Hygroscopicity


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
Related to Hygroscopicity: polymorphism

Hygroscopicity

 

the ability of materials to absorb moisture from the air.

Hygroscopicity is a property of wettable (hydrophilic) materials of capillary-porous structure (such as wood and grain), in whose fine capillaries moisture condenses; of water-soluble substances such as table salt, sugar, and concentrated sulfuric acid; and especially of chemical compounds that form, with water, crystalline hydrates. The amount of water absorbed by a porous material (hygroscopic wetness, or Whyg) increases as the moisture content of the air increases, reaching a maximum when the relative humidity of the air is 100 percent. For wood, the maximum Whyg is about 30 percent (in terms of weight), whereas for wheat it is about 35 percent. It is important to know the hygroscopicity of a material in order to determine drying and wetting processes. Hygroscopicity is also considered in long-term storage and transportation of materials, especially by sea. Hygroscopicity explains the dampening and even deliquescence of a number of salts when stored in the open air. Some hygroscopic substances, such as concentrated sulfuric acid, are used to dry the air.

References in periodicals archive ?
In the analysis of the representativeness of the model hygroscopicity, the experimental data were compared to the values estimated for each model, checking the percentage of mean relative error (P), mean estimated error (SE), and the chi-square test ([chi square]) according to Eqs.
The response surface for the variables that were significant in this study, that is, hygroscopicity and concentration of curcumin, are given in Figure 1.
Of the components of the composites described in this paper, at RH of 100% glycerol showed the highest hygroscopicity (Fig.
Cargo may suffer considerable damage due to their hygroscopicity in standard intermodal containers.
Microcrystalline cellulose is the appropriate choice due to its less hygroscopicity and good flowability.
physicochemical characteristics of salt solutions, forming in pores of material in presence of moisture: density, thermal conductivity coefficient, concentration, pressure of water vapour above the surface of saturated solution as well as above dilute solution, hygroscopicity and heat of vaporization;
Salt-joining makes a hydrophobic molecule hydrophilic; the result, especially in psychoactive drugs, is improved kinetics, absorption, or physicochemical properties (eg, stability, hygroscopicity, fluidity)Y This may be the reason for differences identified between generic and brand-name amitriptyline, nortriptyline, desipramine, and trimipramine.
Although galenIQ is known for its excellent compactability and low hygroscopicity, the combination of its other important properties makes this excipient a highly functional filler-binder for use in tabletting and other technologies, such as wet granulation and dry/ roller compaction.
Hygroscopicity of secondary organic aerosols formed by oxidation of cycloalkenes, monoterpenes, sesquiterpenes, and related compounds.
252) Hygroscopicity refers to the ability of a compound to absorb water from the air, rendering it sticky.
Having a very high dilution potential, excellent chemical and mechanical stability, and a very low hygroscopicity galenIQ[TM] is highly suitable for formulations with active ingredients.
Data on physical properties includes coverage of such properties as boiling point, bulk and tap density, compression characteristics, hygroscopicity, flowability, melting point, moisture content, moisture-absorption isotherms, particle size distribution, rheology, specific surface area, and solubility.