【摘要】 蔗糖酯是一种对环境无害的表面活性剂,含有与淀粉相容的极性头.将不同比例蔗糖硬脂酸酯加入到玉米淀粉或20%尿素增塑的玉米淀粉中,在热水中煮浆后浇铸成膜.采用X-射线衍射法表征淀粉膜的结晶结构,并测定了浆膜在不同相对湿度下的吸湿性以及浆膜的拉伸性能.结果表明,蔗糖酯可与淀粉形成V-型包合配合物,并影响淀粉的B-型结晶,因此改变淀粉的吸湿性和力学性能.添加0.5%蔗糖酯使淀粉的吸湿率提高,随着蔗糖酯进一步增加,淀粉的吸湿率下降.含尿素20%的淀粉混合物中添加不同比例的蔗糖酯,对淀粉材料的结晶度、结晶形态,以及吸湿率和力学性能产生了不同的影响.蔗糖酯与尿素对淀粉材料改性具有协效作用.含蔗糖酯0.5%的尿素增塑淀粉膜显示出非晶特征,且具有较高的断裂伸长.更多还原

【Abstract】 Sucrose stearate(SS) is an environmentally sound surfactant with a polar head compatible with starch.Different proportions of SS was blended with corn starch or plasticized corn starch with 20% urea.The mixture was pasted with hot water and cast into films.The crystal structure of the films was characterized by using X-ray diffraction,and the moisture adsorption and the tensile performance were tested.The results indicated that SS interacted with amylose to form a V-type inclusion complex and had influences on the B-type crystallization of starch.Therefore the moisture adsorption and the tensile performance of starch films changed with their SS content.The moisture adsorption of the starch film increased upon adding a small amount of SS(say,0.5%),and then decreased with further increase of the content of SS.After adding SS into the plasticized starch with urea 20 wt%,the crystallinity,crystal size,moisture adsorption and tensile property of the starch films changed with the SS content in a complicated manner.SS and urea showed a synergistic effect of modification on starch materials.The starch film plasticized with 20 wt% urea and combined with 0.5 wt% sucrose stearate showed an amorphous feature of X-ray diffraction and higher elongation at break.更多还原