prefazione
ISO (Organizzazione internazionale per la standardizzazione) è un'alleanza globale di organismi di normalizzazione nazionali (Organismi membri dell'ISO). Lo sviluppo di standard internazionali viene solitamente effettuato attraverso i comitati tecnici ISO. Ciascuna istituzione associata interessata ad una materia sulla quale è stato costituito un comitato tecnico ha il diritto di essere rappresentata in tale comitato. In questo lavoro sono coinvolte anche organizzazioni internazionali governative e non governative che collaborano con l'ISO.

Draft international standards adopted by technical committees are circulated to member bodies for approval before being accepted as international standards by the ISO Council. They are approved under the ISO process, which requires at least 75 per cent approval from voting member bodies.

Lo standard internazionale ISO 304 was developed by the Technical Committee ISO/TC91, Surfactants.

The second edition cancelled and replaced the first edition (ISO 304-1978), which was a minor revision.

Users should note that, unless otherwise noted, all international standards are revised from time to time, and unless otherwise noted, any reference herein to any other international standard is meant to be the latest version.

ISO 304-1985 “Determinazione della tensione superficiale del tensioattivo mediante stiramento di film liquido”

introduzione
Surface tension is a basic property of liquids in general, especially surfactant aqueous solutions.

Tuttavia, in the case of surfactant solutions, measurements of this property do not allow any assumptions to be made about its decontamination, bagnabilità, schiumoso, emulsifying activity, eccetera. Infatti, no relationship can be established between the properties of the surfactant and the surface tension of the solution.

1 Scope and domain of application
This standard specifies a test method for determining the surface tension of surfactants and aqueous or organic solutions containing one or more surfactants by drawing liquid membranes.

It is also suitable for surface tension measurement of pure liquids or solutions other than those described above.

Nota – A number of methods have been established to determine surface tension, ad esempio:

UN) Method of drawing liquid film by plate, stirrup or ring:

B) Methods for measuring the rise of liquid in capillary tubes;

C) maximum ball pressure method;

D) falling weight method;

e) Drop or handless ball method;

F) suspension droplet method;

G) Dynamic method based on flow characteristic measurement;

H) Methods for studying waves generated in capillary jets.

The draw-based liquid film approach has significant advantages in terms of simple procedures and commercial availability of highly automated equipment.

2 Materiali di riferimento
ISO 862, Surfactants — Vocabolario.

ISO 2456, Surfactants – Water used as a test solvent.

Solo la sezione informativa standard è pubblica. Per vedere il contenuto completo, è necessario acquistare lo standard attraverso i canali ufficiali.