absorbent materials defined in 1939 yearabsorbent materials - Absorbent Materials;
absorbent materials - Materials which have the property of absorbing liquids, gases, heat, light, or sound. In building, bricks, stone, cement and concrete need damp-proofing treatment to prevent their absorption of water. Bricks vary in their absorbent qualities from 3 per cent of their volume for the hardest blue bricks to 22 per cent for ordinary stock bricks, the average brick absorbing water to about 15 per cent of its volume. Stone varies from J per cent for granite to 10 per cent for sandstone and 13 for Portland stone. Absorption in concrete depends upon the proportions and quality of the cement and sand used.
Chemicals used to absorb moisture from the air include sodium chloride and zinc chloride (driers).
For surgical and other purposes. cotton is made absorbent by removing from the fibre its natural wax. Waste or unspinnable cotton is boiled with caustic soda leaving a virtually pure cellulose. This is employed for surgical dressings, for making gun-cotton, and in the manufacture of artificial silk.Gases are absorbed by carbon, especially wood charcoal, in varying proportions. One volume of amorphous (non-crystalline) carbon can absorb as many as 85 vols. of hydrochloric acid or 90 vols. of ammonia, the amount increasing considerably with the temperature. Because of this property, charcoal is used in gas masks as a dyspepsia remedy, and in industrial processes. See Adsorption.
Certain materials such as asphalt and bitumen have special capacities for the absorption of heat and have therefore to be insulated against it. Thermal insulation in general is achieved by the presence of inert air cells in fibrous or sponge-like material.
Materials used in the absorption of sound are noted under Acoustics.
near absorbent materials in Knolik
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