LED-induced controlled radical polymerization with an in situ bromine–iodine transformation and block polymerization combined with ring-opening polymerization using one organocatalyst†
A simple white light-emitting diode (LED) induced controlled radical polymerization (CRP) with an in situ bromine–iodine transformation was successfully conducted via organocatalysts. N,N,N′,N′′,N′-Pentamethyldiethylenetriamine (PMDETA), tributylamine (TBA), and hexamethylphosphoric triamide (HMPA) were employed as organocatalysts in this CRP system due to their green, inexpensive, easy-to-handle and highly reactive features. All the three organocatalysts exhibited high efficiency in this CRP system. The polymer molecular weight and distribution (Mw/Mn = 1.02–1.19) of poly(methyl methacrylate) were satisfactory up to fairly high conversions at room temperatures. Well-defined copolymers demonstrated living features of controlled radical polymerization which also indicated that functional methacrylates were also appropriate for this system. Various solvents were added in this CRP system which widely broadened the applicability. Notably, using PMDETA as an organocatalyst for both in situ bromine–iodine transformation CRP and ring-opening polymerization (ROP), poly(methyl methacrylate)-b-poly(L-lactide) (PMMA-b-PLLA) was successfully synthesized in “one-pot”.