Durability of the wettability properties of a polypropylene film with a low-pressure CH4-O2plasma treatment

Surface Functionalization of Face Masks with Cold Plasma and Its Effect in Anchoring Polyphenols Extracted from Agri-Food

To improve the capability of non-woven polypropylene-based fabric (NWF-PP) used for face mask production to retain active biomolecules such as polyphenols, the surface functionalization of NWF-PP-directly cut from face masks-was carried out by employing cold plasma with oxygen. The nature/structure of the functional groups, as well as the degree of functionalization, were evaluated by ATR-FTIR and XPS by varying the experimental conditions (generator power, treatment time, and oxygen flow). The effects of plasma activation on mechanical and morphological characteristics were evaluated by stress-strain measurements and SEM analysis. The ability of functionalized NWF-PP to firmly anchor polyphenols extracted from cloves was estimated by ATR-FTIR analysis, IR imaging, extractions in physiological solution, and OIT analysis (before and after extraction), as well as by SEM analysis. All the results obtained converge in showing that, although the plasma treatment causes changes-not only on the surface-with certain detriment to the mechanical performance of the NWF-PP, the incorporated functionalities are able to retain/anchor the active molecules extracted from the cloves, thus stabilizing the treated surfaces against thermo-oxidation even after prolonged extraction.

The mechanism of adhesion and graft polymerization of a PNIPAAm thermoresponsive hydrogel to polypropylene meshes

In this study, a commercial and fully flexible monofilament mesh has been used for the deposition of a thermosensitive hydrogel, generated by graft copolymerization of N-isopropylacrylamide (NIPAAm) and N,N'-methylene bis(acrylamide) (MBA) monomers. The mechanism of adhesion and graft copolymerization have been elucidated combining micro- and standard spectroscopy techniques such as Raman spectroscopy, FTIR spectroscopy and XPS, before and after the activation of the polypropylene (PP) fibre surface by using oxygen-plasma. The good covalent interactions among NIPAAm monomers and PP fibres, and the hydrogel chain growth in such flexible bidimensional structures, were demonstrated. Additionally, the thermoresponsive properties of PNIPAAm were obtained (VPTT behaviour). The bilayer system is stable below and above a low critical solution temperature (LCST) of 33.2 °C.