Theoretical analysis and interpretation of vibrational spectra of polyacrylonitrile and polymethacrylonitrile

Vibrational Study on the Structure, Bioactivity, and Silver Adsorption of Silk Fibroin Fibers Grafted with Methacrylonitrile

“…Upon grafting, Raman bands at 2989–2939–2873 cm −1 (CH 3 and CH 2 stretching [ 32 , 33 , 34 , 35 ]), 2237 cm −1 (C≡N stretching 32–35]), 1454–1403 cm −1 (antisymmetric CH 3 bending and symmetric CH 2 bending [ 32 , 33 , 34 , 35 ]), 1174 cm −1 (CC stretching + CH 3 and CH 2 bending [ 33 ]), 977 cm −1 (CC stretching + CH 3 and CH 2 bending [ 33 ]), 703–685 cm −1 (CH 3 and CH 2 out-of-plane deformation [ 33 ], C-CN stretching [ 32 ]), and 586 cm −1 (CH 3 and CH 2 rocking [ 33 ], CN bending [ 32 ]), strengthened due to MAN incorporation ( Figure 1 and Figure S1, Supplementary Material ). The absence of any strengthening at about 1625 cm −1 , where C=C stretching falls [ 32 , 34 ], suggests the actual polymerization of MAN onto silk fibroin.…”

“…In the IR spectra, bands at about 2980 cm −1 (CH 3 and CH 2 stretching [ 33 , 34 , 35 ]), 2235 cm −1 (C≡N stretching [ 33 , 34 , 35 ]), 1470–1445 cm −1 (antisymmetric CH 3 bending [ 33 , 34 , 35 ]), 1390 cm −1 (symmetric CH 3 bending [ 32 , 33 , 34 , 35 ]), 1217 cm −1 (backbone skeletal CC stretching + CH 3 and CH 2 bending [ 33 , 35 ]), and 976 cm −1 (ν CC stretching and + vinyl CH out-of-plane bending [ 33 , 35 ]) were identified as markers of MAN grafting ( Figure 2 and Figure 3 ). At increasing weight gain, these bands were observed with progressively increasing intensity ( Figures S2 and S3, Supplementary Material ); the A 1217 /A 1230 absorbance ratio was found to correlate well with the MAN content ( Figure 6 ).…”