Tg and rheological properties of triazine-based molecular glasses: incriminating evidence against hydrogen bonds.
Bis(mexylamino)triazines have been identified as a family of compounds showing an exceptional propensity to form glassy phases as opposed to crystals. The particularities of this family of compounds are their ability to self-assemble through hydrogen bonding in well-defined patterns to form supramolecular aggregates which pack poorly and the wide range of glass transition temperatures (T(g)) that can be attained through minor structural modifications. Representative bis(mexylamino)triazines were studied by rheology to establish correlations between their rheological properties and their molecular structure, and all compounds were found to behave in a similar fashion except for the temperature at which glass transition takes place. FTIR and NMR spectroscopy experiments were performed on the molecular glasses studied herein; comparisons between the viscosity, T(g), hydrogen bonding, and association constant (K(a)) in CDCl3 solution have revealed a relationship between the rheological properties, the T(g) of the molecular glasses, and the extent and strength of hydrogen bonding present in the material.
Plante
André
A
Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, K7K 7B4 Canada.
Mauran
Damien
D
Carvalho
Simão P
SP
Pagé
J Y S Danny
JY
Pellerin
Christian
C
Lebel
Olivier
O