Preparation Of Organic/Inorganic Composite Media And Research On Its Combustion Inhibitory Properties

Combustion is a chemical phenomenon,the essence of which is a free radical chain reaction.In our life,we sometimes use the heat generated by combustion,and sometimes we also want to avoid the danger brought by combustion.Burning out of control will evolve into a fire,which will not only threaten the safety of human life,but also cause serious damage to social property.The common fire extinguishing agent on the market has a single component,low fire extinguishing efficiency,poor functionality to reduce the temperature of the flame area,corrosive,poor resistance to re-ignition and other deficiencies,there is an urgent need to develop a new composite fire extinguishing medium with various components to solve the above problems.In addition,the slow combustion of pyrotechnics can be applied to some special occasions,such as the slow unfolding of certain parts of spacecraft and inflatable hemostatic bandage unfolding,etc.These require a certain degree of inhibition of the burning process of pyrotechnics to achieve the effect of slow deployment.Therefore,in this thesis,a new organic/inorganic composite medium was first developed using perfluoro(2-methyl-3-pentanone)and porous materials,and then four polyesters were synthesized by enzyme-catalyzed polymerization to investigate the properties and effects of both in terms of combustion inhibition.The details of the study are as follows.Perfluoro(2-methyl-3-pentanone)was loaded onto porous molecular sieves in the means of physical adsorption to obtain composite media,which were characterized by FT-IR and NMR,etc.,confirming the success of the loading experiments.The adsorption conditions were optimized by orthogonal tests,and the optimal reaction conditions were obtained: 6 m L of perfluoro(2-methyl-3-pentanone)addition per unit mass of molecular sieve(1 g),500°C of molecular sieve pretreatment temperature,1 h of evacuation time and 8 h of decompression adsorption time.8.57% of perfluoro(2-methyl-3-pentanone)loading was achieved under this condition.Then,the loading process was scaled up to prepare the composite medium,and its combustion inhibition performance was tested under the same conditions,using class A and B fire experimental models.The results showed that the combustion suppression performance of the composite medium was three times that of the ordinary ABC dry powder.Then,the mechanism of the excellent combustion suppression performance of the composite media was explored and described.Four polyesters were synthesized by enzyme-catalyzed polymerization as binders for pyrotechnics,all with molecular weights ranging from 800 to 6000 g/mol.The enzyme-catalyzed polyesters were used for the combustion inhibition of pyrotechnics,and compared with the traditional binder phenolic resin,the combustion inhibition rate of pyrotechnics was found to be 27.10%,resulting in a slower combustion rate of pyrotechnics and excellent retarding performance.The mechanism of the combustion inhibition of pyrotechnics by enzyme-catalyzed polyester was investigated and successfully explained by the " string bag" theory.