Properties of poly(binaphthoxyphosphazene)s were investigated employing molecular dynamics simulations in the original microcanonical ensemble. In particular we have applied our methodology to the case of isotactic poly-(2,2´-dioxy-1,1´-binaphthylphosphazene) (P-DBNP) in order to estimate the vitreous transition temperature Tg, the energy barrier Δμβ for β-relaxation of the BNP unit, and the thermodynamic entropy of the system. According to our results, the transition is consistent with the Adam-Gibbs model and the specific rotation of α and β-relaxations, which varies significantly with the molecular weight Mw. Our results suggest a rapid interconversion between the different proportions of the chiral R and S repeating units (70% and 30%, respectively) of the non-isotactic copolymer below 523 K and a slow atropisomerization of the DBNP units above 523 K which, in agreement with recent predictions on glassy polymer matrices, becomes much faster as the temperature approaches Tg ~ 573 K.
Áreas temáticas de ASJC Scopus
- Materiales electrónicos, ópticos y magnéticos
- Cerámicos y compuestos
- Física de la materia condensada
- Química de los materiales