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以壳聚糖为原料,双氧水、次氯酸钠和高碘酸钾分别作为氧化剂,采用正交实验法分别研究了3种氧化体系中氧化剂用量、反应pH和反应时间等因素对氧化产物羰基含量的影响,最后对3种氧化体系中最高羰基含量的氧化产物进行红外谱图及扫描电镜分析。结果显示:在60℃下,双氧水最佳氧化参数是pH4.0,用量15%,6 h,得到氧化壳聚糖的羰基含量为46.87%;次氯酸钠氧化参数为pH9.0,用量25%,3 h,羰基含量为30.72%;而高碘酸钾氧化参数为pH3.0,用量100%,4 h,羰基为94.45%。同时氧化后的壳聚糖红外图谱也显示了羰基吸收峰。SEM说明经过预处理及氧化改性后,壳聚糖的表面形貌发生一定程度的变化,其表面由最初的光滑平整到粗糙不平。
Using chitosan as raw material, hydrogen peroxide, sodium hypochlorite and potassium periodate as oxidant respectively, the effects of oxidant dosage, reaction pH and reaction time on the carbonyl content of the oxidation products were studied by orthogonal experiment. Finally, the oxidation products with the highest carbonyl content in the three oxidation systems were analyzed by infrared spectroscopy and scanning electron microscopy. The results showed that the optimum oxidation parameters of hydrogen peroxide were pH4.0 at 60 ℃, the carbonyl content of the oxidized chitosan was 46.87% at the dosage of 15% and 6 h, the oxidation parameter of sodium hypochlorite was pH9.0, the dosage of 25%, 3 h, the carbonyl content was 30.72%, while the oxidation parameter of potassium periodate was pH3.0, the dosage was 100%, 4 h and the carbonyl was 94.45%. At the same time, the oxidized chitosan infrared spectrum also showed the carbonyl absorption peak. SEM shows that after pretreatment and oxidative modification, the surface morphology of chitosan changes to some extent, the surface smooth from the initial smooth to rough.