DIMETHYLACRYLAMIDE COPOLYMER

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... 

The synthesis of glycopeptides have been performed manually as well as by using automated or semiautomated peptide synthesizers on poly(eth-yleneglycol)-poly(A,A-dimethylacrylamide) copolymer (PEGA) [13,16-22], polystyrene-1% divinylbenzene copolymer [23-37], kieselguhr-supported... 

Soluble polystyrene supports differ from the terminally functionalized PEGs and polyethylene oligomers discussed above in that the catalyst moieties are attached to polystyrene via pendant groups, the loading of which can affect both the catalyst activity and separability. One example of a simple polystyrene-supported catalyst is the polystyrene copolymer-supported quaternary ammonium salts 66 and 67 [ 103]. These copolymers can be prepared with varying ratios of the styrene unit in the copolymer - the most active catalysts had 20-40 mol% of the vinylbenzylammonium groups in the copolymers. The utility of these catalysts was studied in a variety of solvents in the addition reaction of glycidyl methacrylate and carbon dioxide (Eq. 23). Polar solvents were most useful. The necessary polymer supports for preparation of catalysts 66 and 67 were prepared from chloromethylstyrene-styrene or chloromethyl-styrene-iV,JV-dimethylacrylamide copolymers that were in turn prepared by radical polymerization of the styrene or acrylamide monomers. The catalysts were recycled up to four times with small (ca. 6%) decreases in activity - de-... 

YI1 Yin, X. and Stoever, H.D.H., Probing the influence of polymer architecture on liquid-liquid phase transihons of aqueous poly(W-dimethylacrylamide) copolymer solutiorts, Macromolecules, 38, 2109, 2005. 

Void-free fibers have been produced by incorporating hydrophilic comonomers, such as sulfonated monomers, acrylamide derivatives, and hydroxyalkyl acrylates [451]. Polymer blends are also effective in reducing macrovoids. Examples include blends of hydrophilic polymers such as polyvinyl methyl formamide [452], poly Ai-vinylpyrrolidone, and acryloni-trile-dimethylacrylamide copolymer [453,454]. Dense fibers can be produced by incorporating comonomers, such as vinylidene chloride, with small molar volumes relative to acrylonitrile. 

Another class of resins consists mainly of PEG and contains no polystyrene. They rely on cross-linking of PEG chains. This class includes the poly(ethylene glycol)-poly-(2i/i2i/ dimethylacrylamide) copolymer (PEGA) supports, developed by Meldal [38], and the newer ChemMatrix [39] resins. While PEGA is unique in being permeable to proteins up to 35-70 kDa, which makes it well suited for biochemical studies of peptides immobilized to the support, the ChemMatrix resins have gained in importance for standard Fmoc-SPPS. See Chapter 2. 

Certain admixtures of carboxymethylhydroxyethylcellulose or copolymers and copolymer salts of N,N-dimethylacrylamide and 2-acrylamido-2-methyl-propane sulfonic acid (AMPS), together with a copolymer of acrylic acid, may... 

A terpolymer fonned from ionic monomers AMPS, sodium vinyl sulfonate or vinylbenzene sulfonate itaconic acid, and a nonionic monomer, for example, acrylamide, N,N-dimethylacrylamide, N-vinylpyrrolidone, N-vinyl acetamide, and dimethylaminoethyl methacrylate, is used as a fluid loss agent in oil well cements [1562], The terpolymer should have a molecular weight between 200,000and 1,000,000 Daltons. The terpolymer comprises AMPS, acrylamide, and itaconic acid. Such copolymers also serve in drilling fluids [1892]. 

A copolymer of N,N-dimethylacrylamide and N,N-dimethylaminopropyl methacrylamide, a monocarboxylic acid, and ethanolamine may serve to increase the viscosity of diesel or kerosene [846]. 

Controlling fluid loss loss is particularly important in the case of the expensive high density brine completion fluids. While copolymers and terpolymers of vinyl monomers such as sodium poly(2-acrylamido-2-methylpropanesulfonate-co-N,N-dimethylacrylamide-coacrylic acid) has been used (H)), hydroxyethyl cellulose is the most commonly used fluid loss additive (11). It is difficult to get most polymers to hydrate in these brines (which may contain less than 50% wt. water). The treatment of HEC particle surfaces with aldehydes such as glyoxal can delay hydration until the HEC particles are well dispersed (12). Slurries in low viscosity oils (13) and alcohols have been used to disperse HEC particles prior to their addition to high density brines. This and the use of hot brines has been found to aid HEC dissolution. Wetting agents such as sulfosuccinate diesters have been found to result in increased permeability in cores invaded by high density brines (14). 

