Plant waste as green reinforcement for polymer composites. A case study of Pteris vittata roots

Pteris vittata is a hyperaccumulator fern able to uptake arsenic by roots accumulating it in the fronds. Recent studies showed that Pteris vittata can be used efficiently for arsenic-contaminated water treatment, paving the way for long-lasting decontamination strategies established on nature-based solutions. This raises the issue of biomass disposal, which rather than being incinerated could represent a valuable untapped source of fibers for sustainable and higher-value biocomposites. Here, Pteris vittata waste roots were collected and used to develop composites based on high-density polyethylene. Composites with two amounts of filler (10 wt.% and 20 wt.%) added with 5 wt.% of maleic anhydride grafted polyethylene, were manufactured and tested in terms of mechanical and thermal properties. Mechanical property analysis showed that, compared to neat high-density polyethylene, composites at 20 wt.% filler content with coupling agent displayed an increase around 54% in tensile strength, 100% in Young's modulus, 46% in flexural strength and 45% in flexural modulus. These results demonstrate the potential of Pteris vittata waste roots application for sustainable composite materials production.