Caffeine-treated wood as an innovative filler for advanced polymer composites

Polymer composites, based on the wood flour originating from an invasive black cherry (Prunus serotina Ehrh.) treated with caffeine to achieve increased bio-resistance, were obtained in this study. The caffeine-treated wood had a significant effect on the supermolecular structure of polymer matrix, resulting in a high content of polymorphic β-PP phase, as well as an increase in nucleation activity of wood surface. The caffeine treatment of wood was an effective method of achieving increased resistance of composites to selected fungi and bacteria while maintaining good mechanical strength and thermal resistance. Addition of black cherry wood to polymer matrix induced inhibition of the release of volatile organic compounds. Increased resistance to fungi and bacteria depended on formation a significant amount of the β-phase up to 35% in the composite with 30% of caffeine-treated wooden filler and a simultaneous decrease in crystallinity from 52% for pure PP to 45% for mentioned composite.