Study Of Novel Amphiphilic Functional Monomer AEBA And Its Hydrophobically Associating Polymers

Water soluble hydrophobically associating polymers have become an important subject in supermolecule field due to their unique solution properties and association behaviors. In this thesis, a novel polymerizable cation amphiphilic compound, 4-(2-(acryloyloxy) ethoxy) benzyl tri-ethyl ammonium bromide (AEBA), was synthesized. It has strong capacity for self-assembly. AEBA can be used to construct the molecular assembly and polymers with desired architecture. Based on this amphiphilic monomer AEBA, several kinds of novel hydrophobically associating polymers with different functions were constructed. The solution properties, hydrophobic association behaviors and aggregate microstructures were studied in detail. A new microhetergeneous copolymerization system composed of AEBA and other hydrophilic monomers was proposed to prepare high performance hydrophobically associating polymers.1. A novel polymerizable amphiphilic compound with self-assembly ability, 4-(2-(acryloyloxy) ethoxy) benzyl tri-ethyl ammonium bromide (AEBA), was designed and synthesized. It exhibits good water solubility, strong self-association ability and response to extra-stimulation (pH, salt). The macroscopic solution properties indicate the surface activity and solubilization of AEBA. Its minimum hydrotrope concentration (MHC) locates near to 0.05 M. The studies of self-association behavior and aggregation microstructure demonstrated that AEBA molecules associate gradually into stack-type aggregates conformation. The critical association concentration CAC is at 1.5×10-3 M. The aggregate size of AEBA increases with concentration.2. The intermolecular association, phase transformation and vesicle formation of AEBA / SDS mixture system were investigated. The results show that addition of AEBA significantly promotes the intermolecular association and decreases the CMC of SDS. With an increase of AEBA / SDS molar ratio, a series of structure transformation"micelle-vesicle-solid particle"occurs, accompanying with the change of the solution appearance ("transparent-semiopaque-turbid"). At a certain AEBA / SDS molar ratio, these two amphiphilic compounds associate into vesicles. High stable polymerized vesicles can be obtained by intra-aggregate AEBA polymerization. Obviously, it is a facile method to prepare hollow nanomaterials.3. A cation amphiphilic homopolymer P(AEBA) was synthesized. It has high self-association ability and response to salinity. The macroscopic solution properties demonstrated that P(AEBA) behaves as polyelectrolyte in pure water but in salt solution it is similar to polysoap. It is very interesting to find that P(AEBA) spontaneously associates into pearl-necklace-like aggregates conformation in pure water. With the addition of salt, the size of the necklace beads increases while their numbers and the necklace length decrease. Finally, the necklace-like aggregate associates into a hollow globule conformation. It should be noted that the pearl-necklace-like aggregate conformation and the aggregate size transformation are theoretically and practically important. It first provides a visualized intermedia aggregation state of such type in the"coil-globule"transformation process for polyelectrolyte, which was suggested by early theoretic predict. Furthermore, with the increase of polymer concentration, two distinct aggregate structures were observed, which induced different solution properties.4. A series of AEBA modified hydrophobically associating polyacrylamides were synthesized using new microhetergeneous copolymerization system. The copolymer P(AM/AEBA) containing a small amount (≤3 mol%) of AEBA exhibits strong hydrophobic associative interactions and thickening efficiency in aqueous solution due to the microblock-like structure of AEBA. As the copolymer concentration above CAC, P(AM/AEBA) forms network structures with large hydrodynamic volume based on intermolecular association, which result in a rapid viscosity enhancement. The polymer chain microstructure (content and length of hydrophobic microblock) and molecular weight are both the main factors to determine the hydrophobic association interactions and thickening effect of P(AM/AEBA). The optimal results can be obtained by properly regulating the number and size of AEBA aggregates before copolymerization, as well as reaction conditions. It should be pointed out that this new microhetergeneous copolymerization system composed of self-assembly monomer can be used to substitute the traditional micellar copolymerization system to prepare high performance hydrophobically associating polymers with microblock structure characteristic. It also provides a facile and environmental friendly method for synthesis other functional polymers with microblock structure.5. A novel microhetergeneous copolymerization technique was used to prepare a series of AEBA modified cation flocculant copolymers P(AM/DMC/AEBA) in aqueous solution. The resulting copolymers contain a small amount (≤3 mol%) of AEBA monomer which distributed as microblock manner along the copolymer chains. The flocculation experiments demonstrated that the microblock-like structure of AEBA promotes the intermolecular hydrophobic interactions and bridge-linkage actions of the macromolecules, resulting copolymers exhibits good flocculation and separation effect. Based on the preliminary results obtained, it is reasonable to expect that flocculants copolymers with higher performance can be synthesized using this novel microhetergeneous copolymerization technique.