Study On Synthesis And Characterization Of Novel Polybenzoxazine

In this paper, two novel kinds of polybenzoxazine resin, which called polybenzoxazine based on diphenyl ether oligomer (PB-D) resin and magnetic microspheres of polybenzoxazine containing Fe3O4 nanoparticles (PBGA/Fe3O4), were synthesized. The thermal stability and the solvent resistance of PB-D resin were also studied. Using reverse-phase suspension solidification, the PBGA/Fe3O4 microspheres were synthesized by self-assembly of the solution-state benzoxazine precursors based on guanidine and bisphenol A (B-G-A). The mechanism of self-assembly and the factors influencing the synthesis of the microspheres were investigated. The obtained magnetic PBGA/Fe3O4 microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM) and ultraviolet (UV). The adsorptive capacity and the adsorptive behaviour of the microspheres on anti-cancer drug 5-fluorouracil (5-FU) were examined.The results showed that the polybenzoxazine resin based on phenol modified diphenyl ether oligomer and phenylamine (PB-D-P-P), the temperature of 5% weight loss was 287℃. For PB-D-P-P resin, its thermal stability was inferior to the polybenzoxazine resin based on bisphenol A modified diphenyl ether oligomer and phenylamine (PB-D-A-P) resin whose temperature of 5% weight loss was only 230℃. Whether increasing the molar ratio of phenol or formaldehyde and phenylamine, there was no significant improvement for the thermal stability of PB-D-P-P resin; The thermal stability of resin was also not significantly improved by added SiO2; The result indicated that when phenol modified diphenyl ether oligomer as phenol resource, the guanidine hydrochloric acid as amine resource, toluene and absolute ethyl alcohol as solvent, the best thermal stability can be achieved, and the temperature of 5% weight loss was 352℃. The PB-D-P-P resin showed high solvent resistance in selected acid solvents and non-polar organic solvents at room temperature and boiling state.The self-assembly mechanism of PBGA/Fe3O4 magnetic polymer microspheres was the spontaneous assembly of benzoxazine precursors and Fe3O4 nanoparticles into spherical micelles in methyl-silicone oil medium and then the core cross-linking of the micelle was carried out by the control of external medium temperature. The XRD and VSM figure indicated that the crystal structure of Fe3O4 was well maintained after wrapped into polymer and the microspheres exhibited superparamagnetism. According to the SEM photograph, the PBGA/Fe3O4 microspheres were completely and perfectly round, relatively uniform, and greatly monodispersion. The surface of PBGB/Fe3O4 microspheres were rather smooth and there was no small molecule. The speed of agitation played an important role in the sizes of the PBGB/Fe3O4 microspheres. When other conditions were fixed, with the increasing of agitation speed, the average size of PBGB/Fe3O4 microspheres became smaller. The saturated adsorptive capacity of the microspheres on anti-cancer drug 5-FU achieved 1.287mg/g and their adsorptive behaviour was in accordance with the Langmuir isotherm equation and the Freundlich isotherm equation. The microspheres which possess high adsorption capacity on 5-FU and brilliant magnetic properties may be a promising delivery vehicle for anti-cancer drug targeting and controlled drug release.