Facile synthesis of chain end functionalized polyethylenes via epoxide ring-opening and thiol–ene addition click chemistry

A wide range of low-molecular-weight, narrow-molecular-weight-distribution chain end functionalized polyethylenes (Cef-PEs), including hydroxyl-, amino-, carboxyl-, sulfo-, chloro-, azide- and trimethoxysilane-terminated polyethylenes, were synthesized under mild conditions via epoxide ring-opening and thiol–ene addition reactions with epoxy- and vinyl-terminated PEs as starting materials, respectively. The selectivities of the functionalizations were excellent. Similarly, amphiphilic polyethylene-block-poly(ethylene glycol) copolymer (PE-b-PEG) was prepared for the first time by simply treating epoxy terminated PE with hydroxyl terminated PEG and potassium hydroxide. A unique combination of primary (hindered-phenol) and secondary (thioester) antioxidants was introduced into the chain end of PE via successive thiol–ene addition and transesterification reactions. All Cef-PEs were characterized unambiguously by NMR, GPC, DSC and FTIR.