Wood flour modified by hierarchical Ag/ZnO as potential filler for wood-plastic composites with enhanced surface antibacterial performance

- Nanostructured Ag, ZnO and Ag/ZnO decorations on wood flour carrier by MW synthesis.
- The growth of inorganic particles on WF surface and reaction mechanism explained.
- Best product by synthesis enhanced with additional ammonia reaction step.
- Model wood-plastic composite with excellent antibacterial performance compounded.
- Synergy effect of Ag and ZnO in Ag/ZnO microparticles on wood flour.

In order to extend application potential of wood-plastic composites (WPC) in interiors with respect to hygienic requirements, wood flour (WF) was modified by nanosilver, nanostructured ZnO and hybrid nanostructured Ag/ZnO surface decorations. A microwave assisted solvothermal synthesis method was employed starting from soluble precursors. Composition of source chemicals and synthesis protocol were intentionally varied to prepare different materials and elucidate the reaction mechanism. Obtained modified wood flour were compounded into a model PVC matrix to assess their antibacterial performance. The surface antibacterial activity was tested according to ISO 22196: 2007 (E) standard. Single silver or ZnO modified WF have significantly lower efficiency than hybrid Ag/ZnO decorating the surface of WF particles. A simple variation of the synthesis method by additional ammonia precipitation step increased largely the performance of the material and excellent efficiency comparable with contemporary medical grade materials was achieved, suggesting the great application potential of investigated systems in WPC-based materials.