The comparison of polymerization activity of typical cationic quaternary ammonium salt monomers

The cationic water-soluble polymers, which are widely used in many areas such as papermaking and separation process, are typically synthesized through polymerization of cationic monomers represented by quaternary ammonium salt. In this work, the polymerization reaction kinetics of three typical quaternary ammonium salt cationic monomers including acryloyl oxygen ethyl trimethyl ammonium chloride (DAC), methyl acryloyl oxygen ethyl trimethyl ammonium chloride (DMC), and methyl acrylamide propyl trimethyl ammonium chloride (MAPTAC) was examined by using the dilatometer method. The results showed that the polymerization rate of all three monomers increased with the increase of initiation temperature, monomer concentration, and initiator concentration. Under the same conditions, the polymerization activity of the three monomers followed the order: DAC > DMC > MAPTAC. The activation energies for the polymerization reaction under the specified conditions were E aDAC = 138.97 kJ/mol, E aDMC = 141.24 kJ/mol, and E aMAPTAC = 226.97 kJ/mol, respectively. The polymerization rate equations were R pDAC = k 1 [ M ] 4.25 [ I ] 0.51 , R pDMC = k 2 [ M ] 3.77 [ I ] 0.50 , and R pMAPTAC = k 3 [ M ] 3.30 [ I ] 0.49 . The polymerization activity of the monomers may be influenced by electronic effects and steric hindrance of the monomer structure. This work has provided a theoretical and experimental foundation for the actual work of structural design and preparation of cationic water-soluble polymers.