Study On The Preparation And Performance Of Polyethylene-based Nanometer Droplet Controlled-release Film

In recent years,the amount of China's agricultural films and coverage area have become the first in the world.The overall trend of developing functional agricultural films have been focused on high performance,multifunction,specialization,serialization,comprehensive integrated technology.With the continuous exploring of functional greenhouse films,developing films with higher strength,better transparency,longer anti-drip performance has become a hot spot of research in the field of agriculture.Anti-drip performance has become one of the most important functions of agricultural films,since it will directly influence the yield and the quality of greenhouse crops and working environment.In our country,PE anti-drip functional films are mainly prepared by adding anti-drip agent in PE master batch.The most widely used anti-drip agents include senior polyhydric alcohols and esters,organic amine surfactant,alkyl phenols surfactants and other organic compounds,which share characteristics like excellent anti-drip ability at low temperature,and the low relative molecular mass and melting point lead to anti-drip agent easy volatilization and decomposition at high temperature processing.In addition,because the polarity difference between anti-drip agent and PE resin is huge,anti-drip agent prone to migration and aggregation,resulting "frost spray" phenomenon,not only affect the film transparency,causing the film surface sticky and adhere dust severely,but also a shorter anti-drip lifespan.Compared to Japan,Europe and other developed countries,anti-drip films lifespan of anti-drip performance in China is short(2-4 months)while crops growth requires at least 5 to 6 months.Therefore,extending the lifespan of our anti-drip agricultural films is extremely important.The enervating anti-drip performance will lead to the following problems:First,it changes light scattering or reflection,which directly affect film transparency and the growth of plants;Second,droplet dripping on the plant will cause the leaves,stems,buds to rot;Finally,it will increase the humidity in the greenhouse,provide a suitable condition for plant disease.These problems will decrease the yield and quality of crops.Therefore,the research of agricultural anti-drip film is vital.In order to improve the anti-drip performance in our country and shorten the gap with foreign advanced technology,we first prepared a novel LD-KS,then used LD-KS and montmorillonite(MMT)synthesized NANO-LD-KS by the solution intercalation method.In the end,evaluating PE/NANO-LD-KS's actual effect through farmland experiment.The specific research contents as follows:(1)The preparation of NANO-LD-KS.Using montmorillonite(MMT)and LD-KS synthesized NANO-LD-KS by the solution intercalation method.FTIR and XRD results demonstrate that LD-KS successfully intercalated into the interlayer of MMT,and the MMT:LD-KS=100:40 is the optimal reaction ratio;TG results showed that,compared with LD-KS,NANO-LD-KS initial decomposition temperature increased by 47.23 °C,the maximum decomposition temperature increased by 270.58 °C,and the thermal stability were improved obviously;FA results showed that the NANO-LD-KS can absorb ultraviolet rays at 254 nm and emission blue violet light at 350?450 nm(which is useful to the growth of crops).(2)The preparation of PE/NANO-LD-KS.NANO-LD-KS Master-batch were prepared by direct melt intercalation method using NANO-LD-KS and other processing aids and PE,through the three layer coextrusion blow molding production process for preparing PE/NANO-LD-KS.XRD results showed that NANO-LD-KS was completely dispersed in PE/NANO-LD-KS;TG results showed that,compared to PE/LD,PE/NANO-LD-KS initial decomposition temperature increased by 9.9 ?,the heat resistance was improved;SCA results showed that PE/NANO-LD-KS,compared to PE/LD,PE/NANO-LD-KS's static water contact angle decreased 15.35°,the wetting ability was improved;Mechanical property test showed that,compared with PE/LD,PE/NANO-LD-KS tensile strength improved 7.90%,the elongation at break increased by 9.51%,tear strength increased by 19.2%,the mechanical properties was improved;Anti-drip performance test showed that,first drop time of PE/NANO-LD-KS was 111s shorter than PE/LD.High temperature anti-dripperformance test and low temperature anti-dripper formance test showed that,PE/NANO-LD-KS anti-drippersistence improved.Among them,the high temperature flow drop performance test,PE/NANO-LD-KS anti-drip duration can reach 5 days while low temperature dripping performance test,PE/NANO-LD-KS anti-dripduration can reach 6-7 days.(3)In order to further verify the actual effect of PE/NANO-LD-KS in agricultural planting,we tested the greenhouse light intensity,air temperature,air humidity,soil temperature,soil moisture,CO2 concentration and other environmental factors.Thefarmland experiment was carried out in Liuhe Base,in Jiangsu Academy of Agricultural Sciences,Nanjing,Jiang-su Province.By the light intensity analysis,PE/NANO-LD-KSlight transmittance is higher than that of PE/LD;By the soil temperature and air temperature analysis,PE/NANO-LD-KS can maintain the soil temperature rangebetween 19.5 °Cto 21.7 °C,more suitable for the growth of polished rod chrysanthemum(Chrysanthemum likes to grow at cooltemperature and the optimum growth temperature is around 20 ?);By theair humidity and soil moisture analysis,PE/NANO-LD-KS airhumidity was increased 4%-20%than the PE/LD,PE/NANO-LD-KSmore conducive to like moisturevegetable growth;by the CO2 concentration analysis,PE/NANO-LD-KSphotosynthesis was more obvious;By the yield and quality analysis,PE/NANO-LD-KScan promote crop 5-6 days prior to the listing,and the quality and yield were increased,the yield can increase 28.9%.The farmland experiment has continued for 18 months(2013.10-2015.03),at present still has good anti-drip performance.Therefore,PE/NANO-LD-KS not only has excellent anti-drip performance,but also can effectively improve the yield and quality of the polished rodchrysanthemum.It's suitable to promotion as a novel agricultural anti-drip film.