Synthesis of Novel Chain-End-Functionalized Polyethylenes via Thiol-ene Click Chemistry

Chain-end-functionalized polyethylenes (Cef-PEs: PE S SH (Cef(1)), PE S furfuryl (Cef(2)), PE-S-NH2 (Cef(4)), PE-S-NH2 center dot HCl (Cef(5)), PE-S-COONa (Cef(6)), PE-S-CHA(Cef(7)), PE-S-SO3Na (Cef(8)), PE-S-OH (Cef(9)) and PE-S-COOH (Cef(10))) are synthesized by thiol-ene addition of vinyl-terminated polyethylene (v- PE) with 1,2-ethanedithiol, furfurylmercaptan, cysteamine, cysteamine hydrochloride, sodium thioglycolate, L-cysteine hydrochloride, sodium 2-mercaptoethanesulfonate, mercaptoethanol, and thioglycolic acid, respectively. PE-S-t-NCO (Cef(3)) is obtained by subsequent reaction of Cef(9) with anhydrous 4,4'-MDI. Cef-PE1-8 are reported for the first time. The conversions of all the reactions are up to 95%-100%. All the Cef-PEs are characterized by NMR, GPC, DSC, FT-IR, and TGA. In the experiments, it is found that alkaline mercaptans and solvents are adverse to the thiol-ene click reactions.