Polyurethane elastomer-based composites containing innovative hybrid fillers with tailored mechanical properties and enhanced bioactivity

The study presents previously unreported line of the research concerning preparation of polyurethane elastomer-based composites containing newly synthesized hybrid fillers of CuO-ZrO₂ and ZnO-ZrO₂ type. The idea behind the selection of materials was dictated by the mechanical durability of ZrO₂ as well antimicrobial activity of ZnO and CuO. The first stage of experimental approach included synthesis of hybrid fillers utilizing a modified sol-gel method which enables the formation of materials with expected chemical composition, unique morphological and structural characteristic as confirmed by micrometric-sized particles and parameters of the porous structure (A_BET = 260 m²/g, V_p = 0.24 cm³/g, S_p = 4.7 nm for CuO-ZrO₂ and A_BET = 210 m²/g, V_p = 0.12 cm³/g, S_p = 4.6 nm for ZnO-ZrO₂). Polyurethane-based composites were synthesized using a one-step method under variable parameters such as filler type and its percentage contribution. Such an assumption allowed to evaluate the impact of fillers addition on polyurethane composites functional properties. Detailed materials characterization confirmed that the prepared composites (especially those containing 5.0 wt% of CuO-ZrO₂) exhibit enhanced mechanical properties with reduction of abrasion by approximately 22 %, an increase of maximum stress by 27 % and an improvement in breaking strength by as much as 156 % compared to the reference sample – which should be considered as an outstanding result. The final stage included antimicrobial tests that confirmed high microbiological purity and antimicrobial activity of composites at the point of contact. Demonstrated antimicrobial properties are of utilitarian nature and provide a perspective for a possible extension of the durability and multi-directional usefulness of products consisting of such materials.