Aramid filament/polyphenylene sulfide staple yarn fabric for pipe rehabilitation: hydrothermal aging and resin impregnation

Cured-in-place pipe (CIPP) technology is an economically and environmentally friendly method for rehabilitation of aged pipes underground. However, the development of liner materials for hydrothermal environments is still in its infancy. As part of this composite, the reinforcing fabric plays a significant role. In this work, a novel fabric consisting of aramid filament and polyphenylene sulfide (PPS) staple yarn was designed and prepared. The resistance of the fabric to hydrothermal conditions and its resin impregnation performance were investigated. Characterization included contact angle, resin capacity, thermogravimetric, thermal shrinkage, interlaminar shear strength (ILSS), yarn debonding and tensile strength test, while the service life was predicted using an accelerated aging method based on the Arrhenius equation. The results indicated that PPS staple yarns significantly enhance the resin wettability, resin capacity, and interfacial strength of the aramid fabric. The PPS staple yarns reduced the resin contact angle throughout the impregnation process and increased the resin absorption capacity from 54.6% to 93.8%. The interlayer shear strength of composites increased from 13.4 to 19.2 MPa. The fabric exhibits high thermal decomposition temperatures and low-dimensional change rate. The hydrothermal aging of the fabrics was conducted at temperatures ranging from 110 to 150°C for 1280 hours. The total number of valid samples reached 270. The long-term tensile strength of the prepared fabrics met the requirements for the liner of district heating pipes. The estimated minimum service life of the fabric is 3.3 years operating at a temperature of 85°C.