Syntheses of an azo-group-bound silica initiator and silica-polystyrene composites

Abstract

In this article, we present a facile method for the synthesis of an azo-group-bound silica (SiO2–azo) initiator. The azo groups were introduced onto the surface of silica (SiO2) nanoparticles via facile condensation between 4,4′-azobis-4-cyanopentanoic acid and the alkyl–hydroxyl groups - immobilized on the SiO2 nanoparticle surface under ambient conditions. The polystyrene (PS) chains were grafted onto the SiO2 nanoparticle surface by in situ polymerization with the resulting SiO2–azo as an initiator, and then, the SiO2–PS composite was prepared. The syntheses and properties of the SiO2–azo initiator and the composite were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, gel permeation chromatography, and differential scanning calorimetry techniques. The results confirm that the SiO2–azo initiator and the composite were synthesized successfully. Styrene was polymerized with the initiation of SiO2–azo, and the resulting PS domain accounted for 48.6% of the total amount of composite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011