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PaperWeek: Lignin and hemicellulose present a world of possibilities

Biorefining expert Peter Axegard enumerated the many end products that can be made from lignin and hemicellulose, the by-products of the kraft pulping process, at the CRIBIQ symposium on forest-based renewable chemicals. The symposium on Monday, Jan. 30, kicked off PaperWeek Canada, PAPTAC’s annual gathering of the pulp and paper industry in Canada.

Axegard, representing the Innventia research organization in Sweden, explained that lignin can be used for its energy value, as an additive to fuel oil, or burned in a lime kiln, or co-fired with coal or bark. However, he sees more promise in its higher value applications. Innventia is working on applications for lignin in carbon fibres, activated carbon, as a hydrophobing agent, and as binder for fibreboard.

“The most spectacular development,” says Axegard, “is that we can melt-extrude lignin for carbon fibre.”

Hemicellulose, says Axegard, is a gold mine of valuable polymers. Xylan, for example, is quite easy to remove from black liquor. Innventia has grafted a lactic acid to xylan to produce an extrudable, modified PLA polymer. Xylan also has potential applications as a fibre additive.