Compounding of MWCNTs with PS in a Twin-Screw Extruder with Varying Process Parameters: Morphology, Interfacial Behavior, Thermal Stability, Rheology, and Volume Resistivity

1, 2, 3, 5, and 7.5 wt% MWCNTs are incorporated into PS in a twin‐screw extruder at varying speeds, throughputs and extruder barrel temperatures. Increased SME at enhanced processing speeds seems to have the single largest effect in enhancing dispersion. A relative evaluation of PS/MWCNT interactions indicate an interfacial layer growth of 24% for 2 wt% MWCNT at 1100 rpm compared to 18% growth at 500 rpm. Raman analysis does not show an MWCNT peak shift but a constant increase in FWHM is observed irrespective of the MWCNT content. A significant enhancement of thermal stability occurs up to 2 wt% MWCNT loading while 1–2 wt% shows the rheological threshold. The volume resistivity decreases dramatically in a 2 wt% sample processed at 1100 rpm compared to those processed at 500 rpm. Increasing the processing speed from 500 to 1100 rpm lowers the resistivity by 10 orders of magnitude in PS with 2 wt% MWCNTs. Variation in dispersion levels with compounding parameters correlates with enhancements in thermal stability and rheological behavior. Raman spectroscopy and calorimetry are employed to understand MWCNT/PS interactions.