Preparation And Properties Of Rice Bran Based Films Materials

With widespread concern over the negative impact of non-degradable plastic products,the demand for biodegradable films is increasing,but its deficiencies in cost and performance make it difficult to promote its application in agricultural land films.Therefore,cheap and easily available film-making raw materials,modified and enhanced bio-based films,and innovative agricultural land film application modes have become the main ways to break through the limitations of biodegradable agricultural land film applications.The use of rice bran,a renewable resource with a wide source and low cost,to prepare agricultural film materials can seek a new breakthrough for the development and promotion of low-cost degradable agricultural films.In this study,a new type of agricultural land film material was prepared using rice bran as the main material.The main research elements are as follows:1)A variety of rice bran-based film materials were prepared using an alkali treatment-wet film forming process.The preferred conditions for film making were determined by screening of film making aids and orthogonal tests: 1:5 ratio of alkali to liquid,50℃and 60 min duration;10% glycerol and 1.6% glutaraldehyde were added to the film forming solution.The tensile strength was 16.9MPa and elongation at break was 1.6%.Structural characterisation showed that the polysaccharides and proteins in the fullcomponent film formed a more thermally stable network structure,and the insoluble substances acted as a synergist,effectively improving the mechanical strength of the rice bran-based film;the weight loss of the full-component film after 60 days of soil burial reached 69.16%,confirming its good degradability.2)The experimental results of the three stages of raw material pretreatment,film forming and post-forming treatment showed that in the raw material treatment stage,the fine grinding treatment of raw material increased the tensile strength of the film by 24.7%compared with the untreated control group;in the film forming stage,the addition of 25℃and p H9 aqueous solution or 55 ℃ and 30% acetic acid aqueous solution to the fullcomponent film forming solution of rice bran could increase the tensile strength of the film by 22.9% and 42.3% compared with the untreated control group.In addition,the addition of exogenous macromolecules such as 20% polyvinyl alcohol,soybean dietary fibre,corn starch,oxidised starch and soybean isolate protein to alcohol washed rice bran increased the membrane tensile strength by 55.3%,11.8%,20%,39% and 40%,respectively,and elongation at break by 92.6%,16.4%,69% and 6%,respectively,compared to the untreated control,16.4%,69%,6% and 33% respectively.Surface silylation modification of the moulded rice bran based full component films resulted in an 81.4% increase in contact angle and a 70% reduction in water vapour transmission rate.3)The liquid agricultural mulch film is prepared from the main material and reinforcement of full-component alcohol-washed rice bran and mugwort dissolved fibres,providing a solution for the convenient and large-scale application of biodegradable mulch.At a mass ratio of 2:5 between the main material and reinforcement,a "soil film" with a tensile strength of 5.12 MPa and an elongation at break of 9.36% was formed and associated with the soil surface particles to form a "soil film" structure of a certain thickness.The temperature fluctuation in the sprayed area was reduced compared to the control area,and the average temperature in the 15 cm deep layer increased by 0.9℃.The soil moisture in the shallow 5cm and deep 15 cm layers increased by 2.1% and 1.7%respectively.