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A series of nanocomposites based on poly(ethylene terephthalate) (PET) and exfoliated graphite (EG) are prepared by melt-compounding method and their morphology, structures, thermal stability, mechanical and electrical properties are then investigated. For manufacturing the nanocomposites, EG, which is composed of disordered graphene sheets, is prepared by the acid-treatment and following rapid thermal expansion of micron-sized crystalline natural graphites. It is characterized that disordered graphene sheets of EG are well dispersed in the PET matrix without forming crystalline aggregates even at high EG content of 7.0 wt.%. Accordingly, thermal and thermo-oxidative degradation temperatures of PET/EG nanocomposites are improved substantially with the increment of EG content. In addition, dynamic storage moduli of the nanocomposites increase noticeably with increasing the EG content. The electrical conduction path of graphene sheets in the nanocomposites is formed at ∼5 wt.% EG.

We report structural features and multifunctional properties of nanocomposites based on poly(butylene terephthalate) (PBT) and exfoliated graphite (EG), which are manufactured by melt-compounding technique. Scanning electron microscope and X-ray diffraction data exhibit that graphene platelets of EG are well dispersed and exfoliated in the PBT matrix even at high EG content of 7.0 wt %. Raman spectra support that graphene platelets of EG are interacted specifically with phenyl rings of PBT chains at nanocomposite interfaces. DSC cooling and following heating thermograms of the nanocomposites demonstrate that graphene platelets of EG play a role as effective nucleating agents for PBT α-phase crystals and thus lead to accelerating the overall crystallization of the nanocomposites. Thermal stability of PBT/EG nanocomposites is improved substantially due to the gas barrier effect of graphene platelets of EG dispersed in the PBT matrix, especially at the active oxygen gas condition. Dynamic mechanical modulus of the nanocomposites is also enhanced significantly with increasing the EG content. The electrical volume resistivity of the nanocomposites is decreased dramatically from ∼ 1018 to ∼ 106 Ω cm by forming the electrical conduction path at a certain EG content between 3 and 5 wt %. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012