On the mechanical properties of poly(ethylene terephthalate). Force-field parametrization and conformational analysis for the prediction of the crystal moduli

✍ Scribed by Carlos Alemán; Sebastián Muñoz-Guerra

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 857 KB
• Volume: 34
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19960415)34:5<963::aid-polb14>3.0.co;2-9

✦ Synopsis

A force-field suitable for the calculation of the mechanical properties of poly(ethy1ene terephthalate) and their relation with the molecular structure of the polymer has been developed. The force-field parameters were derived from quantum mechanical AM1 calculations and tested against thermodynamic and vibrational spectroscopy data available for a set of closely related small molecules. The crystal moduli of the two solid phases known for poly(ethy1ene terephthalate) were estimated by means of this new force-field considering both the isolated chain and the chain within the unit cell. Results were qualitatively consistent with reported x-ray data showing that the triclinic crystal form is stiffer than the mesomorphic phase provided that sample heterogeneities were taken into account. Although overestimated moduli resulted for both cases, divergences with experimental values were found to be slighter than those obtained by other theoretical methods.