The poplar sector also advances toward the circular economy

ProPopulus Team

Moving toward a more circular economy is one of the challenges of the European Union for the next decade. Succeeding in replacing the current linear economic system with a circular one could generate many benefits for society.

According to the European Parliament, along with other benefits, we could also reduce pressure on the environment. In addition, security in the supply of raw materials would be improved, increasing competitiveness and stimulating innovation.

The EP also points out that moving towards a circular economy would boost economic growth (an additional 0.5% of gross domestic product) and job creation (700,000 jobs in the EU alone by 2030).

Linear versus circular

The linear economy is the traditional model where to manufacture products, raw materials are extracted, processed, and transformed into products. Then, these products are discarded, without considering the environmental footprint and its consequences.

Circular economy, on the other hand, encompasses the economic, technical, and environmental systems that aim to eliminate waste while maximizing the reuse of resources.

A virtuous circle

Circular systems use design, recycling, reuse, remanufacturing, and restoration to create a closed-loop system. They are based on the idea of ​​preserving ‘virgin’ materials, reducing waste generation, and maximizing waste reuse.

Virgin materials are unused raw materials, which have never been subjected to any other processing than for their production, such wood or metallic minerals.

Manufacturing products from virgin materials use more natural resources than producing goods from recycled materials.

Closing the waste cycle and recovering waste has never been more critical. This is because continued population growth, coupled with an unsustainable economic system, is putting increasing pressure on natural resources, whereas “waste” represents a real source of usable and recyclable materials.

Objective, circularity in the poplar sector

The Centre for Industrial Technological Development (CDTI by its Spanish acronym), a Public Business Entity, dependent on the Spanish Ministry of Science and Innovation, together with four companies —Garnica, Eco3G Consultores, AITEX and Tecnalia­— has launched a project to boost circularity in the poplar sector chain

The project, called Recircularity, is funded and supervised by the CDTI. Its objective is to use the waste generated by poplar wood transformation processes, reducing the pressure on forests and plantations, the need for virgin raw material, and the carbon footprint.

Luis Aramburo, Garnica’s project manager and RD, who is responsible for the project at the company, explains that waste is “the fraction of by-products generated by the transformation into plywood, especially in the form of wood dust from the sanding process as well as bark, and accounts for a high percentage of the raw material that enters the factory”.

“We are seeking to replace materials of petrochemical origin, such as XPS, with others of bio-origin in the manufacture of sandwich panels,” he explains. The idea, he points out, “is to increase the useful life and the added value of this by-product”.

According to Aramburo, this project could be replicated: “We want to design a sustainable process to manufacture more competitive and ecological products, offering solutions to consumer needs.”

Process and products

Initially, the use of sandpaper dust from wood will be evaluated to subsequently incorporate the bark. After carrying out a complete characterization of the poplar sandpaper powder, laboratory processes are applied to confer fire-retardant and/or water-repellent properties to these residues, with the idea of ​​using them in the production of sandwich panels.

These panels are made up of a core which is the central part of the panel, and a rigid fibre that serves as the “skin” of the board, giving it consistency and lightness at the same time.

Rigid Panel Tecnalia

This research project seeks to replace the core and skins of the sandwich panel maximizing the use of sandpaper dust from wood.

Firstly, the rigid panels that make up the skins contain 70% sandpaper dust from wood in their composition, in the two production methods tested. Alternatively, the core replacement has been addressed by manufacturing foams and honeycomb-type structures using in both cases between 30% and 40% sandpaper powder.

Honeycomb structure from sandpaper dust from wood
Composite from sandpaper dust from wood to make honeycomb structures

The research is carried out in parallel by two of the companies participating in the project.

On one hand, Tecnalia carries out research using micronized and thermocompression processes for the manufacture of rigid panels and foams. On the other hand, AITEX uses wet-laid technology to reuse the sandpaper dust from wood, mixing fibres of vegetable origin with thermoplastic fibres also of bio-origin (PLA and Lyoncell).

Foam from sandpaper dust from wood

In the case of the fabric formation process using wet-laid technology, the aim is to generate veils that can be compressed to create the outer “skins” of the sandwich panel. The creation of cores with a structure like honeycomb panels for use in sandwich panels is also being investigated.

What's going on