Sustainable composite sandwich panel combines recycled and bio-based materials for lightweight vehicle structures

Gurit and Rubisco have developed a new composite sandwich panel that integrates recycled and bio-based materials, offering a lightweight structural solution aligned with circular economy objectives and applicable to transport interiors and vehicle structures.

The panel combines three core technologies: Gurit’s recycled PET structural foam, Gurit’s AMPRO BIO epoxy resin and Rubisco’s BioTEX hemp fibre reinforcement. Depending on configuration, the panel can achieve up to 100 percent recycled or bio-based material content while maintaining structural performance.

Lightweighting and sustainability in vehicle applications

Composite sandwich structures are widely used in lightweight engineering, where outer skins carry tensile and compressive loads while a lightweight core provides stiffness. In this case, hemp fibre skins are laminated with bio-based epoxy resin and bonded to a recycled PET core, creating a panel that balances strength, low weight and environmental performance.

For bus and transport applications, such materials can support:

Interior panels and wall linings

Ceiling structures and partitions

Acoustic and thermal insulation elements

The combination of low density and structural rigidity contributes to overall vehicle weight reduction, supporting energy efficiency and extended range in electric buses.

Material technologies and performance

At the core of the panel is Gurit PET, a structural foam made from up to 100 percent post-consumer recycled content. It offers strong compressive properties, low density and reduced resin uptake, while enabling up to 65 percent lower CO₂ emissions compared to conventional foam cores.

The outer skins use BioTEX hemp fabric, engineered for structural reinforcement in composite systems. Hemp fibres provide a balance of strength and low weight, while also enabling a distinctive surface finish for visible interior applications.

The AMPRO BIO epoxy resin binds the structure together, incorporating plant-derived feedstocks while maintaining mechanical performance, adhesion and processing consistency.

Design flexibility and integration

The panel system is fully configurable, with adjustable core thickness, laminate structure and dimensions. This allows engineers to tailor the material for different performance requirements, ranging from lightweight decorative panels to load-bearing structural components.

This flexibility supports integration across a wide range of vehicle applications, enabling manufacturers to standardise material concepts while adapting to specific design constraints.

Outlook

The Gurit and Rubisco collaboration reflects a broader shift in composite engineering, where performance and sustainability are increasingly addressed together. By combining recycled polymers, bio-based resins and natural fibre reinforcement, the panel demonstrates a pathway for reducing environmental impact without compromising structural requirements.