Thermomechanical and dielectric properties of novel pyridine-based polyurethane urea elastomers

In this article, novel pyridine-based polyurethane urea elastomers were synthesized from 1,6-hexamethylene diisocyanate and poly(tetramethylene oxide) glycol of molecular weight 1400 which was chain extended with 3,4-diaminopyridine. These new heterocyclic polyurethane urea elastomers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and static mechanical measurements as a function of pyridine moieties content and the crosslinkers structure from the hard domains. This settlement of the amine groups on the pyridine rings realizes weak intermolecular hydrogen bonds compared with other pyridine derivatives studied by us. The molecular dynamics and local relaxation of these polyurethane urea elastomers were investigated using broadband dielectric spectroscopy. Results show that pyridine content slightly increases the glass transition temperature and has low dielectric strength of the segmental relaxation as a result of weaker cohesive domains.