Preparing Hydrophobically Associating Polyacrylamide In New Micellar And Its Rheological Behaviour

N-dodecylacrylamide (C₁₂AM) and N, N-di-dodecylacylamide(DiC₁₂AM), which are strong hydrophobic monomers, were synthesized in the research, The chemical structure of two kinds of hydrophobic monomers confirmed using FTIR and 1H-NMR spectra. The solubilization properties of C₁₂AM and DiC₁₂AM in the micellar solutions of sodium dodecylsulfate (SDS) and a surface-active monomer, sodium 2-acrylamido-dodecyl sulfonate (NaAMC₁₂S), were studied with tuebidimetric determination. The experimental results show that,because the aggregation number (Nagg) of SDS is larger (62), the solubilized amount of C₁₂AM and DiC₁₂AM in the micellar solution of SDS is greater. As compared with in the micellar solution of SDS, the solubilized amount of C₁₂AM and DiC₁₂AM in the micellar solution of NaAMC₁₂S is much smaller because of the littler aggregation number of NaAMC₁₂S micelles.The micellar solutions of sodium dodecylsulfate (SDS) and sodium 2-acrylamido-dodecycane sulfonate (NaAMC₁₂S), which is a surface-active monomer, were prepared, on the basis of the solubilization properties of N-dodecylacrylamide (C₁₂AM) in the two micellar solutions, the micellar copolymerization of acrylamide (AM) and C₁₂AM was performed in the two micellar solutions, and bipolymer C₁₂AM/AM and terpolymer C₁₂AM/NaAMC₁₂S/AM were obtained, respectively. Their infrared spectra were measured and the structures were characterized. Their hydrophobic association property and rheological behaviour were mainly studied by using fluorescence probe technique and viscosimetry. The experimental results show that in the micellar solution of surface-active monomer NaAMC₁₂S, the copolymerization of AM and hydrophobic monomer can be realized favorably. Because the surface-active monomer also participates in the copolymerization, the product is a terpolymer, C₁₂AM/NaAMC₁₂S/AM. As compared with the biopolymer C₁₂AM/AM, the terpolymer has stronger hydrophobic association property owing to the incorporation of the surface-active monomer NaAMC₁₂S. To prepare hydrophobically association polyacrylamide (HAPAM) in the micellar solution of surface-active monomer not only simplifies the process of micellar copolymerization owing to avoid the procedure to remove surfactants, but also enhances the hydrophobic association property of HAPAM. Therefore, the method put forward in this work is a significant improvement for the conventional micellar copolymerization.In the new micellar copolymerization system was prepared using sodium 2-acrylamido-dodecycane sulfonate (NaAMC₁₂S) as a surfactant, which is a surface-active monomer, and the copolymer of acrylamide (AM) and N,N-didodecylacrylamide (DiC₁₂AM) which is a twin tail-type acrylamide was performed, and hydrophobically associating polyacrylamide (HAPAM) containing twin tail-type acrylamide was obtained. This copolymer is a terpolymer DiC₁₂AM/NaAMC₁₂S/AM because of incorporating of NaAMC₁₂S. The terpolymers with serially varying microstructures were prepared via controlling the copolymerization conditions. The chemical structure of the terpolymer was characterized with infrared spectrum. The relationship between the chain microstructure and hydrophobic associativity for the terpolymer DiC₁₂AM/NaAMC₁₂S/AM was mainly studied with fluorescent probe technique and apparent viscosity measurement. The experimental results show that the micellar copolymerization of AM and DiC₁₂AM can favorably realized. The HAPAM containing disubstituted acrylamide, DiC₁₂AM, has much stronger hydrophobic association property than HAPAM containing monosubstituted acrylamide, N-dodecylacrylamide (C₁₂AM), so the twin tail-type acrylamide as a hydrophobic monomer is valuable for the preparation of HAPAM with high performance. Analogous to general HAPAM, the main structure factors effecting on the hydrophobic associativity are hydrophobe content, hydrophobic microblock length and the micromolecular weight.