HTPB-based Polyurethanes: a Correlation Study Between Morphology and Mechanical Behaviour

Hydroxyl-terminated polybutadiene and tolylene diisocyanate were used to prepare two series of polyurethanes by a two-step process. In the first series, the prepolymers were chain-extended with aliphatic compounds (1,3-propanediol, 1,4-butanediol and 1,6-hexanediol) and in the second, an aromatic chain extender (dihydroxy isopropyl-N-aniline) was used. Some results from mechanical testing showed different trends in comparison with previously reported results for similar systems. These findings were interpreted in terms of reactant reactivity, experimental procedures and morphology. Morphology was studied by means of swelling experiments, differential scanning calorimetry and scanning electron microscopy.