Effect of plasticizer on the electrical, thermal, and morphological properties of carbon black filled poly(propylene)

Poly(propylene) (PP)/carbon black (CB) composites are melt‐blended in a Brabender mixer with varying CB content. With the special‐grade conductive CB, the surface resistivity of PP/CB composite was reduced by 13 orders of magnitudes by increasing the CB content from 0 to 15 wt%. The plasticizer poly(ethylene glycol) di‐methyl ether (PEGDME) is used (0–5 wt%) to improve the dispersion of the CB in the polymer matrix and to reduce the surface resistivity of the composites. But the PEGDME plasticizer used here has no positive effect on the surface resistivity of the composites; in fact, it enhances the surface resistivity value by one order of magnitude at higher concentration (5 wt%). The scanning electron microscopy (SEM) pictures indicate that the presence of foreign material (plasticizer) especially at higher concentration disrupts the continuous carbon network inversely affecting the conductivity values. Finally, the optimization of the input variables (CB and PEGDME loading) is done using the design of experiment approach. POLYM. COMPOS., 38:2472–2479, 2017. © 2015 Society of Plastics Engineers