Incorporation of superparamagnetic nanoparticles into poly(urea-urethane) nanoparticles by step growth interfacial polymerization in miniemulsion

Superparamagnetic materials encapsulated in a polymeric matrix are interesting for several applications, including biomedical, separation, and biotechnology and enzyme immobilization. In this work, superparamagnetic poly(urea-urethane), PUU, nanoparticles were obtained by interfacial miniemulsion polymerization. Magnetite nanoparticles presenting superparamagnetic behavior were obtained by co-precipitation method and after the synthesis the magnetic nanoparticles, MNPs, were coated with oleic acid, OA, to provide a hydrophobic surface. The synthesis of PUU nanoparticles was performed using 1,6-hexanediol as polyol and IPDI as diisocyanate. The MNPs-OA were incorporated in-situ during the interfacial miniemulsion polymerization. PUU with MNPs-OA were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, electromagnetic vibrating sample magnetometry, VSM, and transmission electron microscopy. Results show a high encapsulation efficiency and VSM analysis showed that PUU with MNPs-OA still presented superparamagnetic behavior after the encapsulation step. (C) 2015 Elsevier B.V. All rights reserved.