干法预处理协同酯化改性制备高取代度苯甲酸淀粉酯及其性能调控

Preparation of highly substituted starch benzoate by dry pretreatment combined with esterification and its property control

关键词:  干法预处理  苯甲酸淀粉酯  耐水性  热塑性  溶解性

Key Words:dry pretreatment  starch benzoate  water resistance  thermoplasticity  solubility

摘要:以木薯淀粉为原料,首先采用干法预处理对淀粉进行活化,再与苯甲酰氯以摩尔比为1：3,在60℃下反应3 h,进行酯化反应。采用核磁共振(NMR)、扫描电镜(SEM)、傅里叶红外光谱(FTIR)、X射线衍射(XRD)、热重分析(TGA)等对不同取代度产物表征分析。结果表明,预处理可以有效去除淀粉致密的结晶结构,增加反应活性位点。酯化后的产物(Bc-ST3),其形貌由原来的圆形变为无规则碎片状,晶体结构由A型转变为V型,且样品得率(86.68%)和取代度(1.036)分别为未预处理样品(Bc-ST)的约1.5倍和1.7倍,酯化剂利用率达34.5%。此外,Bc-ST3表现出优异的耐水性、热塑性和溶解性,具有在生物材料、可降解包装材料和复合材料等领域的应用潜力。

Abstract:Using cassava starch as raw material, the starch was activated by dry pretreatment, and then reacted with benzoyl chloride at 60℃ for 3 h to esterify. Nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used to characterize the products with different substitution degrees. The results showed that pretreatment could effectively remove the dense crystalline structure of starch and increase the reactive site. The morphology of the esterified product (Bc-ST3) changed from round to irregular fragment, the crystal structure changed from A-type to V-type, and the sample yield (86.68%) and degree of substitution (1.036) were about 1.5 times and 1.7 times of the unpretreated sample (Bc-ST), respectively. The utilization rate of esterification agent reached 34.5%. In addition, Bc-ST3 shows excellent water resistance, thermoplasticity and solubility, which has the potential for applications in biomaterials, degradable packaging materials and composite materials.