Experimental investigation of the mechanical properties of PTFE scrims under high temperature conditions

Abstract Polytetrafluoroethylene (PTFE) scrim has become one of the most commonly used high-temperature flue gas filter materials due to its well-recognized performance in high temperature conditions. In practical engineering applications, some failure cases of PTFE scrim have been reported in the industry. However, few studies have been carried out to investigate the mechanical properties of PTFE substrate under such similar conditions. In this study, six common PTFE scrims were selected and subject to tensile tests at a temperature ranging from 25 °C to 260 °C. The test results show that the stress-strain curve of the PTFE scrim changes significantly with increasing temperature and PTFE scrim undergoes different stretching stages. Excessive elongation affects the service lifetime of the filter material. The elongation at break of the PTFE scrim increases slightly with increasing temperature. In the whole temperature range, the strength decreases significantly with the increase of temperature. Especially when below the glass transition temperature, the strength of the PTFE scrim decreases almost linearly with the increase of temperature. When the temperature reaches 260 °C, the strength retention of PTFE scrim is only 20% of that at 25 °C. This study also evaluates the influence of the factors affecting the strength retention of PTFE scrim by grey correlation analysis. The single yarn diameter and basic weight have the greatest impact. This finding will provide guides and insight for the PTFE scrim manufacturing industry in the aspect of optimizing the mechanical properties of product under high temperatures.