SALICYLIC ACID IN GAS GENERATING COMPOSITIONS.

摘要

Gas generating compositions based on salicylic acid as fuel, a mixture of KNO_3 and KClO_4 as oxidiser and different binders such as phenolic resin, epoxy resin, poly vinyl chloride (PVC), polyester resin, nitrocellulose (NC ), plasticised ethyl cellulose ( PEC) ,ethyl cellulose ( EC ) ,polyvinyl alcohol (PVAL) and poly vinyl acetate (PVAC) etc. have been studied. The heat of combustion was determined in argon medium. The compositions were ignited in closed vessel and Pmax, rise time & ignition delays were recorded. Heat output & pressure values are highest for NC compared to other binders. The composition containing polyvinyl alcohol shows very slow burning as reflected in the rise time/ ignition delay. Impact, friction and spark sensitivity data show that these compositions are reasonably safe to handle. All these compositions are less sensitive to friction ( 32 to 36 Kg in Julius Peters apparatus). Compositions containing phenolic /PVC binder are more sensitive to impact compared to other binders. Computer program (REAL) was utilised to calculate the values of Pmax and the results were compared with experimental values. Thermodynamic and chemical equilibrium parameters are also discussed.. As per thermochemical calculations the quantity of CO liberated per kg of composition is about 3.5 moles in the case of NC binder whereas with other binders this is of the order of 8 to 14 moles/kg.These compositions will be useful for airbag inflation, floatation jackets etc.