ELECTRICALLY CONDUCTIVE COMPOSITES BASED ON EPOXY RESIN MODIFIED WITH GRAPHENE

The development of composite materials based on polymers modified with carbon nanostructures (CNS) is a promising area of scientific research as their application allows one to more efficiently improve the functional properties of polymers in comparison with other modifiers. The paper deals with the study of the electrically conductive properties of an epoxy resin modified with the expanded graphite compound (EGC), which was previously modified with the phenol-formaldehyde resin (PFR) by ultrasonic treatment in an aqueous solution. The authors flocculated the resulting concentrated dispersion of EGC with PFR with the acetic acid, filtered and washed with water. The PFR-modified EGC aqueous paste was introduced into the ER matrix by the mechanical stirring in a three-roll mill. The study proved that the modification of RSF with FFS before introduction into the epoxy matrix contributes to the better distribution of the carbon material, as well as to the decrease in the size of its particle aggregates. The authors carried out the investigations of the electrical conductivity of the composites obtained by hot curing, according to which they found that samples based on epoxy resin containing 9 wt.% graphite modified with PFR had the maximum electrical conductivity of 6.2×10^-4 S×cm^-1, which was 2 orders of magnitude higher than the electrical conductivity of samples using graphite without preliminary processing. The percolation threshold was observed at 3 wt.% graphite in the epoxy composite. The obtained results prove that the use of EGC modified with PFR as the epoxy resin filler allows achieving higher electrical conductivities than when using untreated EGC. Moreover, the use of PFR for the EGC modification has an advantage over other surfactants as, due to the interaction of active PFR molecules with the epoxy resin molecules, there is no need in further removal of the surface-active substance (SAS) from a composite.

electrically conductive composites, epoxy resin (ER), phenol-formaldehyde resin (PFR), graphene, graphene nanoplatelets (GNP), ED-22 resin, expanded graphite compound (EGC)