1. Laboratory of Eco-Environment-Related Polymer Materials; Ministry of Education, China; Gansu Key Laboratory of Polymer Materials; College of Chemistry and Chemical Engineering; Northwest Normal University; 730070 Lanzhou Gansu People's Republic of China
2. College of Chemical Engineering and Technology; Key Laboratory for New Molecule Design and Function of Gansu Universities; Tianshui Normal University; 741001 Tianshui People's Republic of China