In Situ Synthesis of Polystyrene/SiO 2 Hybrid Composites via a 'Grafting Through' Strategy Based on Nitroxide-mediated Radical Polymerisation

Abstract

Polymer-grafted nanosilica hybrid composites that possess a hard backbone of nanosilica and a soft shell of brush-like polystyrene (PSt) were prepared via a ‘grafting through’ strategy based on nitroxide-mediated radical polymerisation (NMRP) using 2,2,6,6-tetramethylpiperidine-iV-oxyl (TEMPO) as the mediator. Two steps were used to graft PSt chains to the surface of nanosilica: anchoring of vinyltrimethoxysilane onto the surface of nanosilica, and then using TEMPO to trap the radicals produced by the reaction of benzoyl peroxide (BPO) with styrene and the vinyl group in grafted vinyltrimethoxysilane molecules. Finally, well-controlled molecular weight (M_n) and narrow molecular weight distributions (M_w/M_n) of PSt chains were grown from the surface of nanosilica. The prepared PSt-g–SiO₂ hybrid particles have been extensively characterised by FTIR, XPS, TGA, and TEM.