The methods of textile chemistry : being the syllabus of a lecture course adapted for use in textile laboratories

Front matter

THE METHODS

OF

TEXTILE CHEMISTRY

Preface

The few books on textile chemistry which have thus far made their appearance, with one or two exceptions are available only in foreign languages. This is to many a source of deep regret, because while attention is given to the study of modern languages in this country, yet technical writing is better understood when the reader has it presented in his native tongue. In the following pages an attempt has been made to systematize approved methods of textile-chemical analysis which are at present only to be found in widely distributed and expensive special works and journals. These methods have for some time formed the syllabus of the author's lecture courses in textile chemistry. They therefore make no claim to completeness, although care has been taken to emphasize the essential points in each case. The student will do well to use some standard manual of chemical analysis such as "Newth" in conjunction with the present volume.

The author hopes that our now prosperous textile manufacturers and merchants may soon realize that accurate methods are not only interesting but necessary in these days of keen competition. At the same time this little volume is intended to be a source of information and ready reference for the textile chemist. To add to the readier understanding of calculations, practical examples have been inserted in many instances. The aim has been

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PREFACE to cover the field of chemical and physical analysis of the textile fibers, yarns and fabrics. Dyestuffs, mordants, and finishing materials are treated of not as raw materials but as substances encountered on the finished goods.

FREDERIC DANNERTH.

204 Walnut Place, Philadelphia, Autumn, 1908.

REFERENCES

In the preparation of this book the following publications were consulted:

P. Bean: The Chemistry and Practise of Sizing and Finishing.

London. 1905, 1906.

Bowman: The Wool Fibre. Manchester. 1885. Cross and Bevan: Cellulose. London. 1 895-1 905. P. Heermann: Textil-chemische Untersuchungsmethoden. Berlin. 1907. J. Herzfeld: Die Technische Pruefung der Game und Gewebe.

Vienna. 1896.

J. M. Matthews: The Textile Fibres. New York. 1907.

H. Silbermann: Die Seide. Dresden. 1898.

Textil u. Faerberei Zeitung. Berlin.

G. Lunge: Chemisch-technische Untersuchungsmetoden. Berlin. IV Edition.

Allen: Commercial Organic Analysis. Philadelphia. 1900. G. Georgievics: Chemische Technologie der Gespinnstfasern. Vienna. 1898.

The Journal of the Society of Chemical Industry. London. The Journal of the Society of Dyers and Colorists.

The "Tables for the Identification of Dyestuffs on the Fiber," by Arthur Green and others, which appeared in the Journal of the Society of Dyers and Colorists, may be consulted in the Yearbook for Colorists and Dyers edited by H. A. Metz. Dyestuffs on animal fibers, 1905, page 47. Dyestuffs on vegetable fibers, 1907, page 49.

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PART I Qualitative Analysis

Reactions of —

PAGE

Wool and hair fibers 8

Natural silk fibers 15

Jute and hemp fibers 19

Cotton, flax, and ramie fibers 21

Imitation silk fibers 27

Detection of —

Rosin, mineral, and vegetable oil, in textiles 29

Mordants on wool 30

Weighting on silk 32

Sizings on cotton 34

Finishing materials in textiles 36

PART II Quantitative Analysis

Analysis of a —

Wool-cotton fabric 45

Wool-silk fabric 47

Cotton-silk fabric 48

Cotton-silk-wool fabric 48

Silk-imitation silk fabric 50

Waterproof fabric r 50

Analysis of —

Textile fibers 56

Raw vegetable fibers 57

Raw wool fibers 59

Raw silk fibers 61 vii viii

CONTENTS

PAGE

The " boiling-off " loss of raw silk 63

The " washing-out" loss of raw silk 64

The " shrinkage " of raw wools 64

Moisture in textiles 66

Mineral matter in textiles : 69

Oil and grease in textiles 71

Arsenic in textiles 72

Weighting in silk fabrics 72

Finishing in cotton fabrics 81

Tensile strength 82

Humidity 86

Specific gravity 87

The fastness of dyes on the fiber 89

Introduction

The word " analysis" as used at the present day includes all the processes and operations made use of by chemists in order to determine the constituent parts of any compound, or to enable them to identify the substance. The process may involve the breaking up of the body into its component parts, or may consist in the simple separation of a mixture. A reaction is a chemical change: if the change was effected only by heating the substance, it is termed a dry reaction; and if any of the substances used to bring about the change were in solution, we speak of a wet reaction. In the following is given a list of the reagents which will be required for the wet reactions; they should be made up as indicated in order to obtain the best results.

10% Caustic potash ... .Dissolve 10 grams of potassium hydroxide in 50 c.c. of water, cool and make up to a total volume of 100 c.c. 1% Caustic potash. . . .Dilute the above solution 1:10, i.e. to 10 cubic centimeters of the 10% solution add 90 c.c. of water.

40% Hydrochloric acid .The concentrated chemically pure acid. Specific gravity 1.20 (24°Be). [100 c.c. of this acid weighs 120 grams.] 3

10% Hydrochloric acid .Max 25 c.c. of the above concentrated acid with 75 c.c. of water.

