SEMICRYSTALLINE POLYMERS VIA RING-OPENING POLYMERIZATION - PREPARATION AND POLYMERIZATION OF ALKYLENE PHTHALATE CYCLIC OLIGOMERS

Preparation of cyclic oligomeric alkylene phthalates via pseudo-high d ilution condensation of alkylene diols with iso- and terephthaloyl chl orides and conversion to high molecular weight polyesters via ring-ope ning polymerization is described. Sterically unhindered amines such as quinuclidine or 1,4-diazabicyclo[2.2.2]octane (DABCO) catalyze the co ndensation significantly faster than other tertiary amines and are use ful for carrying out this conversion in high yield, in the first direc t reaction of diol and diacid chloride to form cyclic polyesters. The mixtures of oligomeric cyclics melt at 150-200 degrees C, providing li quids of low viscosity. Ring-opening polymerization using tin or titan ate catalysts affords high molecular weight polymers within minutes. C omplete polymerization of PET oligomeric cyclics can be achieved at 18 0-200 degrees C, significantly below the polymer's melting point of 22 5 degrees C, and with molecular weights as high as 445 x 10(3). Polyme rs formed via such a process are more crystalline than conventionally prepared polyesters.