Tissue adhesives are widely used in the biomedical industry for applications such as bandages, secondary dressings, and wound closure. Although there are no specific standards that address testing using a variable angle fixture, other similar ASTM standards for this test method include: ASTM F2255, F2256, F2258 and F2458. The adhesive strength of these products must be clearly defined before put to use in a clinical setting. If the adhesive is not strong enough, the product may lead to infection or poor healing. If the adhesive is too strong, the underlying tissue may become damaged upon removal.
We conducted one example of an adhesive test by using a variable angle fixture that would simulate the action of peeling the adhesive off a patient. We used a 3345 electromechanical test frame configured with a 50 N load cell, a single 250 N capacity pneumatic grip with 25 mm x 25 mm flat metallic faces, and the variable angle peel fixture for this test. The variable angle peel fixture was set at a 135° angle, to best simulate the line of pull that would be seen during normal use of the adhesive product. We used leather as the substrate during this test to best simulate the surface properties of human skin.
The 3 Peel, Tear and Friction Software Module®Bluehill is highly recommended for this type of test. This software module allows for measurement of the first peak load, average load and average load per width, the most commonly used calculations.