COMBUSTION AND SMOKE EMISSION PROPERTIES OF POLY(ETHYLENE-TEREPHTHALATE) FILLED WITH PHOSPHORUS AND METALLIC OXIDES

Incorporation of red phosphorous into poly(ethylene terephthalate) (PE T) confers good fire retardancy. However, the initial rates and levels of smoke emission of these red phosphorous filled PET samples increas e dramatically with increasing loading of phosphous. In order to overc ome these limitations, metallic oxides such as magnesium oxides, alumi num oxide and antimony trioxide are used to replace part of the phosph orous. The smoke suppressant properties of these samples were found to improve significantly as the amounts of metallic oxides increased. In fact, some of the samples exhibit 'synergetic' fire retardancy as the amounts of magnesium or aluminum oxides reach the 'optimum' value. In addition, the magnesium oxide samples always exhibit better fire reta rdancy and smoke suppressant properties than aluminum oxide and antimo ny trioxide samples. In order to understand these interesting behavior s, thermogravimetic analysis, limiting N2O index, and surface temperat ure analysis during combustion were investigated. Possible mechanisms accounting for these behaviors are discussed. (C) 1998 Elsevier Scienc e Limited. All rights reserved.