Liu’s research group

Create polymeric-like lignin building blocks

Kraft pulping enables large-scale wood-based biorefining, producing chemicals, materials, and fuels in one factory. In Sweden, kraft pulp mills produced approximately 4 million tons of Kraft lignin, which is now mainly used for energy purposes. Valorizing this lignin into high-value products is important to further improve economic efficiency and meet society's need for more renewable feedstocks.

Secondary processing, including chemical modification and fractionation, is important to answer several fundamental questions about these raw feedstocks: how many lignin molecules exist in Kraft lignin? Can we develop cost-effective ways to process them toward more uniform building blocks? What will be the key performance index to evaluate our process?

We believe lignin building blocks follow similar patterns when extracted and polymerized, making it possible to create building blocks with high consistency and good cost-effectiveness.

Platform characterisation of lignin building blocks

Is it possible to fully elucidate the structural models of the technical lignin?

Lignin is known for its hydrophobicity, mechanical reinforcement, and environmental resistance compared to other bio-based polymers. Can we connect these properties and biological activities to its molecular structure? Fortunately, multiple advanced tools have been developed over the last few decades to characterize its chemical structure.

In our group, the core techniques we use are nuclear magnetic resonance and gel permeation chromatography. The former provides fundamental structural details about its major linkages, fundamental units, and surface functional groups; the latter, combined with a series of detectors including multi-angle light scattering, UV detector, differential refractive index detector, and viscometer detector, provides more information about its molar mass, conformation, and degree of branching.

These quantitative factors help us understand the starting molecule more fundamentally and provide building blocks with enhanced properties and activities.

Converting lignin toward performance-advantaged polymeric materials;

Plastic materials have contributed significantly to improving our quality of life. However, their reliance on petroleum-based precursors, together with the environmental impacts associated with their production and improper end-of-life management, poses serious sustainability challenges. Reducing the carbon footprint of polymeric materials is therefore crucial for achieving global sustainable development goals.

Lignin macromolecules, such as kraft lignin, exhibit valuable polymer-like characteristics, including molar-mass-dependent glass transition behavior, moldability, low density, hydrophobicity, and resistance to chemical degradation. These properties make lignin a promising renewable feedstock for making polymeric materials.

In our group, we aim to harness lignin’s inherent structural advantages—such as its abundant surface functional groups and highly branched architecture—to develop high-performance polymeric materials. Representative examples include non-flammable and shape-memory polymeric foams, as well as lignin-modified polymers.

Through these studies, we seek to demonstrate that lignin’s sophisticated macromolecular structure can be an advantage in advanced material applications, enabling products that not only have a lower environmental footprint but also deliver enhanced performance.

Why join us?

Liu's research group at Chalmers values diversity, equity, and inclusion because different backgrounds, experiences, and perspectives strengthen creativity, collaboration, and scientific excellence.

The group members are committed to creating a welcoming environment where everyone is treated with respect, has fair access to opportunities and resources, and feels confident contributing to their ideas.

• Interested students from any background are welcome to contact Liyang Liu.

• All vacacies at Chalmers are listed here: Vacancies

• More information about research at Chalmers is available on the Chalmers webpage We train new researchers.