Ignition Characteristics And Case Analysis Of Typical Nitrocellulose

Nowadays,Nitrocellulose is widely used at military and civilian fields.In military field,it can be used as smokeless powder,blasting plastic,explosives,single or double base machine gun and propellant rocket;as for the civilian field,it is used as the main binder or film-forming agent in paint,ink and paint manufacturing process.While it is widely used,simultaneouslythe danger receive widespread attentions.The decomposition temperature of nitrocellulose is very low,and it is possible to accelerate the decomposition process when the temperature exceeds 40?.In addition,the ignition temperature of nitrocellulose is only slightly greater than 170?,and it is easy to be ignited.The tendency of nitrocellulose to spontaneously ignite and be easily ignited by the outside world has caused many accidents in recent years.However,the majority of present researchs and analysises on Nitrocellulose material are all about to the thermal stability analysisincluding phase change thermal analysis,thermal analysis and thermal decomposition analysis.There is still no relevant literature on the combustion characteristics of Nitrocellulose,so it is necessary to analyze the thermal stability and the combustion behaviors of nitrocellulose.Thermal stability includes kinetic parameters,thermodynamic parameters,half-life and critical thermal explosion temperatures,and combustion behaviors inlunclude the parameters like ignition time,heat release rate,fire growth coefficient,weight loss rate,and flame temperature,especially the heat release rate.At present,the domestic has happened many fire accidents which improper use or storage of nitrocellulose.In this paper,two typical nitrocellulose accident cases are analysed including accident in Hebei xingtai,accident in Hebei hengshui,accident in Guangdong huizhou and in particular major fire explosion accident in Tianjin.Nitrocellulose accidents emerge in endless and this has to do with burning characteristics of nitrocellulose.So it is necessary to measure and analysis combustion characteristic parameters ofnitrocellulose.Based on the above analysis,the thermal stability of white soft fiber nitrocellulose and white chip nitrocellulose were analyzed by differential calorimeter.The activation energy E and the pre-exponential factor A were calculated and compared by ASTM E689-16 and ASTM E2839-12.The relevant thermodynamic parameters,half-life and critical thermal explosion temperature were also measured.At last,the thermal stability of two forms of nitrocellulose was compared.Moreover,some of the combusion properties of the four kinds of different Nitrocellulose samplesare considered by means of the ISO 5660-1 cone calorimeter in this paper.And have determinedthe effects of different forms of Nitrocellulose samples on combustion behaviors such as ignition time,HRR,FGI overall weight loss percentage,MLR and the temperature changes over material at 1cm and 10cm,also provided the basis on fire risk to some extent.Furthermore,some researchers argue that oxygen consumption calorimetry is likely to over-predict the chemical heat release.Nitrocellulose is a kind of organics,its thermal decomposition will also produce a significant proportion of carbon dioxide.Therefore,the producedcarbon dioxide is not entirely generated from the combustion.So,another thermal chemistry method basedon stoichiometry for heat release rate calculation is adopted to validate the effectiveness of the oxygen consumption calorimetry.The result show that the two methods are found to be in good agreement when there no additional radiation,but with the rise of additional radiation flow,the radition can make Nitrocellulose to parse CO2 before combustion,which may cause the test results of chemical calorimetry deviated.In summary,the HRR has a higher accuracy using oxygen consumption calorimetry.Thus,theoxygen consumption calorimetry is considered to be a appropriate technique todetermine the burning behaviours of differentNitrocellulose samples.