Cooling Dispersed phase

GEL. A colloid in which the disperse phase has combined with Ihe continuous phase to produce a viscous jelly like product. Only 29f gelatin in water forms a stiff gel. A gel is made by cooling a solution, whereupon certain kinds of solutes (gelatinI form submicroscopic crystalline particle groups lhal retain much solvent in the interstices (so-called "brush-heap-1 structure). Gels are usually transparent but may become opalescent. 

Gas-continuous impinging streams with a liquid as the dispersed phase has wide application, such as in the combustion of liquid fuel droplets, absorption, water-spray cooling of air, etc. [9]. In such systems the dispersity of liquids plays a very important role affecting heat and mass transfer rates, because it influences both the interface area and the mean transfer coefficient. Wu et al. [68] investigated the influence of impinging streams on the dispersity of liquid. 

Because nanocomposites are made from different phases with different thermal expansion coefficients and elastic moduli, they inevitably develop residual thermal stress during cooling after sintering. Assuming the dispersion phase is spherical particulate in the matrix material, residual stresses can be developed due to differences in the thermal expansion and elastic constants between the matrix and the particles [23] ... 

Lipstick and lip balms are usually concentrated suspensions of solid oils in a liquid oil, or in a mixture of liquid oils. The dispersed phase, about 60 mass%, comprises oils and/or wax that are solid at room temperature. The continuous phase, about 40 mass%, comprises an oil, or mixture of oils, that is liquid at room temperature. These products are formulated at relatively high temperature, where they are liquid, and are then cooled to allow a significant yield stress to develop. Lipsticks and lip balms contain a variety of waxes, oils, pigments, and emollients, including ... 

The crystal growth rates of PVDF, PA-6, and POM amount to at least lOpm/min in the temperature range where their crystallization steps occur (6,52,67). A dispersed particle, therefore, once nucleated, crystallizes promptly and the primary rather than the secondary nucleation is the rate-controlling factor of the crystallization kinetics of the dispersed phase. Thus, the crystallization temperatures as observed in the DSC-cooling run agree roughly with the nucleation temperatures. 

Figure 3.43. DSC cooling curves (10°C/min) for PP/PS blends difference in the crystallization behavior in blends with PP as a matrix phase and as a dispersed phase [Santana and Muller, 1994],...

Principle of Coincident Crystallization It has been observed that this phenomenon is connected with the phase dispersion of the minor component, and is enhanced when the dispersion becomes finer. Upon cooling from the melt, a finely dispersed phase can exhibit fractionated crystallization, what implies that none, or only part of the dispersed droplets crystallize at their bulk r. This type of crystallization is related to the lack of heterogeneities in the droplets, required for nucleation at the bulk T. 

Flow field and cooling condition between injection molding and compression molding are essentially different. In particular, the flow-induced molecular orientation and/or the distorted shape of the dispersed phase have to be considered seriously in the injection molding. This part deals with the relation between morphology and mechanical properties in the injection-molded products for iPP and iPP/EHR blends (65). This is directly important for the industrial application. The characteristics of these samples are summarized in Table 9.5. 

---