Study On Degradable Nutrition Plastic Film On Plateau

The rapid development of agricultural technology lead to the demand of film is continuously increasing. After computation, so far, it takes 30-100 years to degrade the waste plastic film. Also, the residues cause adverse affect in soil environment, and some degradation products even cause secondary pollutions. These facts suggest that it is important to strengthen the research of friendly degradable plastic film and degradation products in plateau environment.The major material as nutritional degradable film in this study selected fully biodegradable corn starch and polyvinyl alcohol. In plateau regions, for shortening degradation period, the photosensitizer is added through the film preparation. Meanwhile, the nutriments (humic acids) are added in this process so that the degradation of plastic film as fertilizer to soil. This article focus on the preparation method and preparation technology of degradable nutritional film in plateau regions. After the biodegradation experiment of the film, and through analyzing the degradation performance, conclusions show as follow:(1)When the proportion of PVA, glycerol and photosensitizer are 40%,25% and 0.3% that mechanical property of degradable nutritional film is best. The tensile strength of degradable nutritional film of plateau is 19.5 MPa, and the elongation at break is 265%. Compared with the environmental film, degradable nutritional film has better mechanical property.(2)After heat preservation and moisturizing experiment of under 5cm soil samples, the temperatures of covered degradable film and degradable nutritional film are 0.22℃ and 0.36℃, and higher than the soil samples with no covered. The results show that degradable nutritional film of plateau has better good effect of heat insulation. Film of water absorption and loss rate increase as time increases, but the water absorption is always greater than the total rate of loss, so that the film can act as a role of moisture(3)By degradation test (UV aging, bury, naturally sunning), the results show that with the increase of degradation time, the hole of film will increase, the weightlessness rate of film will increase, the mechanical property of film will decrease, and the carbonyl index of film will increases. The film starts to degrade after 30 days after, and the degradation period is about 80-90days.(4)After using degradable nutritional film, the soil nutrient content of nitrogen, potassium and phosphorus increase approximately 0.32%,0.1% and 0.06%, the results show that using nutritional degradable film of plateau can improve soil fertility.