peptide bond

Although the methylene unit is a flexible chain, the amide group is a rigid bond because the strong polarity and large amount of hydrogen bond.

The results may indicate that carbonyl groups of MMA unit forms interassociated hydrogen bonds with amide groups of MAAM.

The substitution of OH adjacent to the amide group at the end of a cleaved alkyl chain may be caused by the presence of oxygen during UV exposure.

The a peak is believed to be associated with the glass transition ([T.sub.g] PA 6), the [beta] peak is due to segmental motion of the amide groups which are not bonded to other amide groups ([T.sub.[beta]]) (23).

The effect of water on polyamide properties, such as the glass transition and the mechanical behavior, is well documented (3-20); due to the presence of polar amide groups along polyamide chains, strong interactions between polyamide and polar solvents like water can be formed.

These results confirm the hydrogen bonding interaction between the amide group and urethane groups of PA6 fiber and CPU thin film coating.

The amide group, -CO-NH- is identified by bands associated either NH or C=0 function.

Aliphatic polyamides (PAs), also called nylons, are a class of semicrystalline polymers that contain amide groups which are intercalated along linear alkane chains [1].

Comparison of PIBSA and PIBSA-MEA IR-spectra [16] shows that release of succinic anhydride at interaction of PIBSA with monoethanol amine is followed by formation of amide group with characteristic frequency of valent fluctuations v(NH) = 3150.3300 [cm.sup.-1] which practically matches the frequency of absorption of N[H.sub.4.sup.+].

The available FTIR spectral evidence showed that the Fractions 4 9 and 10 probably contained methyl/aryl/ketonic/carboxylic acid/acid anhydride/amine/nitrile or some secondary amide group along with some OH groups due to some alcohol or phenol.

PNVCL contains hydrophilic carboxylic and amide groups, where the amide group is directly connected to the hydrophobic carbon-carbon backbone chain.

[sup.13]C NMR spectrum also supported the presence of amide group from the deshielding value of carbon attached to -CONH group at [delta] 169.3 ppm and carbonyl group (part of a five member ring) at [delta] 169.47 ppm.

The intramolecular polar amide group of PA6 can be found in hydrogen bond, increasing the intermolecular forces, and exhibiting relatively high strength, good toughness, chemical and abrasion resistance, and so forth.

There are signals belonging to the aromatic substituent on the amide group and three more at 8.54 to 8.06 ppm, 8.34 to 7.95 ppm, and 7.87 to 6.70 ppm for aromatic benzophenone core.

The [sup.13]C NMR spectrum of 3 contains peaks at 13.16 ppm for methyl group bound to steroid nucleus; at 21.66-114.44, 124.60, and 132.46-154.76 ppm for steroid moiety; at 115.30, 125.00-129.36, and 163.56 ppm for phenyl bound to amide group; at 170.32 ppm for amide group; and at 219.76 ppm for ketone group.