Modified polyethylene oxides

Solution Associations in Hydrophobically-Modified Polyethylene Oxides... 

The solution associations of some hydrophobically modified polyethylene oxides have been investigated. It was found that as the hydrophobe level increased in the pol nners, the apparent molecular weight and intrinsic viscosity increased, indicative of increased intermolecular association. Additionally, the solution associations appear to be augmented in salt solution. 

Table 1. Hydrophobic Monomer Incorporation and Light Scattering Results for Several Hydrophobically Modified Polyethylene Oxides in Aqueous 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]. 

Fluidized aqueous suspensions of 15% by weight or more of hydroxyethyl-cellulose, hydrophobically modified cellulose ether, hydrophobically modified hydroxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, and polyethylene oxide are prepared by adding the polymer to a concentrated sodium formate solution containing xanthan gum as a stabilizer [278]. The xanthan gum is dissolved in water before sodium formate is added. Then the polymer is added to the solution to form a fluid suspension of the polymers. The polymer suspension can serve as an aqueous concentrate for further use. 

T. Ohsaka, Y. Shintani, F. Matsumoto, T. Okajima, and K. Tokuda, Mediated electron transfer of polyethylene oxide-modified superoxide dismutase by methyl viologen. Bioelectrochem. Bioenerg. 37, 73-76 (1995). 

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. 

Devalapally H, Shenoy D, Little S, Langer R, Amiji M (2007) Polyethylene oxide)-modified poly(beta-amino ester) nanoparticles as a pH-sensitive system for tumor-targeted delivery of... 

The parameters of treatment were chosen since these led to the most pronounced changes of polymer surface in our previous experiments [70-74]. It was observed elsewhere that plasma treatment of polymer macromolecules results in their cleavage, ablation, alterations of chemical structure and thus affects surface properties e g. solubility [75]. The chemical structure of modified polyethylene (PE) was characterized by FTIR and XPS spectroscopy. Exposition to discharge leads to cleavage of polymeric chains and C-H bonds followed by generation of free radicals which easily oxidize [10,76]. By FTIR spectroscopy the presence of new oxidized structures within whole specimen volume can be detected. IR spectra in the 1710-1745 cm" interval [71,77] from PE, exposed to... 

To the first category belong the homo- and copolymerization of macromonomers. For this purpose, macromolecules with only one polymerizable end group are needed. Such macromonomers are made, for example, by anionic polymerization where the reactive chain end is modified with a reactive vinyl monomer. Also methacrylic acid esters of long-chain aliphatic alcohols or monofunctional polyethylene oxides or polytetrahydrofurane belong to the class of macromonomers. 

It is, of course, possible to prepare a molecule that has both polar and nonpolar characteristics. This is the basis of surfactant chemistry. Typically, a nonpolar molecule is modified by sulfonation. The well-known Pluronic family of surfactants is based on block polymerization of polypropylene oxide (the hydrophobe) and polyethylene oxide (the hydrophUe). It is conceptually possible to build a polyurethane 2005 by CRC Press LLC... 

The effects of longer and shorter side chains on the epoxide compared to PBO are shown in Table VII. Polyethylene oxide led to a small improvement in impact strength and melt flow rate, but the heat distortion temperature was decreased. Polypropylene oxide and polyhexene-1 oxide had enhancing effects similar to and even a bit greater than those of PBO. Polyphenylglycidyl ether appeared to be inert when added to modified CPVC. Finally, in this application, the linear PTHF was harmful to properties. 

The growth of these materials is reflected in the number of polymers which are being glass reinforced. These include polypropylene, polystyrene, styrene acrylonitrile, nylon, polyethylene, acrylonitrile-butadiene-styrene, modified polyphenylene oxide, polycarbonate, acetal, polysulfone, polyurethane, poly (vinyl chloride), and polyester. In addition, the reinforced thermoplastics available now include long-fiber compounds, short-fiber compounds, super concentrates for economy, a combination of long and short fibers, and blends of polymer and fibrous glass. 

Scheme 3.5 Polyethylene oxide)s of different molecular weight hydrophobically modified with alkyl isocyanates of different length chain. (Fron ref. [23]).

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