Fabrication And Characterization Of Starch Based Film

Starch is one kind of renewable natural polymer materials, which is very widespread and low-cost. The resource of starch is rich in our country, and the research and innovation of starch product or its related industry are closely related to the development of agriculture, food industry, medicine and other industries. Not only the research of the structure, character of the starch from different kinds of plant, but the study of expanding the type and modification methods of starch, both are very significant for the development and utilization of starch product.The oil resource is becoming shortage and environment is rapidly deteriorative now. Preparation of the starch based composite materials with special function to take the place of traditional plastic, using ample, cheap and renewable starch as material, has great practical significance and application value. The starch based composite materials, which is renewable, environmental, low-cost and capable, can be prepared and widely used in our life by the deepened study of the starch type, other additives and modification methods.The difference between native starch and modified starch was studied by comparing the molecule structure, the gel viscosity and the property of the composited films made from different types of starch. Also, more understanding and deeper analysis about the tensile strength and viscosity of these starches was gained. In addition, the effect of the factors, containing the gel viscosity, the content of plasticizer, the kinds of fortifier or some others, on the property of the composite material, such as the mechanical strength, ductility and hygroscopic property, was investigated. All the studies above have provided a theoretical basis for further research of starch-based composite materials with special function.The experiments showed that molecule structure of starch, viscosity of gel and the mechanical strength of materials all changed, when the raw material was modified by different kinds of amylase. So, isoamylase was chosen as the modifier in the following experiment. Meanwhile, the effect of the dosage of enzyme, the content of fortifier and some other factors, on tensile strength, water permeability and friability of the starch capsule shell was also studied. It is found that the viscosity of gel decreased to about 3000 mPa-s, meeting production requirements of medical hard capsule and availing to control the thickness of the capsules. The addition of 3% carrageenan,0.2% poly vinyl alcohol (PVA),0.5% sodium alginate, etc. ensured the gel property of the starch sol, and increased the tensile strength and toughness of the film when the water absorption performance was stable. When the concentration of the sol was 12%, the surface of the capsules could be smooth, and the thickness could be uniform, the brittle broken performance was also very well controled. In conclusion, corn starch modified by isoamylase can be used as a raw material for the preparation of medicinal plant capsules. And also, a new kind of plant capsule, which is superior and conforming to the standard of medicinal material, can be prepared by the method of using isoamylase to tailor corn starch.Sodium dodecyl benzene sulfonate, which is one kind of anionic surfactant, was used as a modifier to embellish the surface of reduced graphene oxide nanosheets. Some representational techniques, such as SEM, FTIR, X-ray and UV-vis, were used in the experiment. We found that, r-RGO, full of oxygen-containing groups, can be well compatible with starch. By comparing with RGO-starch composited films and GO-starch composited films, the lightproof r-RGO-starch composited films have stronger mechanical strength, better watertightness. That is to say, the composited film has been developed with new performance to protect water and light.