Anionic polymerization of acrylic monomers. 6. Synthesis, characterization, and modification of poly(methyl methacrylate)-poly(tert-butyl acrylate) di- and triblock copolymers

Poly(methyl methacrylate)-b-poly(tert-butyl acrylate) (PMMA-b-PtBA) copolymers have been successfully synthesized by the sequential anionic polymerization of methyl methacrylate (MMA) and tert-butyl acrylate (tBA) in THF at -78-degrees-C. Although the order of monomer addition makes a difference on the initiation efficiency, it has no significant effect on the final achievement. Mono- and bifunctional initiators based on alkali metals can be used. When the initiators are modified by LiCl as a ligand, the polymerization of each block appears to be living, the molecular weight and composition can be predicted, and the molecular weight distribution is narrow. Size exclusion chromatography supports the absence of homo-PtBA in the PtBA-b-PMMA samples. The PtBA blocks can be quantitatively hydrolyzed into polyacid ones as supported by titration and H-1 NMR analysis

New prospects for “living” anionic polymerization of (meth) acrylic esters

peer reviewedThe living low temperature polymerization in polar solvents of most methacrylates, even functional ones, can now be performed by direct and experimentally convenient anionic methods, thanks to the use of α‐methylstyrene and of complex‐purified monomers. A diversified family of block copolymers has thus been generated, that are used as compatibilizing agents in the designing of interesting heterophase materials: i.e. blends of polymers and inorganic fillers, and liquid‐solid dispersions. The living polymerization of acrylates (or of methacrylates under more drastic conditions) raises additional requirements: they have been met to a large extent by the use of specific ligands of the growing ion‐pair. Resulting structures such as f.i. block copolymers and end‐functionalized oligomers of a low dispersity, should have a great interest in the molecular engineering of (meth)acrylate‐based products. Finally, these new initiators lend themselves to structural and mechanistic studies which should shed some light on the critical features of these living propagation processes. Copyright © 1990 Hüthig & Wepf Verla

Control of living anionic polymerization of (meth)acrylates : active complex species, macromolecular engineering and possible scaling-up

Tailored polymerization of acrylic and methacrylic esters, particularly methyl methacrylate (MMA), has been the topic of a frantic research effort during the last decade. It is the purpose of this paper to present one of the main lines of that quest, and to evaluate its potential versus other new approaches

Contribution of polyalky(meth)acrylates to the design of PVC melt viscosity

The shear viscosity of poly(vinylchloride) (PVC) at 200°C can be decreased by at least one order of magnitude by the addition of as little as 5 wt% poly n-alkyl-(meth)acrylates (PMA) of a much lower dynamic viscosity than PVC. For this effect to be observed, the polymeric additive must be immiscible with PVC at 200°C. The average size of the dispersed phases is observed in the range of 0.5 to 5 m; size fluctuation in this domain has no significant effect. When these conditions are met, there is a linear increase in the shear viscosity ratio blend/PVC from 0.2 to 1.0 with increasing logarithmic values of the dynamic viscosity ratio of the additive over PVC [(log(/)) from -4 to -1]

Anionic polymerization of various methacrylates initiated with LiCl-complexed sBuLi

A simple alkyl lithium initiator (sBuLi) complexed with LiCl (10 molar equiv.) has been used to initiate the anionic polymerization of various methacrylic monomers, i.e. methyl methacrylate (MMA), tert-butyl methacrylate (tBuMA), glycidyl methacrylate (GMA), and dimethyl amino ethyl methacrylate (DMAEMA) in tetrahydrofuran at -78°C. Only the homopolymerization of tBuMA proceeds in a living manner, as evidenced by both the linear plot of experimental molecular weight (Mnexp) vs theoretical ones (Mncal,) (slope % 0.93) and monomer resumption experiments. However, three types of block copolymers, i.e. PtBuMA-b-PMMA, PtBuMA-b-PGMA, PtBuMA-b-PDMAEMA, have been successfully synthesized with a predictable molecular weight, and narrow molecular weight distribution