Advancing bio-based materials to reduce plastic pollution

Researchers from the Adolphe Merkle Institute’s Polymer Chemistry and Materials group are working to reduce reliance on fossil-based plastics by creating advanced materials from cellulose, a renewable, plant-derived polymer. Two recent studies from the group demonstrate how cellulose-based materials can be tailored for either short-lived, biodegradable packaging or durable, high-performance applications.

Cellulose is the most abundant natural polymer on Earth. It forms the structural framework of plants and is found in wood, cotton, and agricultural waste. Industrially, cellulose is extracted from these sources using well-established pulping and chemical processes. While raw cellulose pulp is primarily used to produce paper, it can also be converted into plastic-like derivatives such as cellulose acetate or hydroxypropyl cellulose (HPC), which the AMI researchers used in one of their studies. Alternatively, cellulose pulp can be disintegrated into cellulose nanocrystals (CNCs). These tiny, rod-shaped particles are only a few nanometers wide and several hundred nanometers long. These highly crystalline particles are extremely stiff and strong, making them ideal as a reinforcing component in composite materials.

With the goal of replacing conventional plastics in food packaging — a major contributor to global plastic waste — the AMI researchers developed all-cellulose nanocomposite films by blending HPC with CNCs. Since both components originate from cellulose, the resulting materials are fully bio-based. Using simple mixing and solvent-casting techniques, the team produced transparent films containing up to 90% CNCs. PhD student Chris Rader, who led both studies, explains these nanocomposites were significantly stiffer and stronger than pure HPC and exhibited a tenfold improvement in oxygen barrier performance — a key property for preserving food. Films with moderate CNC content also showed reduced water vapor permeability and retained their mechanical integrity under humid conditions. “Importantly, all of the materials readily disintegrated in water, which may help reduce their environmental persistence if discarded,” he added.

In a complementary study, the team pursued a different strategy: enhancing performance and durability by chemically grafting synthetic polymer chains directly onto CNC surfaces. This strategy afforded so-called “hairy nanoparticles,” where flexible and rigid polymer segments are chemically attached to the CNCs and surround the latter. These hybrid particles self-assemble into nanostructured materials that combine strength, stiffness, and toughness. Compared to similar polymers without CNCs — or to traditional nanocomposites made by simple mixing — these new materials showed markedly improved mechanical performance. The key lies in the intimate molecular integration between the reinforcing CNCs and the polymer matrix, which prevents particle aggregation and ensures efficient load transfer.

“These two approaches target different application spaces — one emphasizing biodegradability and ease of processing, the other durability and mechanical performance — but they share a common vision: replacing conventional plastics with materials derived from a renewable and industrially scalable resource,” said Rader. Together, these studies highlight the versatility of cellulose and underscore the importance of combining sustainability with functionality — a critical step toward a circular materials economy.

References: Rader, C.; Fritz, P. W.; Ashirov, T.; Coskun, A.; Weder, C. One-Component Nanocomposites Made from Diblock Copolymer Grafted Cellulose Nanocrystals. Biomacromolecules 2024, 25 (3), 1637–1648.

Rader, C.; Grillo, L.; Weder, C. Water and Oxygen Barrier Properties of All-Cellulose Nanocomposites. Biomacromolecules 2024, 25 (3), 1906–1915.