Polyacrylamides nonionic

Anionic and nonionic polyacrylamides effectively remove suspended soHds such as silt and clay from potable water. SuppHers provide special grades which meet EPA/FDA regulations for residual acrylamides. A recent pubHcation (102) states that hydrolyzed polyacrylamides with narrow interchain charge distributions provide better performance in flocculation of clay. These polymers were prepared by alkaline hydrolysis. (See Flocculating agents.)... 

Acidic suspensions such as those produced by acid leaching often respond to natural products such as guar as well as nonionic polyacrylamides and anionic polyacrylamides containing sulfonic acid groups. 

Figure 1. Intrinsic viscosities for nonionic polyacrylamides in water and aqueous solutions of various pH and ionic strength ((%, 4) water (, O, m) aqueous solutions (pH range 2,5 7.0 and ionic strength range 0,013-. 503) containing a nonionic surfactant (either Tergitol or polyethylene oxide = 300,000))...

Figure 2. Molecular weight calibration curves for nonionic polyacrylamide for a single column (4 ft X Vs in. i.d.) containing 2000 A CPG-10 (200/400 mesh) packing with aqueous salt solutions as mobile phase.

Figures 6, 7 and 9 show calibration curves using two multi-column combinations and illustrate the degree of "optimization obtained in this system. The mobile phases for Figures 6 and 7 contained 0.025 g polyethylene oxide and ion exclusion and adsorption effects should therefore be largely eliminated. Figure 6 shows that reasonably good resolution can be obtained with a combination of five columns but does exhibit some loss of peak separation at the low cuid high MW ends. In Figure 7 the effect of adding a sixth column of small pore size is illustrated and it is seen that resolution at the low MW end is thereby somewhat improved. This calibration curve is effectively linear with a change of slope at 500,000 MW. It should provide a useful aqueous GPC system for MW and MWD determination of nonionic polyacrylamides.

Figure 7. Molecular weight calibration curve for nonionic polyacrylamides for a 6-column combination (each 4 ft X in, Ld.) with 3000 A, 3000 A, 2000 A, 1000 A, 729 A, and 500 A CPG-10 (200/400 mesh) packing.

Figure 8. Chromatograms for nonionic polyacrylamide standards and Standard C for the column combination shown in Figure 6.

Two recent attempts to develop aqueous GPC for the characterization of nonionic polyacrylamide have been reported (10,11). 

Figure 10. Chromatograms for nonionic polyacrylamide staruiards for the column combination (mobile phase and flow rate given in Figure 9)...

The adsorption of nonionic polyacrylamide is also increased in the presence of calcium, indicating specific interaction of calcium and the polymer. 

The flocculation responses studied are settling rate, percent solid settled, supernatant clarity, sediment volume and slurry viscosity. The polymer concentration and polymer anionicity required for maximum flocculation were seen clearly to depend on the response studied. Both the settling rate and the supernatant clarity with the nonionic polyacrylamide flocculent showed at pH 4.5 a marked increase to a maximum at about 25 mg/kg, whereas with the anionic polymer settling rate and supernatant clarity showed maxima at 10-25 mg/kg, but the system was totally... 

The presence of pre-adsorbed polyacrylic acid significantly reduces the adsorption of sodium dodecylsulfonate on hematite from dilute acidic solutions. Nonionic polyacrylamide was found to have a much lesser effect on the adsorption of sulfonate. The isotherm for sulfonate adsorption in absence of polymer on positively charged hematite exhibits the typical three regions characteristic of physical adsorption in aqueous surfactant systems. Adsorption behavior of the sulfonate and polymer is related to electrokinetic potentials in this system. Contact angle measurements on a hematite disk in sulfonate solutions revealed that pre-adsorption of polymer resulted in reduced surface hydrophobicity. 

Fig. 32. Influence of M on drag reduction effect for nonionic polyacrylamide samples, d = 6.1 mm (data taken from Gampert, Wagner 1985)...

Solid Polymer. Completely dry polyacrylamide is a bottle while solid. The phy sical properties of nonionic polyacrylamide are listed in Table 1. 

In general nonionic polyacrylamides do nor interact strongly with neutral inorganic salts. 

Dry nonionic and cationic material caused no skin and minimal eye irritation during primary irritation studies with rabbits. Dry anionic polyaciylamide did not produce any eye or skin irritation in Laboratory animals. Emulsion nonionic polyacrylamide produced severe eye irritation in rabbits, while anionic and cationic material produced minimal eye irritation in rabbits. Polyacrylamides arc used safely for numerous indirect food packaging applications, potable water, and direct food applications. 

Since the ammoniiun cations are placed in the middle and the sulfonate anions at the end of the side chain of 23b, the complex can be solubilized due to free anionic groups of 23b (Scheme 19a). In contrast, PDMAPAA-Q and ionenes bind to 23b via the sulfonate groups, which are located at the end of side chain (Scheme 19b and c). The ammonium cations of PDMAPS are thus strongly shielded as hydrophilic solubihzing groups because they are surrounded by two hydrophobic polymer main chains in the complex. Table 3 summarizes the yields and UCSTs of the IPCs resulting from the addition of anionic (PAA, PMAA, NaPSS), cationic (polyDADMAC, PDMAPAA-Q), and nonionic (polyacrylamide, PAAm) polymers to 23b. 

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