Preparation and characterization of UV‐curable acrylic membranes embedding natural antioxidants

We examine the behaviour of acrylic resin‐based membranes containing natural antioxidants, such as Galla Chinensis tea powder extract (TP) and Taiwanese green propolis (TGP), in different concentrations ranging between 5 and 20 wt %. Membrane morphology was investigated by means of Environmental Scanning Electron Microscopy (ESEM), while the UV‐curing reaction was monitored by Fourier‐Transform Infra‐red (FTIR) spectroscopy. In most cases Thermogravimetric (TG), Differential Scanning Calorimetric (DSC) and Dynamo‐mechanical Thermal (DMT) analyses showed that the desirable characteristics of the UV‐cured acrylic resin are not substantially altered by the presence of the organic fillers. The release kinetics of polyphenols and flavonoids, determined in water for TP‐containing membranes (ETx) and in ethanol/water mixture (7:3 v/v) for TGP‐containing ones (EPx), was satisfactory, reaching a plateau after 24 h. Finally, preliminary antibacterial tests against S. Epidermidis were performed on the membranes with higher additive amount and gave positive results for ET‐type; on the contrary, no inhibitory effect was observed for the tested EP‐type membranes.