Roberto Canteri

Surface study of perfluoropolyether–urethane cross-linked polymers

A surface study of two different monocomponent polyurethane coatings containing perfluoropolyether macromers is presented. Different techniques were used in order to investigate the structural characteristics of the two polymers. In particular, transmission infrared spectroscopy provided information about the chemical groups and linkages present in the polymer network, and attenuated total reflectance spectra showed a higher concentration of urea groups close to the surface. X-ray photoelectron spectroscopy analysis at two different sampling depths showed clear evidence of fluorine enrichment and nitrogen depletion in the first nanometres of material with respect to the bulk composition of the two polymers. Analysis of the outermost layer by time-of-flight secondary ion mass spectrometry confirmed the XPS data with a predominant presence of fluorinated fragments. Contact angles of the two coatings with water and paraffins were measured and the critical surface tension of wetting, γc, was estimated (13–16 mN m−1 at 20 °C) and compared with the known data of other fluoropolymers. Copyright

Influence of olive (cv Grignano) fruit ripening and oil extraction under different nitrogen regimes on volatile organic compound emissions studied by PTR-MS technique

AbstractVolatile organic compounds of extra virgin olive oils obtained from the local Italian cultivar Grignano were measured by proton transfer reaction–mass spectrometry (PTR-MS). Oils were extracted by olives harvested at different ripening stages across veraison, performing each extraction step and the whole extraction process in nitrogen atmosphere to observe the changes in the volatile profiles of the oils. Principal component analysis carried out on the full spectral signature of the PTR-MS measurements showed that the stage of ripening has a stronger effect on the global definition of volatile profiles than the use of nitrogen during oil extraction. The fingerprint-like chemical information provided by the spectra were used to construct a heat map, which allowed the dynamical representation of the multivariate nature of mass evolution during the ripening process. This provided the first evidence that some groups of volatile organic compounds displayed a time course of regulation with coordinated increasing or decreasing trends in association with specific stages of fruit ripening. FigureInfluence of olive fruit ripening and oil extraction in nitrogen atmosphere on volatile organic compounds has been evaluated by means of PTR-MS and multivariate data analysis.