Flame retardant and dielectric properties of glass fibre reinforced nylon-66 filled with red phosphorous

Incorporation of red phosphorous into glass fibre reinforced nylon-66 compo sites not only confers good fire retardancy but also retains good dielectri c properties, that makes them suitable for application as electrical insula tion components. The limiting oxygen index (LOI) and Underwriter's Laborato ry Bulletin 94 (UL-94) flame retardancy rating of the red phosphorous fille d nylon-66 composites increase consistently with their red phosphorous cont ents. However, the arc resistance and dielectric strength were found to dec rease as the phosphorous contents increased. On the other hand, the presenc e of glass fibre not only improves the flame-retardant properties but also plays an important role in improving the dielectric strength of the composi tes. However, the arc resistance reduces significantly with the glass fibre loading. To understand these interesting phenomena, thermogravimetric anal ysis, limiting nitrous oxide (N2O) index, smoke emission properties and gas temperature analysis of the burning polymer during combustion were investi gated. Possible mechanisms are discussed. (C) 2001 Elsevier Science Ltd. Al l rights reserved.