酸碱处理对制备再生桉木颗粒板的影响

废弃人造板中的胶黏剂影响人造板的回收利用。笔者利用化学法对废弃桉木颗粒板中的胶黏剂进行处理,分别探究不同浓度的硫酸、甲酸、硝酸、氢氧化钾分解废弃木颗粒板中脲醛树脂的最佳条件。结果表明,在90℃,水浴处理2 h条件下,甲酸浓度大于60%,硫酸浓度大于25%,或硝酸浓度大于25%可完全分解固化后的脲醛胶黏剂;对酸处理后的木颗粒的颜色、形貌、化学性质进行分析,甲酸对木颗粒的形态、颜色影响较小。用酸处理后制得的再生木颗粒板,力学性能相对于未经处理的再生木颗粒板得到显著提高。

Effect of Acid and Alkali Treatments on the Preparation of Regenerated Eucalyptus Particleboard

Adhesives in waste wood-based panels affect their recycling and reuse. In this paper, chemical method was used to treat the adhesives in waste eucalyptus particleboard. The optimal conditions for decomposition of urea formaldehyde resin in waste board by sulfuric acid, formic acid, nitric acid and potassium hydroxide were investigated respectively. The results showed that when the concentration of formic acid was greater than 60%, the concentration of sulfuric acid was greater than 25%, or the concentration of nitric acid was greater than 25%, the cured urea formaldehyde adhesive could be completely decomposed using a 90℃ water bath for 2 hours. The color, morphology and chemical properties of the regenerated particles after acid treatment were analyzed. Formic acid had little influence on the morphology and color of the wood particles. The mechanical properties of the regenerated particleboard prepared by acid treatment were significantly improved compared with the untreated regenerated particleboard.