Dienes, copolymerization methacrylates/acrylates

Monomers which can add to their own radicals are capable of copolymerizing with SO2 to give products of variable composition. These include styrene and ring-substituted styrenes (but not a-methylstyrene), vinyl acetate, vinyl bromide, vinyl chloride, and vinyl floride, acrylamide (but not N-substituted acrylamides) and allyl esters. Methyl methacrylate, acrylic acid, acrylates, and acrylonitrile do not copolymerize and in fact can be homopolymer-ized in SO2 as solvent. Dienes such as butadiene and 2-chloro-butadiene do copolymerize, and we will be concerned with the latter cortpound in this discussion. 

Relatively few comonomer pairs undergo anionic copolymerization to incorporate significant amounts of both monomers into the polymer chains [3, 45]. In general, the comonomer that is most reactive (lowest p/f value for the conjugate acid of the propagating anion) [2] will be incorporated to the practical exclusion of the other comonomer. Comonomer pairs that can be effectively copolymerized include styrenes with dienes and methacrylates with acrylates, that is, comonomer pairs with similar reactivity. 

Novel iron carbonyl monomer, r)4-(2,4-hexadien-l-yl acrylate)tricarbonyl-iron, 23, was prepared and both homopolymerized and copolymerized with acrylonitrile, vinyl acetate, styrene, and methyl methacrylate using AIBN initiation in benzene.70,71 72 The reactivity ratios obtained demonstrated that 23 was a more active acrylate than ferrocenylmethyl acrylate, 2. The thermal decomposition of the soluble homopolymer in air at 200°C led to the formation of Fe203 particles within a cross-linked matrix. This monomer raised the glass transition temperatures of the copolymers.70 The T)4-(diene)tricarbonyliron functions of 23 in styrene copolymers were converted in high yields to TT-allyltetracarbonyliron cations in the presence of HBF4 and CO.71 Exposure to nucleophiles gave 1,4-addition products of the diene group.71... 

Keywords Living polymerization, Living copolymerization, Rare earth metal complexes, Alkyl methacrylate, Alkyl acrylates, Lactones, Ethylene, 1-Olefins, Conjugated dienes, Acetylene... 

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