PYROXYLIN.

PYROXYLIN.

Some few weeks ago the plant of the G. W. Richardson company, manufacturers of horn and pyroxylin plastic combs, was badly damaged by fire. The premises arc well sprinklered and were free from any obstructions to the distribution. From the nature of the material—pyroxylin—used in the factory the underwriters’ classification was “Special hazard.” The fire started in a “plate” of celluloid, which had been removed from a steam table and packed among others on an adjoining bench, On the second floor of the main building the processes included stock-cutting, bending, rubbing and polishing. The stock used was principally celluloid, and some fibrcloid. The steam tables were located in the northwest corner of the room, and were used to soften the stock before cutting. It is claimed that a piece of stock, thought to have been celluloid, which had been heated on the steam table and afterwards removed and placed among other pieces on the bench nearby, in some inaniur became ignited. It is supposed to have been due to decomposition set tip in the stock while on the steam table, which continued after it had been placed among other hot pieces on the bench. This is only a theory, and it was impossible to obtain any additional light on the subject. These steam tables and benches were located very close to each other, as usual, and more or less stock was on the benches About 10 in. from the steam tables there was said to he about SIM) lb. of sheet-stock. The employes were at work at the steam tables; hut the fire spread so rapidly that, although it is claimed they made an attempt to extinguish it. they were obliged to escape by a window. The tire quickly spread to the loft where horn-stock in wooden trays was seasoning. The floor between the second floor and lift was not com idete, leaving an opening about 15×20 ft., and there was also a small opening about 8 in square dircctlv over the spot where the tire started. The fire spread in the direction of these openings, a comparatively small amount of damage hv fire to the building having been caused on the second floor. The roof of the building was hip slate, joisted. The principal damage by tire was confined to the horn stock in the loft, some damage to the second floor of the building, and to the roof, a part of which fell in Considerable damage was hv water to the machinery throughout the building, and possibly to some stock. From the above it will he seen how dangerous a material pyroxylin is to work with, owing to its liability to detonate and deflagrate without the aid of any external fire, hut simply when the heat in this case that from steam -rises beyond a certain thcrmometrical degree Although not identical with guncotton, it is of the same family, and into its composition enter the same constituents. Its qualities resemble very closely those of the last mentioned explosive, from which, however, it is distinct, as it is more highly nitrified and is soluble in alcohol, ether and the like. It is derived from wood by distillation. and was formerly employed to designate crude wood-spirit (CHiOH). It contains, besides acetic acid, creosote, and eight or ten other substances, one of which, wood-naphtha, is a volatile, strong smelling, mobile liquid, resembling alocohol. but having a different composition, and. when purified by treatment with lime to remove acetic acid, etc., becomes a pure-spirit known as methylie alcohol, burning with a flame like that of common alcohol. It is a good solvent of resinous substances, and, being cheaper than common or ethylie alcohol, is much used in the arts and manufactures.

As has been said, pyroxylin, like guncotton, also enters extensively into the composition of celluloid (cellulose-t-oid—the termination oid expressing resemblance). Cellulose itself is a carbohydrate and forms the essential part of woody fibre (C6H10O5)n, and is found in a nearly pure state in uncolored and imstarcbed cotton and linen, in uncolored woodpulp and unsized paper, of all of which it forms the essential framework. When washed several times with a warm solution of potassium hydrate, then with dilute hydrochloric acid, then with ammonia water and alcohol. it is in a pure state and is white, translucent, unalterable in the air, and decomposable only by strong acids. When submitted for about five minutes in a divided state to the action of strong nitric acid and then washed, it becomes guncotton, its explosiveness being due to the fact that the cotton loses a portion of its hydrogen and takes in its place nitric peroxide, whereby it becomes unstable through the number of atoms in the molecule being increased. It contains much more both of oxygen and hydrogen than ordinary cotton, and, like potassium chlorate, becomes a substance highly charged with oxygen and, therefore, explosive,’ the oxygen producing the combustion, when the beat is applied, while the nitrogen, on being set free, expands with the other gases and adds force to the explosion. It may be added that the sulphuric acid, which is often employed in preparing guncotton of itself, adds nothing to its explosive properties. The strong attachment of that acid for water simply removes the water from the cotton, and, in that way, makes more room for the combination of the acid with the cotton. In the same way, pyroxylin may be called the first cousin of guncotton. differing from it, as before noticed, only in its being more highly nitrified. Specifically, it is the highest nitrates of cellulose, which arc soluble in ether and alcohol, in contradistinction to guncotton—the lower nitrates of cellulose. It may he conventionally styled soluble guncotton, and is used extensively in the preparation of collodion—a strong adhesive for coating wounds and forming the sensitive film in photography. It must not be confounded, however, with xyloidin, or nitramidin, a substance greatly resembling it, and obtainable by the action of nitric acid on starch.

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