Characterization of polypropylene/polystyrene boehmite alumina nanocomposites: Impact of filler surface modification on the mechanical, thermal, and rheological properties

The influences of surface treatment and the concentration of boehmite alumina (BA) particles on polypropylene and polystyrene (PS) (80/20) blends produced via melt compounding were examined. The results show that p-toluene sulfonic acid-treated BA particles yielded the highest stiffness improvement (27.5%), followed by untreated particles (25.7%), and dodecylbenzene sulfonic acid-treated BA particles (8.5%). Transmission electron microscopy revealed that p-toluene sulfonic acid-treated BA particle agglomerates were dispersed in the PS phase, whereas untreated particles formed agglomerations at the interfaces. Dodecylbenzene sulfonic acid-treated particles were poorly dispersed in both matrices. Differential scanning calorimetry showed that both untreated and p-toluene sulfonic acid-treated BA particles acted as nucleating agents in the blend because of the shifting of crystallization peaks to higher temperatures by 12 and 8 °C, respectively. A significant increase in decomposition temperatures occurred upon 7 wt % loading of all types of BA particles into the blend. Heat deflection temperature measurements showed that all types of BA particles improved the thermal properties of the blend.