Surfactant acrylamide copolymers

Regardless of the application, the placement (i.e., terminal or internal, isolated or in block sequences) of the hydrophobe-modified monomer in the macromolecular chain is important to the performance of the polymer. The difficulties encountered in determining the sequence structure of hydrophobe-modified acrylamide (water-insoluble) monomers in acrylamide copolymers are discussed in Chapter 20. In this respect, the bicontinuous nature of microemulsions may prove an advantageous method of synthesis. The surfactants used in such a process, however, are significantly more interfacially active than the surfactants used in most application formulations and may detract from the performance of RAM copolymers. The most recent patent (20) in the RAM area discusses the synthesis of RAM copolymers by a microemulsion process, but complexities due to surfactant differences in formulations are not addressed. 

To elucidate the mechanism of chain association, we prepared three series of N-alkylacrylamide-acrylamide copolymers containing up to 0.75 mol % of Cg, Cio, and C12 N-alkylacrylamide monomers. The copolymerizations were conducted with potassium persulfate as the initiator in an aqueous medium containing a high concentration of sodium dodecyl sulfate surfactant (28). The reaction parameters and solubility of the resulting copolymers are given in Table I. Table I indicates solubility in water of all... 

Surfactant-acrylamide Polymers. Copolymers of acrylamide and alkylarylpoly(ethoxy)-acrylate were prepared using standard free radical solution polymerization techniques. The alkylarylpoly(ethoxy)-acrylate monomers referred to as Surf" monomers were water dispersible and thus additional surfactants were not needed to effect random copolymerization. These so called "PAM-SURF" polymers were prepared with a variety of Surf monomers containing different amounts of ethylene oxide and different alkylaryl functionality. 

A fluid loss additive for hard brine environments has been developed [1685], which consists of hydrocarbon, an anionic surfactant, an alcohol, a sulfonated asphalt, a biopolymer, and optionally an organophilic clay, a copolymer of N-vinyl-2-pyrrolidone and sodium-2-acrylamido-2-methylpropane sulfonate. Methylene-bis-acrylamide can be used as a crosslinker [1398]. Crosslinking imparts thermal stability and resistance to alkaline hydrolysis. 

Ethoxylated methylcarboxylates Propoxyethoxy glyceryl sulfonate Alkylpropoxyethoxy sulfate as surfactant, xanthan, and a copolymer of acrylamide and sodium 2-acrylamido-2-methylpropane sulfonate Carboxymethylated ethoxylated surfactants (CME) Polyethylene oxide (PEG) as a sacrificial adsorbate Polyethylene glycols, propoxylated/ethoxylated alkyl sulfates Mixtures of sulfonates and nonionic alcohols Combination of lignosulfonates and fatty amines Alkyl xylene sulfonates, polyethoxylated alkyl phenols, octaethylene glycol mono n-decyl ether, and tetradecyl trimethyl ammonium chloride Anionic sodium dodecyl sulfate (SDS), cationic tetradecyl trimethyl ammonium chloride (TTAC), nonionic pentadecylethoxylated nonylphenol (NP-15), and nonionic octaethylene glycol N-dodecyl ether Dimethylalkylamine oxides as cosurfactants and viscosifiers (N-Dodecyl)trimethylammonium bromide Petrochemical sulfonate and propane sulfonate of an ethoxylated alcohol or phenol Petrochemical sulfonate and a-olefin sulfonate... 

The first type is a standard polysoap derived from a polymerizable surfactant leading to poly(sodium 11-acryloyloxyundecane-l-sulfonate) PSl whereas the second polysoap is an alternating copolymer of maleic acid anhydride and acrylamide leading to a polymer with carboxylic acid groups and hydrophobic n-alkylamide groups PS2 (see Fig. 6.9). The organometaUic catalyst was not covalently bound to the polysoaps in the catalytic experiments. 

