木材液相乙酰化的研究

<正>木材的结构和化学组成,决定了它的吸湿性和易遭腐朽、虫蛀。这是木材的两个主要缺点,严重影响其利用。 木材乙酰化是一种化学改性处理。它是木材成分的酯化反应。所采用的乙酰剂与木材分子上的羟基起作用,疏水性乙酰基取代了亲水性羟基。由于乙酰基的引入导致膨体(增积)作用,使木材具永久尺寸稳定性。乙酰化的木材,对真菌具抗性,且无毒;木材多孔性不变,材色鲜艳悦目。所以,它是提高木材使用价值的重要途径之一。 成材的乙酰化用液相处理,必须清除处理后木材中残留的乙酰剂,然而在气相乙酰化中,则些道工艺可以减免。但它不适用于处理厚尺寸木材。我们对液、气两相乙酰化分别进行了试验,都作了尺寸稳定性和乙酰基含量等方面的测定。 本文是液相处理的研究结果。试验中,为降低工艺利用时的成本,还进行了剩余反应液的测定。各项测定均得到肯定的结果。

A STUDY ON LIQUOR PHASE ACETYLATION OF WOOD

Excellent effects of treatment can be obtained by acetylation carried out in the liquor phase without catalysts.Dimensional stability measurements of 3 species (Finns massoniana, Lamb., Fraxinus mandshurica, Rupr. and Tilia amurensis, Rupr.) indicated: 1 ) Anti-shrink efficiencies (ASE) 60.40-86.77 per cent, 2 ) Equilibrium moisture content decreased by as much as 50.80 to 72.77 per cent, 3) After conditioning at 35 c and 50 per cent relative humidity for a week, change of moisture content reduced by 53-79 to 72-77 per cent and swelling reduced by 52.79 to 76.96 per cent.Under the treatment conditions used, it was the difference between wood species rather than the ratios between acetic anhydride and wood that made a much more important effect.The colour of the wood treated was more bright than natural. The porosity of wood was not changed.The remaining solution was analysed after the reaction had been finished. Results indicated that it still contained acetic anhydride at an amount of 20.80 to 21.60 per cent, which can be used again.