1. Department of Physics, Chalmers University of Technology, 412 96 Gothenburg, Sweden
2. FibRe-Centre for Lignocellulose-Based Thermoplastics, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
3. Tetra Pak, 221 86 Lund, Sweden
4. Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
5. Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland