Recycled materials improve the properties of wood plastic composites

The use of recycled mineral wool fibres as filler in wood plastic composites improves, in certain cases, the moisture resistance of the composites and reduces their environmental impacts. It also improves the recycling rate of construction waste towards the 70 per cent target by 2020 imposed by the European Union. This was the finding in a doctoral dissertation to be defended at Lappeenranta University of Technology, LUT.

Mineral fillers are widely used in wood plastic composites, the most common applications of which are decking products for outdoor construction, to improve the properties of the composites and to reduce their raw material costs. Olli Väntsi's dissertation revealed that the moisture resistance of wood plastic composites can be improved by replacing wood fibres with recycled mineral wool. Environmental impacts were compared in situations where both wood fibres and virgin glass fibres were replaced with recycled mineral wool.

The mineral fillers used in wood plastic composites are usually virgin materials. The use of recycled mineral wool makes it possible to replace these virgin materials with recycled material. As no beneficial uses for mineral wool waste previously existed, it ended up disposed of in landfills.

The development of new applications for recycled materials is important in view of effective markets for recycled materials. Effective markets for recycled materials could benefit waste producers, companies operating in the waste sector and the manufacturing industry.

Olli Väntsi, M.Sc. (Tech.), will defend his doctoral dissertation in the field of mechanical engineering entitled Utilization of recycled mineral wool as filler in wood plastic composites at the Lappeenranta University of Technology (LUT) on 9 October 2015 at 12 noon in room 1383. Professor Raimo Alén from the University of Jyväskylä, Finland, will be the opponent. Professor Timo Kärki from LUT will serve as the custos.

Library information: The dissertation has been published in the Acta Universitatis Lappeenrantaensis research series (number 663) of the university, ISBN 978-952-265-855-5 and ISSN 1456-4491. The dissertation is available for reading on the Lappeenranta University of Technology's LUTPub database at A printed version of the dissertation may be purchased from the Aalef bookshop, tel. +358 44 744 5511, or at kirjakauppa(at), and from the LUT Shop online shop at The research was funded by South Karelia Regional Fund of the Finnish Cultural Foundation and the Research Foundation of Lappeenranta University of Technology.


The doctoral candidate's personal information:

Name: Olli Väntsi

Year and place of birth: 2 May 1983, Paimio

Home municipality: Lappeenranta

Education: M.Sc. (Tech.), Lappeenranta University of Technology, 2011

Employment: Doctoral student, Lappeenranta University of Technology, 2011–2015, R&D Manager, Stora Enso Wood Products Oy 2015–


Further information:

Olli Väntsi, tel. +358 44 2767082,