Study On Micellization Behavior Of Acrylamide-type Anionic Surface Active Monomer And Copolymerization Mechanism Of Surface Active Monomer And Acrylamide

Anionic surface active monomer of sodium 2-acrylamido-tetradecane sulfonate(NaAMC₁₄S) and sodium 2-acrylamido-tetradecane sulfonate(NaAMC₁₂S) was synthesizedby using acrylonitrile,tetradecene and dodecane as main raw materials, and the chemicalstructure of NaAMC₁₄S was characterized with FTIR and ¹H-NMR. The solubility ofNaAMC₁₄S,NaAMC₁₂S and sodium dodecyl sulfonate (SDS) in aqueous solution weredetermined by UV spectrophotometry, the critical micelle concentrations at differenttemperatures were measured by using surface tension measurement , at the same time theirsaturated adsorption amounts and molecular areas at the interface of gas/water weredetermined with Gibbs isotherm absorption equation, and their aggregation numbers ofmicelles at different concentrations and at the critical concentrations were measured bysteady-state fluorescence probe method in which pyrene was used as fluorescence probe andbenzophenone as quencher. The micellization behavior data of the two sufmers in addition toinorganic electrolyte (NaCl) were also measured. The copolymerizations of NaAMC₁₄S andAcrylamide (AM) were carried out in aqueous solution, above and below CMC of NaAMC₁₄Srespectively. The compositions of the copolymers were characterized via conductometrictitration method, the thermal behaviors of the copolymers were measured by DSC, and theproperties of hydrophobic association of the copolymers were determined by usingfluorescence probe technique. The experiment results show that compared with generalsurfactants they have two hydrophilic groups, so they have strong solubilities in water, lowerKrafft temperatures. Poor abilities to decrease surface tension of water (i.e. poor surfaceactivities ), lower surface adsorption amounts, greater molecular areas at the interface ofgas/water, and much smaller aggregation numbers of micelles due to the loose micelles. Ascompared with the two homologous compounds of NaAMC14S and NaAMC12S, the effects ofthe chemical structures on the micellization behaviours and the micellar behaviours inaddition to inorganic electrolyte (NaCl) are the same as ordinary surfactants. There are twokinds of copolymerization mechanisms as the different concentrations of NaAMC14S. Theexperiment results also show that when the copolymerization of NaAMC14S and AM isperformed above the critical micelle concentration of NaAMC14S, the copolymerizationprocess keeps to micro-block copolymerization mechanism, and a large compositional driftoccurs during the copolymerization. Whereas when the copolymerization of NaAMC14S andAM is performed below the critical micelle concentration of NaAMC14S, the polymerizationprocess is carried out in agreement with random copolymerization mechanism, and thevarying of the copolymer composition with the conversion is slower. The DSC thermogramsof the copolymers and the result determined by fluorescence probe technique prove the abovemechanisms fully.