Characterization Of Furfural Residue Lignin Structure And Optimization Of Manufacture Craft Of PF Resin Adhesive Modified By Furfural Residue Lignin

In this report, different organic solvents were used to extract lignin from furfural residue at various conditions under ultrasound and microwave irradiation. The filtrate was collected and concentrated at reduced pressure, and the lignin was precipitated with H2SO4 by adjusting pH to 1.5-2.0. The chemical structure of the different lignin preparations were comparatively studied by ultraviolet-visible spectrophotometer (UV-VIS), Fourier transform infrared spectrometer (FT-IR), gel permeation chromatograph (GPC), nuclear magnetic resonance (NMR) as well as thermogravimetric analysis (TGA).Analyses suggest that under the same condition of microwave irradiation extracting, sets of adding 70% alcohol,1% NaOH and 90% dioxide,1% NaOH exhibit better properties than others. In the former treating condition, the optimum ultrasound irradiation extraction condition is:treating temperature no higher than 30?, power of 380W and time of 40min; for the latter one, the optimum ultrasound microwave extraction condition is:treating temperature of 80?, power of 500W, time of 2h.In addition, although water bath treatment also acquires equivalent results,it costs much longer time.Finally, the lignin-phenol-formaldehyde resin adhesives were prepared with obtained furfural residue lignins, and the optimum conditions were:lignin substitution rate of 40%,20% amount of NaOH (based on the weight of phenol and lignin), F/P=1.8 (mole ratio), the reaction time of 2.5 h. The properties of adhesives are:viscosity of 287.70 mPa.s, pH=11.54, solid content of 53.24%. The performances of plywood made by the optimum conditions are:bonding strength of 1.057 MPa, formaldehyde emissions of 0.261 mg/L, reached the requirement of first grade plywood and the limitation of Eo grade of National Standard GB/T 9846-2004, respectively.