Ethyl acrylate polymerization, transfer

Polymerization processes are characterized by extremes. Industrial products are mixtures with molecular weights of lO" to 10. In a particular polymerization of styrene the viscosity increased by a fac tor of lO " as conversion went from 0 to 60 percent. The adiabatic reaction temperature for complete polymerization of ethylene is 1,800 K (3,240 R). Heat transfer coefficients in stirred tanks with high viscosities can be as low as 25 W/(m °C) (16.2 Btu/[h fH °F]). Reaction times for butadiene-styrene rubbers are 8 to 12 h polyethylene molecules continue to grow lor 30 min whereas ethyl acrylate in 20% emulsion reacts in less than 1 min, so monomer must be added gradually to keep the temperature within hmits. Initiators of the chain reactions have concentration of 10" g mol/L so they are highly sensitive to poisons and impurities. 

ESI mass spectrometry ive mass spectrometry ESR spectroscopy set EPR spectroscopy ethyl acetate, chain transfer to 295 ethyl acrylate (EA) polymerizalion, transfer constants, to macromonomers 307 ethyl methacrylate (EMA) polymerization combination v.v disproportionation 255, 262 kinetic parameters 219 tacticity, solvent effects 428 thermodynamics 215 ethyl radicals... 

Items b and d may be related since the decrease in rate begins to be observed at about 40% conversion, i.e. at the point where [AN] has fallen to about 2.25 M. It is interesting to note that we ( ) and others ( 5) have also noted very slow rates of polymerization of ethyl acrylate at 1 M concentrations in ethyl acetate using either tetrabutyl ammoniurn bromide or 18-crown-6 as the phase transfer catalyst. Further studies in this area are needed. 

AA acac alt AIBN Ar Bd Bu BuA BuMA BzMA CMSty CR CT CTFE DBP DPn EA HEA HEMA HFP acrylamide acetylacetonate alternating azobisisobutyronitrile aromatic group butadiene n-butyl n-butyl acrylate n-butyl methacrylate benzyl methacrylate chloromethyl styrene counter-radical transfer constant chlorotrifluoroethylene dibenzoyl peroxide average degree of polymerization in number ethyl acrylate 2-hydroxyethyl acrylate 2-hydroxyethyl methacrylate hexafluoropropene... 

Emulsion polymerization with the chain transfer agent l-benzyl-2,5-cyclohexadiene-1-carboxylic acid was also used to prepare poly(ethyl acrylate-co-methacrylic acid). Poly(N-vinylpyrrolidone) was prepared using the chain transfer agent l-i-propyl-2,5-cyclohexadiene-1 -carboxylic acid. 

Smooth, but one-way, mechanistic crossover from olefin polymerization to group-transfer polymerization is possible with lanthanocene catalysts, since insertion of an acrylate into the propagating metal alkyl to form an enolate is energetically favorable. Block copolymers of ethylene with MMA, methyl acrylate, ethyl acrylate, or lactones have been prepared by sequential monomer addition to lanthanide catalysts and exhibit superior dyeing capabilities. However, the reverse order of monomer addition, i.e., (meth)acrylate followed by ethylene, does not give diblocks since the conversion of an enolate (or alkox-ide) to an alkyl is not favored. Therefore, although... 

H. Datta, N.K. Singha, A.K. Bhowmick, Beneficial effect of nanoclay in atom transfer radical polymerization of ethyl acrylate a one pot preparation of tailor-made polymer nanocomposite. Macromolecules 41 (1) (2008) 50-57. 

Zeng, R, Shen, Y., Zhu, S. 2002. Atom Transfer-Radical Polymerization of 2- N,N-Dimethylamino)Ethyl Acrylate.23 1113-1117. 

Matyjaszewski K, Gaynor SG, Muller AHE. Preparation of hyperbranched polyacrylates by atom transfer radical polymerization. 2. kinetics and mechanism of chain growth for the self-condensing vinyl polymerization of 2-((2-Bromopropionyl)oxy)ethyl acrylate. Macromolecules 1997 30 7034-7041. 

Hikita, M., Tanaka, K., Nakamura, T. et al. (2004) Aggregation states and surface wettability in films of poly(styrene-block-perfluorooctyl ethyl acrylate) diblock copolymers synthesized by atom transfer radical polymerization. 

Liang YZ, Li ZC, Chen GQ, Li FM (1999) Synthesis of well-defined poly (2-beta-D-glucopyranosyloxy)ethyl acrylate by atom transfer radical polymerization. Polym Int... 

SGI nitroxide was attached to latex particles made of poly(styrene-co-chloromethylstyrene) of 60 nm diameter previously prepared via atom transfer radical addition [83]. Microspheres grafted with the homopolymer poly (2-dimethylamino ethyl acrylate) (PDMAEA), as well as block copolymers poly (styrene-h-DMAEA) and poly(butyl aciylate-h-DMAEA) were prepared by Sl-NMP in DMF at 112 C, with the initial addition of free SGI to ensure polymerization control. 

Kajtna and Sebenik described the synthesis of pressure-sensitive adhesives based on polyacrylates by suspension polymerization. The monomers used were 2-ethylhexyl acrylate (2-EHA) and ethyl acrylate (EA), and dibenzoyl peroxide (DBF) was used as initiator. Surface-active agents [modified ester of sulfocarboxylic acid (SCA) and ethoxylated oleyl alcohol (EOA)], chain transfer agent (w-dodecanethiol) (CTA) and suspension stabilizer [poly(vinyl alcohol) (PVA)] were also used. Various organically modified montmorillonites were used as fillers. It was observed that the kinetics of suspension polymerization were independent of the presence of the montmorillonite in the system, as shown in Figure 1.8. 

The continuous bulk polymerization of methyl methacrylate was used as an example in Section 5.2. A stirred bulk polymerization like that used for styrene (Section 5.4) could be adapted for methyl methacrylate. A suspension process for poly(methyl methacrylate) was described in Section 5.4. The polymerization of ethyl acrylate most often is carried out in emulsion. A process such as that used for vinyl acetate is suitable (Section 16.4). Like vinyl acetate, the monomer is slightly water soluble, so true emulsion polymerization kinetics are not followed. That is, there is initiation of monomer dissolved in water in addition to that dissolved in growing polymer particles. Ethyl acrylate is distinguished by its rapid rate of propagation. Initiation of a 20% monomer emulsion at room temperature by the redox couple persulfate-metabisulflte can result in over 95% conversion in less than a minute. As with vinyl acetate polymerization, a continuous addition of monomer at a rate commensurate with the heat transfer capacity of the reactor is necessary in order to control the temperature. 

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