Alternating regulation in copolymerization of methyl methacrylate with styrene by a series of ethylboron chlorides

Abstract

It is well known that electron-donating monomers such as styrene and butadiene can be copolymerized alternatingly with polar vinyl monomers such as methyl methacrylate and acrylonitrile in the presence of metal halides ~ '). With metal halides previously reported, such as alkylaluminium halides '), zinc chloride'), and stannic chloride'), the mole ratio of metal halide to polar vinyl monomer in the reaction mixture must be 0,3 -1 ,O or even higher, in order to achieve satisfactorily an alternate regulation of the resulting copolymer. Although a patent ' ) claims that quite a wide range of mole ratios (0,0005 to 10) of metal halide to polar vinyl monomer may be applied to achieve alternating copolymerization, no experimental results of the copolymerization at any mole ratio smaller than 0,2 has been described so far.

Problems of control of the reactivity of macroradicals and the growth of polymer chains

“…Initiation by the TIBB ± OEP system gives rise to a copolymer with a narrower composition distribution of fractions. 88 Hirai et al, 89,90 who studied the controlling influence of boron compounds on the composition of the MMA ± St copolymer, demonstrated that photoinitiation in the presence of 1 mol % of boron trichloride or ethylboron dichloride gives rise to an alternating St ± MMA copolymer. On the basis of kinetic measurements and study of the microtacticity of copolymers, it was concluded that copolymerisation involves the ternary complex `MMA ± St ± organoboron compound'.…”

Polymerization of coordinated monomers. XX. Ab initio molecular orbital study on the binary molecular complex composed of methyl methacrylate and boron trichloride

“…We already showed that the sequence of the copolymer of MMA with styrene was almost completely regulated alternatingly by boron trichloride ( BC13) even at a small molar ratio, 0.01 to MMA. 5,6 The equilibrium constant for the formation of the binary molecular complex between MMA and BC13 was determined by the chemical shift changes of MMA protons due to the complex formation with BC13 in di~hloroethane.~ Among the various metal halides, the equilibrium constant for the formation of the binary molecular complex between MMA and BC13 was very large. As the next step, determination of the structure of the binary molecular complex composed of MMA and BC13 is required for the elucidation of the polymerization mechanism in the presence of BC13.…”