Composites of kraft lignin

Kalle Nättinen, Lamfeddal Kouisni, Michael Paleologou, Lisa Wikström, Tom Browne, Niklas von Weymarn

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsProfessional


Many materials, man-made and natural, have a composite structure, i.e. they comprise two or more constituent materials with distinct differences. Concrete is a common example. It consists of sand or gravel, cement and water. Wood is also a composite. It has strong, crystalline cellulose structures glued together by hemicelluloses and lignin. The unique structure of wood can, however, not be processed as such using common industrial material processing techniques. For decades, the market for composite materials has witnessed small steps towards increased use of bio-based constituents instead of the petroleum-based ones and especially, bio-based/natural fibers instead of man-made glass fiber. A key driver for this change is the fact that natural fibers are often cheaper and lighter. Sustainability issues also play a part in this change. In this research, the main objective has been to develop technologies and competences enabling the production of novel composite materials, in which wood-derived, industrial kraft lignin and cellulose fiber are the main constituents. The lignin would thus replace the petroleum-based plastics as matrix constituent. The more specific objectives of the research were to determine the melt processability of kraft lignin, plasticize kraft lignin with case-suitable plasticizers to ease the processing of the material and produce kraft lignin-based composite test products reinforced with cellulose fiber. Kraft lignin was not processable without plasticization. Suitable plasticizers were found, the plasticized kraft lignin was melt compounded with cellulose fibers, and test samples were injection molded. DSC analysis was conducted and mechanical properties were measured. The initial tensile test results of the plasticized lignin reinforced with cellulose fibers were promising. Addition of cellulose fibers into plasticized lignin matrix improved mechanical properties of the lignin significantly.
Original languageEnglish
Title of host publicationNWBC 2012
Subtitle of host publicationThe 4th Nordic Wood Biorefinery Conference
EditorsKlaus Niemelä
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
ISBN (Electronic)978-951-38-7881-8
ISBN (Print)978-951-38-7880-1
Publication statusPublished - 2012
MoE publication typeD3 Professional conference proceedings
Event4th Nordic Wood Biorefinery Conference, NWBC 2012 - Helsinki, Finland
Duration: 23 Oct 201225 Oct 2012 (Full proceedings)

Publication series

SeriesVTT Technology


Conference4th Nordic Wood Biorefinery Conference, NWBC 2012
Abbreviated titleNWBC 2012
Internet address

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