Price, D.M.; Reading, M.; Hammiche, A.; Pollock, H. M.; Branch, M. G.; Localised thermal analysis of a packaging film. Thermochimica Acta 332(2) (1999) 143-149
A scanning probe microscope fitted with a fine platinum wire active heating element was used to examine the topography of a 300 µm thick cross-section of a seven layer polyolefin laminate designed for a food packaging application. Localised thermomechanical analysis was carried out by positioning the probe over selected regions and heating the wire whilst detecting the change in cantilever deflection using the microscope stage. Different grades of polyethylene and a poly(ethylene-co-vinyl alcohol) barrier layer could be identified from their softening behaviour at a spatial resolution of 10 µm or better - even in cases where there were no obvious changes in image contrast.