Epoxy resin coatings doped with layered double hydroxide for enhanced anti-permeation performance

Excessive permeation from in-service fuel storage tanks at gas stations can lead to serious damage to the environment. Epoxy resin (EP), as a common impermeable coating, its performance may gradually fail due to corrosion and other problems. Layered double hydroxide (LDH), serving as a lamellar inorganic nanofiller, can be incorporated into epoxy resin to improve the anti-permeation properties, while easy agglomeration and poor compatibility of LDH in epoxy resin make the composites difficult to achieve the desired performance. In this work, sodium dodecyl sulphate (SDS) was adopted to connect LDH and epoxy resin from the interfacial enhancement and interlayer regulation points of view. A series of advanced characterizations were applied to analyze the chemical state and morphology of LDH-SDS/EP composite castings. When doped with 3 wt% LDH-SDS, its mass change rate after 28 days of immersion in No.0 diesel fuel was 0.093%, and the flexural strength reached 95.56 MPa, which indicated that the interfacial and interlayer regulation by SDS enhanced anti-permeation performance and effectively alleviated the loss of mechanical properties of the composite coating. Molecular dynamic simulation was further used to reveal the mechanism of enhanced anti-permeation performance by SDS regulation. The results showed that the enhanced anti-permeation performance by SDS regulation could be attributed to the regulated nanofillers of stronger molecular binding with EP matrix and reduced nanofiller/polymer interface. The regulation of LDH can be widely employed to enhance the performance of epoxy resin in extensive applications.