

由X-射线衍射证明壳聚糖在进行化学改性(羧甲基化)后,晶体结构已破坏,呈无定形结构,因而在任何pH范围内均溶于水。用元素分析法与红外光谱法测定羧甲基壳聚糖的取代度DS>1和脱乙酰化度为84%～92%,由此推断在C_2和C_6位上均有羧甲基取代,化学改性后的壳聚糖为N,O取代(即为N,O-CMC)。由凝胶过滤色谱测得N,O-CMC的分子量约为10~5～10~6,1%(W/V)的N,O-CMC溶液在50s^(-1)时的表观粘度为20mPa·s左右。

The X-ray diffraction data showed that the crystalline structure of chitosan was disrupted after chemical modification. The modified chitosan was amorphous, so N,O-CMC had good water solubility at all pH values. The DS>1 and DD=84%～90% were obtained by elemental analyses and IR. It was shown that there were carboxymethylation at C_2 and C_6 position of modified chitosan. The molecular-weight distribution of position of N, O-CMC were determined by gel filtration. The molecular weight of N, O-CMC was about about10~5～10~6. The viscosity of N, O-CMC solution (1%W/V)was about 200 mPa·s at50s^(-1).