Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector
Investigation of thermo-oxidative aging of silicone-based adhesives: substantiating separability between environmental and mechanical damages
Silicone polymers are widely used in industrial automobile applications as sealants and are often filled with PDMS resins and silica fillers to improve mechanical properties. In service conditions, Silicone is susceptible to damage and decay mechanisms due to two parallel micro-mechanisms; (i) chain scission and (ii) formation/ reduction of the cross-links, both of which are present in thermal oxidation aging at high temperatures. We found both damage mechanisms to co-occur in the course of thermal aging. In general, long-term isothermal damage (as one type of environmental damage) is often accompanied by mechanical damage. This study aims to understand and describe whether environmental damage can be systematically isolated from mechanical damage throughout the aging process. Quasi-static tensile tests were done to characterize the effects of coupled mechanical & environmental damage on the mechanical behavior. On the other hand, the kinetics of damage in micro-structure was validated through chemical tests such as Fourier-Transform Infrared Spectroscopy (FTIR) and cross-linking density (CLD) analysis to understand the difference between mechanical and environmental degradation. Dynamic Mechanical Analysis (DMA) and Scanning Electron Microscopy (SEM) tests were also utilized for a better understanding of the nature of aging. In the presence of oxygen and heat at 0 (%) relative humidity (RH), a decline in toughness and flexibility is observed with increasing time and temperature. It is primarily attributed to the chain scission during oxidation reactions at high temperatures.
» Publication Date: 09/12/2022
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement Nº 768737
