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The lipophilic modification of dimethyldiallylammonium chloride monomer (DMDAAC) with resulting excellent lipophilic performance can provide an effective way to improve the application performance of the resulting monomers and copolymers. In this paper, polymethylamyldiallylammonium chloride (PMADAAC) homopolymer was prepared by using methylamyldiallylammonium chloride (MADAAC) as the monomeric unit, 2,2'-Azobis(2-methylpropionamide) dihydrochloride (V50) as the initiator and ethylenediaminetetraacetic acid tetrasodium (Na4EDTA) as a metal ion complexing agent via an aqueous solution polymerization method. Using the intrinsic viscosity of the product as the inspection index, the polymerization reaction conditions were optimized by the response surface optimization method, and the optimum conditions obtained were: w(MADAAC)=70.2%, m(V50):m(MADAAC)=2.05%, m(Na4EDTA):m(MADAAC) =0.0141%, T1=55.0 °C, T2=60.0 °C and T3=80.1 °C, with the reaction lasting 9 h (see below). The average value of the intrinsic viscosity ([η]) of the obtained product was 0.84 dL/g, and the monomer conversion degree (Conv.) was 72.77%. The molecular weight characterizations of PMADAAC showed that the highest Mw of PMADAAC was 2.380 × 105 and its polydispersity index d(Mw/Mn) was 1.952 for optimum properties. The results indicated that the introduction of the amyl group could increase the lipophilicity of the diallyl quaternary ammonium salts based on its good water solubility. For the demulsification performance of simulated crude oil O/W emulsions, the demulsification degrees were 88.9% for PMADAAC, 83.6% for polymethylpropyldiallylammonium chloride (PMPDAAC) and 45.5% for polydimethyldiallylammonium chloride (PDMDAAC), all at the same intrinsic viscosity. [ABSTRACT FROM AUTHOR]

Quaternary ammonium salt polymers, a kind of polyelectrolyte with a quaternary ammonium group, are widely used in traditional and emerging industries due to their good water-solubility, adjustable cationicity and molecular weight, high efficiency and nontoxicity. In this paper, firstly, the properties and several synthesis methods of typical quaternary ammonium salt monomers were introduced. Secondly, the research progress on the synthesis of polymers was summarized from the perspective of obtaining products with high molecular weight, narrow molecular weight distribution and high monomer conversion, and special functional polymers. Thirdly, the relationships between the structures and properties of the polymer were analyzed from the perspectives of molecular weight, charge density, structural stability, and microstructural regulation of the polymer chain unit. Fourthly, typical examples of quaternary ammonium salt polymers in the application fields of water treatment, daily chemicals, petroleum exploitation, papermaking, and textile printing and dyeing were listed. Finally, constructive suggestions were put forward on developing quaternary ammonium salt polymers with high molecular weights, strengthening the research on the relationships between the structures and their properties and pinpointing relevant application fields. [ABSTRACT FROM AUTHOR]