壳聚糖的光敏改性及其胶束化行为

Photosensitive modification of chitosan and its micellization behavior

用1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)在室温下催化壳聚糖(CTS)上的氨基与巯基乙酸的羧基反应生成酰胺键,得到侧基有巯基封端的CTS-HS,以PEG2 000为增溶剂在水溶液中与CTS-HS络合后冷冻干燥得到CTS-HS/PEG复合物。以偶氮二异丁腈(AIBN)为引发剂,甲基丙烯酰氧乙基肉桂酸酯(CEMA)和聚乙二醇甲基丙烯酸酯(MPEG)为共聚单体,加入含巯基的CTS-HS/PEG复合物为链转移剂进行自由基溶液聚合,得到壳聚糖光敏接枝物CTS-g-P(CEMA-co-MPEG)。用FTIR对壳聚糖光敏接枝物结构进行了表征。将壳聚糖光敏接枝物溶于水,在水溶液中直接形成胶束,用紫外-可见光分光光度计、Zeta电位仪、纳米粒度仪和透射电子显微镜研究了胶束的性质和形态。以白油为油相,研究了壳聚糖光敏接枝物的乳化性能。结果表明,壳聚糖光敏接枝物CTS-g-P(CEMA-co-MPEG)具有光敏性,可吸收波长在275 nm左右的紫外线,可在水溶液中自动形成粒径为120 nm左右的球形胶束,所得胶束在较宽的pH范围内均可稳定存在,并有较好的乳化性能。

Mercapto- terminated graft polymer CTS -HS was synthesized through amidation reaction between chitosan and mercaptoacetic acid with combined catalytic action of 1 - （3 - dimethylaminopropyl） - 3 - ethylcarbodiimide hydrochloride （EDC） and N - hydroxy succinyl imide （NHS） at room temperature. The CTS - HS was complexed with a solubilizer PEG2 000 in aqueous solution and, after freeze - drying, formed CTS - HS/PEG complex. The complex CTS - HS/PEG was used as chain transfer agent and polymerized by free radical solution polymerization with methacrylyl oxyethyl cinamate （CEMA） and polyethylene glycol methacrylate （MPEG） as inter - polymeric monomers as well as azodiisobutylonitrile （AIBN） as initiator. The final product was chitosan photosensitive graft copolymer CTS -g- P （CEMA -co -MPEG ）. Chemical structure of the product was characterized by FTIR. The micelles properties and morphological structure of the product in water was studied by UV - Vis spectroscopy, zeta potential analyzer, nano - particle size analyzer and TEM. Emulsifying performance of the product was studied with white paraffin oil as oil phase. Results showed that the product CTS -g -P（ CEMA -co -MPEG） displays photosensitivity and can absorb ultraviolet rays with wavelength range of about 275 nm. In aqueous solution, the product can self - assemble spherical micelles with particle size of about 120 nm and the micelles can be stable in a wide range of pH in water. Emulsifying performance of the product is quite good.