A new solid-state process for chemical modification of PET for crystallization rate enhancement

It was recently shown that the crystn. rate of poly(ethylene terephthalate) (PET) can be enhanced by introduction of diamide units either by use of comonomer during polymn., or during a subsequent extrusion process. Here, the authors demonstrate an alternative solid-state chem. modification process where the amide groups are introduced into com. PET by exposing the PET pellets simply to vapors of ethylenediamine at 125 Deg, i.e. far below the m.p. of PET. The authors make up for the corresponding decrease in mol. wt. by a subsequent solid-state polymn. They find that the crystn. rate enhancement is at least comparable to that achieved by using talc as nucleating agent. [on SciFinder (R)]