Bioderived materials usually have an economic cost that significantly increases the final price of the products in which they are used.

Scientists around the world are still trying to create new sustainable materials, but unless these materials are scalable and cost-effective, they won’t have a practical impact. For this reason, researchers at the University of Delaware seek to develop an economical and practical bioplastic.

This is an investigation that has drawn attention, since bio-derived materials, although they may imply environmental advantages, usually have an economic cost that significantly increases the final price of the products in which they are used.

An abundant bioplastic

Thomas H. Epps III, responsible for leading the research, explained in the journal Science Advances: “This work demonstrates the potential of technical lignin as an inexpensive and abundant resource to produce value-added chemicals and materials and a scalable valorization pathway. for the selection of raw materials, intensified deconstruction, product manufacturing and economic evaluation”.

Lignin belongs to a group of complex organic polymers found in key structural materials in the supporting tissues of most plants. Lignins are crucial in establishing cell walls, particularly in wood and bark, because they do not rot easily and are rigid.

However, lignin is also a waste product, known as technical lignin, that is generated during industrial processing in the pulp and paper industry. One billion tons of technical lignin are generated annually. However, it is considered difficult to reuse due to contamination, and as a result it is usually burned for heat or used as filler for rubber tires.

Epps and his team believe there is more to technical lignin than meets the eye and that there is potential value for such an abundant resource. In their research, they demonstrate the potential to convert technical lignin into high-performance plastics, which can be used in applications such as additive manufacturing (3D printing).

A truly economical process?

One of the main problems with lignin upgrading is that most of the processes to do it operate at very high pressures, are expensive and difficult to scale up. The main drawbacks of current industrial techniques include safety concerns, capital costs, and energy consumption associated with traditional solvents, temperatures, or pressures used in the process.

To address these issues, the UD team used glycerin (instead of methanol) so that the process could be carried out at normal room temperature.

Glycerin is an inexpensive ingredient used in liquid cosmetics, soaps, shampoos, and lotions for its moisturizing abilities. But here, glycerin helps break down lignin into chemical building blocks that can be used to make a wide range of bio-based products, from 3D printing resins to different types of plastics, flavor and fragrance compounds, antioxidants, and more. .

The use of glycerin provided the same chemical functionality as methanol, but at a much lower vapor pressure, eliminating the need for a closed system. This change allowed the researchers to perform the reaction and separation steps simultaneously, leading to a more cost-effective system.