1. Key Laboratory of Rubber-Plastics of the Ministry of Education, School of Polymer Science & Engineering, Qingdao University of Science and Technology, 53-Zhengzhou Road, Qingdao 266042, P. R. China
2. School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China