Methodology

Generation: Sustainable Feedstock

The first part of the CIRCULAR-C project focuses on transforming a variety of sustainable plant-based residues into valuable building blocks for green chemistry and materials.

Types of feedstocks that are analysed in CIRCULAR-C:

  • Agricultural feedstock
  • Forestry feedstocks
  • and food production streams

Components which CIRCULAR-C tries to isolate

  • cellulose,
  • hemicellulose,
  • and lignin.

What should these components bring:

  • environmental sustainability
  • suitability for industrial-scale processing

State-of-the-art biorefining methods will be applied to the feedstock mixture which will undergo optimized fractionation and extraction processes. These processes will harness controlled acid dosing and tailored solvent use to efficiently separate the components. Advanced analytical tools and continual process optimization enable the production of multiple product streams both at lab and industrial scale.

Formulation: Circular Components

The second part of the CIRCULAR-C project involves the use of several innovative techniques to develop next-generation components for sustainable wood panels.

CIRCULAR-C enhances the strength and flexibility of cellulose fibres in panels:

  • with conventional pilot refining,
  • novel compression refining at high solid content,
  • and targeted chemical surface modifications.

This improves the bonding capacity of functionalized fibre mats.

To match the sustainable structure within the panels, micro- and nanocellulose coatings are engineered for their exterior. These novel adhesives enable efficient fibre disintegration through enzymatic HefCel processing, and their fire-retardant properties are further enhanced through the chemical phosphorylation of nanocellulose.  

To guarantee the recyclability of the CIRCULAR-C wood panels, it is necessary to ensure that the chemicals form reversible bonds.

The CIRCULAR-C advanced adhesive formulations:

  • with lignin,
  • furfural and maleic anhydride,
  • incorporating thermoset resin chemistry
  • and unique thermoreversible systems based on dynamic covalent bonding.

(Re)Assembly: Sustainable Insulation Panels

In the third part of the Circular-C project, research and industry partners test the innovative bio-based formulations by incorporating them into construction panels and insulation materials under real-world manufacturing conditions. Functionalized fibres and novel adhesives – developed with reversible chemical bonds and high biobased content – are integrated into floor panels, furniture, and insulation panels through advanced techniques such as high-pressure hot pressing, spray coating, and dynamic resin curing.

These circular products are engineered for disassembly and recycling. The panels incorporate up to 80% recycled material and non-polyurethane insulation foams synthesized from lignin and cyclocarbonate chemistry. The performance of these products is rigorously tested for properties such as strength, fire resistance, recyclability, and low emissions, with industry benchmarks and NEB (New European Bauhaus) principles serving as a guide. The results are showcased in demonstration prototypes, highlighting the project’s capacity to create safe and sustainable construction materials that are fully traceable and designed for circularity throughout their lifecycle.

Disassembly: Recycling and Secondary Markets

The focus of the fourth part of the Circular-C project is to optimize and validate the disassembly and recycling of the panels, thereby ensuring that products and materials retain value throughout their lifecycle:

 

CIRCULAR-C’s cutting-edge mechanical milling technique for:

  • bio-based thermoset adhesives
  • and novel thermo-reversible adhesives
    -> construction and insulation panels can be disintegrated and assessed for reuse in new applications.

The analyzation of fibre length and material quality allows for:

  • high-grade recycling into fresh construction products
  • lower-quality streams are transformed into moulded cellulose items or tested for use in specialty papers and packaging.

Advanced methods such as image-based fibre characterization and conceptual evaluations of thermal end-of-life strategies, including combustion, pyrolysis and gasification, are employed to further maximize circularity and products for climate-friendly markes.

Product information system

  • General technical specifications
  • Product mode, category
  • (Re-)Assembly information
  • Compliance
  • Warranty information
  • Proof of insurance and certifications
  • EPR compliance data
  • Material
  • Substances of concern
  • Raw materials
  • Recycled content
  • Responsible supply chain
  • 3rd party assurances
  • Supply chain due diligence report
  • Product performance (incl. durability)
  • Events tracking incl. repairs, malfunctions, accidents
  • Component number type, location, weight
  • Circularity information
  • Removal instructions
  • Technical assistance contact
  • Disassembly instructions
  • Recyclability of low quality streams
  • Design, redesign
  • Hazardous assessment
  • Human health & safety
  • Environmental, social sustainability

Digital Product Passport

The fifth part of the Circular-C project pioneers the implementation of digital product passports (DPP) for bio-based construction and furniture products, fully aligned with evolving EU regulations. Starting with a structured data model developed through stakeholder workshops, the project encodes essential product and sustainability information in transparent, machine-readable formats. Physical QR code tags are designed and applied to panels and insulation products with careful consideration given to durability, data capacity and compliance with ISO and GS1 standards and a secure software ecosystem with seamless back-end data integration.

Safe and Sustainable by Design

The sixth part of the Circular-C project provides a comprehensive evaluation of the safety, circularity, and sustainability of the entire process and its products. It also involves evaluating the decisions that guide the process from initial conception to full-scale industrial implementation. Co-creation workshops are held to design the CIRCULAR-C products and processes.

SSbD in CIRCULAR-C with:

  • Economic feasibility through life cycle cost analyses
  • qualitative and quantitative risk assessment for human health and environmental safety
  • early innovation screening
  • exposure hotspot profiling
  • social and environmental life cycle assessments based on ISO and EU methods
  • cradle-to-grave analyses: carbon flows, social benefits, and circularity metrics

By continually integrating and visualizing these diverse assessment outcomes, the CIRCULAR-C project lays the groundwork for market-ready products that are not only technically and economically robust, but genuinely safe and sustainable by design.

Success Story

To maximise the impact of CIRUCLAR-C we combine:

  • targeted communication
  • stakeholder engagement with co-creation workshops and gamified engagement sessions
  • knowledge transfer through clustering and networking with related EU initiatives and the New European Bauhaus
  • exploitation and replication strategies

This involves engageing with researchers, industry professionals, policymakers, and the general public to encourage acceptance and adoption across the value chain. Knowledge is shared widely through open-access publications, policy briefs and scientific events. A clear pathway for IP protection, business model development and training empowers industry stakeholders to utilize and replicate the project’s circular solutions long after its conclusion, thereby driving sustainable change in the construction and bio-based sectors.