Flame retardancy of polycarbonate enhanced by adding fly ash

Abstract

We have developed a flame-retardant polycarbonate resin whose flame retardancy is greatly enhanced by adding fly ash (a by-product from thermal power plants). Fly ash with comparatively small average particle sizes (<10 mm) raised the flame retardancy of polycarbonate because of the hydrogen bond that forms between the polycarbonate and the hydroxy group on the fly ash surface. This bond primarily improves the heat resistance of the polycarbonate and also isomerizes the polycarbonate to promote carbonization. The polycarbonate with 25 wt% of the fly ash showed good other main characteristics, such as mechanical properties and moldability, comparable to those of a flame retardant polycarbonate reinforced with glass fiber, used for electronic products such as desktop computers, etc. Applying the fly ash eliminates the need to use current retardants such as organic halogen compounds and thus promotes the perceived environmental safety of flameretardant polycarbonate. In addition, being able to use less raw resin by adding the fly ash means that less energy is required to manufacture flame-retardant polycarbonate.

Fly Ash Pollutants, Treatment and Recycling

“…Usta (2012) showed that FA significantly enhanced fire resistance and thermal stability of polyurethane foams due to the inert nature of FA with fire. A similar effect was found with polycarbonate (Soyama et al 2007). …”

A polycarbonate/magnesium oxide nanocomposite with high flame retardancy

“…7,9,15–18 For example, fly ash could improve the flame retardancy by promoting carbonization and forming hydrogen bond between the hydroxyl group on the fly ash surface and the carbonate group of the polycarbonate. 16 Graphite oxide could increase the flame retardancy through forming a continuous protective char layer, which acted as a thermal insulator and a mass transport barrier. 7 Recent studies indicate that combination of physical effect and chemical reaction from inorganic materials may have synergistic effect to improve the flame retardancy.…”

“…15 Therefore, it would be necessary to develop inorganic compounds which not only can improve flame retardany for PC, but also are environment friendly. 7,9,[15][16][17][18] For example, fly ash could improve the flame retardancy by promoting carbonization and forming hydrogen bond between the hydroxyl group on the fly ash surface and the carbonate group of the polycarbonate. 16 Graphite oxide could increase the flame retardancy through forming a continuous protective char layer, which acted as a thermal insulator and a mass transport barrier.…”

Effect of Particle Size and Concentration of Fly Ash on Properties of Polytrimethylene Terepthalate

“…[6,7] In this investigation we studied the effect of fly ash with three varying particle sizes and concentration on the properties of PTT. Recently many investigators studied the effect of fly ash on the properties of thermoplastics and thermosets [8][9][10][11][12][13][14][15]. Fly ash is the finely divided mineral residue resulting from the burning of pulverised coal in thermal power stations.…”