Preparation Of Porous Diacetate Fiber By Dry Spinning Process And Its Adsorption Performance For Flue Gas

With the development of technology and the strengthening of people's environmental awareness,the demand for natural renewable fiber materials has become increasingly significant.As a kind of environmentally friendly fiber material with strong adsorption capacity,good dimensional stability,and biodegradability,cellulose diacetate fiber is one of the current research hotspots of environmentally friendly fiber adsorption filter materials.Porous cellulose diacetate fiber not only retains the good properties of the raw material,but the porous structure can give it a larger specific surface area and surface energy,which is conducive to improving the comprehensive performance of porous cellulose diacetate fiber material.Dry spinning is the most extensive spinning process for producing cellulose diacetate fiber.Therefore,seeking a production process for preparing porous cellulose diacetate fibers by dry spinning is of great significance for further expanding the application field of cellulose diacetate fibers and enhancing the product value of porous cellulose diacetate fibers.Firstly,diacetate cellulose composite fibers were obtained from highly volatile solvent system,in which diacetate cellulose with a certain amount of CaCO₃ was dissolved in dichloromethane/acetone blend solvent.And then the diacetate cellulose porous fibers were constructed by removing CaCO₃ from diacetate cellulose composite fibers.In this work,The effect of mass fraction,CaCO₃ and also solute ratio on the rheology properties of spinning solution was investigated.The morphology and specific surface area of the as-spun diacetate cellulose fibers were characterized by scanning electron microscope?SEM?,3D field microscope,and BET.The aldehydes adsorption effect of fibers was tested and analyzed by ultraviolet-visible spectrophotometer?UV-Vis?.The experimental results show that when the concentration of the spinning solution decreases,the fluidity of the spinning solution will be significantly enhanced.Taking the shear rate of 80s^-1 as an example,when the spinning concentration increases from 15wt%to23wt%The viscosity of the spinning solution increased from 8.15 Pa·s to 52.7 Pa·s,and the structural viscosity increased from 2.42 to 6.24.With the increase in the doping amount of organically modified nano-calcium carbonate in the spinning solution system,The rheological parameters showed a downward trend as a whole.The viscosity of the flow curve?taking the shear rate at 80 s-1 as an example?gradually decreased.When the doping amount of calcium carbonate increased from 3 wt%to 8 wt%,the spinning solution performance Viscosity decreased from38.6 Pa·s to 8.28 Pa·s,and Structural viscosity index decreased from 4.98 to3.62.In the process,the content of dichloromethane increases,the solvent evaporation rate of the spinning solution increases,and the viscosity and surface tension of the spinning solution increase.Comprehensively considering the rheological properties of the spinning solution and the morphology of the porous cellulose diacetate fiber,it was found that as the concentration of the spinning solution increases,the fluidity of the spinning solution decreases and the spinning stability will be significantly improved.The fiber diameter is more uniform,but the concentration is too high will cause the viscosity of the spinning solution to be too large to spin well.Simultaneously,the increase of the doping amount of calcium carbonate particles in the spinning solution will change the distribution of calcium carbonate in the cellulose diacetate fiber.After removal,it will improve the internal porous morphology of the fiber and help to increase the specific surface area of the fiber.When the calcium carbonate is increased to 6wt%,the fiber specific surface area can be expanded by about 3 times,but when the calcium carbonate is increased to 8wt%,the spinneret will be blocked.As the proportion of methylene chloride in the spinning solvent increases,the spinning stability increases,and the solvent volatilization zone The effect of pore formation on the surface of the fiber is enhanced,and the fiber surface gradually transitions from non-porous to a clear porous structure.The test results of the adsorption of porous cellulose diacetate fibers show that with the increase of the specific surface area of the fiber,the quality of the particulate interception of the total phase of the flue gas by the filter can be significantly improved,and the content of aldehydes in the mainstream flue gas can be reduced.The filter made of porous diacetate fiber,compared with the filter prepared by the non-doped calcium carbonate obtained,the total phase particulate retention quality is improved by more than 2 times,and The aldehydes contained in mainstream smoke decreased by 51.2%,and the aldehydes trapped in the filter increased by 65.4%.When the mass ratio of porous cellulose diacetate fiber in the filter increases,the filter's adsorption and filtration effect on flue gas increases significantly.When the mass of porous cellulose diacetate fiber in the filter is increased to 130 mg,the total phase particulate matter adsorbed by the filter is increased by more than 7 times,and the aldehydes contained in mainstream smoke are reduced by 67.5%.And The mass of aldehydes contained in the filter leaching solution increased by 1.26 times.In addition,when porous cellulose diacetate fiber samples are placed in different positions in the filter,the filter will have different effects on the adsorption of aldehydes in cigarettes.When the porous fiber filter section is in the middle,and the non-porous fiber filter section on both sides,the filter has the best adsorption and filtering effect.