Abstract
Five epoxy resins of different chemistry and functionality were cured with DDS (4,4′-diaminodiphenyl sulfone) using 2, 8 and 14 h curecycles. Both Differential Scanning Calorimetry (DSC) and Thermomechanical Analysis (TMA) were used to characterize reaction behavior and cured properties of the resin systems. In addition, static mechanical tests and density measurements were integrated with the thermal characterization methods to correlate resin properties with process time. Flexural three-point bending experiments showed that the resins tended to have higher yield stress and toughness values at extended cure times. The improved mechanical properties could be attributed to the full development of the epoxy molecular structure, in the form of cross-linked networks and molecular rearrangement. These results suggest that extended cure times or high temperature post-curing may be required to obtain the resin's ultimate mechanical properties for high performance composites.
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The authors would like to thank Dr. Andri Filippov of Shell Development Company for his interest in this work. Financial assistance and material support for this research were provided by Shell Development Company while instrument support was provided by TA Instruments through project support to the Polymeric Composites Laboratory of the University of Washington.
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Chinn, D., Shim, S.B. & Seferis, J.C. Thermal and mechanical characterization of high performance epoxy systems with extended cure times. Journal of Thermal Analysis 46, 1511–1525 (1996). https://doi.org/10.1007/BF01980758
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DOI: https://doi.org/10.1007/BF01980758