| N-vinyl pyrrolidone (NVP) copolymers are synthesized by N-vinyl pyrrolidone (NVP) and another monomer or more which combine the advantages of both polyvinyl pyrrolidone (PVP) and another copolymer. PVP is a kind of homopolymer that has many advantages (higher solubility, low cytotoxicity, bio-compatibility, good film-forming properties, chemical stability, etc.) and has important application in medicament, chemical for daily use, food, drink, cosmetics, new material and many other fields. So it attracts more and more attentions. Because of the high cost of PVP, copolymerization of NVP has become the hot spot. As an amphiphilic and bio-compatible monomer, it can be used for synthesis of a lot of copolymers with many vinyl monomers by various methods. At present, the synthesis, characters, structure and application of NVP copolymers have been the focus. Based on the research background and the development needs, the purpose of this paper is focused on the synthesis and properties of water-soluble amphiphilic NVP copolymers, and investigate the aggregation behavior of copolymers in aqueous solution and temperature-resistance and salt-resistance.The main work are as follows:1. Amphiphilic copolymers P(NVP/DMFA) were synthesized by radical aqueous copolymerization of N-vinyl pyrrolidone (NVP) and dodecafluoroheptyl methacrylate (DMFA). The structures of P(NVP/DMFA) were confirmed by1H-NMR,19F-NMR, FT-IR and elemental analyses. The thermal stability of P(NVP/DMFA) was studied by TGA and DSC. The aggregation behavior of P(NVP/DMFA) in aqueous solution was studied by dynamic laser light scattering and surface tension as a function of copolymer concentration, temperature or added salts. The results indicated that P(NVP/DMFA) was good surface active in aqueous solution and the surface tension was reached to34mN·m-1when the copolymer concentration was lOg·L-1. The increase of temperature and addition of salts promoted the surface tension of P(NVP/DMFA) solution reduced. When at low copolymer concentration, it tend to form intramolecular association. And with increasing copolymer concentration, the copolymer aggregation behavior became intermolecular association. The addition of small amounts of salts (NaCl、CaCl2、MgCl2) can increase the polarity of solution, and be beneficial for intramolecular association and copolymer aggregate shrinkage. Further addition of salts lead to the intermolecular association. These results indicated P(NVP/DMFA) is an amphiphilic copolymer and has good temperature-resistance and salt-resistance. The study of system AP-P4-P(NVP/DMFA) showed that the addition of P(NVP/DMFA) could greatly improve the viscosifying ability and heat stability of AP-P4solution.2. Amphiphilic copolymers P(NVP/MA) were synthesized by radical copolymerization of N-vinyl pyrrolidone (NVP) with maleic anhydride (MA) in aqueous solution. The structures of P(NVP/MA) were confirmed by1H-NMR, FT-IR and elemental analyses. The thermal stability of P(NVP/MA) was studied by TGA and DSC. The aggregation behavior of P(NVP/MA) in aqueous solution was studied by surface tension, resonance scattering spectra and dynamic laser light scattering as a function of copolymer concentration, temperature, added salts and aging time. The results indicated that surface activity of P(NVP/MA) in aqueous solution had not obtain very good results as expected. The increase of temperature and addition of salts promoted the surface tension of P(NVP/MA) solution reduced. When at low copolymer concentration, it tend to form intramolecular association. And with increasing copolymer concentration, the copolymer aggregation behavior became intermolecular association. The addition of small amounts of salts (NaCl、CaCl2、 MgCl2) can increase the polarity of solution, and be beneficial for intramolecular association and copolymer aggregate shrinkage. Further addition of salts lead to the intermolecular association. The increase of temperature was beneficial for aggregate stretching and intermolecular association, leading to the hydrodynamic radius of copolymer increase. Thermal degradation lead to the hydrodynamic radius of copolymer in solution decrease. The study of system AP-P4-P(NVP/MA) showed that the addition of P(NVP/MA) could greatly improve the viscosity ability and heat stability of AP-P4solution. 3. Modified P(NVP/MA)(HDA-P(NVP/MA)) was synthesized via chemical reaction with hexadecanamine (HDA) which can react with anhydride of P(NVP/MA). The structures of HAD-P(NVP/MA) were confirmed by’H-NMR, FT-IR and elemental analyses. The thermal stability of P(NVP/MA) was studied by TGA and DSC. The aggregation behavior of P(NVP/MA) in aqueous solution was studied by surface tension, resonance scattering spectra and dynamic laser light scattering as a function of copolymer concentration, temperature, added salts and aging time. Because of the hexadecanamine, the solubility of HAD-P(NVP/MA) was worse than P(NVP/MA). The results indicated that the copolymer HAD-P(NVP/MA) showed good surface activity in aqueous solution. The increase of temperature and addition of salts promoted the surface tension of HAD-P(NVP/MA) solution reduced. When at low copolymer concentration, it tend to form intramolecular association. And with increasing copolymer concentration, the copolymer aggregation behavior became intermolecular association. The addition of small amounts of salts (NaCl、CaCl2、 MgCl2、) can increase the polarity of solution, and be beneficial for intramolecular association and copolymer aggregate shrinkage. Further addition of salts lead to the intermolecular association. The increase of temperature was beneficial for aggregate stretching and intermolecular association, leading to the hydrodynamic radius of copolymer increase. Thermal degradation resulted in the decrease of hydrodynamic radius of copolymer. The result showed that the introduction of hexadecanamine lead to stronger temperature-resistance. The study of system AP-P4-HAD-P(NVP/MA) showed that the addition of HAD-P(NVP/MA) could greatly improve the viscosifying ability and heat stability of AP-P4solution. |
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