丙烯酸接枝壳聚糖水凝胶的制备

The Methods of Hydrogel and Acrylic Acid Grafted Chitosan

以壳聚糖与丙烯酸为原料,首先使用三种方法制备改性壳聚糖。第一种方法用丙烯酸直接改性壳聚糖,第二种方法在反应体系中加入氢氧化钾调整p H值,第三种方法在丙烯酸和壳聚糖混合物中加入引发剂过硫酸铵制备改性壳聚糖。分别对三种方法改性的壳聚糖进行红外光谱表征并测定其接枝率。结果表明,以过硫酸铵为引发剂方法改性的壳聚糖接枝率最高,达到68%。然后进行丙烯酸接枝壳聚糖制备水凝胶的合成工艺研究,将吸水性和电镜扫描图像分数作为评分指标。通过正交实验得到最佳工艺条件为在100m L反应体系中过硫酸铵量为0.5 g,丙烯酸量为3 m L,壳聚糖量为1.5 g,反应温度为60℃,20 m L交联剂(100 m L含三聚磷酸钠和六偏磷酸钠分别为3 g和5g),此时所制得的水凝胶吸水性能最优,吸水率达到821%。

In this paper, chitosan and acrylic acid were used as materials. The modified chitosan was prepared by three methods. In the first method, chitosan was modified with acrylic acid directly; in the second method, the p H value of the reaction system was adjusted by adding potassium hydroxide; in the third method, the initiator ammonium peroxydisulfate was added into the mixture of acrylic acid and chitosan for preparing the modified chitosan.The three methods were evaluated by the IR spectra of modified chitosan and the percent of grafting. The results showed that the highest percent of grafting of modified chitosan reached 68%. Then, the hydrogel was prepared with acrylic acid grafted chitosan, the water absorption and electron microscope scanning image scores were used as evaluation indexes. The optimum conditions were obtained through orthogonal experiment. In 100 m L reaction system, ammonium peroxydisulfate was 0.5g, acrylic acid was 3m L, chitosan was 1.5g, reaction temperature was60℃, 20 m L crosslinking agent(100m L crosslinking composed of 3g sodium tripolyphosphate and 5g sodium metaphosphate). Under the conditions above, the water absorption of N-carboxyethyl chitosan hydrogel reached821%.