Polyethylene oxide -poly copolymer

In a similar manner polyisoprene-polyethylene oxide block copolymers can prepared301. It is surprising that the poly(methyl methacrylate) anion can be successfully used for the polymerization of ethylene oxide without chain transfer302. Graft copolymers are also prepared by successive addition of ethylene oxide to the poly-... 

Polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) (Pluronic) block copolymer is a very efficient reducing agent and nanoparticle stabilizer. Au NPs of about 10 nm can be stabilized with PEO-PPO-PEO block copolymer solutions in water and at room temperature and using HAuC14 as precursor. The formation of gold nanoparticles is controlled by the overall molecular weight and relative block length of the block copolymer [118]. 

Alexandridis P, Hatton TA. Polyethylene oxide)-poly(propylene oxide)- poly(ethylene oxide) block copolymer surfactants in aqueous solutions and at interfaces thermodynamics, structure, dynamics, and modeling (review). Colloid Surf A Physicochem Eng Aspects 1995 96 1 16. 

Poly (ethylene oxide)/poly (butylene oxide) copolymers In polyethylene oxide)-poly(butylene oxide) (PEO-PBO) diblocks with short blocks, unfolded PEO blocks crystallize into lamellar crystals, and the PBO... 

Almgren. M., J. Van Stam, C. Lindblad, P. Stilbs, and P. Bahadur. 1991. Aggregation of polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers in the presence of sodium dodecyl sulfate in aqueous solutiod.. Phys. Chem. 95 5677-5684. 

La, S. B., T. Okano, and K. Kataoka. 1996. Preparation and characterization of the micelle-forming polymeric drug indomethacin-incorporated polyethylene oxide)-poly(-bana Dartate) block copolymer micelles.J. Pharm. Sci85 85-90. 

Graft copolymers of poloxamers and either poly(acrylic acid) or chitosan change from a sol to a gel at temperature above 37 °C. The appearing gel forms a stable matrix that can retain a drag for its sustained release. The triblock copolymer consisting of polyethylene oxide)-poly(/-lactide)-poly(ethylene oxide) (PEO-PLLA-PEO) is also temperature-sensitive but shows an opposite gellation property. At low... 

Polyethylene oxide)—poly(/-lacride)b block copolymer biodegradable/bioerodible... 

Extensive neutron reflectivity studies on surfactant adsorption at the air-water interface show that a surfactant monolayer is formed at the interface. Even for concentration cmc, where complex sub-surface ordering of micelles may exist,the interfacial layer remains a monolayer. This is in marked contrast to the situation for amphiphilic block copolymers, where recent measurements by Richards et al. on polystyrene polyethylene oxide block copolymers (PS-b-PEO) and by Thomas et al. on poly(2-(dimethyl-amino)ethylmethacrylamide-b-methyl methacrylate) (DMAEMA-b-MMA) show the formation of surface micelles at a concentration block copolymer, where an abrupt change in thickness is observed at a finite concentration, and signals the onset of surface micellisation. 

SBA-15 is prepared under acidic conditions using polyethylene oxide)-poly(propylenc oxide)-poly(elhylene oxide) triblock copolymers, (EO)n(PO)7o(EO)n, as templates, e.g. Pluronic P123 (n = 20), Pluronic L121 (n - 5) or Pluronic F127 (n = 106). In a typical synthesis [54,551 based on the original procedures [33], 4.0 g of (EO)2o(PO)7o(EO)2o copolymer was dissolved in 150 g of 1.6 M HC1. To this solution was added 8.50 g of TEOS, and the resulting mixture was stirred until TEOS was dissolved. The mixture was heated in an oven for 24 h at 308 K. and then 24 h more at 373 K. under static condition. Silica products were filtered, dried (without washing), and calcined at 823 K. 

In most cases the catalytically active metal complex moiety is attached to a polymer carrying tertiary phosphine units. Such phosphinated polymers can be prepared from well-known water soluble polymers such as poly(ethyleneimine), poly(acrylic acid) [90,91] or polyethers [92] (see also Chapter 2). The solubility of these catalysts is often pH-dependent [90,91,93] so they can be separated from the reaction mixture by proper manipulation of the pH. Some polymers, such as the polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers, have inverse temperature dependent solubility in water and retain this property after functionalization with PPh2 and subsequent complexation with rhodium(I). The effect of temperature was demonstrated in the hydrogenation of aqueous allyl alcohol, which proceeded rapidly at 0 °C but stopped completely at 40 °C at which temperature the catalyst precipitated hydrogenation resumed by cooling the solution to 0 °C [92], Such smart catalysts may have special value in regulating the rate of strongly exothermic catalytic reactions. 

