Adhesion testing for texture analysis and materials testing

What is an adhesion test?

Adhesion is the force that resists the separation of two bodies in contact. An adhesion test measures the adhesive characteristics of a product by measuring the forces to separate the product from the test surface which it comes into contact with. Adhesiveness ('Stickiness') is most commonly measured with a cylinder probe, which is pressed (application of compression), onto the surface of the sample after which the force to pull the probe off it is measured. The higher the force to separate these surfaces, the more adhesive is the product. The distance the probe needs to be pulled away from the product before the two surfaces are separated will also indicate its viscoelastic behaviour, and depending upon the product, its ‘tailing’ or ‘stringiness’ characteristic.

The success of the measurement depends on the means of being able to hold the sample in order to pull away from it and measure the ‘withdrawal’. Stable Micro Systems has a wide range of solutions for the purpose of holding down a product in order to be able to successfully measure its adhesive properties. The operator is given the ability to control the data acquisition rate (2000pps advised for maximum detail collection from a quick test), the probe separation rate, the probe material and a controlled force to apply to the sample.

View a complete set of adhesion testing probe and attachment options

What happens during a typical adhesion test?

A test can be performed to assess internal stickiness – this normally uses a cylinder probe or blade that has a surface area smaller than the sample and thereby enters the sample and stickiness is measured upon withdrawal. For the measurement of surface stickiness the cylinder probe (larger or smaller) would not enter the sample, instead a special ‘adhesive test’ would be chosen whereby the force to contact the surface of the sample is chosen and held for a period of time before withdrawing the probe and measuring stickiness. 

For this 'adhesive test' stickiness (withdrawal forces) is displayed in the positive region of the curve whereas in a normal 'Return to Start' test a stickiness characteristic (if present) would be measured in the negative region of the curve.

There are tests available for the measurement of stickiness of the semi-solid sticky samples and additional options for the associated measurements of peel characteristics of a material from a substrate, for example:

To see how to perform adhesion tests using a TA.XTplusC Texture Analyser to measure adhesiveness, stickiness, tackiness, peel force etc., watch this video and see typical adhesion tests in action: