ISO TR 13097:2013 pdf free

ISO TR 13097:2013 pdf free.Guidelines for the characterization of dispersion stability
The volume concentration of the dispersed phase of a dispersion is one of the primary requirements of any product design and it should be homogenous within the entire product during the entire life span. In general, the higher the volume concentration, the higher the physical stability (e.g. less phase separation).
Formulators have to achieve product specifications and sufficient dispersion stability as demanded by the application or customer. This is accomplished by choosing the state of the dispersed phase (e.g. size distribution, shape, density match, restrictions to oversize, surface charge and coating) and the appropriate behaviour of the continuous phase. Traditionally, electrostatic stabilization has been principally used. Today, polymeric additives are commonly employed to tailor properties of the continuous phase of innovative products. Two essential aspects with regard to dispersion stability are particle-particle interactions and interactions between the dispersed and continuous phase. Tuning of particle interactions is an important tool to stabilize a dispersion. Electrostatic, steric and depletion stabilization or combinations of these are the most commonly used approaches. The theoretical foundation of these approaches is based on the classic DLVO (Derjaguin, Landau, Verwey, Overbeek) theory (see Overbeek[10]) and more recently, the extended DLVO theory.[1] In general, any specific interaction energy between two particles (e.g. double layer interaction, van der Waals attraction, steric interaction) is calculated as a function of the particle distance. The dependence on the distance is interaction specific. The different interaction energies are additive and the resulting energy-distance curve allows for stabilization evaluation.[11] It should be emphasized that products today (e.g. paints,nutritional suspoemulsions, cosmetic multiple emu sions) often consist of several dispersed phases, and that the continuous phase may contain many constituents.
This complex structure of dispersions implies that a single parameter is generally insufficient to characterize or predict the stability state of a dispersion.
Figure 1 and Figure 2 schematically display a selection of primary and secondary mechanisms,respectively, which, over time, change the state of the dispersed phase and/or homogeneity of the dispersion. They are indicators of loss of stability. Additionally, aged dispersions may undergo phase separation that is obvious by visual observation. Destabilization mechanisms are sequenced simply for the sake of clarity and cannot be distinguished in most practical cases.ISO TR 13097 pdf download.