SR&NI Atom Transfer Radical Random Copolymerization of Styrene and Methyl Methacrylate: Incorporation of Diatomite Platelets

Abstract

Mesoporous diatomite platelets were employed to prepare various random poly (styrene-co-methyl methacrylate)/diatomite composites by in situ simultaneous reverse and normal initiation technique for atom transfer radical random copolymerization (SR&NI ATRP) technique. Nitrogen adsorption/desorption isotherm, SEM and TEM were employed for evaluating some inherent properties of the pristine diatomite platelets. Conversion and molecular weight determinations were carried out using GC and SEC respectively. Addition of 3 wt% diatomite platelets leads to increase of conversion from 76 to 92%. Molecular weight of poly (styrene-co-methyl methacrylate) chains increases from 12893 to 14907 g mol^-1 by addition of 3 wt% mesoporous diatomite; however, polydispersity index values increases from 1.18 to 1.44. Copolymers composition was evaluated using ¹H NMR spectroscopy. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 67.6 to 73.4 °C by adding 3 wt% of mesoporous diatomite platelets.