Infrared spectroscopic characterization of oriented polyamide 66: Band assignment and crystallinity measurement

Transient Confinement of the Quaternary Tetramethylammonium Tetrafluoroborate Salt in Nylon 6,6 Fibres: Structural Developments for High Performance Properties

“…It is worth noting that, contrary to Vasanthan et al [ 58 , 59 ], the above FTIR results found in this research study do not show any crystalline phase peaks at 924 cm −1 for any of the types of the nylon 6,6 fibres considered.…”

“…The band at about 949 cm −1 is found to be compatible with the breathing of the NC4 skeleton, although that band at 1049 cm −1 can be assigned to the stretch vibration modes of the [BF 4 ] anions groups too. It is worth noting that, contrary to Vasanthan et al [58,59], the above FTIR results found in this research study do not show any crystalline phase peaks at 924 cm −1 for any of the types of the nylon 6,6 fibres considered. It is worth noting that, contrary to Vasanthan et al [58,59], the above FTIR results found in this research study do not show any crystalline phase peaks at 924 cm −1 for any of the types of the nylon 6,6 fibres considered.…”

“…It is worth noting that, contrary to Vasanthan et al [58,59], the above FTIR results found in this research study do not show any crystalline phase peaks at 924 cm −1 for any of the types of the nylon 6,6 fibres considered. It is worth noting that, contrary to Vasanthan et al [58,59], the above FTIR results found in this research study do not show any crystalline phase peaks at 924 cm −1 for any of the types of the nylon 6,6 fibres considered. Moreover, the FTIR spectra showed four new absorption bands for the 3 wt.% as-spun salt-confined nylon 6,6 fibres at the wavenumbers 1494 cm −1 , 1054 cm −1 , 1041 cm −1 and 951 cm −1 .…”

“…However, the FTIR peak at 1180 cm −1 for the neat fibres does not change its position due to either the salt-confinement or due to the hot drawing processes—this peak is used as a reference band for the nylon 6,6 fibres. This observation of assigning the 1180 cm −1 band as a reference band for the nylon 6,6 fibres was also mentioned by Vasanthan and Salem [ 58 ] for the FTIR band assignment of the heat-treated nylon 6,6 fibres as can be deduced from Figure 2 a.…”

IR spectroscopy of crystalline polymers from ab initio calculations: Nylon 6,6

“…It should be also noted that, in the case of the doublet of bands predicted at 1194 and 1174 cm -1 the projection method reveals that a significant coupling of different normal modes of the 1D chains is present and thus the trend in intensity cannot be simply interpreted carrying out a one-to-one correspondence with the bands of the 1D chain. Based on these results, it is appropriate to assign the bands observed at 1201 and 1180 cm -1 as markers of crystallinity, confirming the conclusions reported in previous papers [45,46]. On the opposite, it is possible to assign the bands predicted at about 1278 cm -1 and 1216 cm -1 in the crystal as markers of regularity while the bands predicted at 1372 cm -1 , 1387 cm -1 and 1305 cm -1 are enhanced in intensity in the crystal and are assigned as markers of crystallinity (see Table S1).…”