Study On Protective Material Against Cyanogen Chloride Based On Modified Polyacrylate

Cyanogen Chloride（CNCl,US military code:CK）is a systemic toxic agent.It is representative of the gaseous chemical warfare agents which are difficult to be adsorbed by porous materials.And it is also a harmful waste gas generated during the processing and use of phosphorus,coal,and cyanide-containing substances.The breakthrough time of cyanogen chloride is often regarded as an important indicator of the protection performance evaluation of gas masks in individual protection and filter for collective protection.At present,the impregnated activated carbon materials used for the protection of toxic and harmful gases have weak protection ability and short breakthrough time against cyanogen chloride,and the interaction mechanism of cyanogen chloride protection is unclear.Research and development of effective protective materials for cyanogen chloride and in-depth exploration of the protection mechanism are urgent issues in the field of military chemistry and environmental protection,which is of great practical significance and theoretical value.This paper focused on the advantages of porous organic polymers and researched cyanogen chloride protective materials based on polyacrylate.Firstly,polyacrylate matrix material with an adjustable pore structure was prepared by emulsion polymerization.Next,the optimization of the composite process of materials was explored to prepare MOF/polyacrylate composites with a high loading rate.Then,a test platform for the protection performance evaluation of the material was built,and a new evaluation method was established.The breakthrough curves were measured completely,and the influence factors of the protection performance were explored.Finally,the interaction mechanism of the material against cyanogen chloride was explored by experimental analysis together with theoretical calculations.The specific content is as follows:（1）Synthesis and structural regulation of the polyacrylate matrix.A stable water-in-oil（W/O）emulsion was prepared with GMA and TBMA as monomers,TMPTA as a crosslinking agent,and water as dispersing phase in an oxidation-reduction initiation system.The polyacrylate matrix was synthesized by emulsion polymerization.The macro-morphology and pore structure of the matrix materials were regulated,and the effects of the factors such as dispersing phase content,emulsifier dosage,high-speed dispersion rate,and the third-phase stirring speed were studied.The through pore-type polyacrylate matrix materials were synthesized,with abundant pores,complete pore walls,and uniform pore size distribution.The particle size is concentrated in 0.4mm～0.9mm,which is suitable for toxic and harmful gas purification.Then,the physicochemical properties of the synthesized matrix materials were characterized to provide a basis for the subsequent modification and loading of active components.The matrix material contains carbon-carbon double bonds（C=C）,carbon-oxygen double bonds（C=O）,epoxy groups,etc.,which have excellent reactivity and are easy to be modified functionally.（2）Preparation and characterization of MOF/polyacrylate composites.The preparation of composite materials by physical method and chemical method was explored respectively.From the loading effect,the stability and loading rate of chemical recombination is better than that of physical recombination,so chemical recombination is further studied.The preparation of composite materials by chemical composite consists of two key steps:the functional modification of the matrix and the growth of MOF.The effects of the type and concentration of the modifier on the modification effect were investigated.When PEI is used as a modifier,the loading density of the amine group is high and the distribution is uniform.Three growth strategies of MOF were proposed:one-pot growth method,stepwise impregnation growth method,and step impregnation layer-by-layer growth method.The loading rate and uniformity of MOF in the composite prepared by the stepwise impregnation method were significantly higher than those of the other two growth methods.The physicochemical properties of the prepared composites were characterized,which proved the successful growth of MOF in the matrix materials.Polyacrylate matrix material has good mechanical properties,easy processing,and excellent adsorption performance coupled with MOF,which can effectively make up for the shortcomings in the application,making large-scale application possible.（3）Performance evaluation of MOF/polyacrylate composites against cyanogen chloride.A test platform for the performance evaluation against cyanogen chloride was built,and a new evaluation method for cyanogen chloride was established.The breakthrough tests were carried out,and the gas chromatograph was used for online and real-time monitoring of the breakthrough concentration.The complete breakthrough curve was measured,which provided comprehensive and detailed data support for the study of the interaction mechanism and the design of protective equipment.Cu BTC/polyacrylate composites prepared by the method proposed in this paper show the best performance against 4 mg/L cyanogen chloride for 47 min,and the adsorption capacity can reach 0.39 mmol/mg.The protection time and adsorption capacity of the composite increased by more than 50%.Finally,the effects of factors such as temperature,humidity,airflow velocity,bed thickness,and other factors on the protection performance were investigated.（4）Research on the protective mechanism of Cu BTC/Polyacrylate composites against cyanogen chloride.The protective mechanism of materials against cyanogen chloride is analyzed comprehensively from the aspect of experimental analysis and theoretical calculation.The effect of cyanogen chloride on the structure and properties of the composite was analyzed by characterization.Through GC-MS,the components of the tail gas were analyzed,and no new gas escaped from the tail gas.Based on density functional theory（DFT）,the interaction mechanism between cyanogen chloride and Cu BTC in composites has been studied by using the DFT-D3 method.The results show that cyanogen chloride was adsorbed by Cu BTC.Cu²⁺in Cu BTC are active sites for the adsorption of cyanide chloride,and Cu²⁺forms Cu-N coordination bonds with cyanide chloride.After adsorbing water molecules,Cu BTC can adsorb more cyanogen chloride and has a stronger adsorption capacity for cyanogen chloride.Meanwhile,charge density difference analysis also shows that the charge density difference of adsorbed cyanogen chloride by Cu BTC after adsorbed water molecules shows a more intense charge transfer.The theoretical calculation results are in conformity with the experimental results,which provides theoretical support for the explanation of the protection mechanism of cyanide chloride.