1. a Center for Degradable and Flame-Retardant Polymeric Materials (MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610064, P.R. China; Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, P.R. China
2. b Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, P.R. China
3. c School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Durban 4000, South Africa
4. d Center for Degradable and Flame-Retardant Polymeric Materials (MoE), College of Chemistry, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610064, P.R. China