Copolymers of sodium acrylate with sodium 2-acrylamido-2-methylpropane sulfonate (220) or N,N-dimethylacrylamide (221) have been found useful for preparing crosslinked systems that must function at high temperatures and relatively high salinity. 

Acrylamide copolymers designed to reduce undesired amide group hydrolysis, increase thermal stability, and improve solubility in saline media have been synthesized and studied for EOR applications. These polymers still tend to be shear sensitive. Acrylamide comonomers that have been used include 2-acrylamido-2-methylpropane sulfonate, abbreviated AMPS, (1,321-324), 2-sulfo-ethylmethacrylate (325,326), diacetone acrylamide (324, 326), and vinylpyrrolidinone (327,328). Acrylamide terpolymers include those with sodium acrylate and acrylamido-N-dodecyl-N-butyl sulfonate (329), with AMPS and N,N-dimethylacrylamide (330), with AMPS and N-vinylpyrrolidinone (331), and with sodium acrylate and sodium methacrylate (332). While most copolymers tested have been random copolymers, block copolymers of acrylamide and AMPS also have utility in this application (333). 

To make further use of the azo-initiator, tethered diblock copolymers were prepared using reversible addition fragmentation transfer (RAFT) polymerization. Baum and co-workers [51] were able to make PS diblock copolymer brushes with either PMMA or poly(dimethylacrylamide) (PDMA) from a surface immobihzed azo-initiator in the presence of 2-phenylprop-2-yl dithiobenzoate as a chain transfer agent (Scheme 3). The properties of the diblock copolymer brushes produced can be seen in Table 1. The addition of a free initiator, 2,2 -azobisisobutyronitrile (AIBN), was required in order to obtain a controlled polymerization and resulted in the formation of free polymer chains in solution. 

Baum et al. apphed RAFT polymerization to synthesize brushes of PS, PMMA, poly(Nd -dimethylacrylamide) (PDMA), and their copolymers on azo-initiator-bound sihcate surfaces [127]. 2-Phenylprop-2-yl dithiobenzoate was added as a free (unboimd) RAFT agent to control the graft polymerization. Because of a very low concentration of surface-bound initiator, a free... 

Poly(M,M-diethylacrylamide-co-M,W-dimethylacrylamide) P(DEA-co-DMA) copolymers with different amounts of DMA can be synthesized by free radical polymerization in THF with AIBN as the initiator (1 mol%). In a typical reaction, the solution mixture is bubbled with dry nitrogen for 30 min prior to polymerization. The temperature is then gradually raised to 68 °C in a period of 2 h and maintained for 18 h. Each reaction mixture was precipitated in ether or hexane after the polymerization. The copolymer composition determined by JH NMR spectra is normally close to the feed ratio of monomers prior to polymerization. The nomenclature used hereafter for these copolymers is P(DEA-co-DMA/x), where x denotes the mol % content of DMA. The chemical structure of P(DEA-co-DMA) is as shown in Scheme 6. 

Recently, Siu et al. [139] studied the effect of comonomer composition on the formation of the mesoglobular phase of amphiphilic copolymer chains in dilute solutions. The copolymer used was made of monomers, N,N-diethylacrylamide (DEA) and N,N-dimethylacrylamide (DMA). like PNI-PAM, PDEA is also a thermally sensitive polymer with a similar LCST, but PDMA remains water-soluble in the temperature range (< 60 °C) studied. At room temperature, copolymers made of DMA and DEA are hydrophilic, but become amphiphilic at temperatures higher than 32 °C. Before the association study, each P(DEA-co-DMA) copolymer was characterized by laser light scattering to determine its weight average molar mass (Mw) and its chain size ( Rg) and (R )). The copolymer solutions (6.0 x 10 A g/mL) were clarified with a 0.45 xm Millipore Millex-LCR filter to remove dust before the LLS measurement. 

Some works were reported in which thermosensitive polymers were conjugated with hydrophobic groups. End-capping random poly(NIPA-co-dimethylacrylamide) [55] and grafting poly(NIPA-co-hydroxymethylacryl-amide) [56] with cholesterol moieties led to self-associating polymers with different morphologies. By dissolution of the copolymers in dimethylfor-... 

Fig. 16 TEM pictures showing nanoparticles of cholesteryl end-capped poly(NIPA-co-dimethylacrylamide). The nanoparticles were obtained by the dialyzing dimethylfor-mamide solutions of copolymers against water and subsequent freeze-drying. The initial concentrations of the copolymer in dimethylformamide were a-c 0.35 wt%, d 0.1 wt%, e, f 1.2 wt%. a, c-f were obtained for the copolymer with Mw = 3400 b was obtained for the copolymer with Mw = 8000. (Reprinted with permission from Ref. [55]. Copyright 2003 Elsevier)...

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