Avaliação do uso de aditivos antichama halogenados e não halogenados na flamabilidade e nas propriedades mecânicas de compósitos de poliéster/fibra de vidro

Abstract

Over the years, the automobile industry has found itself in the obligation to manufacture automobiles made from polymeric parts, in order to reduce their weight. However, the parts made of composites that have fiber-reinforced polymeric resin in their composition are flammable, causing risk to users. Thus, the use of halogenated additives (Tris (2,3 - dichlorisopropyl) phosphate (D) and Tris (1,3 - dichlorisopropyl) phosphate (F)), commercially known as Datifire FR-2 and Fyrol FR-2, respectively, was evaluated contents of 30 % and 50 % by mass and non-halogenated (alumina) in the contents of 30% and 50 % by mass to delay or extinguish the burning of these materials. Composites made from gel coat, unsaturated polyester resin and fiberglass were obtained by the RTM process (resin transfer molding). To assess the technical feasibility of using these composites, the viscosity and curing time of the resin were evaluated, mechanical properties such as tension, bending and impact and also vertical burning. Despite the increase in viscosity when incorporating the additives, there was no difficulty in injecting the composite. Regarding the curing time, it was found that with the non-halogenated additive, the resin has a curing time shorter than that observed for halogenated additives. It was also found that the increase in the content of incorporation of halogenated additives to the resin increased the curing time. For both additives there were losses of mechanical strength, however it is observed that the higher the content of additives added, the greater the reduction in mechanical properties. Regarding flammability, composites incorporated with alumina undergo ignition followed by a self-sustained burning in the first flame application to the specimen, which prevents the material from being classificated according to UL 94. For composites containing 30 D and 30 F in the first application of flame for 10 s, each specimen supports the flame from 10 to 11 if it goes out, however, in the second application of the flame there is self-sustaining of the flame, which prevents it from being classificated in the UL 94 standard. Composites containing 50 D and 50 F obtained better performance, being classified as V1 according to UL 94. Thus, composites with 50 D and 50 F showed better performance in relation to flammability, however the high content used, makes the parts used in the automotive area, their mechanical properties are reduced. However, the composite with the 50 D additive obtained better mechanical properties than the composite with 50 F. In short, it improves the flame retardant effect of the composite, which reflects in safety for users of collective vehicles, however it is reduced the mechanical strength of the material. [resumo fornecido pelo autor]