Preparation And Properties Study Of NBC Nanofibers By Electrospinning

The improvement of mechanical properties of energetic materials contributes to the improvement of the stability of the charge,so it has been widely studied in various fields in recent years.Nitrifying bacterial cellulose(NBC)is a new type of cellulose fiber ester produced by nitrification of bacterial cellulose through mixed acids.Its unique three-dimensional network structure is conducive to composite with other energetic materials,thereby improving the mechanical properties of materials.However,the mechanical properties of a single NBC material are still unclear,the basic data are incomplete,and the mechanical differences between it and traditional nitrocellulose(NC)have not been reported.Therefore,this article uses electrospinning method to prepare NBC fibers,and compares the mechanical properties of NBC fibers with NC fibers at the micro and macro levels,in order to provide a data basis for the research of NBC.The specific research content of this paper is as follows:(1)preparation of NBC fiber by electrospinningThe effects of solvent parameters(solvent type,mass fraction of electrospinning solution)and electrospinning parameters(electrospinning voltage,reception distance,and propulsion rate)on NBC electrospinning were studied.It was found that when ethanol/acetone(1:1)mixed solvent was used,an NBC fiber with an average diameter of 510 nm could be obtained when the mass fraction of electrospinning solution was3%,the electrospinning voltage was 25 k V,the reception distance was 20 cm,and the propulsion rate was 10 m L/h,Thermal analysis showed that the highest exothermic peak of the fiber sample was 11.3 ° C higher than that of the raw material,The halfseam width of the exothermic peak is significantly narrowed,and the thermal decomposition efficiency of NBC fiber is improved.(2)comparison of properties of NBC fiber and NC fiber with different N content.Three kinds of n content(11.90%,12.40%,12.95%)of NBC and NC fibers were used for electrospinning,and the morphology,thermal and mechanical properties of NBC and NC fibers were characterized.The results show that the tensile strength of NBC fiber with the same N content is higher than that of NC fiber,and the elastic modulus of single NBC fiber is larger.When the content of N is 11.90%,the tensile strength of NBC fiber is 14.8 MPa,and the hardness of single NBC fiber is 2.04 GPA,which is 15% and 22% higher than that of NC fiber with the same content of N,respectively.The fiber samples were moved forward compared with the highest decomposition peak temperature of the raw materials,among which NBC fiber with11.90% N amount moved forward the most,to 15.8 °C,and NC fiber moved forward by 9.9 °C,which proved that NBC and NC had a certain autocatalytic phenomenon in the reaction after changing from powder to fiber.In the tests of NBC raw materials and fibers with N content of 12.95%,the apparent activation energy of NBC fibers was180.81 k J/mol,which was 47.8% lower than that of NBC raw materials of 268.03 k J/mol.(3)the FP/NBC composite film was prepared by electrospinning.The morphology,specific surface area,surface roughness,pore size distribution,and contact angle of the FP/NBC composite membrane were tested.It was found that the NBC fibers could be uniformly loaded on the filter paper,with a thickness of 135.46μ m.Compared with filter paper,the specific surface area and total pore volume of the composite membrane have both doubled,and the contact angle of FP/NBC composite membrane to water can reach 152.7 °,belonging to the hydrophobic category.