Sodium acrylate

Fig. 2. Functional groups on modified polyacrylamides (a) formed by reaction with dimethylamine and formaldehyde (Mannich reaction) (b), quatemized Mannich amine (c), carboxylate formed by acid or base-cataly2ed hydrolysis or copolymerization with sodium acrylate and (d), hydroxamate formed by...

Derivatives of hemicellulose components have properties similar to the ceUulosic equivalents but modified by the effects of thek lower molecular weight, more extensive branching, labile constituents, and more heterogeneous nature. Acetates, ethers, carboxymethylxylan (184), and xylan—poly(sodium acrylate) (185) have been prepared. 

Copolymers of sodium acrylate with sodium 2-acrylamido-2-methylpropane sulfonate (AMPS) or /V, /V- dim ethyl acryl am i de (52) have been used to prepare cross-linked systems at high temperatures and salinity. Chromium cross-linked gels, prepared from a 3 1 blend of partially hydrolyzed... 

The simplest monomer, ethylenesulfonic acid, is made by elimination from sodium hydroxyethyl sulfonate and polyphosphoric acid. Ethylenesulfonic acid is readily polymerized alone or can be incorporated as a copolymer using such monomers as acrylamide, aHyl acrylamide, sodium acrylate, acrylonitrile, methylacrylic acid, and vinyl acetate (222). Styrene and isobutene fail to copolymerize with ethylene sulfonic acid. 

For copolymers of acrylamide with sodium acrylate, the preexponential factor K and exponent a of [tj] = KM depend on copolymer composition (Table 3). 

Table 3 Dependence of Constants K and a of [T7] = KM° on Mole Fraction of Sodium Acrylate (Xsa) for Copolymer Acrylamide with Sodium Acrylate in 0.5 M NaCl at 25°C [9]...

Anionic polyacrylamide was prepared by gamma radiation-initiated copolymerization of acrylamid with sodium acrylate in aqueous solution at optimum conditions for the copolymerization [17]. The copolymerization process produces water-soluble poly (acrylamide-sodium acrylate [pAM-AANa] of high molecular weight [17,54]. 

In previous works [18-20,23,102] water-soluble polymers such as polyacrylamide (pAM), polysodium acrylate (pAA Na), poly(acrylamide-sodium acrylate) (pAM-AA Na), poly(acrylamide-diallyethylamine-hy-drochloride) (pAM-DAEA-HCl), and poly(acrylamide-sodium acrylate-diallyethylamine-hydrochloride) (pAM-AANa-DAEA-HCl) were used in the recovery of cations and some radioactive isotopes from aqueous solutions. It was found that the floe is formed between the added polymer and ions of the solution in the flocculation process with the formation of a crosslinked structure. The formed cross-linked structure is characterized by [103-105] ... 

T. Siyam, Studies on Gamma Radiation Induced Copolymerization of Acrylamide Sodium Acrylate as Floccu-lant, M. Sc. Thesis, Fac. Sci., Cairo Univ. (1982). 

PSt or PMMA, respectively, was coupled with polymethacrylate having a PEG side chain or methylammo-niumchloride side chain to prepare a block copolymer for giving a hydrophilic surface [55]. Also, PSt-b-PVP [36,37], PSt-b-(hydrophilic vinyl copolymer) [56], PSt-b-po y(sodium acrylate) (PNaA) [57], and PSt-b-PNaA-b-(polyperfluoroacrylate) (PFA) [58] were synthesized for the same application. 

Figure 5 Corona discharge behavior of polystyrene added with polystyrene-b-poly(sodium acrylate) [57].

Consider sodium acrylate, NaC3H302. Xa for acrylic acid (its conjugate acid) is 5.5 X 10-5. 

Associative copolymers of acrylamide with N-alkylacrylamides, terpoly-mers of acrylamide, N-decylacrylamide, and sodium-2-acrylamido-2-methyl-propane sulfonate (NaAMPS), sodium acrylate (NaA), or sodium-3-acrylamido-3-methylbutanoate (NaAMB) have been shown to possess the required rheologic behavior to be suitable for enhanced oil-recovery processes [1184]. 

The addition of hydrogenated castor oil to a copolymer of acrylamide and sodium acrylate formulation will suspend the copolymer and retard the settling process [1657]. 

