Multi-factor coupled aging and recycling of meta-aramid filter bags

The meta-aramid (PMIA) filter bag is one of the most common filter materials used in high-temperature exhaust filtration. However, the current understanding of the recycling of this material, and the durability and stability in multi-factor coupling environments is limited. In this work, the aging characteristics of PMIA filter bags under multi-factorial coupling were investigated, and the effect of the aging degree on the recycling. Firstly, the performance of the filter bags before and after aging was characterized by FT-IR, mechanical properties, SEM, and EDS analysis. The results show that the mechanical properties and thermal stability of the PMIA filter bag rapidly deteriorated under multi-factor coupling. Moreover, The PMIA can be completely dissolved in a LiCl-DMAc mixed solution. Therefore, LiCl-DMAc mixed solution can be used to dissolve used needle felt and prepare it into a thin film. The light transmission deteriorates of the recycled films made from aged needle felt, while still maintaining good tensile strength (σt) >55 MPa with Young’s modulus (E) >2 GPa. The effect of the aging degree of filter bags on the performance of recycled films was systematically investigated. The whole process does not cause environmental pollution. This study provides useful information for the degradation and recycling of PMIA.