| Summary: | 碩士 === 國立中興大學 === 森林學系所 === 96 === In this study, wood of Cryptomeria japonica was liquefied in phenol or phenol/resorcinol mixture with H2SO4 as a catalyst. The liquefied wood or PF resin prepared from the liquefied wood were mixed with RF resin to prepare the polyblending resins. In addition, the liquefied wood was reacted with formaldehyde to prepare the liquefied C. japonica based-copolymers resins. The room-temperature setting properties, bonding strength and thermal properties of these polyblending resins and copolymer resins which containing the resorcinol were investigated. The results showed that using the mixture of phenol with resorcinol as a solvent had a worse liquefaction effect than phenol. Those liquefied products had a higher residue content and viscosity. The gel time of polyblend resins were more shortened as the rate of liquefied C. japonica or PF resin added into RF resin increased. The weight retention of cured polyblending resins after solvent resistance test was decreased for which blending with liquefied C. japonica, but it had not be influenced for which blending with PF resin. The TGA analysis of the cured polyblending resin showed that increasing the amount of liquefied wood added would decrease the heat-resistance. The polyblending resin prepared from RF resin blending with the liquefied wood S1 at a weight ratio of 50/50 had the bonding strength and wood failure conformed to the request of the CNS 11031 standard. On the other hand, the polyblending resin prepared by blending RF with liquefied wood S2, that liquefied with phenol/resorcinol cosolvent, had a good dry bonding strength at the weight ratio of RF/S2 of 30/70, but with a low wood failure. However, if the polyblend resin was prepared by blending RF with PF, both the bonding strength and wood failure could fit the request of CNS standard at the weight ratio of 30/70. When the phenol liquefied C. japonica was used to prepare the room-temperature setting copolymer resins, reacted the liquefied wood with formaldehyde in an alkali condition to form a resol-type PF resin, and then added the resorcinol to undergo the copolymerization would be a more suitable synthesis method. The gel time of this copolymer resin was substantially shortened than traditional PRF resins, and the cured copolymer resins had high weight retention at dissolve testing. The copolymer resin with 30% of resorcinol had bonding strength the same as traditional PRF resins. When phenol/resorcinol liquefied C. japonica was used to prepare the room-temperature setting copolymer resins, synthesized under acid condition using the method like for preparation the traditional RF resin would be more suitable. But the molar ratio of formaldehyde to liquefied wood should be set as 0.25/1. Wherein, the copolymer resin that prepared from the liquefied wood that with 50/50 of phenol/resorcinol as a solvent had the best dry and wet bonding strength.
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