On-demand Construction And Performance Research Of Agricultural Cellulose-based Composite Film

The plastic agricultural film plays a role in increasing temperature,retaining moisture,eliminating weeds as well as reducing pests and diseases,providing a good internal environment and microclimate for crop growth,which can enhance crop yields.However,the widely used films in the market are polymeric organic polymer films of polyolefin type,which can cause soil bleaching and affect the growth of crops due to untimely cleaning and recycling,ultimately affecting food production.Thus,to pursue green ecological agriculture,the development of degradable films is an emerging demand for future agriculture.Plant cellulose materials,owing to their abundant raw materials,low cost,and degradable properties,have shown significant research value and good application prospects in the research of degradable agricultural film.This thesis adopts biodegradable plant cellulose as raw material,and focuses on the on-demand construction and functional design of cellulose-based agricultural film.It explores the physical and chemical regulations in the preparation and application of cellulose-based composite film,to solve the problem of limited thermal preservation performance,difficult degradation,and functional singularity of plastic agricultural film.The correlation research is significant in promoting green agriculture and building an energy-saving and low-carbon society.The main research contents are as follows:（1）preparation of thermal insulation AgNW/cellulose composite film for agricultural applicationThe composite film（AgNW/Cellulose）with dual insulation function was prepared via hydrothermal method,solvent blending and evaporation technique by using waste sawdust cellulose,cross-linking agent and functional material silver nanowires as raw material.Due to the excellent infrared reflection and electrical conductivity of the AgNWs,dual thermal insulation can be achieved through heat reflection and electrical heating.As a result,it is shown that the temperature difference between the two sides after covering the composite film is 8.74°C compared to the pure cellulose film,effectively inhibiting heat dissipation.In addition,at a safe voltage of 3 V,it generates a rapid thermal response and uniform electrical heating,raising the surface temperature of the composite film up to 25.7°C within 150 s,which provides an effective solution for crop warming in extreme environments.（2）Preparation of transparent and UV resistant M-RC/LS composite film membrane for agricultural applicationIn response to the shortcomings of AgNW/cellulose composite film,having low transparency and not fully meeting the demand of crops for sunlight,the transparent cellulose-based composite film material was designed and prepared.Using agricultural waste corn husk as raw material,transparent cellulose-based film was prepared by ionic liquid regeneration,followed by surface deposition and surface hydrophobic modification techniques to prepare transparent UV resistant composite film material（M-RC/LS）.The results indicate that introducing lignin derivatives can reduce UV light transmission,shield about 95%of UV light,and allow about 80%of visible light transmission,which can better achieve the UV resistance of the film material.The work provides a resource utilization reference for agricultural waste,which combined with its excellent transparency and UV resistance,is of great value in protecting crop safety and may provide a new idea for replacing petroleum-based plastic films.（3）Preparation of transparent thermal insulation LCNF/Cu NW/PDMS composite film for agricultural applicationsThe composite film with thermal insulation and high light transmission is constructed on demand to meet the combination of sunlight and temperature requirements for plant growth.Lignocellulosic nanofibers（LCNF）were used as the base film and Cu nanowires as a radiation insulation layer to form a composite film material（LCNF/Cu NW）.The transparent hydrophobic agent PDMS was then wrapped around both sides of the film to avoid the collapse of the cellulose substrate and oxidation of the metal nanowires.Results show that adding functional materials to the composite film increases the internal temperature by approximately 5°C,allowing for better autonomous insulation in cold environments.In addition,the visible light transmittance of the composite film is over 70%（>600 nm）,and the UV resistance is up to 95%,ensuring the transmission of the beneficial light sources,enhancing its potential for application in agriculture.（4）Preparation of transparent thermal insulation H-LCNF/SiO₂ composite film for agricultural applicationThe previous section on transparent insulation composites relied primarily on metal as the functional material for insulation,however,reducing heat loss in addition to the way of thermal radiation,enhancing their thermal insulation effect employing lowering the thermal conductivity can envisage.Accordingly,on demand,transparent and thermal insulation cellulose-based composite film material with a hollow structure was constructed.Similarly targeting LCNF as the cellulose-based material,transparent and insulating cellulose-based composite film material（H-LCNF/SiO₂）was prepared by blending hollow silica with LCNF to form a film,then modifying with cetyltrimethoxysilane for surface hydrophobicity.The results demonstrate that the composite film shows low thermal conductivity（0.07±0.002W/mk）,effectively extending the heat transfer path and reducing the heat dissipation rate.Furthermore,the composite film exhibits excellent optical properties,allowing through to 77%of visible light sources and good UV resistance.This research provides a material that differs from traditional metal insulation by constructing a hollow structure to achieve thermal protection,with the advantage of being more energy efficient and environmentally friendly,promising potential applications in agricultural films.