Study On Preparation And Properties Of Nano All-cellulose Composite For High Adsorption Based On The Dissolution Of Cotton Stalk In Ionic Liquid

21 century,creation of new materials has become an important focus of widespread concern in the world of science and technology development.Preparation of new materials and the use of waste reprocessing and recycling of its increasing attention.Because of its unique cellulose renewable and carbon balance has been unprecedented attention,the natural cellulose annual output of about 9 × 1010 t,to meet human materials,environmental protection and increasing biocompatibility.So,explore new materials cellulose and cellulose-containing waste resources efficient utilization of essential importance.The problem with waste cotton stalks as raw materials,through the 1-buty-l-3-methylimidazolium chloride?[BMIM]Cl?dissolved cellulose solution preparation with cotton stalk bark fiber composite using a coagulation bath-regenerated cellulose and thermoforming processes to prepare fully cellulose composite material.Respectively,to explore the cellulose solution viscosity,reinforcing fiber length,mass percentage,pressing temperature,pressing pressure,coagulation bath type,plasticizer glycerol concentration,temperature regeneration and regeneration time and the effect of drying on Composites.In addition,based on the whole cellulose composite material preparation process,through the cotton stalk cellulose and chitosan complex ionic liquids were mixed and dissolved to prepare a cellulose / chitosan solution,using supercritical CO₂ drying method with high adsorption performance composite materials,and investigate its adsorption and adsorption temperature,adsorption time and compounding ratio on the adsorption properties.Topics using scanning electron microscopy,X-ray diffraction?XRD?,Fourier transform infrared spectroscopy,etc.internal structure,changes in the fiber structure of the whole cellulose composites,as well as changes in the mechanical properties of the crystalline characterization.The results show that under the same conditions of concentration,cellulose concentration of 8%,the cellulose solution viscosity with temperature changes in the most significant by 2194 Pa.s 90 ? is reduced to 434 Pa.s 120 ?,and decreased 80.14% and greatly reduce the viscosity at 105 ?.And at the same temperature,the solution viscosity of cellulose fibers of different quality of cotton stalks and with the gradual increase of the percentage of concentration of the cellulose growing trend.At 105 ? conditions,cellulose solution viscosity increased rapidly over the concentration range of 2% to 8%,an increase of 211.11 %;in 8% to 12% range,the viscosity of the rate of change is slow,growth rate of only 107.04 percent.With the continued increase in the concentration of the cellulose,the viscosity of 12% to 16% growth rate of 153.28 percent: and in 18% to 20% cellulose concentration range of viscosity changes flatten growth rate of only 5.90%.By comparing the tensile properties of the composites found at 105 ?,the critical concentration of the solution of cellulose 8%,the tensile strength reaches a maximum for 45.23 MPa.In the cotton stalks and regenerated cellulose fiber obtained infrared spectroscopic analysis,cotton stalk fiber configuration is?type,?configuration is regenerated cellulose,cellulose crystal ? configuration and the wave number 1425cm^-1 and 1428cm^-1 appears crystal ? stretching vibration absorption peak configuration was confirmed without any new chemical functional groups generated in the fiber dissolution and regeneration process belongs only to physical changes.XRD curve,2? angle of 14.72 °,16.30 ° and 21.92 ° characteristic diffraction peaks may appear to correspond to the crystal structure of cellulose ??110?,?110?and?200?crystal face;2? = 21.36 °,22.0 ° and 23.22 ° characteristic diffraction peaks may appear to correspond to the cellulose crystal structure ??110?,?200?and?110?crystal plane.It confirmed the cellulose dissolution and regeneration process is cellulose I into the cellulose II type crystal lattice structure change significantly.By optimum conditions integrated tensile strength and taking into account production costs,reduce consumption and other factors,the whole cellulose preparation of the composite material finally obtained optimum conditions were: a fiber length of 10 mm,the reinforcing fiber content of 26.7%,the pressing temperature 50 ?,pressing pressure of 6MPa,select a coagulation bath of deionized water,1.5% glycerol concentration,the regeneration temperature is 0 ?,regeneration time 16 h,the drying method using a vacuum drying oven.Optimal use of technology obtained sheet tensile strength 59.85 MPa,elongation at break of 4.33%.Cotton stalk cellulose supercritical CO₂ drying preparation/CS composites were Heavy Metal Pb²⁺ ion adsorption performance test results showed that the cellulose / chitosan ratio of 1: 2,the adsorption capacity of the composite up to 38.683 mg/g;at the same time in the adsorption temperature of 10 ?,the adsorption capacity of 15.46mmg/g;the temperature is 50 ?,the adsorption reached 15.55mg/g,small changes,only less than 1%,indicating that the adsorption temperature on the adsorption properties of the material was less affected.When adsorption 50 min,the adsorption reached 25.56mmg/g,the adsorption rate was 51.52%;in 50-100 min,adsorption rate begins to gradually reduce the adsorption rate decreased to 16.60%.With time adsorption time,adsorption curve to flatten,adsorption stable at 34 mg / g around this level.