Ida Norberg defended her doctoral thesis "Carbon fibers from kraft lignin" at Innventia in Stockholm. Her thesis shows that lignin has great potential for use as a raw material for manufacturing carbon fiber.Carbon fiber is strong and light, with many applications. Demand is mainly limited by the high cost of production, with the petroleum-based raw material and fiber spinning accounting for around 50 percent of the cost.Thanks to the LignoBoost technology, developed by Innventia, pulp mills can extract extremely pure lignin which could be used for carbon fiber, thus increasing access to a raw material for carbon fiber. According to studies reported on in Ida Norberg's thesis, the cost of production could also be lowered by using lignin.Ida Norberg carried out much of her doctoral work within the framework of the LigniCarb research project, with the aim of examining and demonstrating the possibilities of making carbon fiber from kraft lignin. One of the outcomes of this work was a brand new research environment at Innventia in Stockholm, where carbon fiber is now prepared on a laboratory scale.In her studies, Ida Norberg has compared lignin from hardwood (birch and eucalyptus) and softwood (a mixture of spruce and pine). One important conclusion is that the differences in the lignin are reflected in the carbon fiber process. Softwood lignin has proven to be harder to liquefy and spin, but once lignin fibers have been produced they are easier to use later on in the process. The opposite is true with hardwood.A major breakthrough came when the team succeeded in spinning fibers from softwood lignin. This had previously been thought impossible, but is of particular interest to the forest industry in the Nordic region and North America.