Lignin has emerged as a promising sustainable material for developing biodegradable products due to the following properties:
- Renewable Resource – Lignin is an abundant waste byproduct of papermaking, biofuels, and biorefineries, making it a renewable and low-cost material.
- Biodegradability – The complex aromatic structure of lignin can be degraded by bacteria and fungi, making lignin-based materials compostable.
- mechanical strength – Lignin can be processed into materials that have high tensile and impact strength when blended with other polymers.
- Thermal stability – Lignin has a high glass transition temperature, allowing lignin-based materials to remain mechanically stable across a wide temperature range.
Some examples of biodegradable materials made from lignin include:
- Bioplastics – Lignin has been blended with PLA, PHBV, thermoplastic starch to make fully biodegradable polymer blends for packaging, bags, and food service items.
- Hydrogels – Lignin’s networks structure allows water-absorbent yet strong hydrogels to be synthesized for agricultural and biomedical uses.
- Films – Transparent and flexible food packaging films have been made from lignin and cellulose nanofibers.
- Coatings – Lignin coatings on fertilizers, seeds, and implants can degrade safely in soil or in the body.
- Carbon fibers – Lignin’s high carbon content allows carbon fibers to be produced that can replace metals and glass fibers.