Water-soluble homopolymers

The solubility parameter of water is 17 or 23, depending on the association structure of water used in the calculation. None of the values listed in Table II are within two units of either value and by the general rules of the solubility concept, none of the polymers in Table II should be water soluble. Homopolymers of monomers c, e, or f in Figure 3 are not water soluble. The solubility values listed for the W-SPs studied do not correlate with the equilibrium pressures observed. A general correlation is noted if the values of the most hydrophobic segments (i.e., the oxypropyl, oxybutyl and acetate) are compared with PMVE. The... 

A reactive surfactant shown next (RS) was used as a comonomer in a seeded polymerization. RS was easily adsorbed on seed particles due to their amphiphilicity. If dialkyl fumarate was preabsorbed in the particle, the polymerization proceeded quickly and resulted in the formation of skin layer of RS-fumarate copolymer. Because the vinyl group in RS is an allyl type, RS in aqueous phase hardly polymerizes and no water-soluble homopolymer was formed. The active ester group of RS on the skin layer was used for the preparation of functional microspheres (18). 

As described in the first part of this section, MVt can reduce protons to give H2 with a platinum catalyst. The presence of Pt colloid in the photoreaction mixture of Ru(bpy) + polymer complex (derived from water soluble homopolymer of Vbpy), MV2+ and EDTA gave H2 gas at almost the same rate as the mixture containing Ru(bpy)j + instead of polymer complex401 (see Scheme 1). The turnover number of the Ru polymer complex exceeded 25 in 1 h s irradiation. The water insoluble polymer complex (5) showed almost the same activity when used as suspensions in a mixture of MeOH/H20 =1/1. 

X HE PRODUCTION OF CATIONIC WATER-SOLUBLE HOMOPOLYMERS and CO-polymers with acrylamide has grown rapidly in recent years (i) because of their diverse commercial applications. These polymers are used for fines retention in paper making, as flocculants and biocides in waste water treatment, as stabilizers for emulsion polymerization, in cosmetics and phar-... 

Imazato and co-workers [29,30] prepared a novel monomer, methacryloyloxydodecyl pyrimidinium bromide (MDPB). A water-soluble homopolymer of MDPB and copolymer of MDPB with acrylamide were also synthesised and the bactericidal activity against oral streptococci was studied. The mechanism of action of these quaternary compounds is assumed to be due to direct cationic binding to cell wall components, which results in disruption of the cell wall membrane, and subsequently results in leakage of critical cell contents and cell death. 

YAZ Yazici, D.T., Askin, A., and Butiiii, V., Thermodynamic interactions of water-soluble homopolymers and double-hydrophilic diblock copolymer, J. Chem. Thermodyn., 40, 353, 2008. 

A similar approach has been also used for the synthesis of covalently linked DHBCs. Polysaccharide based DHBCs were prepared by end-to-end eoupling of two readily available biocompatible water-soluble homopolymers [35]. The synthesis was a two step reaction where a) a terminal aldehyde group of a dextran homopolymer was oxidized and b) a monoamine end functionalized PEG reaeted with the oxidized dextran, via a lactone aminolysis reaction. Interestingly, the obtained polymer could be chemically modified, in a controlled way, in order to produce neutral-cationic or neutral-anionic DHBCs. 

Mayer, A. B. R. and Mark, J. E. CoUoidal gold nanoparticles protected by water-soluble homopolymers and random copolymers. European Polymer Joumal,34( 1), 103-108 (1998). 

The modification of water-soluble homopolymers by grafting a low amount of hydrophobic groups (of the order of 1 % of the monomers reacted is a typical figure), such as alkyl chains, leads to amphiphilic polymers which have a tendency to self-associate by hydrophobic interaction. This weak aggregation (Figure 20.8) leads to an increase in viscosity and in other rheological characteristics, and hence the use of these associative thickeners as rheology modifiers in paints and other products. 

Water-soluble homopolymers and copolymers are of high technical importance because of their wide-spread application in hydrogels, thickeners, viscosifiers, floccu-lants, membranes, coatings, etc. Mostly, these polymers are obtained from free-... 

