以新型塑化剂制备的淀粉膜性能研究

STUDY ON THE PROPERTIES OF STARCH-BASED FILM USING NEW PLASTICIZERS

分别以N-甲基-N-(2-羟乙基)甲酰胺(HEF)和N-(2-羟丙基)甲酰胺(HPF)为新型的淀粉塑化剂,利用流延法制备热塑性淀粉膜,与以传统塑化剂甘油制备的热塑性淀粉膜(GSF)进行了对比。用扫描电镜(SEM)观察淀粉膜(SF)的微观形貌,以HEF为塑化剂制备的淀粉膜(HESF)和以HPF为塑化剂制备的淀粉膜(HPSF)均是均一连续相的材料。用X-射线衍射(XRD)表征淀粉膜的结晶,原淀粉的双螺旋结晶消失,诱导结晶形成。用差示扫描量热仪(DSC)测淀粉膜的玻璃化转变温度。在75%相对湿度(RH)下对淀粉膜的水蒸气透过性能和力学性能进行测定。HESF和HPSF的水蒸气透过率(WVP)比GSF低,即HESF和HPSF的水蒸气阻隔性能优于GSF。随着塑化剂含量的增加,淀粉膜的断裂伸长率增加,但是抗拉伸强度下降。

N-（ 2-hydroxyethyl）-N-methylformamide（ HEF） and N-（ 2-hydroxypropyl） formamide（ HPF） were used as new plasticizers respectively for corn starch to prepare thermoplastic starch film（ SF） by casting method. The properties of starch film using traditional plasticizer glycerol（ GSF） was compared with that of the starch films using new plasticizers. The morphology of SF was examined by scanning electron microscopy（ SEM）,homogeneous materials were formed for both SF using HEF as plasticizer（ HESF）and SF using HPF as plasticizer（ HPSF）. Crystallinity of SF was characterized by X-ray diffraction（ XRD）,the double helical structure crystal lattice of the original corn starch disappeared,and the induced crystallinity formed. The glass transition temperatures（ Tg） of SF were measured by differential scanning calorimetry（ DSC）. At relative humidity（ RH） 75%,the water vapor permeability（ WVP） and mechanical property of SF were tested. The WVP of HESF and HPSF were lower than that of GSF,i. e. the water vapor barrier properties of HESF and HPSF were better than that of GSF. With the increasing of plasticizer content,the elongation at break of starch film increased,but the tensile strength decreased.