Temperature Dependence of Hydrogen Bonding in Toluene Diisocyanate Based Polyurethanes

Morphology and conductivity changes in a thermoplastic polyurethane‐based copolymer consisting of different soft segments

“…O bond) represents the degree of phase mixing between hard and soft segments. Recently, several studies have attempted to elucidate the relationships between the structure and properties within TPUs with Fourier transform infrared (FTIR) spectroscopy [12][13][14][15][16][17][18][19][20][21][22][23] and differential scanning calorimetry (DSC). [23][24][25][26] Seki and Sato 27 and McLennaghan and colleagues 28,29 proved that the doping of lithium salt to TPUs results in an increase in the soft-segment T g and a loss of the higher temperature endothermic transitions.…”

A Dynamic Mechanical Study of Phase Segregation in Toluene Diisocyanate, Block Polyurethanes

“…These materials were found to give rise to a smaH angle, x-ray-scattering intensity maximum which became more pronounced as the hard-segment content increased (15). The x-ray ~results indicate that these materials display some phase segregation, but •no hard-segment relaxation could be detected by dynamic mechanical testing as carried out in this study because of the low modulus of these materials above the a relaxation.…”

“…The glass transition for both isomers was found to be in the region -50° to -60°C, above the literature value for high molecular-weight PTMO, -84°C (19). The elevation of the soft-segment Tg over that of the pure PTMO homopolymer can he attributed to a combination of the copolymer effect and effective crosslinking of the PTMO ether oxygens by hydrogen bonding with the diisocyanate amine group, an association which has been found to be significant for block copolyurethanes (13,14,15).…”

“…Schneider, Paik Sung, and co-workers have completed an extensive study of TDI polyurethanes (12,13,14,15). This work differs from previous studies by the separate characterization of block polyurethanes prepared from the two isomers of TDI.…”

Preparation and properties of waterborne polyurethane–urea anionomers. I. The influence of the degree of neutralization and counterion

“…Some researchers have reported that the band centered around 1725 cm Ϫ1 is attributable to the stretching of urethane carbonyl groups, whereas the urethane carbonyl stretching around 1710 cm Ϫ1 is due to hydrogen bonding in disordered regions. 17,18 This urethane carbonyl stretching around 1710 cm Ϫ1 is attributable to the carbonyl participating in the urethane linkage of interfacial regions or being dissolved in the soft phase. The stretching of the stronger hydrogen bonds in ordered or crystalline regions occurs at a lower frequency around 1695 cm…”