Polyfethylene oxide

Preparation of polyfethylene oxide) (PEO) and poly(arylene ether) based hydrophilic-hydrophobic block copolymer is of special interest because PEO has been proven to be particularly reliable and versatile for the surface modification of biomaterials. The first poly(ediylene oxide)-/ /oc/c-polysulfonc (PEO-fc-PSF) copolymers were reported by Aksenov et al.217 They employed diisocyanate chemistry to link hydroxy-terminated sulfone oligomers and polyfethylene... 

Cohn D, Stem T, Gonzales MF, and Epstein J. Biodegradable polyfethylene oxide)/poly( -caprolactone) multiblock copolymers. J Biomed Mater Res, 2002, 59, 273-281. 

Fig. 6.9 Molar conductivity as a function of LiClOit concentration in oxymethylene-linked polyfethylene oxide) at 298 K (Gray et ai, 1991).

Kaneko, Y., Nakamura, S., Sakai, K., Aoyagi, T., Kikuchi, A., Sakurai, Y,, and Okano, T. Rapid deswelhng response of poly(A-isoproplyacrylamide) hydrogels by the formation of water release chaimels using polyfethylene oxide) graft chains. Macromolecules 1998, 31, 6099 - 6105. 

Considerable effort has been carried out by different groups in the preparation of amphiphihc block copolymers based on polyfethylene oxide) PEO and an ahphatic polyester. A common approach relies upon the use of preformed co- hydroxy PEO as macroinitiator precursors [51, 70]. Actually, the anionic ROP of ethylene oxide is readily initiated by alcohol molecules activated by potassium hydroxide in catalytic amounts. The equimolar reaction of the PEO hydroxy end group (s) with triethyl aluminum yields a macroinitiator that, according to the coordination-insertion mechanism previously discussed (see Sect. 2.1), is highly active in the eCL and LA polymerization. This strategy allows one to prepare di- or triblock copolymers depending on the functionality of the PEO macroinitiator (Scheme 13a,b). Diblock copolymers have also been successfully prepared by sequential addition of the cyclic ether (EO) and lactone monomers using tetraphenylporphynato aluminum alkoxides or chloride as the initiator [69]. 

Alexandridis P, Athanassiou V, Eukuda S, Hatton TA. Surface activity of polyfethylene oxide)-f>tock-poly(propylene oxide)-f>tock-poly(ethylene oxide) copolymers. Langmuir 1994 10 2604-2612. 

TABLE 1. Physical Properties of Polyfethylene oxide-6-[(R)-3-hydroxybutyrate] diol-h-ethylene oxide Prepared by Transesterification of [(R)-3-hydroxybutyrate] with Methoxy Polyethylene Glycol... 

O. Lukin, J. Phys. Chem. B 2007, 6620-6627 for Janus-type polyfethylene oxide) dendrimers see X. Feng, D. Taton,... 

As an impressive phase study, it was observed that a blend system composed of CAB having 54 mol % butyryl side groups and polyfethylene oxide) (PEO Mn = 35 000) yielded a phase diagram with a lower critical solution temperature (LCST) boundary, and a cloud point of 168 °C at the critical composition of CAB/PEO = 40/60 (w/w) [112]. 

Table 8. Molecular characteristics of copolymers polystyrene-polyiethylene oxide) (SEO) and polybutadiene-polyfethylene oxide) (BEO)...

Nonionic miniemulsions can be made by using 3-5% of a polyfethylene oxide) derivative as surfactant, resulting in larger, but also very well defined latexes [51]. Chern and Liou used a nonionic surfactant nonylphenol poly-ethoxylate with an average of 40 ethylene oxide units per molecule [53]. Particle sizes between 135 and 280 nm were realized. The particle size mainly depends on the type and amount of the hydrophobe and therefore on the degree of the suppression of Ostwald ripening [53]. 

Polymers such as polyfvinyl alcohol), dextrans, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and polyfethylene oxide) can be used as dynamic or permanent coatings. The latter mode is generally more effective. 

Figure 10. XPS valence band spectra of the linear polyethers (I) polyfmethylene oxide), (2) polyfethylene oxide), (4) poly(tetramethylene oxide) (A).

The conformations of rigid chains will not be much different in the amorphous state near Tm than they are in the crystal lattice. This means that the melting process confers relatively little additional disorder on the system A5m is low and Tm is increased correspondingly. For example, ether units in polyfethylene oxide) (1-42) make this structure more flexible than polyethylene, and Tm of high-molecular-weight versions of the former species is only 66"C. By contrast, poly(/ -xylene) (11-1) is composed of stiff chains and its crystal melting point is 375°C. 

The HLB scale was introduced hy W. C. Griffin of Atlas now I.C.I, America) (1949, I9S4, 1980) as an aid particularly to the use of nonionic surfactants in the formulation of cosmetics. His scale (Table )) is related to the solubility of the materials in water for nonionic suifactants on polyfethylene oxide) the HLB number may be found simply by dividing the percentage of ethylene oxide in the product by five (Griffin, 1954). Davies (1957) has devised group constants that permit calculation of HLB values for other types of suifactani (Table II). Greth and Wilson (1961), also of... 

From ref. 116. The Q range is centered at 0.5 A Abbreviations PDMS, poly(dimethylsiloxane) PPO, polyfpropylene oxide) PTHF, poly(tetrahydrofuran) PEO, polyfethylene oxide) PIB, polyisobutylene. 

Stringer, J.L. Peppas, N.A. Diffusion of small molecular weight drugs in radiation-crosslinked polyfethylene oxide) hydrogels. J. Control. Release 1996, 42, 195-202. 

Delamarche, E. Donzel, C. Kamounah, F. S. Wolf, H. Geissler, M. Stutz, R. Schmidt-Winkel, P. Michel, B. Mathieu, H. J. Schaumburg, K. Microcontact Printing Using Poly(Dimethylsiloxane) Stamps Hydrophilized by PolyfEthylene Oxide) Silanes. Langmuir 2003, 19, 8749-8758... 

Concentration dependence of specific viscosity for linear polyfethylene oxide) with = 5 X 10 gmol in water at 25.0°C. Data courtesy of S. Singh. 

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