Wood fibre could hold the key to recycling and upcycling billions of products – not only in the construction industry but also in the household and automotive industries.
Now, scientists are turning to waste wood power—or wood ash—to create fully recyclable products out of wood-plastic composites (WPC) to fuel construction across the Asia Pacific region, responsible for more than 30% of WPC-based building projects worldwide.
WPC is a manufactured process that combines up to 80% of wood fibres—offcuts from the sawmilling process—into a plastic matrix. To date, most studies have focused on projects in the construction industry; however, a range of new studies are also looking at the potential for WPC as a packaging material.
The market for WPC is enormous, and with wood consumption expected to rocket to 2.2 billion cubic metres over the next five years, material scientists are now looking to add value to a massive supply of wood powder.
Which, when combined with recycled plastics and demolition waste, could be used in engineering and reconstituting disused materials into new products.
Published last week, Upgrading mixed plastic wastes to prepare wood plastic composites via solid mechanochemical method, Chinese scientists are now using advanced manufacturing systems to pulverise wood powders into plastic wastes, creating a new generation of wood-plastic composites (WPC), which are far more robust than previous generations.
WPC is crucial to China’s push to drive construction both inside China and across the Global South. The current market, worth US $6.41 million, is expected to grow 11.6% annually over the next decade. China is investing heavily in new tech as it grapples with a fourfold increase in timber demand over the coming thirty years.
However, until now, the vast majority of manufacturers have avoided recycled waste, given problems with material collection and handling and the unstable nature of recycled materials.
Led by Qingquan Jiang from the Polymer Research Institute of Sichuan University, Professor Jiang said, “Wood fibres exhibit excellent mechanical properties, low density, and high plasticity.” Before adding that “most recycled wood fibre blends have poor strength, often exhibiting “poor interfacial compatibility with most hydrophobic polymers.”
That’s when the scientists used a new type of solid-state shear milling (S3M) equipment inspired by Chinese stone milling. This equipment provides greater reinforcement to the material, exerting a stronger squeeze and shearing over the milling materials.
The study, backed by the Chinese Government, found that “S3M technology has the potential to industrialise the recycling of wasted wood fibres and plastics,” with Professor Jiang stressing the “crucial role in facilitating the high-value utilisation of waste wood powder fibres and mitigating plastic pollution.”
The result is that “solid-state shear milling (S3M) is an effective strategy to improve interfacial compatibility” between mixed recycled plastics and wooden fibres, with the mechanically induced pulverisation “favourable in preparing highly-filled (structurally sound) WPC.”
