OSA改性高直链玉米淀粉复合疏水膜的制备及性能研究

Preparation and properties of hydrophobic composite film based on OSA⁃modified high amylose corn starch

选用辛烯基琥珀酸酐(OSA)对高直链玉米淀粉(HACS)进行酯化处理,制备了3种不同改性程度的OSA淀粉(OS⁃3、OS⁃6、OS⁃9)。以3种OSA淀粉为原料,明胶为复配大分子,制备了3种OSA改性高直链玉米淀粉复合膜(OS⁃3/GEL、OS⁃6/GEL、OS⁃9/GEL),考察了复合膜的透光性、水溶性、吸湿性、水蒸气透过率及表面疏水性。结果表明,相比原淀粉复合膜,OSA改性高直链玉米淀粉复合膜各项性能均得到改善。其中OS⁃6/GEL的性能表现最佳,透光率达到87.72%,水溶性下降了24.5%,吸湿性下降了29.6%,水蒸气透过率下降了30.35%,表面最大静态接触角达到124.6°,动态接触角在3 min后仍达到100°以上;OSA改性降低了原淀粉的结晶度,提高了成膜组分间的相容性;OSA基团的引入使得淀粉与明胶分子中羟基作用减弱,二者间产生更为强烈的氢键作用。OSA改性改善了原淀粉复合膜的疏水性能,适量OSA基团引入制备得到的OS⁃6/GEL性能最佳,成膜表现出优异的疏水性能。

In this study,high amylose corn starch(HACS)was esterified with octenyl succinic anhydride(OSA)to obtain three types of OSA starchs with different degree of modification(OS⁃3,OS⁃6,and OS⁃9).Three types of OSA⁃modified high amylose corn starch composite films(OS⁃3/GEL,OS⁃6/GEL,and OS⁃9/GEL)were prepared using the as⁃prepared OSA starchs as raw materials and gelatin as a compound material.The light permeability,water solubility,moisture absorption,and surface hydrophobicity of the composite films were investigated.The results indicated that the properties of OSA⁃modified starch composite films were greatly improved compared to the unmodified starch composite film.OS⁃6/GEL exhibited the best performance with high light transmittivity of 87.72%.However,its water solubility,moisture absorption,and water vapor transmittance decreased by 24.5%,29.6%,and 30.35%,respectively.In addition,its maximum static contact angle and dynamic contact angle reached 124.6°and more than 100°,respectively,after contact with water for 3 min.X⁃ray diffraction results indicated that the crystallinity of the original starch was reduced by the OSA modification,and the compatibility between the film⁃forming components was improved.Infrared spectroscopy analysis demonstrated that the introduction of OSA group weakened the interaction between the starch and the hydroxyl groups in gelatin molecules,causing the stronger hydrogen bonding between the two groups.Based on the properties and structure of the composite films,it could be concluded that the OSA modification enhanced the hydrophobic properties of the high amylose corn starch composite films.Through introducing an appropriate number of OSA groups,the resultant OS⁃6/GEL presented the best properties and excellent hydrophobic performance.