Thermal, mechanical and flame spread properties of hybridized flame retardant in oil palm fibre-polyester panel

Abstract

In order to mitigate the start and spread of flame of combustible materials, flame retardants (FR) are incorporated during processing that influences mechanical and thermal properties. In this paper six (6) FR species derived from aluminium hydroxide (ATH), ammonium polyphosphate with gum arabic powder (APP-GAP) a new FR, ATH/APP-GAP hybrid formulation and CB synergist at 0, 12, 15 and 18% loading ratio were developed in oil palm fibre reinforced polyester composites panel using hand lay-up compression moulding technique. The effect of the FR on the mechanical, thermal and flame spread properties were then evaluated. Flame spread results using radiant panel flame spread apparatus show hybrid flame retardant panel traveled less distance of 150 mm from 450 mm of the control without FR which represents a 67% decrease and indicative of a weak available flame spread energy that led to flame extinguishment. Mechanical properties obtained with the universal testing machine reveals improved tensile strength, tensile modulus and flexural strength in the case of the 12%ATH non-hybrid FR by 16.2%, 5.9% and 71.2% respectively, indicative of ATH having great affinity with the polyester resin and effective transfer of stresses. Thermogravimeteric analysis reveals that the 12%ATH non-hybrid FR and the 15%APP-GAP/CB non-hybrid-synergist FR are more thermally stable before degradation began around 376 °C and 391 °C and fully degraded at 421 °C and 415 °C respectively. Char residue at 900 °C also confirms that the non-hybrid synergist residual mass at 17.47% indicative of a rich decomposition nature of APP-GAP–CB into a more stable char structure could be a good flame retardant. The results obtained indicates that the new concept of APP-GAP to formulate an hybridized FR and non-hybrid-synergist in oil palm fibre-polyester panel is feasible to meet the expectations of a good flame retardancy and thermal stability but do not support improved mechanical properties.