The flammabilities of a series of polyesters, varying both the diol length and the degree of aromaticity of
the diacid units were evaluated using cone calorimetry. Addition of inorganic additives, copolymerization
with sulfoisophthalate ionomeric units and with the phosphorous flame retarding agent, phospholane,
were also examined. A strong, linear relationship between the polymer carbon:hydrogen ratio
and various flammability indicators was established. The phospholane was demonstrated to produce
only a modest reduction in flammability, whereas the isomeric comonomer produced an unexpectedly
strong reduction in all aspects of flammability tested. Addition of inorganic modifiers resulted in varied,
and relatively modest changes in polyester flammability