Poly oxyethylene Macromonomers

In a patent dated 1965 Stowe35) laid the basis for the copolymerization of PEO macromonomer with comonomers such as acrylonitrile. It was searched for an increased wettability of polyacrylonitrile films or fibers by a permanent surface modification. ro-Styryl poly(oxyethylene) macromonomers readily copolymerize with acrylonitrile in water emulsions. They can also be copolymerized with styrene-sulfonates in the presence of poly(vinylpyrrolidone). The presence of small amounts of such copolymers in polyacrylonitrile fibers was shown to increase their wettability and their receptivity to dyes and to make them more resistant to electric loading (antistatic fibers). No characterization data on the copolymers formed have been reported. 

Further studies on the preparation of networks coated with hydrophilic chains at the surface are being made. 

Watanabe62) studied systematically the copolymerization of ra-methacryloyl-polyoxyethylenes, with monomers such as acrylonitrile, styrene, butyl methacrylate, and methacrylic acid. It should be mentioned that the macromonomers that he prepared are very short so that no difficulties were encountered to isolate the graft copolymers formed. There are many applications for these graft copolymers, e.g. as additives in polyacrylonitrile films and fibers they cause improved antistatic properties. They have been tested as varnishes, coatings, and wood dimensional stabilization agents. 

PEO macromonomers were also reacted with isocyanates to introduce urethane linkage, the methacrylic ester functions being used to cure the material in a later step. 

This very interesting investigation is to our knowledge the first exemple of a macromonomer fitted at the chain end with a heterocycle susceptible to cationic homo-and copolymerization. 

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Polyethylene oxide)macromonomers have thus been synthesized by two-step processes. Poly(oxyethylene)mo nomethyl ethers with widely varying molecular weights are commercially available. They are obtained by anionic polymerization of oxirane initiated by monofunctional alkoxides261 such as potassium 2-methoxyethanol. 

Nuclear magnetic resonance monitoring of the synthesis of amphiphilic copolymers has also been reported by Larazz et al. [174] for the copolymerization of a methacrylic macromonomer with amphiphilic character derived from Triton X-100 (MT) with acrylic acid (AA). In situ H NMR analysis was used to monitor comonomer consumption throughout the copolymerization reactions, initiated by AIBN in deuterated dioxane, at 60 °C. The results from two different approaches used by the authors to estimate the reactivity ratio of the macromonomer indicate that AA is less reactive than the macromonomer MT and a model monomer with lower molecular weight but same structure, suggesting that methacrylic double bond reactivity was not affected by poly(oxyethylene oxide) chain length. 

The block copolymer poly[block-poly(4-vinylpyridine], abbreviated P[MG8-4VP], was prepared by anionic living polymerization techniques by the synthetic pathway shown in Scheme 3 [49]. The polymerization of macromonomer MGS was initiated by 1,1-diphenylhexyllithium and the polymerization was allowed to proceed for up to 3 h at — 60°C and followed by the addition of the 4-vinylpyridine monomer, at which time the solution turned yellow-orange indicating the formation of the 4-pyridyl anion. The 4-vinylpyridine monomer was allowed to react for up to 3 h, after which time the living polymer was terminated with methanol. The block copolymers were purified by precipitation using a mixture of hexane and THF (90 10 v/v) followed by a second precipitation from diethyl ether. 

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