1% Hydrochloric acid .Dilute the 10% acid 1 to 10. 98% Sulphuric acid . . . .The concentrated chemically pure acid. Specific

gravity 1.84 (66° Be). 10% Sulphuric acid. . . .Dilute the above solution 1 to 10. 100% Nitric acid The concentrated chemically pure acid. Specific

10% Nitric acid Dilute the above solution 1 to 10.

Calcium hypochlorite . . .A clear solution having a specific gravity of

1. 01 (20 Tw) is prepared by rubbing down

chloride of lime with water in a mortar.

Add more water, allow to settle, and finally

decant.

Schweitzer1 s reagent. . . .An ammoniacal solution of cupric oxide.

Cross and Bevan prepare this reagent as follows: 2 grams of copper sulphate are dissolved in 100 c.c. of water. Hydrated copper oxide is precipitated from this solution by adding a slight excess of a 10% solution of sodium hydroxide. Wash the precipitate entirely free from alkali, drain, and mix with a 10% solution of glycerol. Preserve in stoppered bottles, and when desired for use wash free from glycerol and dissolve in ammonia water of 20% strength. Bronnert, Fremery & Urban prepare a Schweitzer's solution containing about 5% of copper and a relatively small amount of ammonia as follows: A cold solution of ammonia is poured over copper turnings in tall cylindrical vessels, and the whole is cooled down to o to 50 C. by placing in a freezing mixture. Cold air is now blown through this mixture of copper and ammonia for about 10 hours. The solutions so obtained are only stable at low temperatures, so that suitable precautions must be observed when using the same.

Millorfs reagent An aqueous solution of mercurous nitrate.

Ten grams of mercury are treated with as much nitric acid as is necessary to dissolve it. An additional 10 grams of mercury is now added and the whole diluted with nine times its volume of water. As copious fumes of the red oxide of nitrogen are evolved, the solution of the mercury should take place under a hood.

Molisch's reagent A 20% solution of a-naphthol in alcohol.

Lassaigne1 s reagent 5 grams of litharge and 5 grams of sodium

hydroxide are dissolved in 100 c.c. of boiling water. PbO + 2NaOH = Na2Pb02 + H20-

INTRODUCTION

Liebernianrt s reagent. ..One gram of Magenta (Fuchsin or Rosanilin) crystals is dissolved in 100 ex. of water. To this is added ammonium hydroxide until the solution is just decolorized.

Loewe's reagent An alkaline copper-glycerol solution.

10 grams of copper sulphate crystals are dissolved in 100 c.c. of water. To this are added 5 c.c. of glycerol and a solution of sodium hydroxide until the precipitate at first formed is just redissolved.

Richardson' s reagent An ammoniacal solution of nickel oxide.

25 grams of nickel sulphate crystals are dissolved in 300 c.c. of boiling water and precipitated with a slight excess of a 10% solution of sodium hydroxide. The precipitate is carefully filtered and washed, then rinsed into a 250 c.c. flask containing 125 c.c. of ammonia (sp. gr. = 0.88). The whole is now made up to 250 c.c. with water.

Eisner's reagent A solution of basic zinc chloride.

100 grams of dry zinc chloride and 4 grams of zinc oxide are mixed with 85 c.c. of water.

HoehneVs reagent Solution I) One gram of potassium iodide

dissolved in 100 c.c. of water, and iodine added in excess.

Solution II) Twenty cubic centimeters of glycerol are mixed with 10 c.c. of water. To this cold solution are added 30 c.c. of concentrated sulphuric acid.

The fiber is first treated with solution I, the excess of reagent is removed with filter paper, and after one or two minutes solution II is applied.

Nickel's reagent A solution of hydrazin sulphate in water.

Zinc-chloride-iodine solution. One gram of iodine crystals, 5 grams of potassium iodide, and 30 grams of zinc chloride are dissolved in 15 grams of water. Nitroprusside solution. A 2 % solution of sodium nitroprusside in water The salt may be prepared as follows: A small quantity of potassium ferrocyanide crystals is boiled with strong nitric acid; finally dilute with water and neutralize the free acid with sodium carbonate. The salt is obtained in the form of deep-red crystals. Test Solutions for Lignin. 1) Phloroglucol in id% alcoholic solution.

Dilute with an equal volume of 10% hydrochloric acid before using. 2) Anilin sulphate or hydrochloride in saturated solution. 3) Indol in 5% solution.

Adatnkiewicz's reagent. A solution of glyoxalic acid in concentrated, sulphuric acid. Adamkiewicz's test may also be carried out as given under the reactions for wool (page n).

Fuchsin-bisulphite solution. One gram of Fuchsin is dissolved in iooo c.c.

of distilled water. Sulphurous acid is now led into this solution (or a few drops of liquid sodium bisulphite is added) until the solution is just decolorized.

Analytical Classification of the Fibers.

The following arrangement of the fibers is based upon their chemical composition. Although this classification is one which has seldom if ever been adopted, it is not materially different from the usual arrangement. Such a classification reminds us that the fibers are chemical compounds, even though they may in some cases be extremely complicated.