Abstract: The solid-state high-resolution variable-temperature¹³C NMRexperiments(including¹³C CP/MAS,¹³C PST/MAS,¹³C DD/MAS and contact time measurements)were carried out on a main-chain liquid-crystalline polyurethane elastomer based on poly(tetramethylene oxide)(PTMO),hexamethylene diisocyanate(HDI) and 4,4'-bishydroxyethyloxybiphenyl(HB2)from room-temperature to 96℃.The HDIand HB2 segments which play the role of hard segmehts of the elastomer were found to be crystalline.The inter-molecular or inter-segmental hydrogen-bonds formed between the carbonyl group and the NHgroup were found to gradually decompose with the increasing of temperature,Asecondary transition of the HB2 crystal was observed at temperatures well below the meltingpoint of the sample.

Key words: Main-chain liquid crystalline polyurethane elastomer, Morphology structure, Hydrogen-bonding interaction, Solid-state high-resolution variable-temperature ¹³C NMR