Synthesis and Thermo-Mechanical Properties of Poly(urethaneurea) Elastomers Based on Heterocyclic Cross-linkers and Purine Diamine as a Chain Extender

摘要

This paper presents the synthesis and studies the properties of two series of linear and cross-linked poly(urethaneurea) elastomers, which contain purine derivatives in their backbone chains. The samples in the linear series are chain-extended with 2,6-diaminopurine in various ratios, whereas in the second series mixtures of 2,6-diaminopurine and various cross-linkers were used. The presence of purine rings within these polyurethanes increases structural stiffness due to the rigidity of the purine unit and also because of the intermolecular hydrogen bonds in the urea groups regions. The characterization of the molecular structure of these poly(urethaneurea)s was achieved by FTIR, whereas thermal behavior was observed through thermogravimetric analysis and dynamic mechanical analysis. Mechanical measurements showed greater elongation and tensile strength for poly(urethaneurea)s with a lower content of purine moieties in the hard segment. The strain at break value is lower in the case of cross-linked samples compared to that of the linear purine poly(urethaneurea) series.