New developments in flame retardancy of glass‐reinforced epoxy composites

Abstract

This work involves the development of novel glass fiber-reinforced composite materials containing a commercially available epoxy resin, a phosphate-based intumescent, and inherently flame-retardant cellulosic (Visil, Sateri) and phenol-formaldehyde (Kynol) fibers. The intumescent and flame-retardant fiber components were added both as additives in pulverized form and fiber interdispersed with the intumescent as a fabric scrim for partial replacement of glass fiber. Thermal stability, char formation, and flammability properties of these novel structures were studied by thermal analysis, limiting oxygen index, and cone calorimetry. The results are discussed in terms of effect of individual additive component on thermal degradation/ burning behavior of neat resin.

Study of the thermal decomposition of flame-retarded unsaturated polyester resins by thermogravimetric analysis and Py-GC/MS

“…That its production remains unchanged on addition of APP suggests that the mentioned polystyrene chain scissions leading to the formation of reactive macroradicals are neither promoted nor hindered by the presence of APP. Overall, APP may promote cross-linking leading to the formation of a "char bonded network" [10].…”

“…These additives achieve their purpose in the condensed phase and their effectiveness is highly dependent on the chemical structure of the polymer; they particularly are effective with high oxygen content polymers [9]. During thermal decomposition, phosphorous is converted to phosphoric and polyphosphoric acids, which consequently promote charring through esterification (cross-linking) of reactive polymer fragments [10]. Formation of carbonised char networks prevent or slow down the transfer of heat and combustible volatiles into the remaining virgin polymer and pyrolysis zone respectively thus 3 retarding the flaming/combustion process [9].…”

“…At temperatures above 260 ºC, APP starts to degrade producing phosphoric acid, which then is converted to polyphosphoric acid which enhances cross-linking of polymer fragments to form a stable char [10]. The condensed phase flame-retardant mechanism of ammonium polyphosphate results in retention of carbon networks hence the observed enhanced residual char.…”

Mechanical performance of heat/fire damaged novel flame retardant glass-reinforced epoxy composites

“…Encouraged by these results, glass -reinforced polyester and epoxy laminates were prepared and studied for flammability properties with a cone calorimeter. In our recent communications [10,11], the effect of different components and physical variables (resin content and thickness of the laminate) on burning behaviour of the laminates has been discussed. In the present paper the effects of fire and heat damage are assessed and the influence of intumescent and flame retardant fibre determined.…”

Halogen-free phosphorus-containing flameretardant epoxy composites

“…(Li, Kang et al et al 2013,) In numerous journal articles, three methods are considered to be effective in endowing epoxy resin and its composites with flame retardancy. One is to incorporate non-reactive flame retardant additives (red phosphorus (Levchik and Weil et al 2006), ammonium phosphates (Wang, Liu et al et al 2009, Lim, Mariatti et al et al 2012, aluminum hydroxide (Zammarano, Franceschi et al et al 2005), intumescence-based (Kandola, Horrocks et al et al 2003, Levchik and Weil et al 2006, Chapple and Anandjiwala et al 2010, Gao and Yang et al 2010), zinc-based (De Fenzo, Formicola et al et al 2009) and boron-based (Yu, Xing et al et al 2016, Zhang, Liu et al et al 2016 flame retardants, etc.). Another one is to develop reactive flame retardants (organophosphorous compounds).…”