末端阳离子淀粉膜的制备及疏水改性

Preparation and Hydrophobic Modification of Terminal Cationic Starch Film

针对淀粉膜材料强度低和疏水性较差的问题,文中以高直链玉米淀粉(HACS)为原料,采用“还原胺化法”在HACS分子链末端引入炔基,然后通过叠氮-炔点击化学反应得到分子链末端带正电荷的阳离子淀粉(TCS),在浇铸成膜过程中利用电场对淀粉膜的力学性能进行调控。此外,为提高淀粉膜的疏水性能,利用羟基硅油对淀粉膜进行涂饰改性。采用傅里叶变换红外光谱(FT-IR)、全数字化核磁共振谱仪(NMR)、二维小角散射(2D SAXS)等方法对TCS进行表征,FT-IR和NMR结果表明成功制备了目标产物TCS。而2D SAXS结果证实,在外加静电场的条件下,TCS薄膜中淀粉分子链趋向有序,这与力学性能测试数据相互印证(电场作用制膜的拉伸强度较无电场处理提高了52.5%)。接触角实验表明,经疏水处理后的羟丙基高直链玉米淀粉/末端阳离子淀粉(HPHACS/TCS)膜接触角提高了48.2%。因此,文中所采用的淀粉改性方法为制备高强度疏水性淀粉膜材料提供了借鉴,可拓展淀粉膜在包装材料方面的应用。

Due to the problems of low strength and poor hydrophobicity of starch film,high-amylose corn starch(HACS)was used for modification.In the first place,the molecular chains of HACS(reducing end)were grafted with alkynyl.Afterward,the azide-alkyne click chemistry reaction was used to the graft cationic to obtain a positive charge located at the end of starch chain(TCS).Based on modified starch,starch films were prepared under the action of an external electric field.Finally,the films were hydrophobized with hydroxy silicone oil.The films were characterized by FT-IR,NMR,2D SAXS,etc.The FT-IR and NMR confirm that the target product(TCS)was synthesized successfully.Combined with the tensile test and 2D SAXS,the results indicate that the molecular chains tend to be oriented with the external electrostatic field.The tensile strength and contact angle of the HPHACS/TCS film are increased by 52.5%and 48.2%,respectively.Therefore,this method can be used as a reference for preparing high strength hydrophobic starch film materials and can extend the application of starch film in packaging materials.