Abstract:

In view of the melt-dripping problem for phosphorus-contatining flame retardant terephthalate (FRPET) during combustion, combined anti-dripping additive was prepared via combination of intumescent flame retardants (IFR) and polytetrafluoroethylene (PTFE). Then combined anti-dripping additive were melt blended into phosphorous-containing flame retardant polyester (FRPE) to obtain modified polyester samples. The thermal properties and flame retardant properties were characterized by means of differential scanning calorimetry, thermogravimetry, limiting oxygen index, horizontal burning test, micro combustion calorimeter (MCC) , cone calorimetry. The results showed that FRPET with 15% of combined anti-dripping additive  (mass ratio of IFR and PTFE is 1:2) can achieve the optimal flame retardancy. Combined anti-dripping additive system has obviously synergistic effect between IFR and PTFE to improve the dripping resistance. The limiting oxygen index value increases to 30% from 25% and the numbers of melt-drops fell to 21 from 46 in 1 min. The char residue at 700℃ increases by 68.77% compared with the control sample (FRPET). In additon, the total heat release and total smoke release decreased significantly according to the MCC and CONE tests.

Key words: flame retardant polyethylene terephthalate, intumescent flame retardant, anti-dripping, polytetrafluoroethylene