木材及木基材料吸湿尺寸稳定性检测方法研究

为实现木材及木基材料吸湿尺寸稳定性横向比较,规范其检测方法,依据现有相关检测标准,借鉴日本工业木材吸湿尺寸稳定性检测方法,结合木质材料特性以及我国的具体情况,提出一种木材及木基材料吸湿尺寸稳定性的检测方法,即以温度20℃、相对湿度65%条件下的材料尺寸为基准,测定在温度40℃、相对湿度为75%和90%的两种吸湿环境条件下的材料尺寸变化。通过该方法对柚木、印茄木、朴木3种不同尺寸的木材和对多层材料、高密度纤维板、普通刨花板3种木基材料的吸湿尺寸稳定性进行测定,以评价该方法的适用性和可行性。结果表明:木材与木基材料试样不超过12 d即可达到吸湿平衡,不同材料尺寸变化率、湿胀系数的大小关系也与实际情况一致。因此木材与木基材料试样均适于用该方法。

Study on the Measuring Method for the Hygroscopic Dimensional Stability of Wood and Wood-based Materials

In order to achieve horizontal comparison of moisture absorption dimensional stability of wood and wood-based materials,standardize their testing methods,this paper drew on the Japanese industrial wood moisture absorption dimensional stability testing method,was based on the relevant testing standards of existing solid wood and wood-based materials and combined with the characteristics of solid wood and wood-based materials and the specific conditions of China,proposed a method incorporating with solid wood and woodbased materials moisture absorption properties evaluation.Specifically,the method was set to measure the dimensional change of wood samples under the two moisture absorption conditions of temperature 40℃,relative humidity 75%and 90%based on the temperature of 20℃and 65%relative humidity.In our experiment,three kinds of solid wood materials,including teak,merbau,and pudding,and three kinds of wood-based materials,including multi-layer materials,high-density fiberboard and ordinary particleboard,were detected using the above method,in order to evaluate the applicability and feasibility of the method.Results showed that the solid wood and wood-based materials can reach the moisture absorption balance less than or equal to 12 days.The relationship between the dimensional change rate and the wet expansion coefficient of different materials was also consistent with the actual situation.As a result,wood samples of different sizes and wood-based material samples were both suitable for the proposed method.