Steam-exploded lignin

Quantitative analysis of phenolysis lignin by 13C NMR has indicated that the amount of phenol bound to the steam exploded lignin is unexpectedly... 

Table II gives a number of derived parameters used to assess the lignin s suitability as a binder. For a full binder, lignins required a minimum of three sites per average molecule for formaldehyde grafting. None of the lignins studied approach this level. At least twice the number of sites found is required for steam exploded lignins and more for the kraft lignin. PF resins have an average of eight sites per molecule, a much higher density than projected, so PF resins are excellent wood binders.

Table 9.1.5. Pyrolysis products at 51(f C of several lignins [6a], The analyzed materials were milled wood lignin (MLW), steam exploded lignin (StE.), a lignin purified by organosolv procedure (Org ), kraft lignin (Kraft), and bagasse lignin (Bag.).

G Bentivenga, C Bonini, M D Auria, A de Bona, and G Mauriello. Fine Chemicals from Singlet-Oxygen-Mediated Degradation of Lignin A GC/MS Study at Different Irradiation Times on a Steam-Exploded Lignin. J Photochem Photobiol A Chem 135(2-3) 203-206, 2000. 

Figure 2. C NMR spectra of A) milled wood lignin B) steam exploded lignin (from Marchessault et al [15]) C) Waterloo pyrolytic lignin. All from poplar wood.

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