Environmentally-friendly controllable degradation agricultural film and preparation method thereof

Abstract

The invention discloses an environmentally-friendly controllable degradation agricultural film. The agricultural film is prepared from the following raw materials in parts by weight through melt blending and extrusion film blowing: 25-50 parts of polyvinyl alcohol, 72-87 parts of starch, 10-20 parts of micro-molecular plasticizer, 0.2-2 parts of modified inorganic nano auxiliary agent, 0.5-1.5 parts of antioxidant, 0.5-1.5 parts of compatibilizer and 0.2-1.5 parts of ultraviolet ray absorbent. The invention also discloses a preparation method for the agricultural film. A certain amount of inorganic nano auxiliary agent which is subjected to surface treatment is added while the micro-molecular plasticizer which can easily form a hydrogen bond with the starch is adopted as a nano composite modifier included in the agricultural film provided by the invention, so that the using amount of the micro-molecular compatibilizer can be greatly reduced to reduce cost and avoid a problem of reduced mechanical property at the later stage of a thin film after PVA (Polyvinyl Alcohol) is modified by the compatibilizer, and the controllable completely biodegradable agricultural film with plastic thin film mechanical property and later stage service performance can also be obtained.

Description

technical field [0001] The invention belongs to the technical field of agricultural mulch and its preparation, and in particular relates to an environment-friendly controllable degradable agricultural mulch and a preparation method thereof. Background technique [0002] At present, drought caused by resource consumption and environmental deterioration is an extremely serious problem in my country's agricultural production. In agricultural production, mulching with plastic film not only has the functions of moisturizing, water retention, fertilizer preservation, pest control and weed control, but also can maintain soil moisture, improve water use efficiency, improve the growth environment of crops, increase crop yield and agricultural benefits, so the application is more widely. According to reports, agricultural mulch has become the third largest agricultural material after chemical fertilizers and pesticides in agricultural production. But unfortunately, the "white pollut...

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Problems solved by technology

But it still has some problems: 1) due to the excessive amount of plasticizer added (at least 24wt%, up to 38wt%), it is inevitable that this type of film will produce plasticizer on the film surface after standing for a period of time. The problem of precipitation, on the one hand, will reduce the mechanical properties of the film in the later stage, affect the performance, and on the other hand, it will increase the cost

2) Because the amount of starch added is not high (only 8.17-38wt%), it will not only make the cost of the obtained film still high, but also affect the degradation rate of the film to a certain extent

3) Due to the added ZnO / SiO 2 The preparation process of composite powder is very complicated, the cycle is long and the chemical reagents used are large, which will undoubtedly affect the production capacity of the film and increase the cost to a certain extent.

[0006] Other studies have shown (Wang Yunfang et al., Progress in Research on Starch-Based Environmentally Degradable Polymer Materials [J], Materials Herald, 2005, 4:12-15), while starch can improve the degradability of plastics, on the one hand it will cause its physical degradation. The decline in mechanical properties makes it difficult to process. On the other hand, it is too hydrophilic and has poor compatibility with most general-purpose resins, resulting in a significant decline in the mechanical properties of the material, thus hindering the industrialization of starch plastics. Wide application in the promotion process

Therefore, in order to ensure the end-use performance of starch-based plastic products, the general solution is to reduce the amount of starch added, but this will bring about higher product costs and slower degradation.

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