Epoxy-based intumescent coatings are widely used in oil and gas industries, shopping complexes and petrochemical plants to provide fire protection to the metallic substrates during the event of a fire. The present work shows how the incorporation of basalt fibers as filler material in an epoxy-based intumescent coating enhances its thermal insulation property. Dispersing agents (ethanol or glycidyl ether) were also added to the coating and their effects on the dispersion of the basalt fibers and the thermal performance of the coating were also discussed. Bunsen burner (ASTM E119) and expansion tests were performed to study the influence of basalt fibers' dispersion on the thermal insulation property of the coating. Coatings and their chars were also analysed by Field Emission Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS) analyses. Thermal stability was investigated using Thermogravimetric Analysis (TGA) in the pyrolysis conditions. Fire test results showed that the formulation containing ethanol as dispersing agent provided a higher fire protection, whereby the backside of the steel plate can reach a very stable plateau at 189 ° C after 15 min exposure. It is also shown that the coating reached the highest expansion of 1087% with a very homogeneous char structure. The FESEM images also confirmed that basalt fibers were well dispersed when ethanol was used, whereas aggregates were formed when no dispersing agent was added. XRD and FTIR showed that the presence of boron oxide, boron phosphate, carbon and silica in the formulations which are thermally stable can improve the thermal performance of the intumescent coating. Finally, TGA confirmed that the thermal stability of formulations containing dispersing agents has been improved.

Numerical pictures of (a) CF (b) IFRC-R (c) IFRC-A (d) IFRC-B chars after Bunsen burner test.

Epoxy resin (NPEL-128) was chosen as the binder and polyamide amine was chosen as the hardener (H-2310, WWRC Malaysia Sdn Bhd). Ammonium polyphosphate (APP) (Exolit AP422) (Clariant Malaysia Sdn Bhd) was chosen as an acid source and swelling agent, Expandable graphite (EG) (Mc-Growth Chemical Malaysia Sdn Bhd) was used for charring and expansion agent, boric acid (Merck Malaysia Sdn Bhd) was used as an acid source and melamine (Sigma-Aldrich Malaysia Sdn Bhd) as the blowing agent. The basalt chopped strands were imported from JN Technologies Pvt Ltd. Basalt strands are mainly composed of SiO2, Al2O3, CaO, FeO, MgO, Na2O, Fe2O3, K2O, TiO2 and P2O. The average diameter of basalt fiber was 14 um with a length of 6 mm. The structures of basalt strand are displayed in Fig. 1. Glycidyl ether (HJ EPIOL-ME 101) and commercial grade Ethanol were purchased from WWRC Malaysia Sdn Bhd. The mild steel plates S355 (100 x 100 x 1.5 mm3 and 50 x 50 x 1.5 mm3) were supplied from TSA Industries. They were sand blasted to remove the dust and impurities from the surface of the steel plates and to produce surface roughness that favours adhesion of the coating onto the steel.

Structure of basalt strand.

Comparison of Coatings: The coatings (CF, IFRC-R, IFRC-A, IFRC-B) are compared to an uncoated steel plate under fire conditions.

Performance Over Time: The temperature increase in the coated plates is initially rapid due to thermal degradation and char formation.

Enhanced Fire Resistance: The incorporation of basalt fibers and other ingredients in the coatings significantly improves the fire resistance of steel plates, which is crucial for safety in fire-prone environments.

Material Efficiency:The coatings not only slow down the temperature increase but also maintain lower temperatures over an extended period, providing more time for evacuation and fire control measures.

Structural Integrity: The detailed analysis of the char formation shows that IFRC-B maintains structural integrity with no cracks, ensuring that the coating remains effective throughout the fire exposure.

Micrographs of (a, d) IFRC-R, (b, e) IFRC-A, (c, f) IFRC-B before burning.

XPS analysis was used to examine the elemental composition of the char. The XPS spectra and elemental composition of char residue for IFRC-R, IFRC-A and IFRC-B are presented in Fig. 11, Fig. 12, Fig. 13, Fig. 14 and Table 3. The ratio of carbon content in the residual char for IFRC-B to IFRC-A (58.01%/51.88%) was 1.11:1. Similarly, the residual percentage of oxygen in the char for IFRC-B to IFRC-A (26.2%/35%) was 0.75:1 as shown in Fig. 12. The intensity of the peaks strongly suggests that the char strength and anti-oxidation of the char for IFRC-B are higher than that of IFRC-A. Higher oxygen percentage in the char represents the degree of oxidation of the char which can decrease the strength of the char [23,31,33].

Enhanced Fire Resistance: The use of commercial ethanol as a dispersing agent in IFRC-B significantly improves the dispersion of basalt fibers, resulting in superior fire resistance. This makes IFRC-B highly attractive for industries requiring stringent fire safety measures, such as construction, transportation, and aerospace.

Superior Material Properties:The dense and highly expansive char formed by IFRC-B, along with its low O/C ratio and high residual weight, indicates excellent anti-oxidation properties and thermal stability. These features suggest that coatings using IFRC-B can provide prolonged protection (over one hour) during fires, making them highly desirable for critical infrastructure and high-risk areas.

Competitive Advantage:IFRC-B's performance, notably better than other formulations, positions it as a leading product in the market for fire-resistant coatings. The ability to maintain lower backside temperatures and form a robust char gives it a competitive edge over existing solutions.

Diverse Application Areas:The potential applications of IFRC-B extend beyond typical construction uses. It can be utilized in industries such as oil and gas, marine, and defense, where fire hazards are significant, and superior fire-resistant materials are crucial.

Regulatory Compliance: With increasing regulations and standards for fire safety across various sectors, the demand for advanced fire-resistant materials like IFRC-B is likely to grow. Products meeting high safety standards will be in greater demand, especially in markets with strict fire safety regulations.