1. German Institutes of Textile‐ and Fiber Research (DITF) Denkendorf Körschtalstr. 26 D‐73770 Denkendorf Germany
2. Institute of Chemical Technology University of Stuttgart Pfaffenwaldring 55 D‐70569 Stuttgart Germany
3. Chair of Macromolecular Compounds and Fiber Chemistry Institute of Polymer Chemistry University of Stuttgart Pfaffenwaldring 55 D‐70550 Stuttgart Germany