Poly l -amidoethylen

Most polymers used in oil field operations and resource recovery are synthetic. The man-made materials in common use are polyO-amidoethylene) ( = polyacrylamide ), poly( 1-amidoethylene-r-( sodium 1-carboxylatoethylene ) ( = partially hydrolyzed polyacrylamide ), poly(l-amidoethylene-r-( sodium 1-(2-methylprop-1N-yl-1-sulfonate)amidoethylene) (AMPS-acrylamide copolymer), and xanthan gum. Xanthan gum is a synthetic because no one finds a pool or river contaminated with Xanthomonas compestris that experiences the right sequence of solute to naturally produce the exocellular gum polymer. A fermenter is a man made object, a tree is not. 

Poly(starch-g-((l-amidoethylene)-co-(sodium 1-carboxylatoethylene))). Poly(l-amidoethylene) is, however, rarely used as a viscosifier. Instead, the homopolyraer is reacted with base (hydrolyzed with NaOH) to convert some of the amide units of the polymer to carboxylic acid units. The acid units on the hydrolyzed polymer dissociate in water and produce a polyanionic polymer. This polyelectrolyte expands in water because of ion-ion repulsion and, as an enlarged molecule, is a better viscosifier. 

Poly(starch-g-(l-amidoethylene)) copolymer is not a polyelectrolyte and will be a smaller molecule in water than an equal molecular weight, partially hydrolyzed poly(l-amidoethylene). Polyelectrolyte effect should, however, cause the graft copolymer to expand in solution in the same way it causes poly(l -amidoethylene) to expand, so a series of hydrolyzed graft copolymers were prepared from poly(starch-g-(l-amidoethylene))(41-43) and these derivatives were tested to determine the effect of hydrolysis on copolymer properties in solution. 

Electrolyte Effect on Polymer Solution Rheology. As salt concentration in an aqueous poly(1-amidoethylene) solution increases, the resulting brine becomes a more Theta-solvent for the polymer and the polymer coil compresses(47) This effect is particularly pronounced for partially hydrolyzed poly(l-amidoethylene). The... 

Copolymer (unhydrolyzed) Copolymer for an equal Molecular Wt Number H O 1 M HNO H20 1 M HNO Poly(l -amidoethylene)a... 

Viscosity Loss Vith Tine. Poly(l-amidoethylene) solutions lose viscosity with time(5l). Several authors have attributed this viscosity loss to oxygen or radical degradation of the polymer(5l), but Francois(52) has shown that changes in viscosity only occur in solutions made from broad-molecular-weight-distribution poly( 1-amidoethylene). Since very... 

Hydrolysis increases the terpolymer limiting viscosity number in water by a factor of up to 45. Other previously published data(66-68) show that these terpolymers are nonnewtonian viscosifiers, metal-ion complexing agents, and effective flocculators. These materials are still "small" molecules in aqueous solution, however, and do not function as effectively when used 1. as nonnewtonian viscosifiers or 2. drag reducing agents as do poly(l-amidoethylene-co-(sodium 1-carboxylatoethylene)) copolymers. 

Sedimentation pictures were taken starting at 20 to 40 min. after clock start and were taken at 20 min. intervals until 160 min. had elapsed. The experiments with the poly(l-amidoethylene) samples were carried out under identical conditions, insofar as possible. 

Figure 3. Concentration of poly(l-amidoethylene) in a centrifuged sample plotted as a function of sedimentation coefficient.

Figure 7. A plot of the integral molecular weight distribution for the poly(l-amidoethylene) standard.

Table I. Average Limiting Viscosity Number and Weight-average, Molecular Weight for the Poly(l-amidoethylene) Sample...

The conversion of poly(l-amidoethylene) homopolymer to a complex, random copolymer by base hydrolysis alters several properties of the polymer. 

Screening Data for Poly(l-amidoethylene-co-sodium 1-carboxylatoethylene),... 

A series of 1-methyl-substituted poly(l-amidoethylenes) were synthesized (9) and found to have limiting viscosity numbers in hydrogen-bond-blocking solvents that were equal to those of poly(l-amidoethylenes) of 10 or more times higher molecular weight. These data show that the concept of... 

This is to be expected since head-to-tail addition of repeat units in amidoethene polymerizations is more common than head-to-head addition (12). Analytical data for carboxyl and imide content for a series of poly(l-amidoethylene)-derived copolymers is contained in Table VII along with rheological test data for aqueous solutions of these samples. The same types of data are given in Table VIII for a series of copolymers derived from po1y(1-amido-1-me thyle thylene). 

Screening Data Partially Imidized Poly((l-amidoethylene)-oo -(sodium... 

The research group at the University of Southern Mississippi has also, with the aid of a Department of Energy grant, studied the synthesis and properties of poly((l-amidoethylene)-co-(l-methyl-1-(sodium... 

Figure 8. Effect of feed composition on zero-shear intrinsic viscosity in 1.5% NaCl of Poly(l-amidoethylene-co-(l-(sodium 2-methylprop-2N-yl-l-sulfonate)amidoethylene)) ( ) and poly-((1-amidoethylene) -CO-(1-methyl-1-(sodium l-oxo-2-oxybutyl-4-sulfonate)) ethylene)) (A) copolymers at high conversion.

Materials and Solution Preparation, The poly(l-amidoethylene) used in all experiments was a molecular weight standard supplied by Poly sciences, Inc., as material 8249, batch 93-5. The polymer was dried for 3 hr. under a vacuum of < 10 Pa at a temperature of 25 C. The polymer was dispersed on a vortex of 0.01 M Na2S04 solution and stirred for 1 day. The solution was then centrifuged to remove undissolved polymer particles and the preweighed centrifuge tube was dried and re weighed. The polymer concentration of the master sample was calculated from the weight of polymer retained in the solution. The concentration of the master sample was 2,115 ppm or 0.2115 g/dL. 

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