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

Novel glass-reinforced epoxy composites containing a phosphate-based intumescent and inherently flame retardant (cellulosic (Visil, Sateri) and phenol-formaldehyde (Kynol)) fibres have been fabricated. These components are added both as additives in pulverized form and as fibre interdispersed with intumescent as a fabric scrim for partial replacement of glass fibre. Fire testing has been performed using a cone calorimeter at an incident heat flux of 50 kW/m(2) and the results have shown that introduction of the intumescent/FR fibre to the matrix can significantly reduce the peak heat release values and smoke intensities evolved by composites. Mechanical testing in tensile and flexural modes of these samples has shown that inclusion of the intumescent/fibre system does not adversely influence their tensile and flexural properties. The effect of heat on mechanical properties has been observed by heating the samples in a furnace at 400degreesC for 5 min and tested for their flexural and tensile strength retentions. The charred samples remaining after cone exposure were also tested for stiffness test. Some of the samples retained up to 21% of the initial stiffness after being exposed to high heat flux in the cone calorimeter whereas, the control sample was rendered unusable after cone calorimeter exposure. (C) 2003 Elsevier Ltd. All rights reserved.