PHASE-BEHAVIOR AND TRANSREACTION STUDIES OF MODEL POLYESTER BISPHENOL-A POLYCARBONATE BLENDS .1. SYNTHESIS, END-CAPPING, AND CHARACTERIZATION OF POLY(2-ETHYL-2-METHYLPROPYLENE TEREPHTHALATE)

The synthesis, end-capping, and characterization of a novel, amorphous polyester, poly(2-ethyl-2-methylpropylene terephthalate) (PEMPT), is described. PEMPT is synthesized by standard two-stage polycondensation techniques. End-group modification employs nucleophilic substitution reactions with heptafluorobutyryl chloride and benzoyl chloride. In addition to the assignment of midchain H-1 and C-13 NMR resonances, end-group resonances of hydroxyl-terminated PEMPTs are identified by proton NMR and confirmed by NMR analysis of the end-capped polyesters. The glass transition temperature (T-g) increases with M(n), following the functional form predicted by Fox and Flory. T(g)s range from 55.2 to 65.4 degrees C with T-g,T-infinity = 67 degrees C. TGA indicates PEMPT to have improved thermal stability compared to linear: aliphatic-aromatic polyesters. PEMPT is soluble in numerous solvents with a solubility parameter of 9.4 (cal/cm(3))(1/2). Observed property differences between the hydroxyl-terminated PEMPTs (as synthesized) and the end-capped polyesters are attributed to the hydrogen-bonding capability of the former.