Scratch resistance of polymers has been the subject of numerous studies, which have lead to specific definitions for plastic characteristic and fracture phenomena during scratch behavior. Viscoelastic and viscoplastic behavior during a scratch process has been related to dynamic mechanical properties that can be measured via dynamic nano-indentation testing. Yet, the understanding of the origin of the fracture process of a polymer during scratch remains approximate. Parameters like tip geometry and size, scratch velocity and loading rate, applied strain and strain rates, have been considered critical parameters for the fracture process, but no correlation has been clearly established.
The goal of this work was to analyze the scratch resistance and indentation properties of PMMA as a function of temperature. Compression and tensile properties from literature have also been compared to the scratch results for more complete understanding of the material's behavior.
The analysis of the evolution of the properties of PMMA at various temperatures, along with the evolution of the fracture toughness during scratch with temperature and scratch velocity has helped in identifying a correlation between the tensile stress-strain behavior and scratch fracture toughness for PMMA. This correlation brings a new understanding of the origin of the fracture mechanisms during a scratch process, and the strain effect on the fracture strength of PMMA.