In the case of inverse systems, hydrophilic monomers such as hydroxyethyl acrylate, acrylamide, and acrylic acid were miniemulsified in non-polar media, e.g., cyclohexane or hexadecane [45,46]. Rather small and narrow distributed latexes in a size range between 50 nmsynthesized with nonionic amphiphilic block copolymers. Depending on the system, the surfactant loads can be as low as 1.5 wt% per monomer, which is very low for an inverse heterophase polymerization reaction and clearly underlines the advantages of the miniemulsion technique. 

The polymerization process of two monomers with different polarities in similar ratios is a difficult task due to the solubility problems. Using the miniemulsion process, it was possible to start from very different spatial monomer distributions, resulting in very different amphiphilic copolymers in dispersion [88]. The monomer, which is insoluble in the continuous phase, is miniemulsified in order to form stable and small droplets with a low amount of surfactant. The monomer with the opposite hydrophilicity dissolves in the continuous phase (and not in the droplets). As examples, the formation of acryl-amide/methyl methacrylate (AAm/MMA) and acrylamide/styrene (AAm/Sty) copolymers was chosen using the miniemulsion process. In all cases the synthe-... 

Hernandez-Barajas J, Hunkeler DJ (1997) Inverse-emulsion copolymerization of acrylamide and quaternary ammonium cationic monomers with block copolymeric surfactants copolymer composition control using batch and semi-batch techniques. Polymer 38(2) 449—458... 

Statistical copolymers were reported for N-vinylimidazole and 13b [50], for acrylamide with 9a [11], 9b [12], and 9c [13], and for terpolymers of acrylamide, sodium acrylate, and 9b [51]. Several hydrolytically stable am-monioacetate and pyridiniocarboxylate monomers based on isobutylene with variable length of hydrophobic side chains did not homopolymerize, but these monomers with surfactant properties are suited for copolymerization with electron-poor monomers [52]. 

The copolymer of acrylamide and ammonium acrylate is used to build viscosity in rinse cycle fabric softeners. This polymer is compatible with nonionic and most cationic surfactants that are used in fabric softener formulations. The polymer is incompatible with anionic surfactants and strong oxidizing agents, and it is sensitive to electrolytes. An example of other cationic polymers useful as thickeners for aqueous acid solutions is described in patent application EP 395282 [24],... 

Quaternized polymers have been found to improve wet combing and reduce static charge. In general, they can be formulated with anionic surfactants greater deposition occurs with a mixture of amphoteric and nonionic surfactants. Two of the most important examples are Polyquaternium-10, a quaternized hydroxyethylcel-lulose polymer, and Polyquaternium-7, a copolymer of diallyldimethylammonium chloride and acrylamide. These are the two most frequently used polymeric conditioning agents in commercial shampoos [46,47],... 

The top reaction (where R = phenyl, R = R" = methyl) has been run with a different diphosphine using a polymeric surfactant as the anion for rhodium to give 90-92% ee.85 Optimization of the phosphine structure would probably raise this to the levels shown in 10.38. The polymeric surfactant was derived from a copolymer of acrylamide with maleic anhydride (10.39). 

Typical polymeric pseudostationary phases include micelle polymers, polymeric surfactants, water-soluble anionic siloxanes and dendrimers [223-231]. Micelle polymers [e.g. poly(sodium 10-undecylenate), poly (sodium 10-undecenylsulfate), poly(sodium undeconylvalinate), etc.] are synthesized from polymerizable surfactant monomers at a concentration above their critical micelle concentration. These polymers have similar structures to micelles without the dynamic nature of the micelle structure. Polymeric surfactants are polymers with surfactant properties [e.g. acrylate copolymers, such as 2-acrylamide-2-methyl-l-propanesulfonic acid and alkyl methacrylamide, alkyl methacrylate or alkyl acrylate, poly (ally lamine)-supported phases, poly(ethyleneimine), etc]. Water-soluble anionic siloxane polymers are copolymers of alkylmethylsiloxane... 

