Predicting the Long Term Life of Polymer Composites Using Time Temperature Shift Factor (TTSF)

The use of Carbon Fiber–Reinforced Polymers (CFRP) has increased in number of industries i.e. aerospace, automobiles, marine, medical and sports due to their light weight and high strength-stiffness. However, their properties are greatly affected under extreme e environmental conditions i.e. high temperatures and moisture uptake. The paper reports an experimental study to determine the response of IM7-carbon/977-2 Cycom epoxy laminates under different humidity and temprature conditions exposed for different time intervals. Short-term 3-point bending tests using Dynamic Mechanical Analysis (DMA) creep test were used to test the dry and fully saturated samples at various temperature levels. The dry coupons were tested at the room temperature RT and at 60-120 °C with 20 °C increment and then at 130 °C, 150-180 °C with 10 °C increment for each next test. The saturated (wet) coupons were tested at RT, 40 - 120 °C with 10 °C increment in temperature for each next test and at 145 °C, 150 °C, and 160 °C. The time-temperature shift factor (TTSF) principle was applied and it is shown that the viscoelastic behavior of the invetigated IM7-carbon/977-2 epoxy laminates, is accurately predicted through the use of TTSF principle. It has also shown that determining the viscoelastic behavior at elevated temperatures helps to predict temperature below the glass transition temperature using TTSF principle . It has been shown that the long-term life of the material can be relatively easily predicted using TTSF by conducting traditional short-term laboratory tests.