Esparto grass

Spartgras, n. esparto grass, esparto. Spartopapier, n. esparto paper. Spar-vorrichtung, /. economizing device. 

Many other plant waxes have also been exploited for various uses, including esparto wax, from esparto grass Stipa tenacissima, and Japan wax, from plants of the Rhus species. 

Most structural work on xylan has been done on that from esparto grass and the principal attack made by way of the methyl ether. Xylan can be methylated by heating with methyl iodide and silver oxide,92-93 but complete etherification is difficult and considerable degradation probably occurs. On the other hand, complete etherification is attained by methylation in two operations with potassium hydroxide and dimethyl sulfate to give a dimethylxylan in almost quantitative yield70 showing [< ]22d — 92° in chloroform. Methylation with potassium hydroxide appears to proceed more readily than with sodium hydroxide.70-92... 

Lignin Nitrate (Nitrolignin). A general term employed to designate nitrated products contg lignin, such as wood, straws, jute, esparto grass, flax and hemp fibers (Ref 1)... 

Foure, Mackie Trench patented in 1873 in England an expl based on NC to which were added rosin, lacquer, ozokerite, collodion, glycerin, and charcoal or soot. The same inventors patented in 1876 expls in which NC was substituted by nitrated sainfoin, esparto grass, agave, hemp, flax, straw, hay, Amer aloe and yucca Ref Daniel (1902), 295 773 (Trench, Faure et Mackie)... 

Esparto Wax. Hard vegetable wax extracted from esparto grass, having a mp of 75 C and the abiliry to blend well, emulsify easily, and impart smoothness to products using it Ref CondChemDict (1961), 449-L... 

Esparto grass none present none present 31... 

Esparto grass (1 3)-D-Xylp none present /3-D-Xylp-(l — 2)-L-Ara 20, 33... 

The Hemicelluloses of Esparto Grass (Stipa tenacissima L.). The Arabinose-rich... 

Xylan from wood has received somewhat less attention from carbohydrate chemists than has the xylan from such rich sources as wheat straw, corn cobs, and esparto grass. However, specific optical rotations of the xylans obtained from the aforementioned sources are of the same general order of magnitude as those of some xylans obtained from wood. Yundt crystallized xylans from paper birch and from barley straw as sphero-crystals, and compared their properties (see Table VII). 

From methylatioii data and molecular-weight determinations, a structure for esparto-grass xylan ([a] D —92°, in aqueous XaOH) has been suggested by Hirst and associates. The molecule consists of about 75 (3-D-xylopyranose units linked 4- 1, with a single branch point (3 —1) linkage. A similar structure has been proposed for a xylan isolated from... 

Fig. 14.—Polymer Single Crystal from Esparto-grass Xylan. (Screw dislocations and lamellar texture are typical of these crystals, which contain folded polymer-chains. The insert shows the schematic diagram of the electron diffractogram that corresponds to the dry crystal form (see Section V,l, p. 460), and confirms that the molecular axis is normal to the lamellar plane).

Hemicelluloses are non-cellulosic low molecular weight polysaccharides that are found together with cellulose in plant tissues 1311. In the cell walls of land plants, xylan is the most common hemicellulosic polysaccharide, representing more than 30% of the dry weight 1321. Most xylans are heteropolysaccharides which are composed of 1,4-linked (3-D-xylopyranosyl residues 133, 134, 135). This backbone chain is substituted with acetyl, arabinosyl, and glucuronosyl residues 133. Homoxylans, on the other hand, consist of xylosyl residues exclusively and have been isolated from esparto grass 136, tobacco stalks 137, and guar seed husk 138. ... 

Marchessault and his coworkers studied, in more detail, similar single crystals of a true xylan from esparto grass. As may be seen from the electron micrograph (see Fig. 5), the hexagonal platelets are similar to those obtained by Yundt, and form more-or-less perfect hexagons. The layer... 

The individual fibres of cellulose are very strong and of varying lengths, e.g. esparto grass 1.5 mm, coniferous wood 3.5 mm and broadleaf wood 1.2 mm, and those that are preferentially used for paper and board are between about 1 and 4 mm in length. 

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