Styrene-ethyleneoxide copolymer

The idea of the preparation of porous polymers from high internal phase emulsions had been reported prior to the publication of the PolyHIPE patent [128]. About twenty years previously, Bartl and von Bonin [148,149] described the polymerisation of water-insoluble vinyl monomers, such as styrene and methyl methacrylate, in w/o HIPEs, stabilised by styrene-ethyleneoxide graft copolymers. In this way, HIPEs of approximately 85% internal phase volume could be prepared. On polymerisation, solid, closed-cell monolithic polymers were obtained. Similarly, Riess and coworkers [150] had described the preparation of closed-cell porous polystyrene from HIPEs of water in styrene, stabilised by poly(styrene-ethyleneoxide) block copolymer surfactants, with internal phase volumes of up to 80%. 

Polymerization Polystyrene-block-polyethyleneoxide samples were prepared by sequential anionic polymerization in THF with cumyl potassium as the initiator. The PEO block lengths were varied from 1 to 25 mole%. Samples were characterized by SEC and H-NMR. Results are summarized in Table I. The monomer to initiator ratio was chosen so that molecular weights of about 50.000 g/mole could be expected for all polymers. The actual molecular weights which were found by SEC were higher. This can be explained by partial precipitation of the initiator in the stock solution. It must be noted also, that SEC elution volumes had been transformed to molecular weights by means of a polystyrene calibration curve. For this reason, some deviation of the actual molecular weight of the styrene/ethyleneoxide block copolymers is expected. 

In aqueous solvent a hydrophobic environment was constructed by using a water-soluble and hydrophobic tri-block copolymer (Scheme 7). The central block is hydrophobic and composed of the copolymer of styrene and N-vinylimidazole (PSI), to which Cu ions can coordinate. This central block was synthesized by UV-irradia-tion polymerization bytelechelic initiator of bis(4-carbomethoxy-phenyl)-disulfide. The reaction of telechelic block with poly-(ethyleneoxide) gave the block copolymer PE0-PSI-PE0. 

The influence of reciprocal miscibility between the methacrylic copolymer containing cyclic anhydride groups and the styrenic oligomers was investigated in the case of monohydroxylated oligomers, which were also prepared by anionic polymerisation of styrene and further deactivation with ethyleneoxide. 

Table 1.1 Reported techniques to selectively degrade one copolymer block. Poly(styrene) PS, poly (dimethylsiloxane) PDMS, poly(ethyleneoxide) PEO, poly(isoprene) PI. poly(lactic acid) PLA. poly(methyl methacrylate) PMMA, poly(vinylpyridine) PVP, 3-pentadecylphenol PDP...

In order to study the stability of gold colloids in solutions of poorly interacting polymers, we chose block copolymers of styrene and ethyleneoxide (PS-b-PEO). Polyethyleneoxide does not interact strongly with transition metal surfaces and is thus a rather poor stabilizer for colloidal gold (5). It can, however, complex lithium cations and can also be protonated (9). In this way, PEO can bind compounds like LiAuCU and HAuCU, and we attempted to load inverse PS-b-PEO micelles by these gold salts. Subsequent reduction was expected to yield small gold crystallites entrapped in the micellar cores. 

Polystyrene (PS) is an addition polymer, which may be produced by bulk, emulsion or suspension polymerization of styrene. Styrene is obtained from ethylbenzene by catalytic delydrogenatioa The PS is a vinyl polymer in which hydrogen is replaced by pheityl group. Its copolymers can be produced using different monomers such as butadiene, acrylonitrile, ethyleneoxide, and divinylbenzene. 

Here we describe an example of the fabrication and investigation of smart responsive nanoparticles by grafting block-copolymers. We grafted triblock copolymer of poly(styrene-fc-2-vinylpyridine-fc-ethyleneoxide) (P(S-b-2VP-b-EO) to silica particles 200 nm in diameter (Fig. 18.9). The particles were modified by 11-bromoundodeciltrimethoxisilane (BUDTMS), then the block-copolymer was grafted by a quatemization reaction to the particle surface. The grafting of the block-copolymer to the silica nanoparticles was proved by FTIR using the diffuse reflection technique. Very well-pronounced... 

A ternary block copolymer, which contains amino groups in the center block, was synthesized by coupling cnt/o-telechelic poly[styrene-co-p-(ami-nomethyl)styrene] with an excess of poly(ethyleneoxide). The center block was prepared by the UV-irradiation polymerization of styrene, p-(amino-methyl)styrene, and bis(/7-acetoxyphenyl)sulfide (molecular weight 42,000). The carboxylic acid derivative of iron-porphyrin was activated with ethyl chloroformate and then reacted with the amino group of the center block of the ternary copolymer. 

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