Experimental Design of Fire Retardant Formulations: SMC Low Profile Formulations

Abstract

The problems originated by fire are important enough to carry out studies related to ignition, flame spread, combustibility, and smoke suppression for the purpose of obtaining materials with better fire behaviour. An improvement in fire properties can be achieved using fire retardants and smoke suppressants. Fire retardants can act by means of chemical reactions where the combustion presents radicals with high energy in the gas phase. They can also react physically by several methods: developing a layer which protects the material from ignition on the surface of the substrate, giving off non flammable gases such as H2O, CO2, SO2, HCl, etc., in order to dissolve the flammable gases and withdrawing the oxygen from the fire area in the gas phase, improving certain reactions such as endothermic ones or surface dehydrations. On the other hand, smoke suppressants can also act physically and chemically (by means of Red-Ox reactions) in the condensed and gas phases. The present work focuses on the study of SMC-LP(Sheet Moulding Compound Low Profile) materials which are widely used in sectors such as: automotive, transport and building. In SMC low profile process, the polyester resins are mixed with thermoplastic additives. In this way, the formulation obtained is called low profile due to the contraction inside the mould tends to zero. On the other hand, using the proper process it is possible to obtain fibre reinforced plastics formulations with different fire retardant and smoke suppressants. The main objective of the present work has been an exhaustive analysis of the possible effects and interactions in fire and mechanical properties due to the different fillers added. This study has been carried out by means of an experimental design with statistical analysis of the results. The scope is focused on a further optimisation of these sorts of materials, in order to obtain a wide range of suitable formulations.