Study On Preparation And Properties Of Jute Mulching Film By Wet-laying Nonwoven Process

In modern agriculture,the use of plastic mulching film can increase crop yields and farmers' incomes,and has achieved rapid growth in China.However,due to the difficulty in plastic film degradation,it has a negative impact on crop yield and environment.Therefore,under the condition of satisfying the heat preservation of the crop,the jute mulching film can not only completely degrade in a certain period of time,but also the degraded product can improve the soil fertility.Therefore,the use of environmentally friendly jute film instead of plastic film has gradually become a research hotspot,which is of great significance for improving crop yield and sustainable development of agriculture in China.The traditional ramie mulching film has good permeability,which makes it poor heat preservation and moisture retention.The products obtained by the wet non-woven method are relatively dense,which may reduce permeability of the mulching film but improve the heat preservation and soil moisture conservation.Therefore,this topic mainly uses the wet-laying non-woven process to prepare the mulching film and explore its performance.The main raw material of the mulching film is jute.The preparation of the wet film is made of sodium carboxymethyl cellulose and water-based polyurethane,respectively.Finally,the performance test and optimization process are carried out.Firstly,the effect of jute shear length on the performance of wet-laying mulching film was discussed.The results show that with the increase of the shearing length,the breaking tenacity and gas permeability of the mulching film is gradually increased.Then,the optimum process parameters for preparing a wet-laying jute mulching film using sodium carboxymethyl cellulose as a binder were determined.The concentration of carboxymethyl cellulose was 1%,the pulverization time of jute was 50 seconds,the concentration of the wet strength agent was 1%,and the hot rolling temperature was 160°C.Finally,wet-laying jute film was prepared by using waterborne polyurethane as binder.The optimum concentration of waterborne polyurethane before and after hot rolling of polyvinyl alcohol was studied.The results show that the wet-laying jute mulching film prepared by using 1.0% aqueous polyurethane as a binder is suitable;the film prepared by using an aqueous polyurethane emulsion as a binder has a smaller dry-and-wet strength and a greater gas permeability than that prepared by sodium carboxymethyl cellulose.The permeability of the jute film was significantly reduced after impregnation with polyvinyl alcohol before hot rolling,but the decreasing degree of permeability gradually decreases as the gram weight increased.The dry strength of the wet-laying jute mulch film after hot-rolling with polyvinyl alcohol was increased,but the wet strength did not change much.Secondly,a slurry was prepared by using a PL4-00 23-liter agitator,and sodium carboxymethyl cellulose or water-based polyurethane was added as a binder to produce a wet-laying jute mulching film on a PL6-C paper sample collector.Comparing the performance of wet jute film prepared by machine with that prepared by hand,the results show that the film prepared by machine is superior to the manual film in gas permeability and dry-and-wet strength,which is mainly reflected in the decrease of permeability and the improvement of strength.Finally,the waterproof treatment of the wet-laying jute mulch film prepared under the optimum process was carried out,and two kinds of waterproof finishing agents(hydrocarbon resin water repellent texnology?M380 and silicone water repellent texnology?638)were selected.Waterproof finishing was carried out with different concentrations,the contact angle and water immersion were tested,and the gas permeability and breaking strength of the jute film before and after waterproof finishing were compared.The results show that the water-based resin waterproofing agent with a concentration of 60g/l was a better choice;through the waterproof finishing,the permeability of the wet jute coating was slightly increased,and the breaking strength was slightly decreased,but the change was small.In addition,the moisture permeability and degradability of the wet-laying jute mulch film were investigated.The results show that the jute film has a certain moisture permeability;and the jute film can be completely degraded in a certain period of time.