Effect of the hard segment structure on properties of resorcinol derivatives-based polyurethane elastomers

Two series of polyurethane elastomers were obtained from poly(1,4-butylene adipate) diol and 1,6-diisocyanatohexane, which were then chain extended with resorcinol derivatives such as benzene-1,3-diol, 2,4-dihydroxybenzaldehyde, or 1-(2,4-dihydroxyphenyl) hexan-1-one. This article investigates the effects induced in polyurethane elastomer properties by varying the hard segment composition through changing the amount of aliphatic diisocyanate and through the influence of the chemical structure of the resorcinol derivatives' chain extenders. The different chemical composition and the presence of different dangling chains on the chain extender structure influenced hard segment cohesion, resulting in important effects on the polyurethane elastomer properties. The incorporation of aliphatic diisocyanate alongside the aromatic chain extender leads to changes in the physical and mechanical properties of the polyurethane elastomers compared with aromatic rigid diisocyanates. These polyurethane elastomers were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and mechanical measurements. We synthesized resorcinol-based polyurethane elastomers with aliphatic-aromatic hard segment structures, with the resorcinol addition making it unnecessary to transform phenolic OH groups into aliphatic OH groups.