Evaluation of the effect of hydrophobically modified silica aerogel on the ARGET ATRP of styrene and butyl acrylate

Abstract

Abstract Hydrophobically modified silica aerocgel was used for in situ random copolymerization of styrene and butyl acrylate by activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) to synthesize tailor-made poly (styrene-co-butyl acrylate) nanocomposites. Nitrogen adsorption/desorption isotherm, SEM and TEM were employed to examine inherent characteristics of the hydrophobically modified silica aerogel. Conversion and molecular weight determinations were carried out using GC and SEC respectively. Addition of 3 wt% hydrophobically modified silica aerogel leads to decrement of conversion from 67 to 48%. Molecular weight of poly (styrene-co-butyl acrylate) chains also decreases from 15993 to 12401 g mol−1 by addition of only 3 wt% hydrophobically modified silica aerogel; however, polydispersity index values increases from 1.07 to 1.34. Linear increase of ln(M0/M) with time for all the samples shows that copolymerization proceeds in a living manner. TGA results indicate that by increasing hydrophobically modified silica aerogel content, slight improvements in thermal stability of the nanocomposites were obtained. DSC results show a decrease in Tg from 44.2 to 35.4 °C by addition of 3 wt% hydrophobically modified silica aerogel.