Preparation and properties of polystyrene nanocomposites containing dumbbell-shaped molecular nanoparticles based on polyhedral oligomeric silsesquioxane and [60]fullerene

Abstract

In this study, we first synthesised dumbbell-shaped Janus molecular nanoparticles (MNPs) based on polyhedral oligomeric silsesquioxane (POSS) and [60]fullerene (C₆₀) (POSS–C₆₀) via Bingel–Hirsch cyclopropanation, with the goal of combining their unique physical and chemical characteristics. The successful preparation of this new Janus POSS–C₆₀ was confirmed by NMR, FT-IR and MALDI-TOF MS experiments. Then a co-precipitation method was used to prepare four kinds of polystyrene (PS) nanocomposites, namely, PS/POSS, PS/C₆₀, PS/POSS/C₆₀ (which is a physical mixture of PS, POSS and C₆₀) and PS/POSS–C₆₀. The effect of POSS, C₆₀, POSS/C₆₀ and POSS–C₆₀ on the properties of PS was investigated. SEM results suggest a good and similar dispersion for all of the four prepared PS nanocomposites. The glass transition temperature (T_g) of PS is decreased with increasing filler content in a similar way for the four kinds of PS nanocomposites. Rheological result suggests a similar trend of the storage modulus change with increasing filler content, disregarding the chemical structure of fillers and combination of fillers. However, it was interesting to find that POSS alone is good for mechanical property reinforcement and C₆₀ alone is good for thermal stability reinforcement for PS, while POSS–C₆₀, which is a particle with chemically bonded POSS and C₆₀, exhibit better reinforcement of both mechanical properties and thermal stability compared with pristine POSS, C₆₀ and POSS/C₆₀. Our work provides some new ideas for the preparation of polymer nanocomposites with novel particle shapes and unique properties.