Unit cell dimensions of poly(ethylene terephthalate)

摘要: The density of crystals poly(ethylene terephthalate), (PETP), Qc is checked by X-ray diffraction assuming a triclinic unit cell and the indices reflections as found Bunn. following dimensions are found: = 4,48A, b 5,85A, c 10,75 A, α 99,5°, β 118,4°, γ 111,2°. This gives 1,515g/cm3 which about 4% higher than that reported Bunn. Negligible differences in spacings for samples annealed at different temperatures (120°C–260°C) have been found. Only an annealing temperature 100°C d-values lead to 1,484g/cm3. For undrawn PETP films 250°C same value drawn was obtained on basis Guinier patterns. No systematic variation crystal plane fibers 220°C containing mole fractions 1,7 4,2% diethylene glycol, (2,2′-oxydiethanol), comonomer.