Synthesis Of Methyl Methacrylate By Group Transfer Polymerization With Tert-Butyl Acrylate Copolymer

Polymers of methyl methacrylate（MMA）and tert-butyl acrylate（t-BA）are widely used in many fields due to their own morphological variability.Such as optical devices,building materials,medical devices,automotive devices,plastic products,electronics,packaging and other industries,covering all aspects of people’s daily life.Therefore,MMA and t-BA are important functional polymers.In this paper,a new type of polymerization method—group transfer polymerization（GTP）is used to synthesize acrylic acid（methyl ester）polymers under the catalysis of organic non-metallic catalyst t-Bu-P₄.Control,high purity,narrow molecular weight distribution,structural diversity and other advantages.Therefore,the research on the synthesis of acrylate polymers by GTP polymerization is of great significance.The specific research contents include:In this paper,the optimal synthesis conditions were first explored through the control group experiments with different monomer ratios,and the optimal feeding sequence was found:initiator,catalyst,monomer;then by changing the concentration of the system during the polymerization reaction,multiple groups of different In the concentration control group,two optimal concentration systems for homopolymerization were found.The system concentration of PMMA was M₀=1 mol L^-1,and that of Pt-BA was M₀=2 mol L^-1;multiple groups of different catalyst ratios were also set to find The optimal catalyst ratio of PMMA is[MTS^Me]₀/[t-Bu-P₄]₀=1:0.01,and that of Pt-BA is[MTS^Me]₀/[t-Bu-P₄]₀=1:0.05.Finally,the optimal polymerization conditions of the GTP polymerization method were found,MTS^Me was used as the initiator,and t-Bu-P₄ was used as the catalyst to synthesize homopolymers of different degrees of polymerization:polymethyl methacrylate（PMMA）,poly（tert-butyl acrylate）Esters（Pt-BA）.The polymer was characterized by hydrogen nuclear magnetic resonance（¹H-NMR）and size exclusion chromatography（SEC）.The proportions of the characteristic peaks of the NMR spectra of homopolymers are all consistent with the theoretical proportions,the SEC curves are all single peaks,the molecular weights of the polymers are all close to the theoretical values,and the molecular weight distributions are all between 1.06-1.20.The polymerization kinetics of PMMA and Pt-BA were also characterized.The kinetic curves of the two polymers were linear,and the conversion rate of the polymerization reaction increased with time,both of which had the characteristics of active polymerization.It shows that the precise activity of PMMA and Pt-BA polymerized by GTP can be controlled.Two block copolymers Pt-BA-b-PMMA with different monomer ratios and random copolymer Pt-BA-r-PMMA with the same monomer ratio as block polymers were also synthesized by GTP method.The two copolymers were characterized by ¹H-NMR and SEC.The proportions of the characteristic peaks of the synthesized polymers were consistent with the theoretical proportions,the molecular weights of the polymers were close to the theoretical values,and the molecular weight distributions were between 1.11-1.20.Moreover,comparing the characterization results of random copolymerization and block copolymerization,it is found that the characterization results of random copolymerization and block copolymerization are very similar.By setting up a control group experiment,the polymerization system was added dropwise in two different ways,namely mixed dropwise and dropwisely adding t-BA first and then MMA dropwise.At the same time,during the polymerization process,1H-NMR was used to carry out multiple sampling inspections,and the polymerization process and final results were analyzed.In addition,through the polymerization kinetics test,it is finally proved that the random copolymerization and block copolymerization of t-BA and MMA are the same substance.Finally,after comparing the results of block polymerization and random copolymerization,it was found that the random copolymer of t-BA and MMA could not be obtained by random copolymerization,and Pt-BA-b-PMMA was obtained.However,the copolymer obtained by random copolymerization is more controllable,and the random copolymerization method is easier to operate,the polymerization synthesis rate is faster,the molecular weight distribution of the obtained copolymer is narrower,and the molecular weight is closer to the theoretical value.Pt-BA-b-PMMA was synthesized by random copolymerization,and PMMA-b-PAAC was synthesized using it as an intermediate.First,the block copolymer PAAC-b-PMMA was obtained by hydrolysis of Pt-BA-b-PMMA,and then the PMMA-b-PANa was obtained by reacting PAAC-b-PMMA with alkali,and then PAAC-b-PMMA was used to react with iso Isopropyl cyanate（C4H7NO）was reacted to obtain PMMA-b-PINAM,and finally the obtained three block copolymers were made into amphiphilic block copolymer micelles,and the critical micelle concentration CMC was determined by fluorescent probe method,dynamic light scattering DLS test micellar particle size distribution.Comparing the test results of the critical micelle concentration and particle size of the amphiphilic block copolymer micelles proves that when the total degree of polymerization of the block copolymer is constant,with the increase of the proportion of hydrophobic ends,the CMC is gradually decreasing,and the micelle particle size is at Gradually increase.And the larger the proportion of hydrophobic ends,the more obvious the size of micelles increases.