222 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1941 



Kunike, of Germany, in 1926 found that purified chitin is soluble 

 in acids, from which the filaments can be spun wet or dry. It has a 

 round or heart-shaped cross section and its tensile strength is 35 kilo- 

 grams per square millimeter as against 25 kilograms per square milli- 

 meter of cellulosic silk. The pale lustrous filaments resemble acetate 

 rayon and real silk. He claims that the production of textiles from 

 chitin offers no commercial difficulties. 



Thor and Henderson, of Visking Corporation of Chicago, 111., have 

 described the production of filaments from regenerated chitin 

 products. The purified chitin in a modified process is xanthated and 

 filaments are obtained by treating it with an alkali and then with 

 carbon bisulfide, filtering, deaerating, and extruding through minute 

 orifices into a setting bath. The films obtained from regenerated 

 chitin resemble those of regenerated cellulose, but differ from the 

 latter in their affinity for dyestuffs. Its dry tensile strength is some- 

 what better than regenerated cellulose, but its wet strength is much 

 lower. The only drawback to its commercial introduction is the 

 insufficient supply of chitin, I understand. 



GELATIN SILKS 



The earliest attempt to produce a commercial textile fiber of a 

 gelatin base was Vandura silk by Adam Miller of Glasgow in 1894, 

 which was not successful owing to its partial solubility in water, 

 and could not be dyed in filament form. This was followed by Bi- 

 chromate silk by Fuchs and Bernstein, in which the glue or gelatin 

 is insolubilized by potassium or sodium bichromate. Gerard, Men- 

 del, and Ohl worked on producing a gelatin filament, but so far no 

 satisfactory and economical textile filament has been produced as far 

 as can be learned. 



OSSEIN FILAMENTS 



Ossein is closely related to gelatin and is obtained from bones by 

 dissolving out the mineral part with phosphoric acid and recovering 

 the ossein by evaporating the mother liquor. There are several 

 methods of obtaining the ossein. Helbronner and Valee have pre- 

 pared such filaments. Early difficulties were brittleness. Carbofil 

 is a German protein fiber obtained by mechanical treatment of horse 

 or ox muscle, previously treated chemically to remove the major 

 portion of soluble proteins. The fibers are 3-8 centimeters long and 

 resemble flax in structure. They are resistant to boiling water and 

 have been used in surgery. 



The Swiss have made a protein fiber known as Marena fiber from 

 hides and leather wastes, which may be mixed with wool in textiles. 



