Polydadmac.

It is usually used as flocculant and sometimes combined with algicide. The trade names include agequat400, St flocculant, pink cure, cat floc, etc. PDMDAAC has synergistic effect with wscp and poly (2-hydroxypropyl dimethyl ammonium chloride). 413 is generally used as coagulant aid in industrial water treatment. After adding alum coagulant, the dosage of coagulant can be saved by 30%. For example, after adding 20 mg / L polyaluminium chloride, add 0.1-0.2 mg / L Polydimethyldiallyl ammonium chloride to increase efficiency.

The molecular weight range of PDADMAC is usually 50000 to 700000, and the dynamic viscosity of 20% aqueous solution is 50-700cps; The molecular weight of products with high degree of polymerization can reach 1000000 to 300000, and the dynamic viscosity is 1000-3000 CPS. The intrinsic viscosity is 80-300ml / g, and the high viscosity can reach 1440ml / g. The product is generally 10-50% solution with a density of 1.02-1.10 g / ml. The dosage in drinking water is required to be less than 10mg / L (Taiwan).

The viscosity behavior of PDMDAAC aqueous solution has significant polyelectrolyte effect. The intrinsic viscosity decreases with the increase of the added salt concentration. When the NaCl concentration is greater than 1 m, the change of the intrinsic viscosity with the added salt concentration is relatively small. The intrinsic viscosity is measured by Ubbelohde viscometer in 1 M NaCl solution at 30 ℃, and the viscosity average molecular weight can be obtained according to the formula.

The molecular weight of PDMDAAC can be obtained from the following formula, in which the intrinsic viscosity is measured in 1 M NaCl solution at 30 ℃: 407.

[ η] = 1.12 * 10-4M0. eighty-two

Huang and Reichert studied the thermal weight loss of PDMDAAC in different temperature ranges. 53.3-130 ℃ weight loss is due to water loss; Keep unchanged between 130-200 ℃; The weight loss at 200-310 ℃ is 41.4%, which is due to thermal decomposition. No melting point was found during the whole heating process. The glass transition temperature of PDMDAAC with molecular weight of 33 kDa is 8 ℃.

PDADMAC is less toxic to rainbow trout than chitosan (Waller et al. 1993). However, PDADMAC for water treatment has restrictions on monomer content.

PDMDAAC in China has high monomer content. The PDMDAAC of two chemical plants was tested and found that the monomer contents were 12.5% and 7.89% (calculated as solid. Converted to 40%, the content in the product was 5.0% and 3.2%), which was much larger than the American Standard of 0.2% and the European standard of 0.5%. 380 for products with unspecified monomer content, the monomer content may be higher. The intrinsic viscosity of PDMDAAC containing monomer is given by the following formula: 411.

log[ η'] = log[ η] + lgX';

[380] Brown et al., 2007; Puschner et al., 2007.

[407] Zhao Huazhang, Gao Baoyu Research progress of dimethyl diallyl ammonium chloride (DMDAAC) polymer Industrial water treatment 1999, (6).

[411] Jia Xu, Zhang Yuejun Effect of monomer conversion on intrinsic viscosity of Polydimethyldiallyl ammonium chloride Journal of Nanjing University of Technology (NATURAL SCIENCE EDITION) 2010, 34(6), 380-385.

[413] US Patent 5529700, Algicidal or Algistatic Compositions Containing Quaternary Ammonium Polymers. one thousand nine hundred and ninety-five.