Study of the domain structure of segmented polyether amidourethane by IR spectroscopy and optical microscopy

Blends of thermoplastic polyurethanes and polyamide 12: Structure, molecular interactions, relaxation, and mechanical properties

“…The concentrations of associated end free NH groups found in TPU of different compositions showed that most amine groups (Ն 80%) were associated. 11,12 The NH vibrations, however, did not allow identification of the hydrogen bonds of different types. Most informative data could be obtained by analyzing the A1 band.…”

“…Like other research, we used the absorption band of amide one (A1) referring to the valence vibrations of CAO carbonyl groups and the band of the valence vibrations of NH group (NH) at wave number 3300 cm Ϫ1 , as the absorption bands are sensitive toward hydrogen bond formation. 12,14,15 When hydrogen bonds were formed, these bands shift to the lower-frequency region; the shift value depends on the hydrogen bond's energy. The concentrations of associated end free NH groups found in TPU of different compositions showed that most amine groups (Ն 80%) were associated.…”

“…9,10 In providing a network of physical junctions in TPU, the decisive role is played by hydrogen bonds, which are labile, and thus can be redistributed depending on thermal effects or owing to modifications. 9,11,12 The hydrogen bonds distribution influences the extent of microsegregation in TPU and the set of properties typical of these materials. It was supposed that properties of blended systems of TPU with other polymers would depend on how the added polymer influences the extent of microsegregation of polyurethane.…”