Preparation Of Cellulose Acetate Butyrate Porous Micro/Nanofibers And Their Properties

The single-guide wet fiber material can directionally transport liquid water,transferring water molecules from the hydrophobic side to the hydrophilic side.This special liquid water transfer capability allows the material to be used not only in the medical and healthcare fields but also in oil-water separation,water collection,and membrane distillation.In this project,a series of cellulose acetate butyrate micro/nanofibers were prepared from cellulose acetate butyrate(CAB)by electrospinning technology,and their morphological structures and properties were investigated.Firstly,the effects of different solvents,different concentrations,and different spinning parameters on the morphological structure of the fiber membrane were investigated.It was found that different solvent systems have a great influence on the morphological structure of the membrane.The average fiber diameter of the membrane obtained in DCM/AC solvent system was at the micron level,and only in this solvent system,nanopores existed on the single fiber.The average diameter of the smallest fiber in DCM/DMF solvent system could reach 228.02 nm,and there were no pores on single fibers.The average diameter of the smallest fiber in DMF/AC solvent system could reach 112.87 nm,and there were no pores on single fibers.Secondly,we conducted performance tests on six types of fiber membranes with widely different structures.The test results showed that when the solvent system DMF/AC volume ratio(V/V)=1:2,the density of CAB porous micro/nanofiber membrane was the smallest,0.079 g·cm-3,and the porosity was as high as 93.70%,when the pore size of the fiber membrane was the smallest,mainly concentrated in the range of 0.4-0.45 μm,and its moisture permeability and air permeability were also small,3951 g/(m2·d),7.53 mm·s-1,respectively.The moisture permeability and air permeability of the four fiber membranes prepared by the DCM/AC solvent system varied less,and with the increase of spinning voltage,the moisture permeability and air permeability of the fiber membranes gradually increased,with the moisture permeability reaching up to 7430 g/(m2·d)and air permeability up to 36.289 mm·s-1.Finally,the CAB fiber membrane prepared by DMF/AC volume ratio(V/V)=1:2 was modified by hydrophilic modification.CAB composite fiber film with hydrophilic and hydrophobic properties was prepared by electrospinning with DCM/AC solvent system on CAB fiber film modified by hydrophilic modification,and its structure and moisture conductivity were analyzed.The results show that the hydrophilic and hydrophobicity of the composite fiber film and the difference in pore size structure provide the wetting gradient and pore size gradient.Based on this,its one-way transport index R was 1037.53,reaching grade 5(grade 5 is the best degree).