Introduction of phosphorus into the polyethyleneterephthalate molecule—II. A study of the influence of the modifier on the properties of polyethyleneterephthalate

The influence of the sodium salt of diethylphosphite, introduced as modifier, on the properties of polyethyleneterephthalate molecule is examined. It is shown that the detrimental effect of the salt on the normal progress of the reaction can be reduced if it is introduced at a later stage of the process. The phosphorus-containing polyethyleneterephthalate so obtained exhibits significantly improved resistance to combustion.