Silane treatment of poly (urea-formaldehyde) microcapsules in different pH values

In this study, poly urea-formaldehyde based (PUF) microcapsules containing linseed oil were prepared via in situ polymerization method. The surface of PUF microcapsules was treated using 3-aminopropyltrimethoxy silane-coupling agent (APS) in three different pH values of 4, 7.5 and 11. FTIR spectroscopy was used to study possible interfacial interactions between microcapsules and APS. The morphology of microcapsules was evaluated using SEM micrographs. FTIR results showed that the silane coupling agent molecules bind strongly to the surface of PUF microcapsules in the pH of 4 and 7.5. Chemical bond (Si-O-C) was formed as the result of chemical reactions between Si-OH and the hydroxyl group on PUF microcapsules. SEM micrographs showed that a thin layer is formed on the surface of PUF microcapsules in the pH of 7.5.