INCREASING FLAME RETARDANCY FOR POLYETHYLENE RESIN REINFORCED BY HYBRID FIBERS BY USING SURFACE COATING LAYER FROM ZINC BORATE - ANTIMONY TRIOXIDE

zinc borate and antimony trioxide was used as a surface coating layer of (5mm) thickness with weight percentage (50%:50%) for each other to increase the flame retardancy for polyethylene resin (GT 8010) reinforced by Boron fibers ,this system was exposed to gas flame (2000ºC) with (10 mm and 20 mm) exposure distances. Method of measuring the surface temperature opposite to the flame was used to determine the heat transferred to composite material. The best results were obtained with large exposed distance and percentage from protective layer which is zinc borate and antimony trioxide.