Valorization of fly ash as a harmless flame retardant via carbonation treatment for enhanced fire-proofing performance and mechanical properties of silicone composites

The Flame-Retardant Mechanisms and Preparation of Polymer Composites and Their Potential Application in Construction Engineering

“…Once burned, an inorganic oxygen insulation and insulation protective layer, containing Si and/or Si-C bonds characteristic of polysiloxane, is formed. In this way, the thermal decomposition of polymer materials is inhibited, and the escape of combustion decomposition products is also prevented, realizing the characteristics of flame retardancy, low smoke production and low toxicity [ 80 , 81 , 82 , 83 ].…”

Flame Retardant Coatings: Additives, Binders, and Fillers

“…Other than that, fly ash can be filled into polymer foams to enhance the flame retardant properties of the foam materials, such as styrene and urethane foams [ 295 ]. Basically, fly ash is inert to flame, which does not emit toxic gases or smoke, which is crucial for environmental issues, and its use has the potential to save money by reusing waste materials as mentioned previously [ 296 ]. Apart from that, the use of fly ash is considered a nontoxic flame retardant filler for flame-proofing polymeric composite materials, as it has shown no harmful effect during its reaction [ 297 ].…”

“…Meanwhile, for other applications, fly ash carbonation has the ability to improve the mechanical and flame-proofing properties of silicone rubber composites. The addition of carbonated fly ash to silicone rubber increases the composites’ penetration time (26 times) as compared with neat cured silicone rubber [ 296 ]. Meanwhile, this carbonated fly ash exhibits up to 3 times higher penetration when compared with silicone rubber composites filled with other fillers, such as aluminum trihydroxide and magnesium hydroxide, which are commonly used fillers [ 299 ].…”

Viscoelastic behaviour of poly(ether-ketone)/fly ash composites fabricated by powder metallurgical route

“…The main constituents of coal FA typically include silica, alumina, iron oxide, and calcium, with varying amounts of carbon. 11–18 As per ASTM C618, FA can be classified as either class F or class C. 11,15,17,19–25 If the FA contains over 70% by weight of SiO 2 , Al 2 O 3 , and Fe 2 O 3 and has low levels of lime, it falls under class F. On the other hand, if the FA contains between 50% and 70% by weight of SiO 2 , Al 2 O 3 , and Fe 2 O 3 and has high levels of lime, it falls under class C. Generally, class C FA (high-calcium) is derived from burning low-grade coals such as sub-bituminous coals or lignite. This type of FA can exhibit cement-like characteristics and can self-harden when it comes into contact with water.…”