Methyl acrylate polymerization chain transfer

If chain transfer of the radical center to a previously formed polymer molecule is followed ultimately by termination through coupling with another similarly transferred center, the net result of these two processes is the combination of a pair of previously independent polymer molecules. T. G. Fox (private communication of results as yet unpublished) has suggested this mechanism as one which may give rise to network structures in the polymerization of monovinyl compounds. His preliminary analysis of kinetic data indicates that proliferous polymerization of methyl acrylate may be triggered by networks thus generated. 

A polymeric composition for reducing fluid loss in drilling muds and well cement compositions is obtained by the free radical-initiated polymerization of a water-soluble vinyl monomer in an aqueous suspension of lignin, modified lignins, lignite, brown coal, and modified brown coal [705,1847]. The vinyl monomers can be methacrylic acid, methacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, vinylacetate, methyl vinyl ether, ethyl vinyl ether, N-methylmethacrylamide, N,N-dimethylmethacrylamide, vinyl sulfonate, and additional AMPS. In this process a grafting process to the coals by chain transfer may occur. 

Monomer and initiator must be soluble in the liquid and the solvent must have the desired chain-transfer characteristics, boiling point (above the temperature necessary to carry out the polymerization and low enough to allow for ready removal if the polymer is recovered by solvent evaporation). The presence of the solvent assists in heat removal and control (as it also does for suspension and emulsion polymerization systems). Polymer yield per reaction volume is lower than for bulk reactions. Also, solvent recovery and removal (from the polymer) is necessary. Many free radical and ionic polymerizations are carried out utilizing solution polymerization including water-soluble polymers prepared in aqueous solution (namely poly(acrylic acid), polyacrylamide, and poly(A-vinylpyrrolidinone). Polystyrene, poly(methyl methacrylate), poly(vinyl chloride), and polybutadiene are prepared from organic solution polymerizations. 

Free radical polymerization of styrene, of acrylate and of methacrylate monomers in solutions at 60° C in the presence of this preformed polymer produced graft copolymers in high efficiency, the chain transfer constants for these mercapto groups with styrene and methyl methacrylate being similar to those found with simple mercaptans (80, 85). 

MALDI-TOF mass spectrometry analysis of poly(methyl acrylate) prepared by the free-radical polymerization of methyl acrylate (MA) in the presence of a cyclic dixanthate under y-ray irradiation revealed that there are at least three distributions, i.e., molecular mass for [ 1-(MA) -H]+ of cyclic polymers, [1-(MA) -THF-H]+, and [1-(MA) -(THF)2-H]+ of linear polymers were observed. The relative content of the cyclic polymers markedly increases at a lower temperature, which may be related to the reduced diffusion rate and the suppressed chain-transfer reaction at the low reaction temperature [39]. 

Pentadienyl-terminated poly(methyl methacrylate) (PMMA) as well as PSt, 12, have been prepared by radical polymerization via addition-fragmentation chain transfer mechanism, and radically copolymerized with St and MMA, respectively, to give PSt-g-PMMA and PMMA-g-PSt [17, 18]. Metal-free anionic polymerization of tert-butyl acrylate (TBA) initiated with a carbanion from diethyl 2-vinyloxyethylmalonate produced vinyl ether-functionalized PTBA macromonomer, 13 [19]. 

Similarly, acrylonitrile, methyl acrylate and acrylamide a-substituted with a benzyloxy group act as chain transfer agents during the polymerization of MMA, St, MA, and VA, which is due to the following fragmentation reaction [94] ... 

Since the product here contains ionic and nonionic groups, it will be an anionic surfactant. Such materials, which are always formed in persulfate-initiated emulsion polymerizations, have been termed in situ surfactants. Their nature has not been studied extensively. In one study, of the polymerization of a 64 36 (w/w) methyl methacrylate butyl acrylate copolymer in the presence of a chain transfer... 

Poly(methacrylic acid) and poly(acrylic acid) (PAA) were prepared by AIBN initiated polymerization of the freshly distilled monomer in deoxygenated methyl ethyl ketone at 60°C. The incorporation of 9,10-dimethylanthracene (9,10-DMA) end-groups in the polymer was achieved by the addition of the chain transfer agent (1% by weight) to the polymerization mixture. Unreacted 9,10-DMA was separated from the polymer by gel permeation chromatography using a column packed with Sephadex LH-20 and methanol as the eluent. Analysis of the PMA sample by NMR indicates that the polymer produced under these conditions consists of 57% syndiotactic, 33% heterotactic and 10% isotactic triads (15). Solution concentrations were 0.02 M in repeating units of the polymer. 

Other examples of peroxy inisurfs can also be found in Russian scientific papers. As for instance in Ref. [41] Voronov et al. describe a polymeric surfactant with peroxy side chains for application as inisurfs in emulsion polymerization. They obtained the polymeric inisurf (Inisurf 2) by copolymerization of a peroxide containing monomer (dimethyl-vinylethinyl-methyl-tm-butyl-peroxide) with acrylic or methacrylic acid or 2-methyl-5-vinyl pyridine with benzoyl peroxide as initiator in the presence of dodecylmercaptan as chain transfer agent. The resulting copolymers are water soluble at appropriate pH-values, surface active, and exhibit a critical micelle concentratioiL... 

Although the previously described polymerization with organocobalt porphyrins (7) is the first example of controlled radical polymerization, the applicability of this system is only limited to acrylic esters (20). Use of 7 for free-radical polymerization of methacrylic esters (21) results in a chain-transfer reaction with respect to the a-methyl group, to give oligomers with terminal unsaturation. 

Zhang, Z., Zhu, X., Zhu, J. Cheng, Z. (2006) Thermal polymerization of methyl (meth)acrylate via reversible addition-fiagmentation chain transfer (RAFT) process. Polymer, Al, 6970-7. 

Lacroix and coworkers reported a reverse iodine transfer pol5mierization (RITP), where elemental iodine is used as a control agent in living radical polymerization [288]. Styrene, butyl acrylate, methyl acrylate, and butyl ot-fluoroacrylate were homopolymerized, using a radical catalyst and I2 as a chain transfer agent. Methyl acrylate was also copolymerized with vinyUdene chloride using this process. 

The reversible addition-fragmentation chain transfer (RAFT) polymerization of vinylidene chloride, methyl acrylate, and a phosphonated monomer named MAUPHOS [CH2=C(CH3)C(0)0(CH2)2NHC(0)0(CH2)2P(0)(0CH3)2]... 

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