Solution homopolymer DADMAC

Polymerizations. Homopolymer DADMAC-Solution Polymerization. To a 1-L four-neck resin pot equipped with a mechanical stirrer, thermometer, condenser, purge tube, and heat regulating device were added 492 g of 55% aqueous DADMAC monomer. The pH was adjusted to 6.0 with dilute hydrochloric acid, heated to 50°C, and purged with nitrogen for 1 hr while stirring. Then, 0.05% Na4 EDTA (based on weight reaction mix) was added followed by 1.5 X 10 2 mol f-butyl-peroxypivalate/mol monomer. The temperature was maintained at 50°C 2°C for 18 hr, at which time the monomer conversion to polymer leveled off at 95%. The polymer was isolated via acetone precipitation. 

Homopolymer DADMAC-Emulsion Polymerization. The equipment setup outlined in the solution polymerization was used to prepare the emulsion polymer. To the resin pot 321.5 g benzene, 138.5 g of 72.2% aqueous DADMAC monomer, and 40 g of 20% aqueous sodium octyl phenoxyethoxy-2-ethanol sulfate were added. The mixture was stirred at 170-180 rpm with a paddle stirrer and heated to 50° 1°C. The suspension was purged with nitrogen gas for 1 hr. Then, 7 ppm Fe+2 (added as Fe(NH4)2(S04)3 6H20) were added, followed by 2 X 10"3 mol f-butylperoxypivalate/mol monomer. The reaction mixture was stirred for 20 hr at 50° 1°C under a nitrogen blanket. The polymer conversion after 20 hr was 90 2%. The product was isolated by adding the benzene emulsion to acetone, filtering the product, and drying. 

The homopolymerization of DADMAC is possible in several organic solvents such as acetone, l-methyl-2-pyrrolidone, tetramethylurea, or dimethylform-amide. Various initiation methods including radical, ionic, or x-ray induced polymerization have been employed [19]. Since the monomer solubility is limited in these solvents, and the resulting homopolymer is soluble only in water, methanol and acidic acid, the polymerization in aqueous solutions are preferred. Polymerization in both homogeneous and heterogeneous systems have been studied and the kinetics and mechanisms were investigated in aqueous solution and in inverse-emulsion [6-16,52,53]. 

Homopolymers of DADMAC and copolymers of acrylamide and DADMAC are applied in the coagulation of fibers recycled from coated broke, a term used to describe a paper which cannot be sold for different reasons [ 176]. It is claimed that polymer solutions and water-in-oil emulsions containing DADMAC offer both superior performance and cost effectiveness compared to the traditional polymer additives used for this purpose [190,194]. 

A set of DADMAC homopolymers was synthesized via inverse emulsion. Concentrations of TAMAC ranging from 0 to 5.0 mol % (based on monomer concentration) were added to the monomer solutions before polymerization to induce branching. All polymerizations were initiated with the same concentration of a conventional free-radical catalyst. These samples were evaluated for their ability to dewater 100% activated sewage sludge. The filtration rate served as a measure of a sample s dewatering ability. 

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