Copolymers styrene/ethylene oxide

CRYSTALLIZABLE BLOCK COPOLYMERS STYRENE-ETHYLENE OXIDE... 

Bahadur, P, N. V. Sastry, andY. K. Rao. 1988. Interaction studies of styrene-ethylene oxide block copolymers with ionic surfactants in aqueous solutitSholloids Surf.29 343-358. 

Poly(styrene-ethylene oxide) block copolymer micelle formation in water a uorescence probe study. Macromolecule 4 1033-1040. 

Further studies were directed to examine different SCBs and the effect of different counterions. Potassium counterions provide improved efficiency as compared to lithium or sodium counterions. The most efficient system in terms of formation of carbanions was achieved with diphenylsilacyclobutane in combination with potassium tert-butoxide and diphenylethylene <2004MI856>. Di-block copolymers from ethylene oxide and methyl methacrylate (or styrene) were synthesized by this method with 85% efficiency (Scheme 14) <2004MI856>. 

S-DMS refers to styrene-dimethylsiloxane diblock copolymers S-l refers to sty-rene-isoprene diblock copolymers S-l-S and I-S-I refer to styrene-isoprene-styrene and to isoprene-styrene-isoprene triblock copolymers, respectively and S-EO and EO-S-EO refer to styrene-ethylene oxide diblock copolymers and to ethylene oxide-styrene-ethylene oxide triblock copolymers, respectively. 

There have been numerous studies employing calorimetric(19), dynamic mechanical, ( ) dielectric, ( ) and morphological(23,24) techniques to elucidate the solid-state behavior of styrene-ethylene oxide block copolymers. These measurements have focused on transition-temperature phenomena, and they have provided reference data on the bulk properties of the copolymers. The evidence accumulated to date indicates that PS and PEO are incompatible in the bulk. While this appears true, in general, one cannot rule out the possibility that PS and PEO have some limited degree of miscibility in the copolymers. It is also unknown, at this time, what influence an interface (e.g., the air-polymer interface) has... 

Another example is Dias Analytics styrenic membrane based on the well-known block copolymer styrene-ethylene/butylene-styrene family.This membrane has good conductivity 0.07 to 1.0 S/cm when fully hydrated. It showed reasonable performance but had poor oxidative stability due to the susceptibility of its aliphatic backbone to peroxide attack. 

Alkyl phenol ethoxylates can also react with P4O10 yielding alkyl phenol etherphosphates as a mixture of mono-/diesters or with maleic anhydride to yield maleic acid monoesters, which then react with NaHS03 to yield sulphosuccinate monoesters. Alkylphenolpolyglycolether sulphates, phosphates or sulphosuccinates are mainly used as primary anionic emulsifiers for the manufacturing of acrylic, styrene/acrylic or vinyl acetate co-polymer dispersions. Another type of non-ionic emulsifier is block copolymers of ethylene oxide with propylene oxide. 

Wilhelm M, Zhao CL, Wang YC, Xu RL, Winnik MA, Mura JL, Riess G, Croucher MD. 1991. Poly(styrene ethylene oxide) block copolymer micelle formation in water a fluorescence probe study. Macromolecules 24 1033 1040. 

Figure 5-34. Morphology of biblock poly (styrene- -ethylene oxide) copolymers cast from nitromethane (N) or butyl phthalate (B). —, Poly(styrene) blocks, —, poly(ethylene oxide) blocks (after C. Sadron).

Figure 6.3. Spherulitic texture of a thin film of a styrene-ethylene oxide block copolymer (w = 0.40) obtained on quenching to 20°C (Kovacs, 1967). Photomicrograph taken with film between crossed Nicols ( 100 x).

Figure 6.15. Dielectric constant of styrene-ethylene oxide block copolymers A, B, and C cast from solution in solvents preferential for the polystyrene component (C, ethylbenzene) and in a mutual solvent (A, B,...

Figure 6.18. Schematic showing rectangular volume element for polystyrene segments in single crystals of styrene-ethylene oxide block copolymers, the cross-sectional area being given as Z. (Lotz and Kovacs, 1966.)...

Block copolymers consisting of segments with widely separated solubility characteristics have generated considerable interest because of their unusual surfactant properties. In fact, one of the earliest commercial block copolymers were the Wyandotte "Pluronics." These were poly(propylene oxide-b-ethylene oxide) prepared by sequential addition of ethylene oxide to sodium alkoxide initiated propylene oxide (37,38). Szwarc (39) and others (40,41) prepared poly(styrene-b-ethylene oxide) by addition of ethylene oxide to polystyrene anions in tetrahydrofuran. Other syntheses of AB or ABA block copolymers of styrene-ethylene oxide include sequential addition in various solvents, and coupling reactions (42,43). 

