Polyurea microcapsules from isocyanatoethyl methacrylate copolymers

The synthesis of two types of isocyanate side chain containing copolymers, poly(methyl methacrylate-co-isocyanatoethyl methacrylate) (P(MMA-co-IEM)) and poly(benzyl methacrylate-co-isocyanatoethyl methacrylate) (P(BnMA-co-IEM)), which were synthesized by Cu(0)-mediated radical polymerization, is reported. Polymerization proceeded to high conversion giving polymers of relatively narrow molar mass distributions. The incorporation of the bulky aromatic groups in the latter copolymer rendered it sufficiently stable toward hydrolysis and enabled the isolation of the product and its characterization by ¹H and ¹³C NMR, and FTIR spectroscopy and SEC. Both P(MMA-co-IEM) and P(BnMA-co-IEM) were functionalized with dibutylamine, octylamine, and (R)-(+)-α-methylbenzyl-amine, which further proved the successful incorporation of the isocyanate groups. Furthermore, P(BnMA-co-IEM) was used for the fabrication of liquid core microcapsules via oil-in-water interfacial polymerization with diethylenetriamine as crosslinker. The particles obtained were in the size range of 10–90 µm in diameter independent of the composition of copolymer.