The above triblocks are not the most efficient emulsifiers or dispersants—the PPO chain is not sufficiently hydrophobic to provide a strong anchor to a hydrophobic surface or to an oil droplet. The surface activity of the PEO-PPO-PEO triblock at the OAV interface is probably due to rejection anchoring the PPO chain is not soluble in water or most oils. Several other di- and triblock copolymers have been synthesized diblocks of polystyrene block-polyvinyl alcohol triblocks of poly(methylmethacrylate)-block polyethylene oxide-poly(methyl methacrylate) diblocks of polystyrene-polyethylene oxide triblocks of polyethelene oxide-polystyrene-polyethylene oxide. 

Polyethylene oxide-poly(beta-benzyl-L-aspartate) ARA triblock copolymers Alpha helix/7(2) helix/alpha helix conformation [110]... 

RAFT polymerization has been used to prepare poly(ethylene oxide)-/ /wA-PS from commercially available hydroxy end-functional polyethylene oxide).4 5 449 Other block copolymers that have been prepared using similar strategies include poly(ethylene-co-butylene)-6/oci-poly(S-eo-MAH), jl poly(ethylene oxide)-block-poly(MMA),440 polyethylene oxide)-Moe -poly(N-vinyl formamide),651 poly(ethylene oxide)-Wot A-poly(NlPAM),651 polyfethylene ox de)-b ock-polyfl,1,2,2-tetrahydroperfluorodecyl acrylate),653 poly(lactic acid)-block-poly(MMA)440 and poly( actic acid)-6focA-poly(NIPAM),4 8-<>54... 

Synthesis of comb (regular graft) copolymers having a PDMS backbone and polyethylene oxide) teeth was reported 344). These copolymers were obtained by the reaction of poly(hydrogen,methyl)siloxane and monohydroxy-terminated polyethylene oxide) in benzene or toluene solution using triethylamine as catalyst. All the polymers obtained were reported to be liquids at room temperature. The copolymers were then thermally crosslinked at 150 °C. Conductivities of the lithium salts of the copolymers and the networks were determined. 

The morphologies of various copolymers composed of polyethylene oxide), PEO, and poly (1,2-butylene oxide), PBut, were recently reviewed by Ryan et al. [61]. The corresponding phase diagrams of PEO-fr-PBut, PBut-fo-PEO-fo-PBut and PEO-fo-PBut-fo-PEO melts are depicted in Fig. 11. In all phase diagrams the semi-crystalline lamellar phase was not attained because of the copolymers low melting points. 

Mean-field lattice theory proved to be capable of predicting the phase behaviour of the ternary block copolymer polyethylene-b-poly(propylene oxide)-b-poly(ethylene oxide), PE-b-PPO-b-PEO in the selective solvent water [164], The ethylene block is known to be highly hydrophobic, and its hydrophobicity does not depend strongly on temperature. The difference in hydrophobicity between PPO and PEO, on the other hand, is moderate... 

Poly(ethylene oxide) (PEO), 10 665, 673-674 13 540, 542-543, 731. See also Ethylene oxide polymers association reactions of, 10 682 behavior in solution, 10 685 commercial block copolymers, 7 648t crystallinity of, 10 690 as a flocculating agent, 11 630-631 low molecular weight, 14 259 oxidation of, 10 682 in paper manufacture, IS 117 preparation of, 20 462 Polyethylene oxide chains, in cationic surfactants, 24 147... 

Polyethyleneoxide-co-polypropyleneoxides, dispersants, S 710t Poly(ethylene oxide) film, physical properties of, 10 68It Poly(ethylene oxide) floe, 11 638 Poly(ethylene oxide)-poly(ethylene terephthalate) copolymers, bioresorbable polymers, 3 738 Poly(ethylene oxide) resins, molecular weight of, 10 684-685 Polyethylene oxides, dispersants, S 706t, 710t... 

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