/lig"nin/, n.1. Bot. an organic substance that, with cellulose, forms the chief part of woody tissue.2. Papermaking. impure matter found in wood pulp.[1815-25; LIGN- + -IN2]
* * *Complex oxygen-containing organic compound, a mixture of polymers of poorly known structure.After cellulose, it is the most abundant organic material on Earth, making up one-fourth to one-third of the dry weight of wood, where it is concentrated in the cell walls. Removed from wood pulp in the manufacture of paper, it is used as a binder in particleboard and similar products and as a soil conditioner, filler in certain plastics, adhesive ingredient, and raw material for chemicals including dimethyl sulfoxide and vanillin (synthetic vanilla flavouring).
* * *▪ organic materialcomplex oxygen-containing organic substance that, with cellulose, forms the chief constituent of wood. It is second only to cellulose as the most abundant organic material on Earth, though it has found relatively few industrial uses other than as a fuel. It is a mixture of complex, apparently polymeric compounds of poorly known structure. Lignin is concentrated in the cell walls of wood and makes up 24–35 percent of the oven-dry weight of softwoods and 17–25 percent of hardwoods. It is removed from wood pulp in the manufacture of paper, usually by treating with agents such as sulfur dioxide, sodium sulfide, or sodium hydroxide. Lignin has a number of industrial uses as a binder for particleboard and similar laminated or composite wood products; as a soil conditioner; as a filler or an active ingredient of phenolic resins; and as an adhesive for linoleum. Vanillin (synthetic vanilla) and dimethyl sulfoxide are also made from lignin.
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