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Suberin is a lipophilic, complex polyester biopolymer of plants, composed of long-chain fatty acids called suberin acids and glycerol. Suberin, interconnected with cutins and lignins, also complex macromolecules, form a protective barrier in the epidermal and peridermal cell walls of higher plants. Suberins and lignins are considered covalently ...
lignin is a heterogeneous, highly crosslinked polymer akin to phenol-formaldehyde resins. It is derived from 3-4 monomers, the ratio of which varies from species to species. The crosslinking is extensive. Being rich in aromatics, lignin is hydrophobic and relatively rigid. Lignin confers structural integrity to plants.
Idealized structure of lignin from a softwood. Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. [1] Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily.
Biopolymers can be sustainable, carbon neutral and are always renewable, because they are made from plant or animal materials which can be grown indefinitely. Since these materials come from agricultural crops , their use could create a sustainable industry.
The lignin is converted to lignosulfonates, which are soluble and can be separated from the cellulose fibers. For the production of cellulose, the sulfite process competes with the Kraft process which produces stronger fibers and is less environmentally costly. idealized scheme for lignin depolymerization by the Sulfite process.
Torrefaction is a thermochemical treatment of biomass at 200 to 320 °C (392 to 608 °F). It is carried out under atmospheric pressure and in the absence of oxygen.During the torrefaction process, the water contained in the biomass as well as superfluous volatiles are released, and the biopolymers (cellulose, hemicellulose and lignin) partly decompose, giving off various types of volatiles. [4]
Lignosulfonates (LS) are water-soluble anionic polyelectrolyte polymers: they are byproducts from the production of wood pulp using sulfite pulping. [1] Most delignification in sulfite pulping involves acidic cleavage of ether bonds, which connect many of the constituents of lignin. [2]
In industrial paper-making processes, organosolv is a pulping technique that uses an organic solvent to solubilise lignin and hemicellulose. It has been considered in the context of both pulp and paper manufacture and biorefining for subsequent conversion of cellulose to fuel ethanol.