POLY(ETHER ESTER)S FROM PIVALOLACTONE, ALKANEDIOLS, AND DIMETHYL TEREPHTHALATE .2. SYNTHESIS AND CHARACTERIZATION

Thermal properties of poly(ether ester)s prepared from pivalolactone ( PVL), a homologous series of alkanediols (nG), and dimethyl terephthal ate via a two-stage melt process were studied. Both the melting and cr ystallization temperatures of the poly(ether ester)s decreased with in creasing length of the alkanediol used. An odd/even effect was observe d, which was explained by assuming a planar zigzag structure. Furtherm ore, it was shown that the structure of the poly(ether ester)s could b e described as consisting of crystalline alkylene terephthalate sequen ces, responsible for the melting behavior, and amorphous nG-PVL units. A Mark-Houwink equation was determined from viscometric data and from the molecular weights of the poly(ether ester)s. It was found that co polymers with molecular weights M(n) greater than or equal to 10 000 c an be prepared by performing the polycondensation step at 275 degrees C for 2.5 h or by applying a postcondensation. Furthermore, upscaling of the process could be carried out from 25 to 1000 g. The poly(ether ester)s were thermally stable up to 280 degrees C and showed a melting behavior dependent upon the alkylene terephthalate block length.