聚乳酸改性糯玉米淀粉的制备及表征

Preparation and characterization of polylactic acid modified waxy corn starch

摘要:

以糯玉米淀粉为原料、异辛酸亚锡为催化剂,在丙交酯熔融体系中制备聚乳酸改性糯玉米淀粉。建立聚乳酸改性糯玉米淀粉取代度的1H-NMR测试方法,并以取代度为响应值,反应时间、反应温度、丙交酯添加量为考察因素,通过单因素和响应面实验优化了聚乳酸改性糯玉米淀粉的合成工艺,得到最优工艺为:反应时间12.46h,反应温度111.75℃,丙交酯添加量为淀粉的258%,预测最大取代度为0.0253,实际取代度为0.0238。通过对最优条件下制备的聚乳酸改性淀粉进行系列表征,证实聚乳酸改性糯玉米淀粉的颗粒结构没有被完全破坏,晶型、分子量等性能优于溶剂法传统技术,使其在可降解材料、药物载体等领域具有广阔的应用前景。

Abstract:

Using waxy corn starch as raw material and stannous isooctanoate as catalyst, polylactic acid modified waxy corn starch was prepared in the melting system of lactide. A 1H-NMR method for determining the degree of substitution of polylactic acid modified waxy corn starch was established. With the degree of substitution as the response value, reaction time, reaction temperature and the amount of lactide as the investigation factors, the synthesis process of polylactic acid modified waxy corn starch was optimized through single factor and response surface experiments. The optimum process was obtained as follows: reaction time 12.46h, reaction temperature 111.75 ℃, lactide content 258% of starch. The predicted maximum degree of substitution is 0.0253, and the actual degree of substitution is 0.0238. Through a series of characterization of polylactic acid modified starch prepared under the optimal conditions, it is proved that the particle structure of polylactic acid modified waxy corn starch has not been completely destroyed, and its crystal form and molecular weight are better than those of traditional solvent technology. It will have a broad application prospect in the fields of degradable materials and drug carriers.