Chemistry Polyurethane is produced by the reaction of a polyol with an diisocyanate (or in some instances a polyisocyanate) in the presence of catalysts. The polyols of choice are poly(propylene glycol), block copolymers of ethylene oxide (10-15%) with propylene oxide, or the newer polymer polyols (based on polymers such as polystyrene or styrene-acrylonitrile copolymer). Polyester diols such as polycaprolactone diol can be used in place of the polyether polyol in this reaction. The isocyanate of choice is a mixture of the 2,4 and 2,6 isomers of tolylene di-isocyanate in the ratio of 80 20, generally referred to as 80 20TDI. Other isocyanates such as diphenylmethane di-isocyanate (MDI), hexamethylene di-isocyanate (HMDI), and isophorone di-isocyanate (IPDI) are also used. A tin-based or amine catalyst is used to promote the reaction. Given the wide choice of reactants available, the reaction can yield foams with a range of different mechanical and thermal characteristics. 

Figure 6.16 Schematic representation of pattern transfer by taking advantage of the self-assembly of two different diblock copolymers poly(ethylene oxide)-b-poly(st5Tene-r-4-hydroxystyrene) and poly(styrene-r-4-vinylpyridine)-b-poly(methyl methacrylate) followed by irradiation and plasma treatment. The images below correspond to square arrays of pores created onto silicon water resulting from the treatments. PS, polystyrene PMMA, polyfmethyl methacrylate) UV, ultraviolet RIE (Reactive Ion Etching).

VanderHart et al. (2001a-c) studied different clay nanocomposites measuring clay exfoliation by relaxation times of hydrogen that sees iron in the montmorillonite clay. They used Fe atoms in montmorillonite clay to determine clay dispersion in Nylon-6 matrix, and degraded alkyl ammoniums (from thermal processing above 200 C) were observed by NMR technique. Hou et al. (2002,2003) studied clay intercalation of poly(styrene-ethylene oxide)-b/ocfe-copolymers using multinuclear solid-state NMR. Hrobarikova et al. (2004) prepared polycaprolactone with laponite or saponite nanocomposites by in sitn polymerization and characterized by CAP NMR to understand how surfactants at clay surface interacted with polymer matrix. Hrobarikova et al. (2004) used solid-state NMR to study intercalated species in poly(e-caprolactone)/clay nanocomposites. 

Association Phenomena.—This section includes polymer-polymer and polymer-small molecule associations. In general, the first type leads to severe spectral broadening resulting in the loss of intensity from conventionally recorded high-resolution spectra. Thus in aqueous solutions of block copolymers of ethylene oxide with styrene and butadiene, no signals from the polyolefin are seen due to the formation of polyolefin-cored micelles. Intermolecular association has also been observed in styrene-ethylene dimethacrylate random copolymers in CCI4, and the... 

Shen et al. [50] carried out a detailed investigation in the MIV mixer, studying the incorporation of (5-carotene and polyethyleneimine (PEI) selected as model drug and cationic macromolecule various copolymers in different physical states were selected an amorphous one, poly(ethylene oxide)-l>-poly(styrene) (PEO-b-PS), a semicrystalline one, poly(ethylene oxide)-b-poly(e-caprolactone) (PEG-fc-PCL), and an ionic copolymer, poly(ethylene oxide)-b-poly(acrylic acid) (PEG-b-PAA) this also allowed the investigation of the influence of the type of interaction forces, in addition to hydrodynamics and supersaturation rate. 

The melting temperature of multiblock copolymers of ethylene oxide with propylene oxide, P(EP), can be compared with that of the triblock polymer PEP [59, 61]. The ethylene oxide and propylene oxide sequences have discrete lengths that range from 45 to 136 units for E and from four to 12 units for P. The value of m varies from 1 to 7. The level of crystallinity in these multiblock copolymers is only about 60% of that observed for comparable PEP copolymers. The melting temperatures of the P(EP) , and PEP copolymers with the same sequence length for E are, however, comparable to one another, the differences in melting temperature being only about 1-3 °C. Similar results are found when multiblock copolymers of poly(styrene) and poly(ethylene oxide) are compared with diblock and triblock ones. 

TLC has been used in the study of many homopolymers polystyrene, poly(methyl methacrylate), poly(ethylene oxide), polyisoprene, poly(vinyl acetate), poly(vinyl chloride) and polybutadiene. Their molecular weight, molecular-weight distributions, microstructure (stereo-regularity, isomerism and the content of polar end groups), isotope composition and branching have been studied. For copolymer characterisation (e.g. purity and compositional inhomogeneity), random copolymers such as styrene-methacrylate, and block copolymers such as styrene-butadiene, styrene-methyl methacrylate and styrene-ethylene oxide have been separated. A good review article on polymers... 

A group at Procter and Gamble [71] have used diblock copolymers of ethylene oxide and propylene oxide, functionalized by a vinylbenzyl chain end, located at the end of the hydrophobic block in the emulsion polymerization of styrene. Good stability vs. electrolyte addition have been observed even if the latex were cleaned with ethanol, when nonionic initiators were used. At variance, if potassium persulfate was used, the latex displays poor stability. 

The same problem of incorporation is also under examination with block copolymer of ethylene oxide and butylene oxide, already quoted above for inisurfs and transurfs, but functionalized with various polymerizable groups such as acrylic, methacrylic, and styrenic. These surfactants are produced by ring-opening anionic polymerization of butylene oxide, initiated by the... 

Nakamura K, Endo R, Takada M (1976) Surface properties of styrene-ethylene oxide block copolymers. J Polym Sci Polym Phys 14 1287-1295... 

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