IMPROVING THE FLAME RETARDANCY USING NANOPARTICLES IN CABLE INSULATION

Abstract

Al(OH)3 (ATH) and Mg(OH)2 (MDH) like materials are frequently used as flame retardants due to their ability to form water and oxide-based substances under the influence of heat. In this study, it is aimed to produce cable insulations with improved flame retardant properties by synthesizing nano-sized Mg(OH)2 and using this material together with EVA (ethylene-vinyl-acetate) copolymer and micro-sized Al(OH)3 and Mg(OH)2 . The study can be divided into four parts. In the first part, the flame retardant properties of ATH and MDH were compared. In the second part, different raw materials were used for the synthesis of Mg(OH)2 nanoparticles; in the third part, the synthesis was carried out at factory scale and compared with the commercial product. The samples were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), X-Ray diffraction analysis (XRD), X-Ray fluorescence analysis (XRF) and Thermogravimetric analysis (TGA). In the last part, different amounts of nano-sized Mg(OH)2 particles were added to the formulas using both ATH and MDH; the effects on flame retardant performances were investigated by the Limiting Oxygen Index (LOI) test and the vertical burning test. Mechanical properties such as elongation and tensile strength were also studied. It has been observed that the synthesized Mg(OH)2 particles with a thickness of 5- 10 nm and lengths reaching 900 nm, mixed in ATH based samples at a maximum rate of 9% and in MDH based samples at a maximum rate of 10%; LOI values increased by 26% for ATH based samples and 38% for MDH based samples. However, considering the losses in mechanical properties with the increase of nanoparticle additive, it has been seen that a maximum rate of 5% nano-sized Mg(OH)2 can be added. Even in this case, the LOI values increased by 8.6% in ATH based samples and 26% in MDH based samples.