e-Polymers (Jun 2024)

Preparation of cardanol-based curing agent for underwater drainage pipeline repairs

  • Li Yu,
  • Wang Guoqing,
  • Guo Yali,
  • Fang Ning,
  • Li Jingxiang,
  • Li Zheng,
  • Li Junhan

DOI
https://doi.org/10.1515/epoly-2023-0190
Journal volume & issue
Vol. 24, no. 1
pp. 105511 – 11

Abstract

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The underwater curing agents have demonstrated promising potential in various applications, especially in underwater repair engineering, yet have proven considerable challenging. Here, we report a cardanol-based curing agent for epoxy resin that achieves robust adhesion to steel and concrete substrates both in air and underwater. Cardanol, paraformaldehyde, and m-phenyldimethylamine are selected as the polymeric monomers to synthesize curing agent by Mannich reaction in the absence of chemical cross-linker agents. The coating is completely cured within 46 ± 1 min in air and 54 ± 2 min under water with an adhesion of 0 or 1 and a hardness of 5H. The impact strength, shear strength, and tensile strength of coating on underwater concrete were 9.58 ± 0.41 kJ·m−2, 13.1 ± 0.3, and 10.5 ± 0.2 MPa, respectively, demonstrating exceptional flexibility and mechanical strength as well as favorable hydrophobicity. This work paves the way for the rehabilitation of underwater drainage network for urban infrastructure and water conservancy projects.

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