| Summary: | 碩士 === 國立中興大學 === 森林學系 === 91 === Summary
In this study, China fir（Cunninghamia lanceolata）and Taiwan acacia（Acacia confusa）were liquefied in phenol using hydrochloric acid（HCl）or sulfuric acid（H2SO4）as a catalyst. The effects of wood species and catalyst on the properties of liquefied wood were investigated.The chemical structure of liquefied wood was analyzed through the Fourier transform-infrared（FT-IR）spectrum analysis. The liquefied wood was reacted with formaldehyde in alkaline conditions. The effects of synthesis conditions on the properties of PF resins and the feasibilities of plywoods and particleboards made with PF resins prepared from liquefied wood were also investigated .
The results are summarized as follows：The wood species and catalysts were the most important factors influenced the effect of the liquefaction. Liquefaction using H2SO4 as a catalyst was better than HCl and China fir was better than Taiwan acacia. FT-IR spectrum analysis showed that phenol could react with wood and changed the chemical structure of wood.PF resins prepared from liquefied wood that used H2SO4 as a catalyst had higher viscosity and shorter gel time than used HCl as a catalyst. The viscosity of PF resins decreased with increasing the NaOH/P molar ratio of synthesis condition. The gel time of PF resins extended as the NaOH/P and F/P molar ratio of synthesis condition increased. Differential Scanning Calorimetry（DSC）analysis showed that PF resins prepared from liquefied wood that used HCl as a catalyst had the same heatsetting properties beside A-H-4（Taiwan acacia；F/P:2.0；NaOH/P:0.4）,and they had similar DSC thermalgram and the highest temperature of exothermic peak. The bonding strength of plywoods made with PF resins prepared from liquefied wood that used HCl as a catalyst meets the requirement of CNS 1349 for type 1 plywood. But plywoods made with PF resins prepared from liquefied wood that used H2SO4 as a catalyst had worse bonding strength, especially wet bonding strength, only C-S-1（China fir；F/P:1.8；NaOH/P:0.4）comes up to the standard. Particleboards made with PF resins prepared from liquefied wood with higher F/P molar ratio, or made with higher hot-pressing temperature promotes the properties of particleboards.
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