| With the improvement of living standards, the people’s demand on living environment is getting higher and higher. It’s easy that exposure to the bacteria for people in their daily lives. The bacterial reproduction ability, the ability to cause disease and capacity for rapid spread, which undoubtedly have caused trouble to people’s basic necessities. Antimicrobial materials can effectively reduce or avoid bacterial cross infection and the spread of disease, therefore, antibacterial products are more and more valued by people. Gemini surfactant is a new type of hydrophilic and oleophilic amphiphilic molecule, which not only has significant chemical properties, but also can be used as a good common disinfectants in the biological aspect. Therefore, cationic Gemini surfactants as novel antibacterial agents have attracted the attention of researchers worldwide. The preparations of antibacterial polymers containing Gemini surfactants were rarely reported in the literatures, so the researches of synthesis and antibacterial properties of Gemini surfactants and antibacterial polymers have important practical significance and application value, which can extend the application of Gemini surfactants, develop new types of antibacterial materials.This thesis mainly studies the cationic poly (styrene-butyl acrylate) nanoparticle, chemical properties of latex films and applications of antibacterial polymers in the field of antimicrobial. Firstly, series of cationic Gemini surfactants with the two moieties linked by a glycol-bis-ethanoate spacer were synthesized by organic synthesis. IR and H1NMR were used for structural characterization of synthetic cationic Gemini surfactant, the critical micelle concentration and the micelle morphology of Gemini surfactant were characterized respectively. Then a series of cationic styrene-acrylic nano-emulsions were prepared by using the surfactants as emulsifiers. Influences of emulsifier variety, emulsifier amount and monomer ratio on structures and properties of the nano-latexes were discussed. The stabilities of resistant Ca2+, Mg2+, H+, OH-, freezing-thawing and high temperature for copolymer emulsion were also measured. Subsequently, cationic Poly (St-BA-AAEM) ternary copolymer nano-emulsion was prepared by introducing the functional monomer,2-(Acetoacetoxy) ethyl methacrylate (AAEM). Influences of AAEM on properties of the nano-latexes were discussed. Finally, antimicrobial activities of cationic Gemini surfactants and cationic styrene-acrylic copolymers would be discussed in detail. The concrete research conclusions are as follows:1. The symmetrical cationic Gemini surfactants with the two moieties linked by a glycol-bis-ethanoate spacer were successfully synthesized by simple two synthetic protocols, which were high yield and purity.2. Blue and transparent poly (styrene-butyl acrylate) nanoparticle was accomplished by semi-continuous seeded emulsion polymerization with cationic Gemini surfactants as emulsifiers. High-performance Gemini surfactant as emulsifier can reduce the dosage, types of Gemini surfactants had little impact on emulsion properties. The average particle sizes of latexs were about70nm at the concentration range of studied emulsifier, when the surfactant dosage was between5.5%-6%, the particle size of narrow distribution polymer nanoparticles came to60nm.3. There was no obvious effect on polymer particle diameter with the vary of amount of functional monomer (AAEM), the z-average particle sizes were about55nm, but the particle size distribution became broaden with increase of AAEM dosage. AAEM and adipic dihydrazide (ADH) successfully cross-linked by FTIR test, and the properties of latex films were significantly improved after crosslinking. The thermal stabilities of latex films reduced with the increase of degree of crosslinking, the mechanical property of the latex film came to best after introducing1%AAEM+ADH.4. Cationic Gemini surfactants against the indicator bacteria Escherichia coli and Staphylococcus aureus exhibited significant antibacterial activities at the concentration range of4-512μg/mL. Among these surfactants, G12-A2A-12exhibited the highest antibacterial activity. The increase of the glycol-bis-ethanoate spacer length did not result in corresponding increase of the antibacterial activity; however, the increase of the alkyl chain length conferred the increase of the antibacterial activity against S. aureus but decrease of such an activity against E. coli. All developed surfactants exhibited the antibacterial activities against E. coli with the order of G12-A2A-12> G14-A2A-14> G12-A3A-12/G12-A4A-12> G16-A2A-16, whereas the activities of the surfactants against S. aureus ranked by the order of G16-A2A-16> G14-A2A-14> G12-A2A-12> G12-A3A-12/G12-A4A-12. 5. Nano-emulsions were prepared by using G12-A2A-12as emulsifier, which had the highest antibacterial activity. It showed that the antibacterial activities of emulsion were higher than small molecule surfactant. Overall, antimicrobial activity of emulsion mainly depended on emulsifier, when copolymer containing toxic groups, bacteriostatic effect decreased instead. The antibacterial properties of latex film not only were influenced by surfactant but also by many other factors, such as the structure of latex film. |
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