Polyacrylic acid grafting

Fig. 1.5 SEM micrographs of (A) donut-shaped poly(aspartate) and MgCl2 by alternate spin CaC03 crystals grown on polyacrylic acid grafted coating and crystallization. (A) and (B) adapted chitosan, (B) CaC03 hollow helix, fractured by from [84] and [85]with permission from Elsevier, micro-manipulation, formed on poly(a-L-aspar- and (C) from [88] (reproduced by permission of tate),and (C) double layered aragonitethin films The Royal Society of Chemistry), grown on a chitosan matrix in the presence of...

Poloxomer3 and polyacrylic acid graft copolymer (so-called Smart Hydrogel) nonbiodegradable... 

In Mishra s work [41], an environmentally benign and efficient route of synthesis of polyacrylic acid grafted carboxymethyl cellulose (CMC-g-PAA) is developed using microwave radiation alone to initiate the grafting reaction. The synthesis is optimized in terms of percentage grafting and intrinsicviscositybyvaryingthe microwave... 

POLYACRYLIC ACID GRAFTED PVC A POLY 2-VP GRAFTED PVC neutralized polyacrylic acid grafted PVC A PVP- POLYOXETANE X DOUBLE GRAFTED PAA-VP-PVC... 

Fig. 6. Schematic of a chemical valve. Glucose oxidase is immobilized on a pH-responsi ve polyacrylic acid grafted onto a porous polycarbonate membrane (a) poly(acrylic acid) is in an expanded conformation that blocks insulin transport (b) the oxidation of glucose is accompanied by a decrease in pH and the transition of poly(acrylic cid) into a compact conformation that results in opening of the pores and transport of insulin. Redrawn from Ref. 82.

UV irradiation of polymers has been observed to be an effective technique to modify polymers for biomolecule immobilization. The polymer surface is modified by photo-induced graft polymerization of different monomers, such as acrylic acid,. -acrylamidomethylpropane sulfonic acid, and styrene sulfonic acid. All these monomers have ionic functionality and lead to high graft densities for the immobilization of collagen and other proteins. The surface density of polyacrylic acid grafts reaches up to lOOpg/cm under appropriate reaction conditions and Is enough for protein immobilization [36]. 

Figure 6.4. Schematic presentation of chem ical valve with gl ucose oxidase immobilizedon a pH-responsive polyacrylic acid grafted on a porous polycarbonate membrane A—poly(acryIic acid) is in an expanded conformation blocking insulin transport B—the oxidation of glucose is accompanied by decrease in pH and transition of poly(acrylic acid) into a compact conformation resulting in opening the pores for insulin...

ACPA azobis(4-cyanopentanoic acid) AIBN azobis isobutyronitrile) BPO benzoyl peroxide DVB divinyl benzene, EGA 2-ethylcyano-acrylate HPC hydroxypropyl cellulose MMA methyl methacrylate PAAc polyacrylic acid PEI polyethyleneimine, PEO/PPO polyethylene oxide/polypyropylene oxide copolymer PVME polyvinylmethylether PVP polyvinylpyrrolidone K-30 DMSO dimethylsulfoxide PGA polyglutaraldehyde CMS chloromethylstyrene PMMA-g-OSA polymethylmethacrylate grafted oligostearic acid. 

The third approach has been to graft the redox couple by means of a covalent bond to the polyelectrolyte backbond as described early in 1965 in the book of Cassidy and Run [20]. Several of these systems are charged polymers in at least one oxidation state, like poly(viologen), poly(vinylferrocene), and so on. Examples of polyelectrolytes like polyacrylic acid with covalently bound viologen were reported by Fernandez, Katz and coworkers [21], hydroquinone [22] and Anson et al. with bound ferrocene [23]. 

The labelled polyacrylic acid PAA-M, used for polarized luminescence measurements, was prepared by grafting of 9-aminoacridine on the PAA-800 000 chain (15). The degree of derivatization of the polyacid (evaluated from the UV-vis spectra of PAA-M And 9-aminoa-cridine) is very low ... 

The molecular weight of the grafted chain of polyacrylic acid, determined by acid hydrolysis, is of the order of 10000. The product differs markedly from the original polyamide in electrochemical properties. As a confirmation of a radical mechanism, radical acceptors prevented the reaction (see Fig. 5). The possibility of a minor and competitive ionic mechanism was also considered. 

Similar grafting experiments by the emulsion technique were described (34) in the system vinyl chloride/copolymer butyl methacrylate-methacrylic acid and in the reverse system, and also in the system styrene/polyvinyl chloride. In this last case again as in homogenous medium, the inverse process failed (vinyl chloride on polystyrene). Grafted acrylonitrile copolymers were also prepared in order to improve their dyeability, by polymerizing acrylonitrile in emulsion in the presence of many different polymers as polyvinyl alcohol, polymethacrylamide and polyvinylpyrrolidone (119, 120, 121), polyvinyl acetate and polyacrylic acid (115), wool (224,225), proteins (136), etc. 

Photolysis of this polymer gives radicals on which side chains can be formed, giving graft polymerization 122, 123, 153). Similarly the polymerization of styrene (152) or vinyl acetate (157) in the presence of bromotrichloromethane gives telomers carrying terminal bromine atoms and trichloromethyl groups. By ultraviolet irradiation (3500 A) in the presence of methyl methacrylate the carbon-bromine links are broken and block copolymers are formed. The telomerization of acrylonitrile and acrylic acid with bromoform is based on the same technique the end groups of both polyacrylonitrile and polyacrylic acid were photolyzed in the presence of acrylamide and afforded polyacrylamide blocks linked to polyacrylonitrile or polyacrylic acid blocks (164, 165). 

Benzodiazepines were the first class of heterocyclic compounds to be synthesized on the SynPhase surface. In 1994, Ellman and co-workers24 reported a 192 member library of structurally diverse 1,4-benzodiazepines. These compounds were prepared on Mimotopes pins that were grafted with polyacrylic acid, the surface originally used for antibody epitope elucidation.10 Ellman and co-workers25 subsequently synthesized a 1680-member 1,4-benzodiazepine library on SynPhase Crowns that were grafted with a methacrylic acid/dimethylacrylamide copolymer, one of the first SynPhase surfaces designed for solid-phase synthesis. The synthesis was performed on a preformed linker-template system in order to avoid low aminobenzophenone incorporation in this case the HMP acid-labile linker... 

Superabsorbent polymers are now commonly made from the polymerization of acrylic acid blended with sodium hydroxide in the presence of an initiator to form a polyacrylic acid, sodium salt (sometimes referred to as cross-linked sodium polyacrylate). Some of the polymers include polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile to name a few. The latter is one of the oldest SAP forms created. 

The simultaneous and desired grafting of polyacrylic acid onto the saturated host polymer proceeds as ... 

Perhaps the most promising applications of grafted cellulose are those related to ionic grafted side chains such as polyacrylic acid. These grafts can be synthesized either by direct... 

Grafted cellulose powders such as Solka Floe have been grafted with polyacrylic acid and also rendered cationic by direct chemical reaction (54). Both of these modified cellulose products have been prepared on a large scale. They appear to show considerable promise for the removal of dyestuffs and other charged impurities from waste water such as textile effluents. They are also able to break emulsions of water and organics by removal of the surfactants (55). 

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