Polymerization of Methyl and Ethyl Methacrylates Initiated with Alkali-Metal Alkoxide Derivatives of Poly(ethylene oxide)

Abstract

ABSTRACT:The polymerization of methacrylates with alkali-metal alkoxide derivatives of poly( ethylene oxide) (PEO) yielded copolymers which consisted of PEO and polymethacrylates containing block and graft units. The block copolymerization was initiated by addition of the alkoxide to the carbon-carbon double bond of methacrylates, and the graft reaction onto the block copolymer formed was thought to proceed by transesterification between the pendant ester groups of the copolymer and the unreacted alkoxide. The grafting of the alkoxide derivative of PEO having two terminal hydroxyl groups resulted in formation of cross-linked copolymers, while the polymerization with the alkoxide having one active end gave soluble copolymers. The relative amount of the grafted ester groups in the copolymers was estimated by NMR spectroscopy.KEY WORDS Anionic Polymerization I Block Copolymer I Graft Copolymer I Poly(ethylene oxide) I Alkyl Methacrylate 1 Alkali-Metal Alkoxide I Crosslinking I Transesterification 1In a previous paper/ it was shown that the polymerization of methyl methacrylate (MMA) with alkali-metal salts of 2-substituted ethanols such as 2-methoxyethanol and 2-dimethylaminoethanol proceeded easily in the presence of hexamethylphosphoramide (HMPA).In this paper, the polymerization of MMA and ethyl methacrylate (EMA) with alkali-metal alkoxide derivatives of poly(ethylene oxide) (PEO) has been investigated, since the formation of block copolymers, poly( ethylene oxide-b-methacrylates), was expected from the similarity of structure between 2-methoxyethanol and the PEO carrying terminal hydroxyl groups. The block or graft copolymers composed of polymers having different properties, e.g., rubbery and glassy or hydrophilic and hydrophobic, have been noted as a kind of new prospective polymer materials. 2 PEO has hydrophilic and rather rubbery properties, while polymethacrylates have hydrophobic and glassy ones. For example, poly(methyl methacrylate-g-ethylene oxide) have already been synthesized by the grafting of alkoxide derivatives of PEO onto poly(methyl methacrylate)."In this study, the synthesis of poly(ethylene oxide-b-methacrylates) was attempted by means of the anionic polymerization of vinyl monomers 190 (MMA and EMA) with macromolecular initiators (alkoxide derivatives of PEO). Such block copolymers, which consist of alkylene oxide and vinyl or diene monomers, have already been synthesized by radical copolymerization, 4 but not by anionic polymerization. EXPERIMENTAL ReagentsTetrahydrofuran (THF) was distilled over metallic sodium under a nitrogen atmosphere. HMPA was refluxed and distilled over calcium hydride in vacuo. PEO having terminal hydroxyl groups was dried by azeotropic 'distillation in toluene. 3 2-Methoxyethanol was refluxed and distilled over calcium hydride under a nitrogen atmosphere. Ethylene oxide (Nippon Shokubai Kagaku) was used without further purification. MMA and EMA were purified by conventional methods, refluxed, and distilled over calcium hydride under vacuum just before use. Sodium ...

Double-Hydrophilic Block Copolymers: Synthesis and Application as Novel Surfactants and Crystal Growth Modifiers

“…The first anionic polymerizations reported for MMA with a PEO macroinitiator were initiated with the disodium salt of low-molar mass PEO in the presence of hexamethylphosphoramide [64] or in the presence of crown ethers as effective binding sites for the alkali metal cations thus increasing the nucleophilicity of the dianions. [24,25,65] Such initiator systems were also used for the polymerization of acrylonitrile (AN) [66 -68] and methyl acrylonitrile.…”

Synthesis of poly(ethylene oxide‐b‐methyl methacrylate)

“…Except in the presence of aprotic dipolar solvents such as hexamethyl phosphoric triamide, alkali metal salts of primary alcohols can not initiate polymerization of methyl methacrylate (MMA) (2,3). However, Tomoi et al reported recently that the disodium salt of low molecular weight PEO (Mn = 200) could initiate polymerization of MMA in tetrahydrofuran (THF), but high molecular PEO salts (Mn = 1000) could not (4).…”

Synthesis and characterization of an amphiphilic graft copolymer with a poly(acrylic acid) backbone and n‐octylphenyl polyoxyethylene side chains

“…Comblike amphiphilic copolymers with chemically different backbones and side chains have a number of features that make them attractive candidates for diverse applications. Depending on the solubility of the main chain and side chains, two qualitatively different scenarios of aggregation behavior are visible 21–24…”

“…Depending on the solubility of the main chain and side chains, two qualitatively different scenarios of aggregation behavior are visible. [21][22][23][24] In this study, a novel amphiphilic graft copolymer poly(acrylic acid) grafted octylphenyl polyoxylethylene ether (AA-C 8 PhEO 10 Ac) was synthesized by the reaction of n-octylphenyl polyoxyethylene acrylate (C 8 PhEO 10 Ac) and acrylic acid (AA) in aqueous solution. This novel acrylic copolymer with amphiphilic character was easily characterized by IR, 1 H-NMR, gel permeation chromatography (GPC), and fluorescence spectroscopy because of the built-in aromatic moiety in its side chain.…”