碳水化合物作添加剂制木质刨花板的研究 Ⅱ糖的作用机理

Research on the reaction mechanism of molasses as a chemicaI additiVe in particleboard manufacture

本研究通过对以糖蜜为助粘剂制造的木质刨花板中木材糖基组成和糖蜜中游离单糖在热压条件下的转化情况和含量变化的研究,解释了糖在木质刨花板中产生胶合作用的方式。结果表明,在热压过程中木材表面化学活性增加,部分纤维素和半纤维素水解。这些水解单糖与糖蜜中的游离单糖均能转化成糠醛,与活化了的木素发生键合作用,生成树脂类化合物,从而达到胶合的目的。经红外光谱测定,在热压后,刨花表面化学基团发生变化,亲水性羟基官能团减少,僧水性羰基官能团增加,说明了糖蜜压制的刨花板具有良好耐水性的原因。这一结论为开发人造板的“无胶”技术提供依据。

This study is aimed to explain the bonding function of sugar in wood-based particleboard by investigating the composition of sugar in particleboard in which molasses acts as a chemical additive and the converting condition of free sugar and its change in quantity during hot pressing. The results shows that the chemical activity of wood surface is incressed during hot pressing and some hemicellulose and cellulose are hydrolyzed into single sugars. The sugars and molasses can be converted into furaldehyde. The furaldehyde can bond with lignin actived under hot pressing to form resinoid. By infrared spectroscopy examination, after pressing, the chemical functional groups of wood slip surface have changed. There are an increase in hydrophobic carhonyl groups and a decrease in hydropliclic hydroxidon groups. These changes of groups can explain the reason that the particleboard bonded with molasses has good waterproof ability.