Mesoporous diatomite-filled PMMA by in situ reverse atom transfer radical polymerization

Mesoporous diatomite was employed to synthesize different poly (methyl methacrylate)/diatomite composites. Diatomite platelets were used for in situ polymerization of methyl methacrylate by RATRP to synthesize tailor-made poly (methyl methacrylate) nanocomposites. FTIR spectroscopy, TGA, nitrogen adsorption/desorption isotherm, SEM, and TEM were employed for evaluating some inherent properties of pristine diatomite platelets. Conversion and molecular weight determinations were carried out using GC and SEC, respectively. Addition of 3 wt% pristine mesoporous diatomite leads to increase of conversion from 84 to 95%. Molecular weight of poly (methyl methacrylate) chains increases from 8600 to 9400 g mol(-1) by addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increase from 1.34 to 1.54. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 75.8 to 81.1 A degrees C by adding 3 wt% of mesoporous diatomite platelets.