The enthalpy relaxation of an epoxy resin modified by three different concentrations of reactive-Graphitic Nanofibers (r-GNFs) has been investigated by standard and modulated differential scanning calorimetry (DSC). From DSC scan at 10 °C/min following cooling at various rates through the transition region, the apparent activation energy, Δh*, was evaluated. The non-linearity parameter, χ, was analyzed by the peak shift method for samples annealed at temperature Tg −20 °C for different period of time (up to 167 h). The non-exponentiality parameter, β, was determined based on the inflectional slope of the complex heat capacity. The experimental results showed that the incorporation of r-GNFs into epoxy network causes greater non-linearity, higher apparent activation energy, and broader relaxation time distribution than the neat epoxy resin. These values were optimum for epoxy resin with 0.3 wt% of r-GNFs.
Differential Scanning Calorimetry Apparent Activation Energy UHMWPE Ultra High Molecular Weight Polyethylene Pure Epoxy
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The authors gratefully acknowledge the support from NASA through Grant NNM04AA62G. We also gratefully acknowledge Dr. Charles M. Lukehart and Mr. Jiang Li (Vanderbilt University) for providing the functionalized graphitic nanofibers.