桉木单板背面裂隙率对胶合板性能的影响

Effects of Veneer Back Cracking Rates of Eucalypt Woods on Performances of Plywoods

为给胶合板生产过程的组坯工艺优化提供理论依据,采用图像处理技术与宏观力学性能试验相结合,分析桉木单板背面裂隙率对胶合板性能的影响,探讨桉木单板背面裂隙率与胶合板性能的相关性。结果表明,不同单板背面裂隙率下,干状、冷水浸泡24 h和热水浸泡3 h胶合板的胶合强度及顺纹静曲强度均差异极显著,横纹静曲强度、横纹弹性模量和顺纹弹性模量均差异不显著。随单板背面裂隙率增大,胶合板在3种条件下的胶合强度、顺纹静曲强度和顺纹弹性模量均呈下降趋势。相关性分析表明,单板背面裂隙率与干状胶合强度、冷水浸泡24 h胶合强度和顺纹静曲强度均呈极显著负相关,与顺纹弹性模量呈显著负相关。单板背面裂隙率对胶合板性能的影响表现为冷水浸泡24 h胶合强度>干状胶合强度>顺纹静曲强度>顺纹弹性模量>热水浸泡3 h胶合强度>横纹弹性模量>横纹静曲强度。

In order to provide theoretical basis for optimization of lay-up process in production of plywoods,effects of veneer back cracking rates of eucalypt woods on performances of plywoods were analyzed by using image processing technology in combination with macro-mechanical performance test.Correlations among veneer back cracking rate of eucalypt woods and performances of plywoods were discussed.Results showed that among different veneer back cracking rates,there were extremely significant differences in bond strength of dry state,bond strength of soaking in cold water for 24 h,bond strength of soaking in hot water for 3 h and modulus of rupture parallel to grain of plywoods and there were no differences in transverse modulus of rupture,transverse modulus of elasticity,and modulus of elasticity parallel to grain.With increase of veneer back cracking rates,bond strengths of three conditions,modulus of rupture parallel to grain and modulus of elasticity parallel to grain showed trends of decrease.Correlation analysis showed that veneer back cracking rates had extremely significantly negtive correlations with bond strength of dry state,bond strength of soaking in cold water for 24 h and modulus of rupture parallel to grain of plywoods,and had significantly negative correlation with modulus of elasticity parallel to grain.Effects of veneer back cracking rate on performances of plywoods were bond strength of soaking in cold water for 24 h>bond strength of dry state>modulus of rupture parallel to grain>modulus of elasticity parallel to grain>bond strength of soaking in hot water for 3 h>transverse modulus of elasticity>transverse modulus of rupture.