1. Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-plastics, Qingdao University of Science & Technology, Qingdao 266042, P. R. China
2. School of Materials and Chemical Engineering, Zhongyuan University of Technology, Zhengzhou 450007, P. R. China
3. School of International Education, Beijing University of Chemical Technology, Beijing 102202, P. R. China