单板层积材的加速老化性能研究

STUDIES ON THE PROPERTIES OF ACCELERATED AGING OF LVL

本文对高频胶合的马尾松LVL和杨木LVL的老化性能进行了讨论,并比较了乳液酚醛树脂胶和酸固化酚醛树脂胶在BDB28和A1080加速老化后的胶合剪切强度的损失率。得出的结论如下:1)乳液酚醛树脂肢胶合的马尾松LVL,胶合剪切强度随老化时间的延长逐渐趋于稳定,最后稳定在老化前强度的70％左右;2)乳液酚醛树脂胶的老化性能比酸固化酚醛树脂胶好;3)对于乳液酚醛树脂胶马尾松LVL和酸固化酚醛树脂胶杨木LVL,可以用BDB28处理方法代替A1080加速老化方法快速测定其胶合剪切强度的损失率。

The durability of LVL bonds made from Pinus massoniana and Populus euramericana under radio-frequency curing was discussed in this paper. The loss in wet bond shear strength of emulsified PF resin and acid-catalyzed PF resin was compared after BDB28 and A1080 accelerated aging test. The conclusions are as follows: 1)The bond shear strength of Pinus massoniana LVL bonded by emulsified PF declined gradually to a constant value,about 70% of the previous strength. 2) The performance of emulsified PF is much better than that of acid-catalyzed PF when LVL is under accelerated aging test. 3)For Pinus massoniana LVL bonded by emulsified PF and Populus euramericana LVL bonded by acid-catalyzed PF,the loss of bond shear strength of LVL can be measured with BDB28 method instead of A1080 accelerated aging test.