Research on the aging mechanism of polypropylene nonwoven geotextiles under simulated heavy metal aging scenarios

We conducted accelerated aging experiments on two types of polypropylene (PP) nonwoven geotextiles (filament geotextile and staple fiber geotextile), immersing them in five different simulated liquids at temperatures of 25 °C, 55 °C, and 85 °C for 200 days. At 85 °C and a pH of 1, the tensile strength and elongation at break of PP filament materials decreased by 95% and 86%, respectively. The presence of heavy metals(arsenic and cadmium), speeds up the aging process in both types of PP geotextiles. Under identical conditions, these heavy metals can increase the loss of tensile strength in geotextiles by more than 7% in 200 days. Increases in temperature, acidic environment, and heavy metal concentration all contribute to faster aging of these geotextiles. Although filament geotextiles exhibit higher tensile strength and elongation at break, staple fiber geotextiles show a lower rate of tensile strength loss during aging and better maintain their tensile strength in high-temperature acidic conditions. During the aging process, cross-linking and recrystallization occur, both of which control the aging rate and the formation of microplastics.