FOURIER-TRANSFORM INFRARED-SPECTROSCOPY STUDY ON EFFECTS OF TEMPERATURE ON HYDROGEN-BONDING IN AMINE-CONTAINING POLYURETHANES AND POLY(URETHANE-UREA)S

Three types of amine-containing polyurethanes and poly(urethane-ureas) , N-methyldiethanolamine (MDEA) and/or tetraethylenepentamine (TEPA) a s the chain extender and poly(ethylene glycol) of MW 400 as the soft-s egment component, have been studied by FTIR. The hydrogen bonding in h ard and soft segments was examined for the extent of phase separation, and the microstructure was evidenced by differential scanning calorim etry(DSC). The temperature effects on the hydrogen bonding were also i nvestigated. They show a significant amount of hydrogen bonding betwee n the hard and soft segments. It indicates that there exists a large a mount of partial phase mixing of hard and soft segments compared to th e conventional polyurethanes. The bulky CH3 groups of MDEA in hard seg ments restrict the hydrogen bonding within the hard segments, while th e TEPA-containing urethane-urea polymers have more distinct phase sepa ration. However, all of the polymers studied are amorphous materials s uch that the dissolved soft segments in the hard-segment domains may i nterfere with molecular packing in the domains. It shows that the hydr ogen bonding in these polymers persists up to 200 degrees C. The hydro gen bonding of NH to the ether oxygen decreases significantly at T > 5 0 degrees C.