1. Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
2. Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Alessandria Campus, 15121 Alessandria, Italy
3. Wallenberg Wood Science Center, Teknikringen 56-58, SE-100 44 Stockholm, Sweden