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In this paper the thermal stability properties of poly(3-methacryloylamino propyl trimethyl ammonium chloride) (PMAPTAC) with a series of molecular weights in various salt solutions were investigated by monitoring the apparent viscosity and viscosity retention rate with aging time, for the first time to our knowledge. Secondly, the thermal stability properties of poly(methacryloyloxy ethyl trimethyl ammonium chloride) (PDMC) solution was studied and compared with that of the PMAPTAC solution under the same conditions. The results showed that the viscosity retention rate of PMAPTAC/salt solutions with salinities from 40 g/L to 200 g/L at 85 °C were about 60%, indicating that PMAPTAC had good temperature and salt resistance. Besides, the temperature and salt resistance of PMAPTAC with 0.62 dL/g was better than that of PMAPTAC with 7.55 dL/g under the conditions of this study. In addition, the viscosity retention rate of PDMC/salt solution with the same intrinsic viscosity as PMAPTAC/salt solution was 45%, indicating that compared with PDMC, the PMAPTAC with viscosity retention rate of 60% had better temperature and salt resistance. We suggest the results obtained in this study will not only fill the current gaps in the research of the temperature and salt tolerance properties of PMAPTAC, but also provide support for the potential application of PMAPTAC products in high-temperature and high-salt environments. [ABSTRACT FROM AUTHOR]

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]