Test MethodApplication of indentation fracture mechanics approach for determination of fracture toughness of brittle polymer systems

The analysis of cracks formed close to hardness impressions is a part of the current trend which deals with the development of simplified approaches for determination of fracture mechanics parameters of brittle polymer materials. However, up to now only very limited experimental knowledge exists of how to calculate the fracture toughness of these materials based on indentation fracture mechanics. Within the scope of this work, fracture toughness values for polymethyl methacrylate (PMMA) and polystyrene (PS) determined on the basis of a method proposed by Laugier have been found to be in good agreement with conventionally determined values. Furthermore, the fracture toughness of a number of other materials such as PMMA/SiO2 nanocomposites and syndiotactic PS has been determined using this Laugier approach.