Synthesis And Properties Of P(MAA-g-EG) Hydrogel Nanoparticles

In this thesis, poly(ethylene glycol)(PEG) macromonomer was prepared first by the reaction of acryloyl chlorlide and methoxy poly(ethylene glycol)(mPEG.). Then, the PEG grafted Poly(methacrylic acid)(P(MAA-g-EG)) hydrogel nanoparticles were prepared by dispersion polymerization of methacrylic acid and PEG macromonomer. Tetra(ethylene glycol) dimethacrylate(TEGDMA) was incorporated as the crosslinking agent, and potassium persulfate was employed as the initiator. The effects on polymerization were investigated, such as medium, temperature, monomer ratio, time, monomer concentration, crosslinking agent, initiator, auxiliary stabilization agent, thermothickeing agent and stiring rate. It's best to operate the copolymerization in deionized water medium at 75℃ for 6hr.The most suitable composition of raw materials is 3wt% monomer concentration at mol ratio of EG/MAA=4/1, 2mol%crosslinking agent, and 2mol% initiator. The IR and 1H-NMR showed that the synthesized PEG macromonomer and P (MAA-g-EG) nanoparticles have the desired structure. P(MAA-g-EG) nanoparticles were characterized by Light Scattering, SEM and TEM. The results showed P(MAA-g-EG) nanoparticles have sphericity figure, with diameter lower than 500nm. P(MAA-g-EG) nanoparticles possess good stability , pH-sensitivity and swelling properties. A conclusion could be drew from the studies on the effect of different polymerization factors on the swelling properties of P (MAA-g-EG) nanoparticles that the higher temperature, monomer ratio(EG/MAA), mole concentration of initiator are propitious to swelling properties. On the contrast, an reverse effect induced by increasing the amount of crosslinking agent. Based on the good pH-sensitivity and nanosized diameter, these nanoparticles could be used for drug controlled delivery system.