Progress Summary: 12-Month Compression Set and Load Retention of Thermally Accelerated Aged Siloxane Specimens (Additively Manufactured by the Direct-Ink-Write (DIW) 3D Printing Technique) Was Measured (Technical Report) | OSTI.GOV

摘要

Motivation: Accelerated aging of polymeric materials is needed to predict their long-term mechanical functionality. Two key metrics used to evaluate their performance are compression set and load retention. A baseline(time=0)mechanical assessment was done prior to initiating the accelerated aging process to acquire initial thickness and load values for future calculation of compression set and load retention.Specimens are beingaged under compressive strain (13%for the current studies) at four different temperatures (25, 40, 55, and 70°C) for at least 1 year; compression set and load retention will be measured at various timepoints. Time-temperature superposition (TTS) will be applied to the isothermal data to obtain long-term predictions. Significance: Compression set is increasing with time and temperature, as expected. The increasing compression set is accompanied by decreasing load retention.The relativelylow compression set indicates the material is performing well.In a previous aging study, the legacy S5370 RTV foam exhibited 40% relative compression set after 12 months at 70°C, which is more than twice that of the DIW material. Progress:Data has been acquired out to the 12-month timepoint. Relative compression set and load retention versus time are shown in Fig. 1.A technical issue with the method of measuring load retention was discovered and previously reported load