The synthesis and characterization of poly(ethylene oxide)‐b‐poly‐(dimethylsiloxane) diblock copolymers

Abstract

Poly(ethylene oxide)‐b‐poly(dimethylsiloxane) (PEO‐b‐PDMS) diblock copolymers have been synthesized by hydrosilation coupling. Allyl‐terminated PEO and dimethylsilane‐terminated PDMS macromers have been prepared by living anionic polymerization, followed by subsequent functionalization. The diblock copolymers, as well as the preformed macromers, have been characterized by gel‐permeation chromatography, vapour pressure osmometry, FTIR spectroscopy and 1H‐, 13C‐ and 29Si‐FTNMR spectroscopy. The results obtained from these techniques are presented in detail for PEO(M̄;n = 2120), PDMS(M̄n = 2220) and the corresponding diblock copolymer.

Synthesis and Solution Properties of Dimethylsiloxane−2-(Dimethylamino)ethyl Methacrylate Block Copolymers

“…and also hydrophilic oligo(ethylene oxide)-based chains. 7,22 It is also noteworthy that attempts were made to calculate the block composition of D2 by comparing the total peak integral for the three pairs of oxymethylene protons at δ 3.20-3.45 originating from the PDMS macroinitiator (and now located at the block junction point) with that of the oxymethylene protons due to the DMA residues at δ 4.00-4.30. Since the former protons are directly attached to the solvated DMA block, it was hoped that this might allow realistic NMR compositions to be calculated even if the PDMS block itself was poorly solvated due to micelle formation.…”

“…This unusual behavior is apparently confined to nitrogen-based hydrophilic blocks since, according to the literature and also our own recent experience, accurate copolymer compositions can be readily obtained for PDMS blocked with a wide range of hydrophobic monomers (styrene, , various methacrylates, etc.) and also hydrophilic oligo(ethylene oxide)-based chains. , …”

“…[3][4][5][6] Generally, such copolymers are prepared by condensation chemistry, i.e., by the coupling of end-functionalized low molecular weight poly(ethylene oxide) and PDMS chains as described by Kiraly and Vincent. 7 PDMS-based block copolymers have also been prepared using so-called "living" polymerization techniques and subsequently used as steric stabilizers for dispersion polymerizations in nonaqueous media. For example, Dawkins and Taylor have utilized poly(styreneblock-dimethylsiloxane) to prepare poly(methyl methacrylate) latexes in n-alkanes.…”

“…In particular, dimethylsiloxane−alkylene oxide copolymers have been used in the manufacture of polyurethane foams for many decades . Other applications for this class of materials include use as antifoam agents, additives in paint and cosmetic formulations, lubricants, emulsifying agents, etc. − Generally, such copolymers are prepared by condensation chemistry, i.e., by the coupling of end-functionalized low molecular weight poly(ethylene oxide) and PDMS chains as described by Kiraly and Vincent …”