Synergic enhancement of thermal properties of polymer composites by graphene foam and carbon black

A series of novel polymer composites consisting of graphene foam (GF), carbon black (CB) and polydimethylsiloxane (PDMS) were designed and fabricated. Their microstructures and thermal properties were studied. An excellent dispersion of CB was achieved not only in the space of interconnected GF, but also in the interior of GF arms. Bi-network of thermal transfer path in the composites was made up by GF and CB when CB content reached 8 wt%. The synergic effect of GF and CB on thermal properties was well proved by the good performance of CB and GF co-filled composite. The 8 wt% CB/GF/PDMS composite has much better properties, namely, 222% and 72% higher in thermal conductivity, 40% and 10% higher in storage modulus and much lower weight loss compared to pure PDMS and GF/PDMS composite, respectively. Besides, the long term stability at 100 °C of thermal conductivity proves the applicability of the novel composite. These results signify a promising application as thermal interface materials (TIMs) of the CB/GF/PDMS composite.