Table 1.
Estimation of the relative amount of the different species present at the surface of CNF-t, CNF-dansyl/EDC-NHS, and CNF-dansyl/DMTMM with respect to the number of cellulose units.
| Signal integrala | CNF-t | CNF-dansyl/EDC-NHS | CNF-dansyl/DMTMM |
|---|---|---|---|
| C4 (total) | 100 | 100 | 100 |
| CO (total) | 25.0 ± 1.2 | 26.5 ± 1.3 | 30 ± 3 |
| Dansyl-amine (total) | na | 1.3 ± 0.1 | 5.5 ± 0.6 |
| Bonded dansyl-amine | na | 0.9 ± 0.1 | 5.5 ± 0.6 |
| Grafted coupling agent derivatives | na | 3.9 ± 0.2b | na |
| Adsorbed coupling agent side productc | na | 0.3 ± 0.1 | 2.0 ± 0.2 |
| Unreacted CO | 25.0 ± 1.2 | 22.0 ± 1.1 | 17.8 ± 1.8 |
Error bars were estimated at 5% for CNF-t and CNF-dansyl/EDC-NHS, and 10% for CNF-dansyl/DMTMM. Larger error for CNF-dansyl/DMTMM is explained by the lower signal-to-noise ratio of the spectrum.
aAll peak integrals reported in the table were normalized to the corresponding C4 peak integral between 82 and 94 ppm (containing both the narrow and the broad resonances of C4) set to 100.
bCalculated by integrating the deconvolution component at 172 ppm (Fig. 4a), which is mainly coming from EDC-N-acylurea. Contribution from NHS (bonded or adsorbed) cannot be excluded.
cCalculated by integrating the deconvolution component at 161 ppm (corresponding to EDC-urea) for CNF-dansyl/EDC-NHS (Fig. 4a) and at 173 ppm (corresponding to DMTMM side product) for CNF-dansyl/DMTMM (Fig. 4b).