Chemical Characterisation of the Fracture Surfaces of Polyester Resin and a Polyester-Based Nanocomposite

A novel in situ fracture stage has been used to conduct micro-compact tension (micro-CT) tests within the preparation chamber of a time-of-flight secondary-ion mass spectrometry (ToF-SIMS) instrument. Tests have been undertaken in the usual ultra-high vacuum (UHV) conditions and in an ambient air atmosphere for comparison. A plain polyester resin system has been compared to an organically-modified silica (ormosil) nanoparticulate reinforced polyester resin nanocomposite. The force/displacement data are recorded permitting critical stress intensity factor, K IC, determination. Comparative surface analysis of the samples fractured in air and in UHV revealed that fracture in UHV prevented atmospheric contamination and adsorption of adventitious hydrocarbon material, particularly airborne silicone oils. This led to superior spectral quality and improved interfacial chemistry interpretation, and has allowed the development of a model of failure in which the integrity of the interface between nanoparticulate and polyester resin remains intact when failure occurs. Such an observation is extremely important given the current level of interest in the mechanical behaviour of systems of this type. Adopting such a methodology has enabled nanomodified polymer systems to be investigated, thus extending the potential application of ToF-SIMS as a useful fractographic tool in the field of nanocomposite analysis.