不同直链含量热塑性淀粉的制备及性能研究

利用转矩流变仪，以丙三醇为增塑剂对不同来源的淀粉进行改性制备热塑性淀粉（TPS）。采用X射线衍射仪（XRD）、热重分析仪（TG）、水接触角测量仪、傅里叶变换红外光谱仪（FTIR）和扫描电子显微镜（SEM）等对获得的热塑性淀粉进行了表征。结果表明，4种热塑性淀粉均含有颗粒状和颗粒状碎片，并且在热塑性木薯淀粉中所含比例更高；淀粉在增塑过程中达到稳态的扭矩依次为木薯淀粉（23 N·m）>玉米淀粉（21 N·m）>马铃薯淀粉（17.8 N·m）>蜡质玉米淀粉（15.2 N·m），这与不同种类来源淀粉的直链淀粉比例差异直接相关；不同类型的淀粉与增塑剂形成氢键的能力存在差异，蜡质玉米淀粉的能力最强；4种热塑性淀粉的亲水性依次为热塑性木薯淀粉（75.9 °）>热塑性玉米淀粉（69.2 °）>热塑性马铃薯淀粉（67.9 °）>蜡质玉米淀粉（64.9 °）。

Preparation and Characterization of Thermoplastic Starch with Different Contents of Amylose

Modified thermoplastic starch （TPS） was prepared through a torque rheometer using different sources of starches as raw materials and propylene glycol as a plasticizer. The resultant thermoplastic starch was characterized with X?ray diffraction， thermogravimetric analysis （TGA）， water contact angle and scanning electron microscopy. The results indicated that there were four types of thermoplastic starches containing granular and granular fragments， in which the proportion of thermoplastic cassava starch was higher. The torque of starch reached an steady state in the carbohydrate process in an increasing order of cassava starch （23 N·m） > corn starch （21 N·m） > potato starch （17.8 N·m） > waxy corn starch （15.2 N·m）. This result is directly related to the amylose ratios among these different starches. According to the infrared analysis result， there was a different hydrogen bonding capability between the different types of starches and plasticizer. Waxy corn starch exhibited the strongest bonding， which was consistent with the TGA results. The four types of TPS presented an increase in the level of hydrophilicity in an order of thermoplastic cassava starch （75.9 °）>thermoplastic corn starch （69.2 °） > thermoplastic potato starch （67.9 °） > waxy corn starch （64.9 °）.