Synthesis and characterization of well-defined poly (4-chloromethyl styrene-g-4-vinylpyridine)/TiO₂ nanocomposite via ATRP technique

Poly (4-chloromethyl styrene-g-4-vinylpyridine)/TiO₂ [(PCMSt-g-P4VP)/TiO₂] nanocomposite was synthesized by atom transfer radical polymerization (ATRP) technique. The synthesis strategy involved three steps. Firstly, the nano-TiO₂ was modified by 3-(trimethoxysilyl) propylmethacrylate (MPS). Secondly, the modified nanoparticles were dispersed in 4-chloromethyl styrene monomers and subsequently polymerized by a free-radical in situ polymerization reaction to yield PCMSt/TiO₂ nanocomposite. Finally, poly (4-vinylpyridine) was grafted from PCMSt/TiO₂ macroinitiator via ATRP technique with the catalysts of 2,2′-bipyridine (Bpy) and Cu(I)Br in toluene as the solvent. TGA results indicated that no polymers adsorbed noncovalently onto the surface of TiO₂ nanoparticles. Also FT-IR spectra and TEM images investigation provided direct and clear evidence for the presence of PCMSt and (PCMSt-g-P4VP) shell on nano-TiO₂ core particles. Ultraviolet–visible spectroscopy (UV-Vis) investigated that these nanocomposites have improved optical properties potentially acting as visually transparent UV filters.