Compatibility of Thermally Reduced Graphene with Polyesters

The compatibility of thermally reduced graphene (TRG) with multiblock copolyesters, composed of poly(butylene terephthalate) (PBT) segments and poly(tetramethylene ether) glycol segments, was examined in detail. The morphology observed by optical microscopy and scanning electron microscopy showed that the compatibility was enhanced with increasing content of the PBT segment in the polyester. This compatibility behavior was analyzed quantitatively, by using the percolation threshold of electrical conductivity, and then further analyzed by using the Hansen solubility parameters to provide a general quantitative guideline to predict the compatibility of TRG with various polymers. The results suggest that the total solubility parameter, (T), value of TRG is larger than 24.0 (MPa)(1/2), and thus that the compatibility with polymer is enhanced as the (T) value of a polymer increases toward 24.0 (MPa)(1/2). However, this prediction does not fit well in the presence of a comonomer such as acrylic acid, which has a high tendency to hydrogen bond with itself.