Anionic synthesis of polymers functionalized with a terminal anhydride group

Polymers bearing a single succinic anhydride at the chain end were synthesized using anionic polymerization techniques. Specifically, the living anions of poly(methyl methacrylate) (PMMA), polystyrene (PS), polyisoprene (PI), and poly(vinylpyridine) (PVP) were found to exclusively undergo a 1,4-conjugate addition reaction with di-tert-butyl maleate. Only a single maleate adds. The gel permeation chromatograms for the synthesized polymers were found to have very narrow molecular weight distributions (M-w/M-n < 1.15) after the end-capping reaction. Pyrolysis (235 degrees C, 2-12 h) of the resulting substituted di-tert-butyl succinate ester efficiently produced the related succinic anhydride functional polymers in the case of PMMA and PS. The functionality of these polymers (f greater than or equal to 0.81) was determined following derivatization reactions with various amines. Nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) of the resulting amides permits quantification of the extent of functionalization. Upon melt blending (200 degrees C) an anhydride terminal PMMA (29 kg/mol) with an amino terminal PS (18.5 kg/mol) all of the monofunctional homopolymers were converted to PS-PMMA diblock within 20 min (GPC and transmission electron microscopy, TEM). A lamellar morphology (TEM) was obtained after further annealing of this sample (72 h).