Now possible to improve the qualities of biocomposites

In Kimmo Hämäläinen's doctoral research study conducted at LUT, the capability to improve the adhesiveness, fire resistance, mechanical strength and water absorption of wood-plastic composite materials has been demonstrated.

Amongst the perceived advantages of wood-plastic composite materials are the lightness of their reinforcement, ecological character and recyclability. From the perspective of the structural parts, a problem is seen, however, in the limitations of the materials with respect to strength, fire resistance and moisture behaviour. At the moment, wood-plastic composites are utilized mainly in terrace construction and in the motor vehicle industry.

Biocomposites are made up partly or entirely of bio-derived materials. International research on these materials has recently been actively pursued. Wood-plastic composites  applying wood-fibre reinforcement, whose potential remains partly unharnessed in manufacturing industry solutions, are also ranked as biocomposites. Qualities of wood-plastic composites can be improved by modifying the surface chemistry of the material, through chemical processing of wood fibres, or by the alteration of the material's structure. 

As research methods of the doctoral study, plasma processing to modify the surface chemistry was used as well as the impregnation of wood fibres and structural alteration by means of the co-extrusion method.

The doctoral dissertation in the technical field by Master of Science in Engineering Kimmo Hämäläinen, Improving the usability of extruded wood-plastic composites by using modification technology, shall be examined on 28 November 2014 at 12.00 noon in auditorium 1381 of Lappeenranta University of Technology. Antti Ojala, Ph.D., Research Team Leader at VTT Technical Research Centre of Finland, shall act as opponent. Professor Timo Kärki from Lappeenranta University of Technology shall act as custos.

The doctoral dissertation has been published in the university's Acta Universitatis Lappeenrantaensis research series, no. 608, ISBN 978-952-265-694-0 and ISSN 1456-4491. The dissertation can be read in the Lappeenranta University of Technology's LUTPub database at  A printed version can be purchased at Aalef Bookshop, tel. +358 (0)44 7445511 or email kirjakauppa(at) .

Candidate's personal information:

Name: Kimmo Hämäläinen
Birthdate and birthplace: 28.7.1978 Lappeenranta
Home municipality: Lappeenranta
Education: Master of Science in Engineering
Employment: LUT 2009−2014

More information:

Kimmo Hämäläinen, tel. +358 40 5568883,