| The research focus on the liquefaction of Chinese Fir(Cunninghamia lancedata(Lamb)Hook.) and Poplar wood(Populus×euramericana(Doda)Guineir cv.'I-214')by phenol in the presence of sulfuric acid used as a catalyst. The effects of reaction time, temperature, phenol-to-wood ratio and catalyst concentration on the phenolation extents were determined. By means of gel permeation chromatography analysis, the molecular weights and molecular weight distributions of liquefied wood obtained under various liquefaction conditions were investigated in order to trace the change in the structural characteristics of the liquefied wood. Adhesive resins were prepared from liquefied wood in a meliorative manner to phenolic resin preparation. The influence of residue contents of liquefied wood and different molar ratios of formaldehyde to phenol on and / of liquefied Chinese Fir and Polar wood resins were investigated. Glue strength and wood failure were measured according to GB/T 17657-1999 4.15 and GB/T 17657-1999 (appendix A).1,Reaction time is one of the most important factors of wood liquefaction. The residue contents of liquefied Chinese Fir and Poplar wood decrease with increasing reaction time and become consistent when reaction time arrives a reasonable level. The and / of liquefied Poplar wood and / of liquefied Chinese Fir wood decrease first and then increase with the addition of reaction time. But the of liquefied Chinese Fir wood just increases as reaction time is prolonged.2,Reaction temperature has great influence on the rate of liquefaction and the molecular characteristic of liquefied Chinese Fir and Poplar wood. Increasing reaction temperature can accelerate the phenolation of wood. With the elevation of reaction temperature, and / of liquefied Chinese Fir and Poplar wood decrease at low temperature region slightly then increase at high temperature region. 3,Liquid ratio shows great effect on the rate of liquefaction. Residue contents of liquefied products are more sensitive in the lower liquid ratio region. Liquid ratio also affects the molecular characteristic of liquefied Chinese Fir and Poplar wood. and / become lower and narrower respectively in the higher liquid ratio region. With increasing the liquid ratio, and / become more and more smaller.4,Reaction temperature depresses effectively under the catalysis of sulfuric acid. The residual contents of liquefied Chinese Fir and Poplar wood decrease with increasing the concentration of sulfuric acid catalyst. But the and / become lager and broader respectively when more and more catalyst is used.5,The critical reaction time depend on reaction temperature, liquid ratio and catalyst concentration of liquefaction . It can be considered as one of the parameters affecting the liquefaction efficiencies of wood. The critical reaction time of Chinese Fir and Poplar wood decreases with increasing the reaction temperature, liquid ratio and catalyst concentration of liquefaction.6,The results of resinification of liquefied Chinese Fir and Poplar wood illustrate that resinificatied reaction become apparently homogeneous when prolonging the reaction time of low temperature region, increasing the contents of sodium hydroxide and decreasing its concentration can enhance the solubility of liquefied wood resins and lower their viscosities, adding formaldehyde totally at the beginning of the reaction can predigest operation procedure and shorten reaction time. The liquefied Chinese Fir and Poplar wood resins prepared by new formulation and method are brown muddy liquid, with viscosities of 666 mPa·s and 713 mPa·s, pH value of 11.47 and 11.36, solid contents of 52.7% and 52.9%, curing time of 232s and 200s, free formaldehyde contents of 0.23% and 0.22%, free phenol contents of 0.81% and 0.56%. 7,The viscosities of liquefied Chinese Fir and Poplar wood resins increase with the improving of residue contents of liquefied products. The resins prepared by liquefied wood without residue have lower viscosity, higher solid contents,...
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