| Summary: | 碩士 === 國立中興大學 === 森林學系 === 89 === SUMMARY
This study investigated the condition of liquefation of China fir (Cunninghamia lanceolata) and Tawain acacia (Acacia confusa) in phenol by acid(HCl and H2SO4) as catalyst. The variance changed in this study including weight ratio of phenol to wood, kind of catalyst and time of liquefaction.
Kind of catalyst, temperature and time of liquefaction were the most important factors influenced the effect of the liquefaction. If H2SO4 was used as catalyst with 5﹪concentration in phenol,the wood meal of China fir would almost completely dissolved after 60 minutes of liquefaction at reaction temperature of 130℃, but the liquefaction of Taiwan acacia would be curing at the same liquefied condition. If HCl was used as a catalyst with 10﹪concentration in phenol , it not only has good liquefaction efficiency after 60 minutes of liquefaction at reation temperature of 120℃, but also could liquefy at lower weight ratio of phenol to wood.
A part of phenol would combine with wood after the reaction of liquefaction. The liquefied wood using H2SO4 as a catalyst had larger amount of combined phenol than that using HCl as a catalyst.
Adhesive prepared from liquefied wood that used H2SO4 as a catalyst,had higher viscosity and short gel time, two exothermic peaks was observed in their DSC thermograms, one at lower temperature with sharp shape, the other at higher temperature with small and broad shape. Adhesive prepared from liquefied wood that used HCl as a catalyst, had lower viscosity and longer gel time, only one exothermic peak with flat and broad shape was observed in their DSC thermograms.
Adhesives prepared by liquefied wood using HCl as a catalyst had better bonding strength than using H2SO4 ,and could come up to the standard of CNS 1349 for type 1 plywood, when the P/W=3. In this study, when the hot-pressing temperature at 135℃ for 5 min,C-H-1 has the best bonding strength after repeated soaking in boiling water 15.6 kgf/cm2.
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