1. Department of Materials Science and EngineeringShinshu University, 3‐15‐1 Tokida, Ueda Nagano 386‐8567 Japan
2. Graduate School of Science and TechnologyShinshu University, 3‐15‐1 Tokida, Ueda Nagano 386‐8567 Japan
3. Institute for Fiber EngineeringShinshu University, 3‐15‐1 Tokida, Ueda Nagano 386‐8567 Japan
4. Division of Chemistry of Renewable Resources, Department of ChemistryUniversity of Natural Resources and Life Sciences Vienna Muthgasse 18, A‐1190 Vienna Austria