Figure 6 The stress-strain behavior predicted by Eq. (16) is observed for /V-isopropyl acrylamide-co-sodium acrylate gel.

Fluid loss additives such as solid particles and water-thickening polymers may be added to the drilling mud to reduce fluid loss from the well bore to the formation. Insoluble and partially soluble fluid loss additives include bentonite and other clays, starch from various sources, crushed walnut hulls, lignite treated with caustic or amines, resins of various types, gilsonite, benzoic acid flakes, and carefully sized particles of calcium borate, sodium borate, and mica. Soluble fluid loss additives include carboxymethyl cellulose (CMC), low molecular weight hydroxyethyl cellulose (HEC), carboxy-methYlhydroxyethyl cellulose (CMHEC), and sodium acrylate. A large number of water-soluble vinyl copolymers and terpolymers have been described as fluid loss additives for drilling and completion fluids in the patent literature. However, relatively few appear to be used in field operations. 

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). 

The hydrolysis of polyacrylamide and acrylamide/sodium acrylate copolymers has been extensively studied [1,2,3,5,6,7,8,-9,10], in relatively strongly alkaline conditions, above pH 12. These studies demonstrated that the hydrolysis of the amide groups is hydroxide-catalyzed and that neighboring ionized carboxyl groups in the polymer inhibit the hydrolysis by electrostatic repulsion of the hydroxide ions. Senju et al. [6] showed that at temperatures up to 100°C, there is an apparent limit to the extent of hydrolysis of polacrylamide when approximately 60% of the amide groups are hydrolyzed. 

The composition and concentration of polymers in the test solutions for hydrolysis are shown in Table 1. The concentration of the sodium acrylate and sodium AMPS copolymers with acrylamide were calculated to provide 0.025 molar solutions of amide units, to simplify the kinetics. 

The rate of hydrolysis of acrylamide is assumed to be equal to the rate of formation of carboxylate groups in the early stages of reaction, for both sodium acrylate and AMPS copolymers. 

The rate of hydrolysis of acrylamide in copolymers with sodium acrylate or AMPS, 2-acrylamido-2-methylpropanesulfonic acid, decreased as the proportion of the anionic comonomers was increased. This effect was much more marked with AMPS than with sodium acrylate, and occurred at 90°, 108°, and 120°C. Typical results at 108°C [Figs. 1 and 2] show the increase in carboxylate content of acrylamide copolymers containing sodium acrylate and AMPS respectively. 

The calculated pseudo-unimolecular rate constants (k) for the hydrolysis reaction [Fig. 3], clearly show the inhibiting effect of AMPS, relative to sodium acrylate at all three temperatures. 

The total carboxylate content in a range of sodium acrylate copolymers is shown in Fig. 4, calculated as the sum of the initial carboxylate and carboxylate formed during hydrolysis. These values may be compared with the total carboxylate content in AMPS copolymers [Fig. 2]. 

Figure 1. Hydrolysis of amide in sodium acrylate (A) copolymers at 108 ° C, pH 8.5, 0.025 M amide.

Table 1 Deformation of Poly(sodium acrylate) Gel in Electric Fields...

The poly(sodium acrylate) hyperbranched graft formed in a simple deprotonation was used to ionically immobilize enzymes. Studies showed that immobihzed glucose oxidase in a 3-poly(sodium acrylate)/Au film retained significant activity on immobihzation and that the enzyme in this ionic assembly remained active for more than 60 days of storage [30]. 

The hyperbranched poly( acrylic acid) graft films -C02H-rich interface on polyethylene can be modified by noncovalent methods just like CO2H-rich interfaces of PAA/Au grafts. This was shown by treating deprotonated 3-PAA/PE films with cationic polyelectrolytes like poly-D-lysine, and amine terminated PAMAM dendrimers at pH 7 [31]. Equation 10 illustrates the entrapment of PAMAM dendrimers in a 3-poly(sodium acrylate)/PE film. In these cases, polyvalent entrapment of the cationic electrolyte was evidenced in the ATR-IR spectriun by the appearance of amide C = O and N - H peaks of the guest dendrimer that were not present in the host 3-poly(sodium acrylate)/PE film. 

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