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以玉米淀粉为原料,乙酸酐为酯化剂,乙酸为活化剂,浓硫酸为催化剂,对玉米淀粉进行酯化改性。酯化淀粉取代度范围为0-0.5。采用傅里叶红外(FT-IR)、扫描电镜(SEM)、差示扫描量热(DSC)手段对酯化淀粉进行了结构、表观形貌以及热塑性的进行了表征。红外分析显示乙酰基的成功引入,淀粉分子之间的羟基缔合基团打开。SEM显示了引入乙酰基之后淀粉的表面结构的变化:酯化淀粉的结构随着取代度的增加变得更加疏松。DSC显示了酯化淀粉熔融温度的降低,成膜变得可能。
Using corn starch as raw material, acetic anhydride as esterification agent, acetic acid as activator and concentrated sulfuric acid as catalyst, corn starch is esterified and modified. The degree of substitution of esterified starch ranges from 0 to 0.5. The structure, morphology and thermoplasticity of esterified starch were characterized by FT-IR, SEM and DSC. Infrared analysis showed the successful introduction of acetyl groups, opening up the hydroxyl associative groups between the starch molecules. SEM shows the change of the surface structure of starch after the introduction of acetyl group: The structure of esterified starch becomes more loose with the degree of substitution. DSC shows a decrease in the melting temperature of the esterified starch, and filming becomes possible.