An overview of some scaling issues in the sample preparation and data interpretation of the microbond test for fibre-matrix interface characterisation

The microbond test has been widely adopted by researchers seeking to characterise the fibre-matrix interface in polymer composites. This test requires the preparation of polymer droplets with a mass as little as 20 ng. This brings with it the possibility of scaling issues causing unanticipated significant differences to the properties and performance of these droplets in comparison to macroscale samples. This paper reviews a number of these potential scaling issues in a range of polymer systems which users of the microbond test should be aware of. Some of these phenomena can affect the magnitude of the test results obtained much more than the fibre-matrix interface effects which the test is used to detect. It is concluded that in many cases the structure and properties of the polymer in such microdroplets is not representative of the same polymer, with the same thermal and environmental exposure history, prepared on the macroscale