Scratch behavior of model epoxy resins with different crosslinking densities

The scratch behavior of model epoxy resins with varying degrees of crosslink density was investigated according to the ASTM D7027/ISO 19252 scratch test methodology. Three model epoxy systems with low, medium, and high crosslinking densities were prepared to systematically investigate how the scratch behavior might be influenced. The effect of crosslinking density on the onset of groove, crack and plowing formation during scratching was investigated. Coefficient of friction measurements, uniaxial tensile and compressive stress-strain curves, and dynamic mechanical analyses were conducted to correlate the intrinsic material properties to the observed scratch-induced deformation of the model epoxy systems. The findings indicate that the scratch behavior of epoxy resins can be directly correlated to their material properties. It is found that both the tensile strength and compressive yield stress determine the resistance against damage formation during scratch. Additionally, a comparison between pencil hardness and scratch test is presented to assess the suitability of both methods for evaluating scratch performance of polymers with significantly different mechanical properties. [Display omitted] •The mechanical properties and scratch resistance of epoxy model systems are significantly influenced by their crosslinking density.•Both the tensile strength and compressive yield stress determine the resistance against damage formation during scratch.•Lightly crosslinked system shows an early crack formation due to its low yield stress causing high frictional forces to develop.•Pencil hardness test results are inconsistent, poorly link to intrinsic material properties, and can be easily influenced by external factors.