The Physical Properties of Lignin

Stable Isotope Tracer Methods in Lignin Research (Laboratory Manual for a Beginner)

“…This is because the macromolecular structure of the CML lignin is a three-dimensional condensed structure that is quite different from the structure of the secondary wall lignin 26) . Examination by the nondestructive methods such as high-resolution solid state NMR 27,28) or other non-destructive spectroscopic methods 29) is recommended for obtaining information on the whole lignin including CML lignin. The mechanical isolation of CML fraction introduced by Whiting 25) or by Westermark 30) combined with the 13 C tracer methods will be useful for better understanding of the heterogeneous nature of lignin in the tracheid walls.…”

Studies of lignin-degrading fungi and enzymatic delignification of cellulosic materials

“…For wood subjected only to -enzyme attac.k and solution i~ formamide, lignin showed a molecular weight distribution with peaks at 1300, at 8500, and over 14000 (Brown et al, 1968). Other results vary between 250 'and 17000000 (Brauns, 1949;Goring, 1971).…”

“…Lignin is not soluble in water, and this property is often the basis for its recovery by precipitation. It is also insoluble in ether and benzene (Brauns, 1949). It is somewhat -22soluble in neutral solvents such as dioxane, ethylene glycol, acetone, and nitromethane (Goring, 1971).…”

“…The heat of combustion of lignin, calculated from microbially rotted woods, is approximately 7970 calories per gram (Kawase, 1962). The density of lignin preparations is usually reported in the range of 1.36 to 1.45 grams per cubic centimeter (Brauns, 1949), whereas because of its spongelike structure its apparent specific gravity is only 0.345 to 0.352.…”