Synthesis Of PAM-b-PVTES Block Copolymer And Its Fixation Performance With Aerosol

The control and removal of radioactive aerosols has always been an important problem in the decommissioning of nuclear facilities and nuclear emergency response.Radioactive aerosols not only have the hazards of ordinary aerosols,but also have radioactive hazards.They are suspended in the air for a long time and can cause internal exposure to human beings after inhalation.Rapid control and removal of radioactive aerosols is an important measure to reduce the consequences of accidents and prevent pollution diffusion.The atomizing fixing agent is currently a commonly used dust removal technology,and the performance of the fixing agent in the atomizing fixing technology is the key to this technology.Based on this,this paper prepared an aerosol fixative with low viscosity and low surface tension,and characterized its structure and performance.It is expected that the low surface tension and low viscosity aerosol fixing agent prepared in this paper and the related atomization fixing test method provide a new idea and technical support for aerosol atomization settlement fixing in relevant nuclear-related sites.(1)In this paper,reversible addition-fragmentation chain transfer polymerization(RAFT polymerization)was used to prepare PAM-b-PVTES block copolymers with S,S-dibenzyltrithiocarbonate(DBTTC)as RAFT reagent,acrylamide(AM)as the first monomer,and vinyltriethoxysilane(VTES)as the second monomer.In this paper,the structure of the polymer was characterized by IR,NMR and DSC,and it was proved that the synthesized polymer was PAM-b-PVTES block copolymer.The relative molecular mass and molecular weight distribution of the polymer were tested by GPC,and the effects of RAFT reagent dosage and monomer ratio on the relative molecular mass of the polymer were studied.The thermal stability of the polymer was analyzed and discussed by TG and DSC.The effects of reaction temperature and reaction time on monomer conversion in polymerization were investigated.(2)The aqueous solution of PAM-b-PVTES polymer was used as aerosol fixing agent,and the effects of monomer ratio on the viscosity,surface tension and contact angle with dust of the fixing agent were discussed.The decrease of RAFT reagent dosage,the increase of VTES dosage and the increase of solid content will lead to the increase of viscosity of the fixative.The results show that with the increase of the dosage of the fixative,the settlement fixation efficiency of the fixative is improved.With the increase of the solid content of the fixer and the viscosity of the fixer,the settlement fixation efficiency increases and the settlement fixation time decreases.The higher the VTES content,the better the settling efficiency.In the atomization spray 30%solid content,n(AM):n(DBTTC):n(VTES)=100:0.2:10 of the fixed agent 50ml(fixative density 104.17 ml/m3),the settlement fixation efficiency is 42.60 min,?_{number concentration}=91.02%,?_{mass concentration}=98.78%.