ABSTRACT This work investigates the impact of incorporating alumina trihydrate (ATH) on the mechanical properties of glass‐fibre‐reinforced polymer (GFRP) composites, while improving their flame‐retardant performance. The use of ATH has been a promising strategy to increase the flame‐retardant properties of GFRP, which are widely used in civil construction. However, high concentrations of ATH, as those used for reaching better flame‐retardant performance, can impair the mechanical properties. Therefore, through a series of comprehensive experiments and analyses, the research aims to shed light on the relationship between mechanical reinforcement and flame retardancy, thereby paving the way for advanced composite materials with superior mechanical strength and enhanced flame retardancy. To achieve this objective, different concentrations of ATH (40, 50, and 60 phr ) were evaluated within the isophthalic polyester matrix in pultruded GFRP. Flammability testing was carried out using the limiting oxygen index, Mass Loss Calorimeter Cone (MLCC), and UL‐94 test. Mechanical evaluations included tensile and flexural tests to measure the material's strength. Additionally, SEM (scanning electron microscopy) analysis was utilised to examine the material's morphology and identify its constituent elements, allowing for a detailed observation of the distribution and interaction of ATH within the composite matrix. Ultimately, the research concluded that the addition of 50 phr of ATH resulted in a significant increase in mechanical strength, including tensile and flexural strength and modulus of elasticity. These findings indicate that incorporating ATH not only enhances the flame retardancy of GFRPs but also strengthens their mechanical properties, achieving an optimal balance between fire safety and structural performance.
Araujo et al. (Thu,) studied this question.