Synthesis And Characterization Of Polyphenol And Its Graft Copolymer By Enzymatic Method

The amino group of 4-aminophenol was protected by benzaldehyde first and then was polymerized in dioxane / buffer using HRP as catalyst. We conduct several experiments and conclude the best condition is: 1,4-dioxane/buffer=0.7, pH=7 and the concentration of substrate is 0.15 mol/L. THF-soluble part determined by GPC indicated the product obatained is principally oligomer, which is partly soluble in many organic solvents (DMF, THF, dioxane, acetone, etc.) and is not soluble in water or in alkanes. FTIR and NMR spectra of the polymer synthesized indicated that the polymerization by this enzyme catalyzed reaction is by ortho substitution on the ring. Through the cleavage of poly (schiff base), poly(4-aminophenol) was obtained.It was soluble in water, ethanol and other polar solvents and is not soluble in petroleum ether or in alkanes. Its solvability was greatly improved compared with poly (schiff base). UV-Vis spectrum shows that polymer has fluorescence characteristic.The surface condnuctivity was ( mearued following doping with iodine) was found to be 10^-5, which means the HRP catalyzed polymer was somewhat conductive.Enzymatic oxidative polymerization of phenol has been carried out in an aqueous organic solvent using horseradish peroxidase as catalyst. The polymerization in a mixture of methanol and phosphate buffer (pH=7.0) (50:50 vol%) produced powdery polymeric materials, which were partly soluble in DMF and THF. The molecular weight of the THF-soluble part determined by GPC was 2600. IR. and 1H NMR spectrum indicates that the polymer was composed of phenylene and oxyphenylene units. Thermogravimetry (TG) and differential scanning calorimetry (DSC) show the enzymatically synthesized polyphenol has high thermal stability properties. K, potassium naphthalene and dikalio benzophenone were attempt in turn in order to introduce PEO side chain and dikalio benzophenone was considered as the appropriatest initiator. The anionic ring-opening polymerization of EO was initiated by macromolecules initiator formed from polyphenol and dikalio benzophenone. The molecular weight of graft copolymer was 4400 and the GPC curve indicates that obtained copolymer was not homopolymer. UV-Vis spectrum shows that fluorescence characteristic of polyphenol was nearly not changed and the conductivity was not damaged according to the measured conductive value.