Shukla, Parshuram G. ; Sivaram, Swaminathan ; Mohanty, Baijayantimala (1992) Structure and dynamics of starch crosslinked with urea-formaldehyde polymers by carbon-13 CP/MAS NMR spectroscopy Macromolecules, 25 (10). pp. 2746-2751. ISSN 0024-9297
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Official URL: http://pubs.acs.org/doi/abs/10.1021/ma00036a028
Related URL: http://dx.doi.org/10.1021/ma00036a028
Abstract
Solid-state 13C CP/MAS studies of starch cross-linked with urea-formaldehyde prepolymer (St-UF) have been conducted to elucidate its structure and dynamics. 13C NMR spectra and spin-spin relaxation times (T2,) were obtained for various St-UF samples having different degrees of cross-linking. Line width and T2 measurements of starch carbons show that a maximum degree of cross-linking it obtained at a urea to starch (w/w) ratio of 0.6. Increasing the urea to starch ratio beyond 0.6 leads to competing self-condensation of dimethylolurea. These results also establish that chemical crosslinking occurs through the primary hydroxyl groups located at the C-6 position of starches.
| Item Type: | Article |
|---|---|
| Source: | Copyright of this article belongs to American Chemical Society. |
| ID Code: | 70074 |
| Deposited On: | 18 Nov 2011 12:55 |
| Last Modified: | 18 Nov 2011 12:55 |
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