Elf Atochem S.a.

Jinshan Wang

Philippe Teyssie

Bruno Vuillemin

Philippe Heim

Philippe Bayard

Poly(alkyl (meth)acrylates) are inexpensively prepared, even on an industrial scale, by anionically polymerizing at least one alkyl (meth)acrylate monomer in the presence of a lithium-based initiator and in a liquid solvent medium in which the solubility parameter .delta. is less than 20, said initiator comprising an alcoholate having the formula ROLi, wherein R has the formula R.sup.1 (OR.sup.2).sub.m, in which R.sup.1 is a linear or branched alkyl radical having from 2 to 4 carbon atoms, R.sup.2 is a linear or branched alkylene radical having from 2 to 4 carbon atoms, and m is 1, 2 or 3.

Anionic polymerization of alkyl (meth)acrylate monomers

The invention concerns the anionic polymerization of alkyl methacrylate in the presence of a priming system. The priming system comprises an organolithium primer and an organic compound of aluminum and pyridine. This priming system allows better polymerization control.

System for priming the anionic polymerization of alkyl methacrylate

Mechanically strong; heat-resistant and transparent PMMA polymers having a high content of syndiotactic triads, a number average molecular weight ranging from 5,000 to 500,000 and a polydispersity index ranging from 1.01 to 1.5, are prepared by anionically polymerizing methyl methacrylate, characteristically at a temperature of at least 0.degree. C., in the presence of (a) at least one organolithium or organosodium initiator and (b) at least one AlR.sup.1 R.sup.2 R.sup.3 ligand, for example at least one di- or tri-phenoxy alkyl aluminum compound.

Highly syndiotactic PMMA polymers

Thermoplastic, elastomeric, conjugated diene (e.g., butadiene)/methyl methacrylate block copolymers having elevated Tg and improved impact strength, well suited as polymer impact strength-modifiers and for conversion into pressure-sensitive adhesives, are prepared by (a) anionically polymerizing a conjugated diene monomer in an apolar solvent medium to provide a living polydiene, (b) next adding an alkali metal alkoxyalcoholate ligand to the medium comprising the living polydiene thus formed, (c) block copolymerizing the step (b) living polydiene with methyl methacrylate comonomer to provide a living copolymer, and (d) reacting the step (c) living copolymer with at least one protonic compound, e.g., water, alcohol and/or acid, and completing the polymerization thereof, with the proviso that polymerization of the conjugated diene and the methyl methacrylate comonomers is strictly carried out in the apolar solvent medium, in particular in toluene, benzene or ethylbenzene.

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Naperville, IL, United States of America

Jinshan Wang