Recycled Materials Pave the Way for Sustainable Biocomposites

New research has demonstrated how recycled wood-polymer composites (WPCs) and textiles could be the key to more sustainable materials. Through innovative methods for creating biocomposites, the study contributes to a circular economy and reduced environmental impact

"This is an important step towards reducing dependence on fossil-based raw materials," says Luísa Völtz, PhD student in Wood and Bionanocomposites at Luleå University of Technology.

Biocomposites, materials in which natural fibers reinforce plastics, have become an increasingly popular alternative to traditional synthetic materials. In her dissertation, Luísa Völtz investigated reprocessing of WPCs and how recycled fibers from discarded textiles can be integrated into these composites to create more resource-efficient and environmentally friendly solutions.
"What we’re seeing is that recycled materials can not only replace virgin materials but also provide better properties in certain contexts," explains Luísa Völtz.
By using a co-rotating twin-screw extruder, an efficient method for melting and blending materials, she studied the effect of recycling in WPCs and how textiles from discarded clothing can be reused in new ways.

Luisa Völtz, PhD student in Wood and Bionanocomposites at Luleå University of Technology.

Can Compete While Reducing Fossil Resource Consumption

In one of the projects, recycling of WPCs was tested. The material underwent nine recycling cycles, and while the strength of the WPCs decreased over time, the material still retained better mechanical properties than virgin plastics.
"This shows that recycled WPC can compete with new plastic materials while also reducing our consumption of fossil resources."
Another project focused on textile recycling, where a new method was developed to integrate textile fibers into plastics with minimal energy input. The results showed that fibers from discarded clothing, such as viscose, cotton and silk, can be used to create high-quality biocomposites. For some biodegradable materials, like Bio-flex, the fibers not only improved strength but also enhanced the material’s processing properties.

Contributing to a Circular Economy

A particularly interesting result was that both recycled textiles fibers and elastomers proved to be excellent substitutes for virgin elastomers in WPCs. This reduced both the carbon footprint and production costs.
"It’s a tangible way to reduce competition for limited resources while contributing to a circular economy," says Luísa Völtz.
The research opens doors to broader industrial applications for recycled materials and strengthens Sweden’s position as a leader in sustainable material development. By focusing on solutions that reduce waste and value resources at the end of their life cycle, Luísa Völtz hopes to inspire more sustainable innovations.
"My goal is to show that sustainability and high performance can go hand in hand," concludes Luísa Völtz.

• Wood and bionanocomposites