Dispersed phase polymers,

Protective colloids or polymeric materials can be adsorbed onto the surface of the dispersed phase. Polymer adsorption can be accomplished simply by... 

Type 2 Soft matrix 4- hard dispersed phase Polymer filled Elastomers... 

A latex has basically two parts, a dispersed phase (polymer particles) and the continuous phase (the water the liquid in which the polymer droplets are dispersed), the process is usually referred to as emulsion... 

Studies have been made of PEST/PO/styrene copolymer blend compatibilization in which a copolymer may be formed between polyester alcohol end-groups and pendent anhydride functionality on a styrene copolymer (Table 5.27). Because the alcohol-anhydride reaction is reversible (with the equilibrium lying on the side of unreacted anhydride), only a relatively small amount of copolymer may be formed. In consequence, the dispersed phase polymer may not be well stabilized against coalescence upon further thermal treatment [Sun et al., 1996]. Alternatively, at least some copolymer may be formed by a degradative mechanism through transesterification between PEST main-chain linkages and a low concentration of pendent acid groups in anhydride-functionalized styrene copolymer (see Section 5.7.12.5). 

The calculated particle diameters from Equation 12.2 may be considered a lower limit, that is, the Taylor limit, due to the assumption of Newtonian behavior of the system and vanishingly small concentration of the dispersed phase. Polymers exhibit non-Newtonian behavior, namely, the droplets elongate elastically before breaking. This behavior corresponds to an increase in interfacial tension, and therefore, particle size increases as predicted by Equation 12.1, over that predicted from Equation 12.2. (This is discussed below and can be seen in the last two columns of Table 12.3). 

Viscosity of the dispersed phase Polymer concentration Volume fraction of dispersed phase to continuous phase Quantity of drug in the dispersed phase Concentration of porosigen Increase of agitation rate Increase of temperature Solvent removal rate... 

Chapter 9 it was explained that the viscosity of an emulsion is little greater than that of the continuous phase. It is not influenced by dispersed phase polymer molecular weight and is influenced by dispersed polymer concentration only at high concentrations. So, if the film-former of a lacquer can be emulsified, then, in principle, the lacquer can be supplied as an emulsion at much higher solids. 

The embedded material should reinforce the matrix, e.g., with respect to flexural strength. Because this effect is absent with interpenetrating networks, these are often not classed as composites, although, according to structure, they are composites with a zero-dimensional dispersed phase. Polymers reinforced with active or inactive particulate fillers are also not classed as composites. 

However, the morphology of an emulsion or blend depends not only on the discussed above dispersive processes, but also on coalescence observed at low dispersed-phase polymer volume fraction, o 0-005 [121]. Analysis of the steady-state shear coagulation of PVC lattices leads to the critical time [122] ... 

Fig. 4.36 SEM images of representative fractured, dispersed phase polymer specimens (A) has obvious dispersed phase particles in a ductile matrix that have poor adhesion (B) has much finer dispersed phase particles (C) has particles and holes where particles pulled out and are on the other fracture face - the adhesion is much better in this case compared to (A) (D) has barely distinguishable particles, although over 20% elastomer is present.

Thus large bodies of polymer theory, rheology of dispersed phases, polymer blend and polymer interface interactions, as well as excluded volume effects of polymer solutions are seen to be true for bread doughs, as indeed they must. 

Whereas many free radically initiated systems have been investigated, ionic initiation has received less attention. Dispersionsof polypropylene initiated by an aluminium/titanium alkyl catalyst were produced on a commercial scale for a short period but failed to find significant uses (21)=, The stabilisation of anion-ically initiated polystyrene with poly(t-butyl styrene) has also been described (l)o In one variant of this system the soluble component is formed first, the disperse phase polymer is then grown from the living polymer until precipitation occurs and polymerisation is continued within the particle by the addition of further styrene. 

The dispersed-phase polymer networks described here show promise as media for controlled drug delivery, where the microdomains may act as reservoirs for sparingly water-soluble drugs which can leach out of the material slowly over long times. They may also be applicable in separations processes by retaining solutes in proportion to their hydrophobicity. 

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