Compatibilization Compatibilizer apparent

Figure 11.20 shows the SEM image of the morphology of 30/70 nylon-EPR blends at two different compatibilizer concentrations. It is apparent that the addition of compatibilizer significantly reduces the size of the dispersed phase. The addition of 10% compatibilizer is sufficient to... 

Apparently, with a very small interphase thickness the two end-cap groups are too few and not easily accessible to affect compatibilization. On the other hand, when four anhydride (An) groups are attached, randomly on each PDMS chain, then the blend of 20% PDMS/4-An and PA 6/di-amine have a very fine and stable morphology (ca 0.5 pm). Thus, the amount of interfacial reaction product, although diminished by small < / values of the unmodified polymer components, is promoted by the larger number and more accessible functional groups in either or both of the reactive components. Finally, Macosko and co-workers (62) have estimated that the minimum fraction of the interphase that has to be covered by reacted compatibilization products to achieve fine and stable morphologies is about 0.2. 

The general shape of the stress-strain curve is the same for all the blends with Q-series and Kraton compatibilizers. This shape is described by two tangent lines drawn from the initial elastic region and the plastic region, respectively. The intersection of the lines is defined as the yield point and is described by a yield stress (ay) and an apparent yield strain (ey). The stress (a) and strain (e) in the plastic region are related by... 

The effect of the presence of compatibilized incompatible components is apparent in PVC plastisols. Monomeric and polymeric esters are good plasticizers for PVC because they have suitable solubility parameters. A good plasticizer is one which, in sufficient quantity, would almost be a solvent for the polymer. However, a good plasticizer, i.e. solvent, in a plastisol results in a high viscosity composition. This may be unsuitable for slush molding or other applications when low viscosity is desirable. The latter is obtained by adding a secondary plasticizer such as a hydrocarbon oil. In reality, the latter is not a plasticizer but actually a non-solvent which converts the good solvent plasticizer to a poor solvent mixture with resultant decrease in plastisol vis-... 

Compatibihzation enhances dispersion, increases the total apparent volume of the dispersed phase, rigidifies the interface, and increases interactions not only between the two phases, but also between the dispersed drops. These changes usually increase the blends viscosity, elasticity and the yield stress. The compatibilizer effects are especially evident at low frequencies. There are two mechanisms that may further affect these behaviors (i) the... 

The rheological consequences of these changes can be predicted from a model system. The emulsion model indicates that making the interface more rigid causes the intrinsic viscosity of the emulsion to increase (see Eq 7.50). Similarly, an increase of the apparent volume of the dispersed phase causes the relative viscosity to increase (see Eqs 7.24-7.25). Furthermore, enhanced interactions between the phases will reduce the possibility of the interlayer slip, and increase formation of associative network formation, which may result in the yield stress. In short, compatibilization is expected to increase melt viscosity, elasticity and the yield stress. 

The references in this review include both journal articles and selected published or issued patents. A large number of reactive compatibilization examples are found in industrial research and are documented mostly in patents. Patent references are included in this chapter if they reveal a novel compatibilization strategy apparently not otherwise documented until later in the journal literature. Numerous examples of industrial compatibilization methods have also been provided in a book based on the patent literature (Utracki 1998). 

Filippi et al. (2004) prepared blends of PA-6 with LDPE in the presence of SEBS-g-GMA. Inefficient compatibilization of PA/PE was observed in comparison to the use of SEBS-g-MA apparently due to cross-linking reactions involving both amine and carboxylic acid end-groups on PA. 

Relationship between apparent shear rate and shear viscosity of NR/ HDPE at various blend ratios without compatibilizers. 

This was claimed to be attributed to the maximum compatibilizing effect or chemical interaction between PP and MNR phases at a loading level of Ph-PP of 5% w/w. Plots of apparent shear viscosity versus shear rate of 60/40 MNR/ PP blends with PP-g-MA and Ph-PP as a compatibilizer are shown in Figures 18.29 and 18.30, respectively. 

Figure 18.26 Relationship between apparent shear stress and shear rate for simple blends of 60/40 MNR/PP with various quantities of Ph-PP compatibilizer.

The maximum apparent shear viscosity was observed at a loading level of 5% w/w for both compatibilizers used. This trend of apparent shear viscosity was found to be the same as the apparent shear stress. 

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