CO 2 /N 2Synthesis And Properties Of Switched Binary Copolymers

CO₂/N₂-switchable polymers have the advantages of intelligent response,environmental-friendly and reuse.The molecular structure and microstructure of the polymers can be modified according to the needs of the people so as to achieve the macroscopic performances of the polymer.C02/N2-switchable polymers have a certain surface activity and rheological properties as polymers,so it has enormous application value in the field of controlling of aqueous solution viscosity and oil emulsification.In this paper,two binary copolymers with opposite CO₂/N₂-switch copolymers were synthesized by selecting suitable C02-switch monomers and non-functional monomers.The CO₂/N₂-switching performances of the two copolymers was characterized respectively,and the CO₂/N₂-switch viscosity controlling performance and diesel emulsification performance were studied.The CO₂/N₂-switch copolymer P（DMAPMA-AM）was synthesized by free radical polymerization with DMAPMA（N-（3-dimethylaminopropyl）methacrylamide）and AM（acrylamide）as monomers.The conditions of synthesis the polymers with the best CO2-switch response were obtained by single factor experiment:n（AM）:n（DMAPMA）= 4:1,w（total mass of monomer）= 25%,-w（initiator）= 0.2%,reaction temperature was 40 ℃,reaction time was 4 h.The conductivity,Zeta potential and particle size of aqueous P（DMAPMA-AM）solution were measured in the condition of C02/N2 aqueous solution.It was proved that P（DMAPMA-AM）could be protonated in the condition of CO2 and the thickness of double layer increased and the average particle size increased.It was concluded that P（DMAPMA-AM）has a good positive C02/N2-switch response performance The polymer was further confirmed by scanning electron microscopy with a microstructure with a C02/N2-switch response.The viscosity of aqueous P（DMAPMA-AM）solution can be significantly increased/decreased under the condition of CO₂/N₂.The optimum conditions for the emulsification of P（DMAPMA-AM）emulsified diesel oil under different conditions were studied,it was that emulsifier dosage was 0.3%,the ratio of oil to water was 6:4,the stirring rate was 3 00r/min,and the stirring time was 60 min.The CO₂/N₂-switchable performance testing showed that the diesel emulsion can be achieved emulsification and demulsification by recirculating dealing with CO₂/N₂.Reverse CO₂/N₂-switch copolymer P（DMAPMA-SSS）was synthesized by using DMAPMA and SSS（sodium p-styrene sulfonate）as monomers.And the optimum conditions were obtained by single factor experiment n（SSS）:n（DMAPMA）= 1:8,w（total mass of monomer）= 20%,w（initiator）=0.4%,reaction temperature was 60 ℃,reaction time was 8h.The conductivity,Zeta potential and particle size of the aqueous solution were measured under the condition of CO₂/N₂.It was showed that P（DMAPMA-SSS）could be protonated by CO2,as the results,the average particle size was reduced,And the polymer is deprotonated by N2,so that the thickness of the double layer increases and the average particle size increases.The viscosity of aqueous P（DMAPMA-AM）solution can be decreased/increased under the condition of CO₂/N₂.What’s more,it can be concluded that P（DMAPMA-AM）has the opposite effect of CO₂/N₂-switch viscosity regulation with P（DMAPMA-SSS）.The optimum conditions for the emulsification of P（DMAPMA-AM）emulsified diesel oil under different conditions were studied,it was that emulsifier dosage was 1.0%,the ratio of oil to water was 7:3,the stirring rate was 400r/min,and the stirring time was 90 min.Switching performance studies have shown that diesel emulsions can achieve emulsification and demulsification after dealing with CO₂/N₂.