Polyethylene oxide, PEO

Figure 4.19 demonstrates the effect of sample concentration on the separation of polyethylene oxide (PEO). At a concentration of 1.6 mg/ml of each... 

Figure 6.21 shows the calibration curves of the SB-800 HQ series using standard pullulan. Because a high molecular weight standard sample is not available, the calibration curves of 805 and 806 are partly estimates (dotted lines). The difference in the conformation between polyethylene oxide (PEO) and pullulan in the solvent causes a shift of the calibration curves of pullulan slightly higher than those of PEO. The OHpak SB-800HQ series is better suited for the analysis of hydrophilic samples than the Asahipak GS/GE series. 

COMPARISON OF FOUR COMMERCIAL LINEAR AQUEOUS SIZE EXCLUSION COLUMNS AND FOUR SETS OF COMMERCIAL POLYETHYLENE OXIDE (PEO) STANDARDS FOR AQUEOUS SIZE EXCLUSION CHROMATOGRAPHY OF POLYVINYLPYRROLIDONE AND PEO... 

The very first studies with radiation crosslinked polyethylene oxide (PEO) have shown that SAH is able to substantially reduce the sensitivity of plants to water shortage [7], to promote their growth, particularly, under conditions of water deficiency [8], to improve seedling survival and the final crop [9], These results stimulated a more detailed analysis of the effects of SAH in the water balance of... 

The qualitative thermodynamic explanation of the shielding effect produced by the bound neutral water-soluble polymers was summarized by Andrade et al. [2] who studied the interaction of blood with polyethylene oxide (PEO) attached to the surfaces of solids. According to their concept, one possible component of the passivity may be the low interfacial free energy (ysl) of water-soluble polymers and their gels. As estimated by Matsunaga and Ikada [3], it is 3.7 and 3.1 mJ/m2 for cellulose and polyvinylalcohol whereas 52.6 and 41.9 mJ/m2 for polyethylene and Nylon 11, respectively. Ikada et al. [4] also found that adsorption of serum albumin increases dramatically with the increase of interfacial free energy of the polymer contacting the protein solution. 

In 1971, Hiatt et al. found that polyethylene oxide (PEO) of molecular weight about 100000 prevented the adsorption of rabies virus to porous glass with an average pore diameter of 1250 A. The support was modified by passage of one void volume of 0.4% solution of the polymer in water, followed by 5 or more volumes of distilled water or buffered salt solution. The virus was effectively purified from the admixtures of brain tissue fluid by means of size-exclusion chromatography on the modified glass column [28]. 

As it was shown in73, 74), methods that can be used to synthesize these copolymers of PAN are those of radical AN block copolymerization in the presence of an oxidation-reduction system in which the hydroxyl end groups of polyethylene oxide) (PEO)73) and polypropylene oxide) (PPO)74- oligomers serve as the reducing agents and tetravalent cerium salts as the oxidizing agents. 

The ability of chitosan hydrochloride to enhance the transcorneal permeability of the drug has been demonstrated [289]. Polyethylene oxide (PEO) was used as a base material to which ofloxacin-containing chitosan microspheres prepared by spray-drying were added and powder compressed resulting in circular inserts (6 mm). 

State-of-the-art thin film Li" cells comprise carbon-based anodes (non-graphitic or graphite), solid polymer electrolytes (such as those formed by solvent-free membranes, for example, polyethylene oxide, PEO, and a lithium salt like LiPFe or LiCFsSOs), and metal oxide based cathodes, in particular mixed or doped oxides... 

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. 

Fig. 8. Adsorption of BSA on surfaces coated with polyethylene oxide (PEO). Influence of the grafting density of PEO at the surface for different polymer chain lengths (---700,-------- 445, and------148 ethylene oxide monomers) on the...

Several experimental parameters have been used to describe the conformation of a polymer adsorbed at the solid-solution interface these include the thickness of the adsorbed layer (photon correlation spectroscopy(J ) (p.c.s.), small angle neutron scattering (2) (s.a.n.s.), ellipsometry (3) and force-distance measurements between adsorbed layers (A), and the surface bound fraction (e.s.r. (5), n.m.r. ( 6), calorimetry (7) and i.r. (8)). However, it is very difficult to describe the adsorbed layer with a single parameter and ideally the segment density profile of the adsorbed chain is required. Recently s.a.n.s. (9) has been used to obtain segment density profiles for polyethylene oxide (PEO) and partially hydrolysed polyvinyl alcohol adsorbed on polystyrene latex. For PEO, two types of system were examined one where the chains were terminally-anchored and the other where the polymer was physically adsorbed from solution. The profiles for these two... 

A new class of amphiphilic, surface-active graft copolymers, hydrophobically modified hydroxyethyl celluloses (HM-HEC s), are comprised of a cellulose backbone with short polyethylene oxide (PEO) and grafted alkyl side chains. They are excellent steric stabilizers of 0/W emulsions. 

Table 2 Data corresponding to polyethylene oxide) (PEO) spheres prepared by different methods (see Fig. 4)...

Table 2.1 illustrates the magnitudes of the characteristic ratio found for typical polymers in dilute solution. The relatively simple polyethylene oxide), (PEO), chain is fairly flexible whereas the cellulosic chain has... 

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