Influence of two different molecular weight epoxy resins on the glass transition of composites manufactured with expanded graphite

Abstract

Developing composites of epoxy resins containing graphite is important for technological and scientific research. The applications of these systems in electronic devices have been seen as a promising research field. To contribute to this field, we evaluated the influence of exfoliated graphite dispersed in two resins with different molecular weights (M_w). The glass transition was estimated by dynamic-mechanic analysis (DMA) and the modulated differential scanning calorimetry (MDSC). We calculated the parameters of the phantom model, Williams–Landel–Ferry (WLF) and Vogel–Fulcher–Tumman (VFT) equations, and the parameters correlated with the Angell fragility. The results demonstrated a strong influence of the M_w on the glass transition and its crosslinking density. A more homogeneous system with lower fluctuations of potential energy was achieved with higher M_w resin suggesting advantageous for the structural stability of crosslinking.

Keywords

Epoxy resin molecular weight expanded graphite glass transition fragility

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