Improvement of thermal stability of EPDM by radiation cross-linking for space applications
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The investigation of radiation effects on ethylene–propylene–diene terpolymer (EPDM) loaded with trifunctional monomer (trimethylolpropane triacrylate, TMPTA) at three concentrations (0, 2.5 and 5 phr) was accomplished by isothermal and nonisothermal chemiluminescence spectroscopies, thermal analysis, mechanical testing and scanning electron microscopy. All these investigations indicate the contribution of monomer to the improvement of degradation strength and the possible extension of improved material over the space and nuclear ranges. The monomer loading of 2.5 phr and 50 kGy exposure dose is the optimal conditions for the improvement in thermal strength of polymer. The radiation effect is related to the cross-linking, but the contribution of radiolysis on the thermal stability at 100 kGy must not be discarded. The modified EPDM presents satisfactory functional features related to the material durability. The oxidative degradation and cross-linking, the main ways to high material performances, are the competitive processes through which EPDM is qualified for special operation purposes.
KeywordsEPDM Cross-linking Thermal stability Radiation resistance
The authors of this paper are grateful to Romania Space Agency (ROSA) for financial support of the project “Biosealing for Mars Sample Containment System” 137/2017 that includes the present results.
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