Char Forming And Smoke Suppression Function Of Zinc Borate And Ammonium Polyphosphate On Wood During Combustion

Wood is one of the four kind construct materials( steel, concrete, plastics, wooden materials), which is widely used in many ways, such as building materials, upholstery materials, furniture and so on. It is well known that wood is easy to burn and involved many fire disaster directly or indirectly. It is essential to study flame retardant mechanism and flame retardant technique of flame retarded wood that protect the lives and property safety of people. Char forming function not only affect the combustible properties such as combustion heat, fire spread speed and limited oxygen index but also can be regarded as basis of maintaining the construction and strength of wood. Smoke and toxic gas not only hinder the rescue action of fireman but also can be considered the primary factor to cause causality. So the function of char forming and smoke suppression have become the key problem of wood flame retarding mechanism. It is significant for supplementing flame retarded wood theory to study the function of char forming and smoke suppression of zinc borate applied in wood flame retarding field systematically.Superfine zinc borate is obtained by solid phase grinding reaction from zinc oxide and boric acid. Synthetic product was characterized by XRD, SEM and XPS, the results show superfine zinc borate is amorphous structure and the average diameter of particles are lower than 30 nm. Solid phase reaction between zinc oxide and boric acid can diminish the size of particles. Zinc borate obtained by solid phase reaction possesses higher superficial activity and superficial effect owing to not absorb solvent and surfactant. Moreover synergist effect of flame retarding process is happened because the synthetic zinc borate is a blends of different compositions and crystalline structure corresponding to different temperature of dehydration. Synthetic technology of superfine zinc borate by solid phase reaction is one of effective and simple methods which prepare nanoparticles of salt owing to free of purification and solvent evaporation process which will lead to agglomeration of particles.Ammonium polyphosphate was prepared from phosphoric acid and urea, and the optimal synthetic technology condition was obtained, that is the molar mass of phosphoric acid to urea is 1:1.8, the temperature of prepolymerization is 124±2℃(time 25min), the temperature of polymerization is 230-240 ℃, the time of polymerization is...