Preparation Of Porous Functional Polymer Materials By Emulsion Template Method And Their Application

Porous polymers have the characteristics of light weight,low density,high specific surface area and high porosity.They are widely used in adsorption,catalysis,thermal insulation and other fields.The preparation methods of porous polymers include direct synthesis,block copolymers self-assembly,hard template method,emulsion template method,etc.Among them,the porous functional polymer prepared by emulsion template method has the advantages of well-developed through-hole structure,regular pore structure,adjustable pore size and easy functionalization.In the early days,attention was paid to the regulation of micropores in porous polymers prepared by emulsion template method.In recent years,with the development of emerging fields,researchers’attention to porous polymers has gradually shifted to the preparation of interface functional materials,which has broadened its application fields.In this paper,based on emulsion template method,porous polymer was prepared.Target oriented and carbon dioxide adsorption materials with high stability and high adsorption efficiency and high sensitivity flexible piezoresistive materials were prepared by target oriented design.The main research contents are as follows:1.A series of polyacrylate porous microspheres were successfully prepared by the combination of emulsion template and suspension polymerization.Then,by loading passivated amine interface layer in the pore channel of microspheres and hydrophobic treatment of the surface of microspheres,a high stability carbon dioxide adsorption material for fluidized bed was obtained.Firstly,the formulation and technology of emulsion polymer template for preparing porous polymer microspheres were studied.By studying the volume fraction and monomer ratio of the dispersed phase of the emulsion template,it is found that the porous microspheres have more developed pore structure when the volume fraction of the dispersed phase is 58%and the glycidyl methacrylate content is40%,and the pore size is 2.3μm to 5.1μm,and the particle size is between 0.91mm and 1.45 mm,which is more conducive to loading the functional groups into the hole in the next step.Then,PEI and PEI modified by propylene oxide were successively impregnated into the microsphere channels.Through the reaction between propylene oxide and PEI,most of the primary amines were transformed into secondary amines,which can inhibit the formation of urea bond.Finally,the surface of the microspheres was hydrophobically modified with epichlorohydrin,and the porous polyacrylate microspheres with three functional layers were used for carbon dioxide adsorption.After 20 cycles,the adsorption capacity of the adsorbent decreased from 48.08%to 0.014%,and the cycle stability was greatly improved.The adsorption capacity of H₂O decreased from 0.54 to 0.31 mmol/g,a decrease of 42.6%.Finally,the test was carried out on a laboratory scale fluidized bed.The adsorption capacity of the adsorbent can reach 2.52 mmol/g,which is expected to be further applied in industry.2.The porous polystyrene glycidyl methacrylate copolymer（PSA）prepared by concentrated emulsion template method is used as skeleton to promote the kinetics diffusion of polyethylenimine modified by long chain fatty acid graft.First of all,polyglycidyl methacrylate was added to prepare polystyrene by concentrated emulsion template method.By changing the monomer ratio and the volume fraction of dispersed phase,a porous scaffold material（PSA）with abundant epoxy graft sites was obtained,with an aperture of 3.18μm～5.03μm.Then,fatty acid modified PEI was grafted on PSA to obtain a functional polymer rich in amino groups.Finally,when it is used for carbon dioxide adsorption,it has high adsorption capacity and high amine efficiency.Finally,the effect of the carbon chain length of fatty acids on the adsorption performance of amino functionalized polymers was studied.When dodecanoic acid is introduced,the soft PEI was supported by the crystal structure of long-chain fatty acids,forming an additional CO₂ channel,which promoted the diffusion of CO₂ to the bottom layer of PEI,and the adsorption capacity was up to 3.13 mmol/g.due to the promotion of kinetic diffusion,The optimum adsorption temperature was reduced from 60℃to 50℃;When octadecanoic acid is introduced,its crystallization behavior becomes more obvious.With little addition,the adsorption capacity at each temperature point has been significantly improved,and the increase is more obvious in the low temperature zone.The adsorption capacity increases from 3.16 mmol/g to 3.4mmol/g at 60℃,and the amine efficiency can reach 0.32 mol CO₂/mol,which is higher than half of the theoretical value.At the same time,the prepared adsorbent also showed good selective adsorption and cyclic stability.3.Using Picking emulsion template method and carbon nanotube（CNTs）as Picking emulsifier,loaded on the surface of the porous polymethyl methoxy siloxane（PDMS）porous matrix,the CNTs/PDMS organic-inorganic composite foam material has a high sensitivity piezoresistive response.The method is based on the Picking emulsion.Taking CNTs as emulsifier,sixteen alkyl three methyl ammonium bromide（CTAB）as CNTs inducer,and adding PDMS emulsion system,the effects of polymerization temperature,CTAB content and CNTs on foam pore structure and distribution of carbon nanotubes were studied.Organic-inorganic composite functional materials with good conductivity.When the composite foam is applied to piezoresistive sensor,the sensitivity increases with the increase of CNTs addition,up to 24.15.When detecting human motion such as finger bending and walking,it shows fast response,high resolution and good stability.