Explore The Active Controllable Free Radical Polymerization Of Methyl Acrylate

Active / controlled radical polymerization combines the advantages of free radical polymerization and ionic polymerization,and makes free radical polymerization controllable.The precise control of the composition and structure of polymer molecules is an important field of polymer research.In this paper,the development process of controlled polymerization is discussed,and the process from traditional free radical polymerization to active controllable polymerization is emphasized.Several types of reactive polymerization and the advantages and disadvantages of their reactions.The polymerization mechanism,polymerization process and properties of the polymerization products of two kinds of living radical polymerization were comparative studied,The two polymerization methods are single electron transfer radical polymerization and atom transfer radical polymerization.At the same time,several influencing factors of single electron transfer radical polymerization are discussed by using the control variable method.The main contents of this paper are as follows:SET-LRP and ATRP were used to prepare poly(methyl methacrylate),the structures of the products were characterized by Fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(~1H-NMR),and compared and analyzed.It is concluded that the infrared absorption curves of the polymerization products are basically the same in the two methods.The NMR spectra shift is basically the same,which shows that the product structure of the two methods is basically identical.Ubbelohde viscometer test products in dilute solution viscosity,gel permeation chromatography(GPC)test products in molecular weight and molecular weight distribution coefficient.As a result of analysis that: the monomer conversion rate of SET-LRP can reach 98% at 50 min,new monomer MA is added after reaction,what monomer will continue to polymerize indicates that the polymerization method is not terminated.The monomer conversion rate of ATRP can reach 92% at270 min.Continuing to add new monomer MA will not continue to polymerize.The chain end group showed no activity after the reaction;Analysis of polymerization of the monomer(M)and residual monomer(M)ratio,and then compared the logarithm value(LN(M/M))and reaction time(T)relationship.SET-LRP is a first-order kinetics,and ATRP is not.Analysis of the products of the two polymerization methods.Variation law of specific viscosity of product with time:the change of specific viscosity of SET-LRP products is linear with time,and ATRP is not.The two polymerization method product was tested by GPC.It can be seen that the molecular weight of SET-LRP is closer to the theoretical molecular weight,and the molecular weight distribution is narrower.The influencing factors of single electron transfer radical polymerization are discussed.The influencing factors are reaction temperature,monomer mass fraction,catalyst particle size,solvent polarity,non-polar two kinds of choice.The author thinks that the most suitable temperature is 30 degrees centigrade,the monomer mass fraction of 30% is more suitable for the catalyst,the smaller particle size,the faster the reaction rate,solvent selection of polar solvents,non polar solvent will cause the reaction rate to slow down,at the same time,the monomer conversion rate decreased.