No abstract

Physical cryogels were obtained using the successive freeze–thaw technique of poly(vinyl alcohol) (PVA)/poly(ethylene brassylate-co-squaric acid) (PEBSA) solutions. The cryogel systems were prepared by using two different molecular weights of PVA and PEBSA with three different ratios between the ethylene brassylate (EB) and squaric acid (SA) comonomers. The presence of interactions, the thermal properties and the morphology were investigated using Fourier Transform Infrared Spectroscopy (FT-IR), thermogravimetry (TGA and DTG) and scanning electron microscopy (SEM), respectively. The influence of the composition on the degree of swelling in a physiological environment was demonstrated. The study highlighted improvements in terms of new network flexibility due to the intermolecular chains interactions brought by the introduction of PEBSA in the cryogel structure. We also concluded that the presence of PEBSA in the PVA/PEBSA cryogel network improved the loading capacity of the new system with specific hydrophobic agents, for example essential oils, which (due to their antimicrobial character) can lead to the use of new systems obtained for various applications.

The inability to meet and ensure as many requirements as possible is fully justified by the continuous interest in obtaining new multifunctional materials. A new cryogel system based on poly(vinyl alcohol) (PVA) and poly(ethylene brassylate-co-squaric acid) (PEBSA) obtained by repeated freeze–thaw processes was previously reported and used for the incorporation of an antibacterial essential oil—namely, thymol (Thy). Furthermore, the present study aims to confer antioxidant properties to the PVA/PEBSA_Thy system by encapsulating α-tocopherol (α-Tcp), targeting a double therapeutic effect due to the presence of both bioactive compounds. The amphiphilic nature of the PEBSA copolymer allowed for the encapsulation of both Thy and α-Tcp, via an in situ entrapment method. The new PVA/PEBSA_Thy_α-Tcp systems were characterized in terms of their influence on the composition, network morphology and release profiles, as well as their antimicrobial and antioxidant properties. The study underlined the cumulative antioxidant efficiency of Thy and α-Tcp, which in combination with the PEBSA copolymer have a synergistic effect (97.1%). We believe that the convenient and simple strategy offered in this study increases applicability for these new PVA/PEBSA_Thy_α-Tcp cryogel systems.