NMR plant of paper
1995
Paci, M. | Federici, C. | Capitani, D. | Perenze, N. | Segre, A.L.
High quality antique sheets of paper have been characterized by 1H NMR relaxations and 13C CP MAS spectra. Paper can be regarded as a bicomponent material made of cellulose and water plus a small amount of organic and inorganic impurities. Semicrystalline fibrous cellulose, rich in water, is present in the I alpha and I beta forms. The amorphous cellulose, with a low water content, contains a higher amount of paramagnetic impurities and it is characterized by quite short 1H spin-lattice relaxations and by 1-13 C resonances with noticeable chemical shifts. Ad hoc tailored pulse sequences are able to produce 13C CP MAS spectra in which only the amorphous content of paper is clearly observed. It is shown that water is fully bound to the cellulose lattice. It also seems reasonable to formulate the hypothesis that a larger concentration of paramagnetic ions is located in the amorphous fraction of highly degraded paper compared with paper in good condition.
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