Impact of silicone oil as an additive on the properties of carbon black-filled acrylonitrile-butadiene-styrene

While carbon black (CB) is frequently incorporated into Acrylonitrile-Butadiene-Styrene (ABS) composites to improve conductivity, UV stability, and other properties, it is widely known to embrittle the polymer. This study explores using silicone oils to recover the ductility and impact strength of CB-filled ABS by leveraging potential molecular interactions. Two silicone oils, polydimethylsiloxane (PDMS) and polydimethylphenylsiloxane (PDMPS), at 0.05 wt% and 0.5 wt%, were incorporated into ABS containing 0.4 wt% carbon black. Molecular, morphological, rheological, thermal, and mechanical properties of the samples were analyzed. Morphological analysis and molecular weight measurements showed that, while PDMS exhibited limited compatibility with CB-filled ABS, PDMPS produced higher apparent molecular weights, higher low-frequency complex viscosity, and a more uniform morphology than PDMS, consistent with stronger molecular/interfacial association of PDMPS in the CB-filled ABS system. These differences after PDMPS addition, especially at 0.5 wt%, were accompanied by recovery of elongation at break and impact strength, two properties markedly reduced by CB, to near-reference levels. Crucially, this recovery was achieved without sacrificing processability, as shown by the maintained Melt Flow Rate (MFR: 15.25 g/10 min for reference vs. 15.00 g/10 min for samples with 0.5 wt% PDMPS). Therefore, PDMPS demonstrates significant potential as an additive for carbon black-filled ABS polymer.