Synthesis of poly(ethylene terephthalate) in the presence of perfluoropolyethers. II. Effect of various catalysts

Abstract

AbstractDimethylterephthalate and ethylene glycol have been polymerized to poly (ethylene terephthalate) (PETP) in the presence of perfluoropolyethers (PFPE) using various catalysts. The polymerizations were carried out at high temperature by the usual two‐stage method and the effect of the fluorinated compounds on the polymerization rate was investigated. Selective extractions were performed to estimated the fraction of PFPE bonded to PETP. In the presence of Fomblin ZDEAL®, a telechelic PFPE macromer bearing methyl ester end groups, the polymerization can only be carried out when the fluorinated macromer is added after the first stage is complete, because of the strong decrease of the transesterification rate with all the catalysts used. Polymerizations were therefore performed by adding Fomblin ZDEAL (10% wt) at the end of the first stage; about 30% of the amount of PFPE in the final products was found to be bonded to PETP for all the catalysts employed. In the presence of Fomblin Z/15®, a PFPE which has not functional end groups, the reaction rate is not decreased in the first stage, however, under the same reaction conditions, the intrinsic viscosity of final PETP is greatly reduced and the amount of PFPE in the resulting material is well below that initially added and is almost completely extractable meaning that a very limited fraction of PFPE is bonded to PETP.