1. a Department of Polymer Chemistry Faculty of Engineering , Kyoto University , Kyoto, Japan
2. b Fiber and Textile Research Institute, Teijin Ltd. , Minohara. Ibaraki-shi, Osaka-fu, Japan
3. c Fiber and Textile Research Institute, Teijin Ltd. , Minohara, Ibaraki-shi, Osaka-fu, Japan
4. d Iwakuni Mill , Mitsui-Toatsu Chemical Co. Ltd. , Iwakuni-shi, Yamaguchi-ken, Japan