Preparation of block copolymers via Diels Alder reaction of maleimide- And anthracene-end functionalized polymers

A number of diblock copolymers were successfully prepared by Diels-Alder reaction, between maleimide- and anthracene-end functionalized poly (methyl methacrylate) (PMMA), polystyrene (PS), poly(tert-butyl acrylate) (PtBA), and poly(ethylene glycol) (PEG) in toluene, at 110 °C. For this purpose, 2-bromo-2-methyl-propionic acid 2-(3,5-dioxo-10-oxa-4-azatricyclo[5.2.1.02,6] dec-8-en-4-yl)-ethyl ester, 2, 9-anthyrylmethyl 2-bromo-2-methyl propanoate, 3, and 2-bromo-propionic acid 2-(3,5-dioxo-10-oxa-4-azatricyclo[5.2.1.02,6]dec-8- en-4-yl)-ethyl ester, 4, were used as initiators in atom transfer radical polymerization, in the presence of Cu(I) salt and pentamethyldiethylenetriamine (PMDETA), at various temperatures. On the other hand, PEG with maleimide- or anthracene-end functionality was achieved by esterification between monohydroxy PEG and succinic acid monoathracen-9-ylmethyl ester, 1, or 4-maleimido-benzoyl chloride. Thus-obtained PMMA-b-PS, PEG-b-PS, PtBA-b-PS, and PMMA-b-PEG block copolymers were characterized by ¹H NMR, UV, and GPC.