Organosilane-modified maghemite nanoparticles and their use as co-initiator in the ring-opening polymerization of ɛ-caprolactone

Hydroxyl and amino groups were introduced on maghemite nanoparticles surface by grafting of (3-glycidoxypropyl)trimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxy silane, in several solvents including water, toluene and N,N-dimethylformamide. Coating of maghemite particles by a biocompatible and biodegradable polyester, namely the poly(ɛ-caprolactone) was then achieved, by an aluminum isopropoxide-catalyzed ring-opening polymerization of ɛ-caprolactone initiated 'from' the maghemite particles surface. Silane and polymer coating were characterized by TGA and DRIFT spectroscopy. In this manner, nanocomposites containing up to 0.43 g of polymer per gram of maghemite were obtained.