Study On The Preparation And Performance Of Polyethylene-based Nano Light Conversion Film

The functionality and performance of agricultural film have been a focus in its research and development.Multi-function agricultural film with high quality and performance are certainly in demand.Moreover,the development of such functional agricultural film has been listed in National Agricultural Science and Technology Development Program.The method of preparing photo conversion film by adding photo conversion agent to traditional PE agricultural film was one of the important means for efficient utilization of solar energy and increasing yield of crops.Economic and social benefits has been achieved since China introduced,researched,applied and extended photo conversion film.However,application was limited even after development and application for nearly thirty years because of several problems including cost,manufacturing process and fluorescence lifetime.Therefore,developing photo conversion film with stable photo conversion property,prolonged lifespan,enhanced strength,better photo transmission,easy molding process and high cost-effective has become hot spots in the filed of agricultural research.Intercalation agent RACA-B with photo conversion function was firstly designed,nano organic/inorganic composite photo conversion agent(NANO-ZG-GG)was then prepared by taking advantage of the structure characteristic of inorganic layered materials.Photo-conversion master batch was prepared by the method of melt intercalation based on NANO-ZG-GG.The triple layer coextrusion blow molding production process and the method of melt intercalation were subsequently utilized for the preparation of new polyethylene nano photo conversion film(PE/NANO-ZG-GG).The field experiments were finally carried out in Liuhe animal science base of Agricultural Sciences Academy of Jiangsu Province,and the actual application effect of PE/NANO-ZG-GG was evaluated.The main research conducted are the following:(1)Preparation of nano organic/inorganic composite photo conversion agent.The functional intercalation agent RACA-B was firstly designed and synthesized.The reaction mechanism and physicochemical properties of RARA-B intercalating into the interlayer of inorganic material was studied under different conditions such as temperature and mass ratio.The nano organic/inorganic composite photo conversion agent(NANO-ZG-GG)was designed and synthesized.Test results by XRD and FTIR analysis showed RARA-B successfully entered into the interlayer of inorganic material.SEM images of NANO-ZG-GG indicated some degree of fold and fracture occurred on the layer surface,resulting loose flaky aggregate.TGA analysis showed the heat resistance of NANO-ZG-GG was improved significantly.Fluorescence spectra demonstrated that when the excitation wavelength ranged from 280 to 300 nm,maximum of fluorescence emission wavelength of NANO-ZG-GG ranged from 390 to 430 nm.Ultraviolet light can be absorbed by NANO-ZG-GG and converted to 370?480 nm blue light emission.The particle size distribution of NANO-ZG-GG was tested by DLS and the results showed the particle size distribution was relatively uniform and can be used as functional additives for photo conversion film.(2)Study on preparation and properties of polyethylene nano photo conversion films.Photo conversion master batch was firstly prepared by the method of melt intercalation based on NANO-ZG-GG.The exfoliated polyethylene nano photo conversion film(PE/NANO-ZG-GG)was prapared by the method of melt intercalation on the base of NANO-ZG-GG and polyvinyl.The photo conversion property and the fluorescence stability of PE/NANO-ZG-GG were studied by fluorescence spectrum analysis.The results showed PE/NANO-ZG-GG could effectively absorb ultraviolet light which was harmful to plants and greenhouse film and convert it into blue-violet light ranged from 380 to 485 nm.The photo stability was basically unchanged and the fluorescence intensity actually increased after covering shed in the field for 9 months.The light transmittance of PE/NANO-ZG-GG was lower than that of the control film in UV-C,UV-B and UV-A band.In the red-orange and blue-violet region,the transmittances of photo conversion film were 2.43%and 1.82%respectively higher than that of the control.Thermogravimentric analysis results showed that the heat resistance of photo conversion films improved due to the addition of nano photo conversion agent.The test of mechanical property results showed the numerical range of tensile strength,elongation at break and right angle tear strength were all better than the national standard,which showed the mechanical property of photo conversion film improved.(3)The field experiments of polyethylene nano photo conversion film.The effect of PE/NANO-ZG-GG was studied by the method of field experiments in Liuhe animal science base of Agricultural Sciences Academy of Jiangsu Province.The environmental factors such as intensity of illumination,air temperature,air humidity,soil temperature,soil moisture and carbon dioxide concentration were monitored and recorded continuously by the intelligent monitoring system.The actual application effect of PE/NANO-ZG-GG was evaluated by analysing the growth of lettuce in the greenhouse which was covered by PE/NANO-ZG-GG.The study showed the transmittance was not affected based on illumination intensity of PE/NANO-ZG-GG.The air temperature in plastic shed greenhouse with PE/NANO-ZG-GG increased faster and the warming effect was better than greenhouse with control film during both sunny and rainy day.PE/NANO-ZG-GG could help increase the soil temperature in the plastic shed greenhouse and the soil temperature rose faster in both sunny and rainy day.In addition,large temperature difference between day and night was more useful for the growth of plants in greenhouse to a certain degree.Combined the effect of photo conversion film on carbon dioxide concentration,air humidity and soil moisture,the environment in plastic shed greenhouse with PE/NANO-ZG-GG was more suitable for the growth of plants.According to the effect of PE/NANO-ZG-GG on the growth of romaine lettuce,photo conversion film had an obvious effect on the height and fresh weight and could effectively improve the yield of lettuce.