ASTM D1037 Internal Bond Test Fiberboard and Wood Adhesives

This specific test is actually only one within ASTM D1037, the Standard Test Method for Evaluating Properties of Wood-Base Fiber and Particle Panel Materials. It specifies the material properties of chipboard, fiberboard, and particle board, which are engineered materials made by gluing wood chips or wood particles together with an adhesive under high pressure.  The internal bond test measures the tensile strength of the material when applying a force perpendicular to the face. The specific procedure is outlined in section 11 of the standard. This testing is especially important considering many of these materials are formed through the adhesion of multiple layers of material.

In principle, the test involves bonding specimen blocks to the top and bottom surfaces of the test specimen with a suitable adhesive. The upper loading fixture should be self-aligning, and the specimen blocks should be 2-inch square by 1-inch in thickness and made from steel or aluminum alloy. The loading fixtures, which grip the specimen blocks, are attached to the test machine and tension is applied perpendicular to specimen surface until the specimen fails. The only calculation required is for the tensile strength. The 3300 table top model is recommended for this testing along with the tensile testing blocks.

The challenges of testing to this standard are:

• Performing a tensile test according to the specifications of the standard
• Ensuring only axial loading
• Recording the required amount of data points to capture the delamination of the adhesive

Instron's Solution:

• Performing a tensile test according to the specifications of the standard- Instron Custom Solutions Group engineers have designed a tension fixture to adhere to the stringent requirements of the tensile blocks as stated in ASTM D1037
• Ensuring axial loading-The tensile blocks are attached to the frame using flexible couplings to ensure that only axial loading is being applied to the wood composite specimen
• Recording the required amount of data points- Bluehill^® Universal allows the user to adjust the data sampling rate of the software, up to 2.5 kHz in order to capture the most data points

It is important to review ASTM D1037 in order to fully understand the test setup, procedure, and results requirements.