1. Department of Polymer Materials and Engineering, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300401, P. R. China
2. Hebei Key Laboratory of Functional Polymers, Hebei University of Technology, Tianjin 300401, P. R. China
3. College of Chemistry and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, P. R. China