Grafting of Poly(ε-caprolactone) and Poly(ε-caprolactone-b lock-(dimethylamino)ethyl methacrylate) from Polymer Microspheres by Ring-Opening Polymerization and ATRP

We report the ring-opening polymerization (ROP) of ε-caprolactone catalyzed by Al(Et)3 and Al[OCH(CH3)2]3 from lightly cross-linked poly(DVB80-co-HEMA) microspheres. The resulting poly(ε-caprolactone) grafted particles with active propagating ends were converted to macroinitiators for ATRP and used further to graft (dimethylamino)ethyl methacrylate (DMAEMA) to produce microspheres grafted with block copolymer. The ROP of ε-caprolactone from the poly(DVB80-co-HEMA) microspheres was carried out both at room temperature and at 70 °C for different reaction times to produce particles with different graft loadings. The subsequent grafting of poly(DMAEMA) blocks using ATRP led to significant particle size increases and to high amine loadings of 5.10 mmol/g of dry particles. The grafted particles were characterized using ESEM, FT-IR, 1H NMR, Coulter particle sizing, and potentiometric titration.