The Industrial Preparation Of Nanocellulose And Its Application In Powder

Binder is the matrix and continuous phase of gunpowder,its performance has an decisive influence on powder’s preparation technology,mechanical properties and energy.Nitrocellulose(NC)is a kind of widely used powder binder,but in the face of modern war of gunpowder put forward such as high strength,high energy more and more stringent requirements,NC also highlights the lack of performance,especially the limitations of low temperature on the mechanical properties.Therefore,it is necessary to improve the low temperature mechanical properties of gunpowder.The use of nanocellulose to improve the mechanical properties of the propellant is regarded as a kind of very good method.On the one hand,because the nanocellulose has the characteristics of high strength and high modulus,it is a kind of very good reinforcement;on the other hand,both nanocellulose and nitrocellulose have the same main chain of the molecular structure,so nanocellulose and nitrocellulose have good compatibility.Currently,the main preparation methods of nanocellulose are physical method and chemical method,among them,the physical method due to the high energy consumption of the preparation process,it restricts the industrial production of nanocellulose;chemical method due to the high cost,low efficiency,thus it is more suitable for application in the laboratory.Aiming at the shortcomings of the above preparation methods,this paper explores a mechanochemical method is an effective means of nanocellulose.The preparation methods of reagent and simple equipment,short preparation cycle,high efficiency,it is suitable for the industrial production of nanocellulose,and through the orthogonal experiment method to optimize the process conditions of preparation of nanocellulose.Withγ-(2,3-epoxy-propoxy)propytrimethoxysilane(KH560)as modifying agent,prepared two different forms of modified nanocellulose,KH560modified nanocellulose1(KCNF-1)and KH560 modified nanocellulose1(KCNF-2).In order to improve the mechanical properties at low temperature of propellant,nanocellulose and modified nanocellulose are added.The effect of nanocellulose on the physical and chemical properties,mechanical properties,combustion performance and energy was studied.Without changing preparation technology of the modified double-base propellant,respectively in the formula of the lower content(22.3%)of nitrocellulose add 0.78%of nanocellulose and KCNF-1,the results show that,the low temperature tensile strength of nanocellulose modified double-base medicine has been increased from 20.23 MPa to 23.77 MPa,the elongation at low temperature has been increased from 1.90%to 2.48%;the low temperature tensile strength of KCNF-1 modified double-base medicine has been increased from 20.23 MPa to23.93 MPa,the elongation at low temperature has been increased from 1.90%to2.41%.At the same time,the modified double-base propellant’s combustion rule and explosion heat have not been changed.Without changing preparation technology of nitramine propellant,respectively adding 1.68%cellulose and KCNF-2 to propellant,the results show that for the modified propellant with nanocellulose,the low temperature drop crushing rate has been decreased from 60%to 20%,low temperature impact strength has been increased from 7.72KJ/m~2 to 10.04KJ/m~2;for the modified propellant with KCNF-2,the low temperature drop crushing rate has been decreased from 60%to 0,the low temperature impact strength has been increased from 7.72KJ/m~2 to9.56KJ/m~2.At the same time,the indicators of physical and chemical properties of nitramine propellant have not been changed.