Effects Of Different Additives On Energy Release Of Cellulose Nitrate Containing Borohydride Magnesium

Compared with metal hydrides,light metal coordination hydrides have significant adv-antages in hydrogen-storage capacity,initial desorption temperature and enthalpy change of desorption reaction.As a representative of light metal coordination hydrides,boron-containing based hydrogen storage alloy has attracted attention due to its high hydrogen-storage capacity,but it is so oxygen-poor that the thermal decomposition reaction cannot take place adequately.Borohydride magnesium and cellulose nitrate can interact with each other.Cellulose nitrate can provide a large number of oxygen atoms for borohydride magnesium,and can also improve the energy of cellulose nitrate.Therefore,borohydride magnesium is expected to be widely used as high-energy additives in cellulose nitrate in the field of explosives.The experimental results show that borohydride magnesium can significantly improve the energy of cellulose nitrate.However,in order to make the energy release of cellulose nitrate containing borohydride magnesium more efficient,the effects of adding different additives are explored and studied.In this paper,through closed-bomb experiment,the heat of combustion experiment and adiabatic accelerated calorimetry（ARC）,the effects of iron oxide（Fe₂O₃）,nanometer iron oxide（nano-Fe₂O₃）,copper oxide（Cu O）,nanometer copper oxide（nano-Cu O）,cobalt oxide（Co O）and nanometer cobalt oxide（nano-Co O）on the energy release of cellulose nitrate containing borohydride magnesium are studied.In addition,the cellulose nitrate and the combustion residue obtained from ARC experiment are compared and analyzed through scanning electron microscopy（SEM）and X-ray photoelectron spectroscopy（XPS）to speculate the reaction degree.The results of closed-bomb experiment and the heat of combustion experiment show that compared with the blank sample,any kind of additives makes different degree of abate about thermal decomposition reaction of cellulose nitrate containing borohydride magnesium occur.Six kinds of additives chosen by this article almost don’t have influence on the burning rate of samples,but the effects of content of additives on the thermal decomposition reaction are still noticeable.ARC experimental results show that Fe₂O₃and Co O can obviously reduce the activation energy of the thermal decomposition reaction of cellulose nitrate containing borohydride magnesium,and make the thermal decomposition reaction occur more easily.SEM image results show that during the combustion process of boron particles,the generated B₂O₃will cover the surface of boron particles to form a dense oxide film,and the further decomposition of B₂O₃will hinder the contact and reaction between the internal B and external oxygen,resulting in the incomplete oxidation of B.The SEM images of samples containing nano-Cu O,Co O and nano-Co O don’t have unfinished B particles.XPS results show that with the increase of Fe₂O₃content,the reaction degree of Mg and B also gradually increases,which indicates that Fe₂O₃can play a catalytic role of borohydride magnesium and the catalytic effect is relatively obvious,but there is no obvious law on the catalytic effect of cellulose nitrate itself.