Lignin-based material could replace fossil plastics and adhesives, claim Stockholm University researchers

29 Nov 2021 --- Researchers at Stockholm University, Sweden, have developed new lignin-based materials to replace conventional plastic packaging and adhesives with a renewable solution. 

The project participants plan to scale-up with European partners and continue developing different “soft segments'” to broaden the material’s reformability and processability.

Lignin is an organic polymer and by-product of the pulp and paper industry, where it is mainly burned to recover chemicals and heat. However, the researchers claim “there is a strong push to use lignin as a building block for new value-added materials serving as carbon stocks during their lifetime.” 

The researchers add they are addressing the “urgent need to develop enabling technologies for a transition to a circular economy.”

The lignin-based materials are resource-efficient since they use industrial lignin and can be “thermally reprocessed and used to substitute thermosetting resins and adhesives.”The researchers plan to develop different “soft segments'” to broaden the material’s reformability and processability (Image credit: Mika Sipponen).

PackagingInsights speaks with Mika Sipponen, head of the research project and assistant professor at the Department of Materials and Environmental Chemistry at Stockholm University. 

“Lignin is currently available in two main commercial grades. In addition, there will be increased availability from lignocellulosic biorefineries, so it is safe to say lignin can be a significant renewable resource in the future.”

“The new lignin-based materials can be used several times, which is central to future’s circular materials.”

Commercialization plans
Sipponen reveals the project is actively seeking partners and further funding from the EU and private companies. “We need to demonstrate the scalability of this technology and develop the material with end-users.”

When it comes to commercialization, Sipponen explains the key features are safety and technical properties, such as barriers. “We haven’t tested this new material with this respect but foresee material stability in contact with food systems and other polymers used in the packaging are central to validate.”Lignin is an organic polymer and by-product of the pulp and paper industry (Image credit: Mika Sipponen).

Biodegradability
Although the project has not focused extensively on end-of-life disposal, Sipponen adds: “Based on the chemistry and combination of two biodegradable components, we expect the product will also be biodegradable.”

“However, more effort is needed to prove this new material complies with all standards and regulations [including for food contact].”

“We are planning to scale up the production together with partners,” he reiterates. “We will also extend the fundamental research to explore new soft segments and demonstrate different types of lignin in this new class of lignin-based material.”

Relatedly, Coca-Cola has produced lignin-based renewable functional fillers from 100% certified hardwood, taken from sawmill and other wood industry side-streams.

By Natalie Schwertheim