To act as possible "conductive bridges between adjacent CNTs, it would also be favorable when the metal NPs are in the vicinity of the CNTs. For this reason, a system in which the AuNPs are grown on the CNTs would be beneficial. This methodology also allows one to control the concentration of AuNPs in the final CNT dispersions. The inability to do this was shown to be the main disadvantage of the synthetic methodologies utilized in the previous section that dealt with QD-containing composites. An amphiphilic block copolymer or water-soluble homopolymer can be used both as a surfactant for the dispersion of individual CNTs, and as a template onto which AuNPs can be grown. 

Oh, J.K., Perineau, F., Matyjaszewski, K. Preparation of nanoparticles of well-controlled water-soluble homopolymers and block copolymers using an inverse miniemulsion ATRP. Macromolecules 39(23), 8(X)3-8010 (2006)... 

Polyacrylic acid (pAA) homopolymers and related copolymers have become a commercially important class of water-soluble polymers. Acrylic acid polymers can range in molecular mass from less than 1000 Da to greater than 1,000,000 Da. A representative set of analysis conditions is... 

Recently, unique vesicle-forming (spherical bUayers that offer a hydrophilic reservoir, suitable for incorporation of water-soluble molecules, as well as hydrophobic wall that protects the loaded molecules from the external solution) setf-assembUng peptide-based amphiphilic block copolymers that mimic biological membranes have attracted great interest as polymersomes or functional polymersomes due to their new and promising applications in dmg delivery and artificial cells [ 122]. However, in all the cases the block copolymers formed are chemically dispersed and are often contaminated with homopolymer. 

Drug Release from PHEMA-l-PIB Networks. Amphiphilic networks due to their distinct microphase separated hydrophobic-hydrophilic domain structure posses potential for biomedical applications. Similar microphase separated materials such as poly(HEMA- -styrene-6-HEMA), poly(HEMA-6-dimethylsiloxane- -HEMA), and poly(HEMA-6-butadiene- -HEMA) triblock copolymers have demonstrated better antithromogenic properties to any of the respective homopolymers (5-S). Amphiphilic networks are speculated to demonstrate better biocompatibility than either PIB or PHEMA because of their hydrophilic-hydrophobic microdomain structure. These unique structures may also be useful as swellable drug delivery matrices for both hydrophilic and lipophilic drugs due to their amphiphilic nature. Preliminary experiments with theophylline as a model for a water soluble drug were conducted to determine the release characteristics of the system. Experiments with lipophilic drugs are the subject of ongoing research. 

In this case, a moderately water-soluble amphiphilic N-vinylcaprolaclam (NVC1) played the role of a fl-unit, and a well-water-compatible N-vinyl-imidazole (NVIAz) served as a P-unil. The polymerization was carried out in a medium of 10% aqueous dimethylsulfoxide (DMSO). The addition of DMSO to the reaction solvent was necessary because of insufficient NVC1 solubility in pure water. It was also shown that in this solvent mixture, the NVCl-homopolymers and NVCl/NVIAz-copolymers retained their LCST-behaviour [26,28]. Hence, the DMSO in the reaction solvent did not significantly suppress the hydrophobic interactions of the NVC1 units. The polymerization was initiated by the redox system (N,N,N, N -tetramethylethylenediamine (TMEDA) + ammonium persulphate (APS)) and was carried out at 65 °C (1st step). This condition was very important, since admittedly the temperature was higher than the phase separation threshold of the reaction bulk when the polymeric products were formed that is, under these thermal conditions, hydrophobically-induced folding as the NVCl-blocks appear was ensured. After completion of the reaction, the... 

PVA Formation Reaction. Poly(vinyl alcohol) is itself a modified polymer being made by the alcoholysis of poly(vinyl acetate) under acid or base catalysis as shown in Equation 1 (6.7). This polymer cannot be made by a direct polymerization because the vinyl alcohol monomer only exists in the tautomeric form of acetaldehyde. This saponification reaction can also be run on vinyl acetate copolymers and this affords a means of making vinyl alcohol copolymers. The homopolymer is water soluble and softens with decomposition at about 200°C while the properties of the copolymers would vary widely. Poly(vinyl alcohol) has been widely utilized in polymer modification because ... 

In accordance with this data the methods of preparation of C60/PVP complexes containing up to 3% of fullerene (Krakovjak et al., 2005b) and water-soluble C60-fullerene complexes with A -vinylcaprolactam homopolymers and copolymers with 0.75-3.3% of C60-fullerene (Krakovjak et al., 2005a) were worked out. 

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