Fire Reaction Properties Of Glass Fiber/Epoxy Resin Composites

Glass/epoxy composites have been widely used in the auto,marine,and aerospace fields.According to its structural characteristics,it can be divided into laminated structure and sandwich structure.Laminates and foam core sandwich composite are the most commonly used laminate and sandwich structure materials in the aviation industry.However,the high flammability of the epoxy resin matrix and its foam core material poses a serious fire hazard.Both the epoxy resin matrix and the foam core material are flammable thermosetting materials.In case of fire,it will cause personal injury and property damage.Therefore,TG analyzer,TG-FTIR analyzer,cone calorimeter,vertical/horizontal combustion tester,limit oxygen index meter and smoke density box were used the fire reaction properties of glass/epoxy composite were studied in this paper.First,the pyrolysis characteristics of glass/epoxy composites were studied.The pyrolysis characteristics parameters of glass/epoxy laminate and its foam core sandwich composite were obtained.A pyrolysis kinetic model is established and calculated using the Kissinger method.Obtain its pyrolysis kinetic parameters and compare and analyze,determine the reaction trigger level and reaction rate,and explore the pyrolysis mechanism;calculate the thermodynamic parameters such as enthalpy change,entropy change and Gibbs free energy based on the kinetic parameter calculations to determine whether the reaction Spontaneous.There are significant differences in the pyrolysis characteristics of the two composites.foam core sandwich composite has a lower initial pyrolysis temperature,and a large amount of hydrogen chloride gas will be released when the pyrolysis temperature of the epoxy resin is not reached,which seriously increases the harmfulness during the pyrolysis.Then,the combustion characteristics of glass/epoxy composites were studied.The combustion characteristics parameters?lighting time,ignition temperature,heat release rate,mass loss rate,flame spread rate,oxygen index,etc.?of the glass/epoxy laminate and its foam core sandwich composite were obtained.Prediction models such as ignition time model,mass loss model and heat release rate model were established.Based on the models,the fire dynamic parameters such as critical heat flux,vaporization heat,and combustion heat were determined.Compared with glass/epoxy laminate,foam core sandwich composite has much lower ignition time,ignition temperature,and limit oxygen index and higher total heat release,peak mass loss rate,and vertical/horizontal combustion rate,the time to peak mass loss rate and peak heat release rate is shorter.Finally,the smoke characteristics of glass/epoxy composites were studied.The smoke characteristics of glass/epoxy laminate and its foam core sandwich composite?smoke production rate,total smoke release,CO/CO₂production rate,Generation rate and specific optical density,light transmittance,etc.?were obtained.Typical smoke density parameters?average smoke production rate,average smoke accumulation rate,smoke extinction index,etc.?were calculated based on smoke density data,and a comparative analysis was performed.There is a significant difference in smoke characteristics between these two composites.Compared to glass/epoxy laminates,foam core sandwich composite release a lot of smoke earlier,with a higher total smoke release,and release carbon monoxide and carbon dioxide faster and more char is formed.