The subject of surfactant-modified, water-soluble polymers, briefly discussed in Water-Soluble Polymers, is addressed in the last three sections (Chapters 16-28) of this book. These associative thickeners are covered in detail, ranging from the maleic acid copolymers of variable compositions introduced in various commercial markets in the early 1960s to the most recent entries (that is, in the open literature), hydrophobe-modified poly (acrylamide). Chapter 23 is complementary to the spectroscopic studies in Chapters 13-15 it explores new approaches to understanding associations in aqueous media. The three hydrophobe-modified polymers that have gained commercial acceptance in the 1980s, (hydroxyethyl)cellulose, eth-oxylate urethanes, and alkali-swellable emulsions, are discussed in detail. In particular, hydrophobe-modified (hydroxyethyl)cellulose, which is... 

Hydrophobic regions can be one or two small, well-defined blocks of pendant hydrophobic moieties in an otherwise water-soluble polymer (2-4). An example is a water-soluble sulfonated BAB triblock copolymer where B is hydrophobic f-butylstyrene and A is vinyltoluene (2). However, hydro-phobic regions can also be less well-defined as well as more numerous in a polymer molecule than is the case for a triblock copolymer (5-22). For example, pendant alkyl esters appear to have been randomly incorporated in styrene-maleic anhydride (5) and vinyl benzyl ether-styrene-maleic anhydride (6-ii) copolymers. Also, alkyl polyoxyethylene acrylate monomers can be copolymerized with acrylamide to yield copolymers with pendant hydrophobic chains (12-15). More recently it was found (16-22) that small amounts of water-insoluble monomers that are solubilized by surfactants into aqueous solutions of a hydrophilic monomer produce copolymers with pendant hydrophobic chains, but the size, number, and nature of the hydro-phobic regions has not been determined. 

Hydrophobically associating polymers consist primarily of water-soluble monomer units with a small number of water-insoluble monomer units. Synthesis of high-molecular-weight random copolymers of acrylamide and alkylacrylamides required a novel aqueous surfactant micellar solution polymerization (2-4) because of the mutual immiscibility of the water-soluble and hydrophobic monomers. The use of surfactant micelles enabled solubilization of the hydrophobic monomer (alkylacrylamide [R]) into the aqueous phase containing the water-soluble monomer (acrylamide [AM]). The resulting RAM polymer after isolation provided homogeneous aqueous solutions. 

Polymer Synthesis. Copolymers of alkylacrylamide (R) and acrylamide (AM), which we called RAM, were prepared with a micellar polymerization technique (4). A micellar surfactant solution was used to disperse the hydrophobic alkylacrylamide monomer into an aqueous phase that contained acrylamide. The monomers were polymerized with a standard free-radical initiator (e.g., potassium persulfate) or a redox initiator to yield the desired random copolymer. Varied temperature and initiator concentrations were used to provide polymers of different molecular weights. Polymerizations were taken to essentially complete conversion. Compositions, in terms of hydrophobe level reported in this chapter, were based on amounts charged to the reactor. Further details on the synthesis and structure of these RAM polymers... 

The copolymers of acrylamide and alkylacrylamide were prepared according to a micellar process in which sodium dodecyl sulfate was used to solubilize the water-insoluble monomer to enable copolymerization with the water-soluble monomer to occur (i). The mixture before the polymerization was clear and free of any emulsion particles or undispersed monomer. Potassium persulfate was used to initiate polymerization, which was taken to complete conversion at 50 °C for 24 h. The polymers were purified from the surfactant by acetone precipitation-redissolution and then dried in a vacuum oven at 25 °C. The amount of hydrophobe actually incorporated was taken to be equal to that used in the polymerization. 

Figure 6, Effect of surfactant concentration on the apparent viscosity of a copolymer of acrylamide with 0,50 mol % decylacrylamide at 25 C, a shear rate of 1,28 s and a copolymer concentration of 0,25 g/dL.

---