木材界面液化的自胶合工艺参数对胶合性能的影响

针对木材的自胶合,引入溶剂催化液化法,以杨木和桉木单板为原料,进行了界面液化自胶合试验。分析了液化剂种类(苯酚、丙三醇)、涂布量(150、300、450 g/m2)、热压温度(125、150、175℃)、热压时间(10、15、20min)和树种(杨木、桉木)5个因子对胶合剪切强度的影响。结果表明:利用液化方法在木材表面构造黏稠过渡层以取代木材界面,实现木材的自胶合在技术上完全可行;单板树种对液化胶合性能有明显影响,在试验的工艺条件下,桉木的胶合性能优于杨木;丙三醇液化胶合性能高于苯酚;热压温度和时间对苯酚液化胶合性能的影响不明显,而对丙三醇影响明显。建议就木材界面液化自胶合的机理开展进一步深入研究。

Technics of Wood Self-adhesion by Interfacial Liquefaction

Acid-catalyzed liquefaction of poplar and eucalyptus wood veneers was conducted for self-adhesion experiment.Effects of 5 processing factors,i.e.liquefaction agents(phenol and glycerol),content(150,300 and 450g·m-2),hot-pressing temperature(125,150 and 175 degrees C),time(10,15 and 20min),and wood species(poplar and eucalyptus),on bonding strength of veneer samples were specifically analyzed.Liquefaction of two wood veneers produced between a sticky transient interfacial layer,which was demonstrated to be technically feasible to bond the two adherent veneers.Wood species had an obvious effect on bonding performance of two surface-liquefied veneers,and the eucalyptus veneers showed higher bonding strengths than the poplar ones.Glycerol-liquefied veneers presented higher bonding strengths than veneers liquefied by phenol.Both hot-pressing temperature and time had significant effects on the self-adhesion of glycerol-liquefied veneers,while had no evident influence on veneers liquefied by phenol.Suggestions on the mechanism of wood self-adhesion by interfacial liquefaction were also given.