Controllable hydrolytic stability of novel fluorinated polyurethane films
A series of polyester-based and polyether-based polyurethane films with fluorinated side chains were synthesised in the study, and the chemical structure of these products was verified using the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) techniques, nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). The hydrolysis of fluorinated polyurethane films was explored via immersion in deionised water at different temperatures, and corresponding hydrolysis process was detected by GPC, scanning electron microscopy (SEM), weighting and tensile tests.
Better hydrolytic resistance
The results revealed that the incorporation of fluorinated side chains could reduce the surface free energy and enhance the hydrolytic stability of fluorinated polyurethane films; the loss of molecular weight and tensile properties of fluorinated polyurethane films was suppressed during temperature-accelerated hydrolysis due to the hindrance effect of fluorinated side chains and increased van der Waals forces and hydrogen bonding. Compared with fluorinated polyester-based polyurethane films, the fluorinated polyether-based polyurethane films exhibited a better hydrolytic resistance. According to the researchers, fluorinated polyurethanes with enhanced anti-hydrolysis performance can potentially be applied to reduce environmental pollution.
The study has been published in Progress in Organic Coatings, Volume 165, April 2022.