Crystal structure and morphology of poly(ethylene terephthalate) single crystals prepared by melt polymerization

Lamellar single crystals of poly(ethylene terephthalate) (PET) have been prepared by our confined thin film melt polymerization method between glass at polymerization temperatures of 150 degrees to 225 degrees C. (010) twinned crystals are frequently observed among these lamellae, especially for those prepared at higher temperatures. Based on [001] and [101] electron diffraction patterns, with a total of 25 independent reflections, the lattice parameters are determined as a=4.657, b=5.836, c=10.831 Angstrom; alpha=96.26 degrees, beta=128.30 degrees, and gamma=106.62 degrees with a calculated density of 1.559 g/cm(3) for a ''perfect'' PET single crystal. Chain packing and molecular conformation in the triclinic unit cell (<P(1)over bar>) were simulated by the Cerius(2) modeling software.