AFM study of the morphology of elastomers based on polyurethanimides with various rigid and flexible fragments

Abstract

The morphological characteristics of the surface of a number of films of elastomers based on polyurethanimides (PUI) were studied by atomic force microscopy (AFM). Significant differences in the surface morphology of PUI films were found depending on the composition: from granular morphology with different grain sizes or spongy morphology with nano - and submicron pores and cavities on the surface, to spherulitic morphology. It is shown that the roughness of the free surfaces formed during the films formation from the solution is significantly lower than the roughness of the surface which was in contact with the substrate. The influence of the chemical structure and size of the rigid diamine fragments in PUI macromolecules on the morphology of the film surface and the presence of different phases in the AFM torsion mode is established. The comparison of the deformation and strength characteristics showed high values of the elongation at break (more than 1400%) in the PUI films with a developed porous structure of both surfaces. The results obtained show the need to control and take into account the morphological parameters of the surface layers of products made of highly elastic imide-containing materials for their use for technical and other purposes. Keywords: synthesis of polyurethanimides, atomic-force microscopy, elastomer films morphology, surface roughness, viscosity and strain-strength characteristics.