Lignin bioplastic

Lignin leftover from paper making is the main component in a new class of innovation bio-based plastics. Millions of tons of lignin are produced each year and typically incinerated to generate energy for the paper making process.

Lignin is the glue in plants, holding the cellulose fibres together, and giving wood its rigidity. The cellulose fibres provide the strength. During the paper making process the lignin is softened and broken down, such as into lignosulfonate (LS) or sulfonlted lignin (SL), which allows the fibres to be formed into paper. It is removed almost entirely from paper that must stay white (archival). Newsprint is made from thermo-mechanical pulp (TMP), which is cheap and efficient but does not fully remove the lignin. This is why it becomes yellow and brittle with time.

Developments in the refining and bleaching processes have made it possible to include more lignin in paper, making the processes more efficient. Even so, there remains an abundance of this natural polymer leftover.