Lignin can replace bisphenol A

Residues from sawmills and the paper and pulp industry can be used to replace bisphenol A. Photo: Mostphotos/Stokkete

Bisphenols are a group of chemicals, the most well-known and well-studied is bisphenol A, which is mainly used in the production of polycarbonate plastics and epoxy. Polycarbonate plastic is used in many areas, such as building material in the automotive and construction industries, as well as in plastic bottles and food containers. Epoxy is found in electronics, in building materials and as a protective coating on the inside of food and beverage cans. Bisphenol A is also used on the surface of thermal printer printing paper, such as cash receipts.

Research has shown that low levels of bisphenol A can be released from polycarbonate plastic and epoxy and transferred to food or beverages that are in contact with the material. In recent years, the use of bisphenol A has been severely restricted because animal studies have shown that the substance is reprotoxic and has endocrine-disrupting properties. Since 2011, the substance has been banned in baby bottles in the EU and since 2020 also in thermal paper for cash register receipts. However, there are no restrictions on the use of other bisphenols yet.

New study in Nature on lignin

Joseph Samec
Photo: Niklas Björling

Research is underway worldwide to find materials that can replace bisphenol A and thus avoid the harmful effects of the chemical. Researchers at Stockholm University and universities in China and the United States have recently published a study in the journal Nature on lignin (a group of substances that are part of the cell walls of plants and are today usually a by-product in the paper and pulp industry). In the study, the researchers have succeeded in developing a new method to fractionate lignocellulose (wood raw material) into different streams to create a non-toxic bio-based plastic that could replace bisphenol A. The fractionation also gives textile fibres, which in turn can be used to substitute cotton.
 
"Our study demonstrates that it is now possible to go from wood directly to a non-toxic bisphenol. We do this by taming the lignin to react in a new way," says Joseph Samec, professor of organic chemistry at Stockholm University and one of the researchers behind the study.

In the past, similar results have been achieved in several steps, and thus with greater efforts of work and energy. The newly developed method is performed under sustainable reaction conditions and the chemicals that are added and formed are not toxic.

Great potential for positive environmental impact

The results may enable parts of wood that are not used as cardboard or planks to be converted into plastics and textiles.
"This means that parts of wood that are not utilized can be transformed to products that can replace fossil-based plastics on the market that are very harmful to the environment, such as bisphenol A; as well as cotton, which has major environmental impact due to irrigation, eutrophication, use of pesticides and land use," says Joseph Samec.

Article in Nature: Selective lignin arylation for biomass fractionation and benign bisphenols
Read more about bisphenols at the Institute of European Chemicals Agency´s web