An unambiguous assignment of the main 1H and 13C-NMR resonances of nylon 11 in trifluoroacetic acid solutions has been carried out by using a combination of 1D and 2D NMR beteronuclear techniques(HMQC)．The spin-spin relaxation time measurements at different temperatures and different eoncentmtions provide information about the detailed structure and the relative arrangement of the nylon chains In solution．The results show that the temperature dependence of the relaxation behavior of nylon 11 solution is obviously different from that of ordinary polymer solutions With increasing temperature

the solvation is strengthened

i. e．the interaction between nylon 11 chain segments and solvent molecules is gradually strengthened．This leads to the dissociation of the hydrogen bonding among the nylon 11 chain segments

and the interaction among main chain of nylon 11 is then weakened．As a result the phenomenon of cohesional entanglement of the main chains due to hydrogen bending among them gradually disappeared．In these cases the solvent molecules come to bind the dissociated free CO and NH groups of nylon 11 molecules．The main chains are coiled and aggregated with a shape of random clew with a part of the solvent molecules included

making the motions restricted along with the α methylene protons of the CO groups staying in the interior of this random clew structure．The dependence of the relaxation process of nylon 11 solution on concentrations shows biexponential behavior

which suggests the existence of two states of the polymer．The fast relaxation component rapidly increases with increasing concentration

it corresponds to the increase of the cohesional entanglement of the main chain due to hydrogen bonding among the nylon 11 chains．This behaviour is related to the increase of the eohesional entanglement points in a unit volume．With the increase of the concentration

the nylon 11 solution gradually becomes soft．solid-like.