Dimensional stability test of modified wood

Modified wood is wood that improves or changes the physical, mechanical, and chemical properties of wood through physical or/and chemical processing methods. Dimensional stability refers to the ability of wood to maintain its original size and shape under conditions of temperature or/and humidity changes. The modified wood dimensional stability test can determine the dimensional stability of modified wood.
Zhongke Testing Reliability Experiment Center has reliability testing capabilities for various types of wood, and provides professional dimensional stability testing and other reliability testing services for modified wood products.

modified wood has undergone wood acetylation, wood heat treatment, wood compression and bending, wood bleaching and staining, including heat-treated wood, resin chemical wood, acetylated wood, etc.

1. Prepare one set of unmodified wood and modified wood samples. The two sets of samples were subjected to humidity conditioning treatment at a temperature of (20±2)°C and a relative humidity of (40±5)% until the mass was constant (the mass difference between the two weighings 24 h apart is considered to be constant if the mass difference is less than 0.1% of the mass of the specimen). The radial, chordal and longitudinal dimensions were measured to an accuracy of 0.001 mm.
2. Put a group of unmodified wood and modified wood samples after conditioning into a constant temperature and humidity chamber with a temperature of (20±2)°C and a relative humidity of (65±5)% for wet treatment. After no less than 480 hours, take out the specimens, use clean degreasing gauze to absorb the surface moisture, and then measure the size again at its original measurement position, accurate to 0.001 mm.
3. Put the unmodified wood and modified wood specimens after the test into the oven together. After drying at a temperature of (103±2)°C for 8 hours, select 3 samples and weigh them once. Then weigh the selected samples every 2 hours. When the difference between the last two weighings does not exceed 0.5% of the sample mass, the sample is considered to be completely dry, accurate to 0.001 g.
Use dry tweezers to remove the specimen from the oven, place it into a weighing bottle in a glass desiccator filled with desiccant, and close the weighing bottle and desiccator cap. After the sample is cooled to room temperature, use dry tweezers to take it out of the weighing bottle and weigh it, and measure the absolute dry weight of the sample.
If the sample is wood containing a lot of volatile substances (resin, gum, etc.), in order to avoid excessive errors in the absolute dry weight measured by the oven drying method, the vacuum drying method should be used instead.

LY/T 2490-2015 Test method for dimensional stability of modified wood
GB/T1928-2009 General principles of physical and mechanical testing methods for wood
GOST 25579-1983 Modified wood - Method for determination of dimensional stability
BS EN 1910-2016 Timber, parquet and timber paneling and cladding Determination of dimensional stability
EN 1910-2016 Timber, parquet and timber paneling and cladding Determination of dimensional stability