. Cyclopedia of textile work : a general reference library on cotton, woollen and worsted yarn manufacture, weaving, designing, chemistry and dyeing, finishing, knitting, and allied subjects . lue, is a gelatinous substance, soltible inwater, from which it can be precipitated by lead acetate. Inves-tigations lead to the conclusion that sericin is a product offibroin through oxidation and hydrolysis. For all practical ])urposes we may consider the fibroin as theactual silk fibre, and the sericin the silk glue or gum whichenvelope it and holds the two constituent fibres of the raw silk 44 TEXTIL
. Cyclopedia of textile work : a general reference library on cotton, woollen and worsted yarn manufacture, weaving, designing, chemistry and dyeing, finishing, knitting, and allied subjects . lue, is a gelatinous substance, soltible inwater, from which it can be precipitated by lead acetate. Inves-tigations lead to the conclusion that sericin is a product offibroin through oxidation and hydrolysis. For all practical ])urposes we may consider the fibroin as theactual silk fibre, and the sericin the silk glue or gum whichenvelope it and holds the two constituent fibres of the raw silk 44 TEXTILE CHEMISTRY AND DYEING. 37 together. It is the sericin that is removed diuiiio- the silk boilingor degumming process. Commercial, or boiled-off, silk usually gives .7 to 1 per centof ash, consisting mainly of the oxides of calcium, magnesium,aluminum and iion. ACTION OF DIFFERENT REAGENTS. 79. Water. Water, either cold or boiling, has no action onsilk other than to remove the sericin from raw silk. 80. Acids. lu general, balanccsilk is readily attacked anddissolved by concentratedmineral acids, while dilutemineral acids and solutionsof the organic acids are much WC/GHTS TH£:nMOMer£f\. •a S/LK SKEINS BEING TESTED milder in their action. Concentrated h y d r o -chloric acid will dissolvemore than its own weight ofsilk. Upon addition of waterto this solution the silkseparates as a flocculent pre-cipitate. If applied in thegaseous state, hydrochloiicacid will rapidly disintegiutesilk. Even when somewhatdiluted, boiling hydrochloricacid has an action on silk,but when very dilute has littleaction other than to removethe sericin. The action oFhydrochloric acid on silk is valiKible in its detection. Concentrated nitric acid ra[)idly destroys silk, dissolving itto a yellow solution, but dilute acid simply coloiS the fibre latter reagent may be used for distinguishing silk fromvegetable fibres. Concentrated sul[)huric acid dissolves silk to a brown viscoussolution. Warm d
Size: 1396px × 1789px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherchicagoamericansch
