Mixtures, incompatible

A reactive polymer (RP) is simply a device to alloy different materials by changing their molecular structure inside a compounding machine. True reactive alloying induces an interaction between different phases of an incompatible mixture and assures the stability of the mixture s morphology. The concept is not new. This technology is now capable of producing thousands of new compounds to meet specific design requirements. 

Table 7.1 shows that rather similar results were also found by Makri et al. (2005) for samples of coarse emulsions containing thermodynamically incompatible mixtures of legume seed protein + xanthan gum. The protein surface load was found to be enhanced in the presence of xanthan gum, especially at elevated ionic strengths. That is, there was observed to be an increase in the adsorption of legume seed proteins at the surface of the emulsion droplets which could be attributed to an increase in the thermodynamic activity of the proteins in the system in the presence of the incompatible polysaccharide (see Table 7.1). Associated with the greater extent of protein adsorption, the authors reported an enhancement in the emulsion stability.

Three different kinds of behavior were observed on addition of the polyethers to PVC and CPVC. First, high-impact resins were sometimes produced without the addition of any other rubber (3, 4). Second, incompatible mixtures with poor properties were obtained. Third, certain polyethers, which in themselves did not lead to PVC s of high impact strengths, seemed to enhance the properties of an already modified CPVC (5). 

Incompatible Mixtures. Even at very low levels, many of the poly-ether additives led to incompatible mixtures. These blends were not successfully milled to a smooth sheet under any conditions tried. Instead, a mass of crumbs was obtained. These crumbs could be molded into a coherent mass, but the physical properties were poor. For example, addition of 8.75 parts of polybutene-1 oxide to Masterbatch B for CPVC alone gave a brittle, free-flowing material with these properties notched Izod impact strength, 0.7 lb/in notch, flow rate 452 g/10 min. This is a particularly interesting result, since PBO has the same chemical formula as PTHF but structurally is a substituted ethylene oxide polymer rather than a linear homopolymer. No further studies were made of such blends. 

The second approach to the use of incompatible mixtures of recycled plastics is to compatibilize them in some way, and thereby improve their performance. One... 

There are hundreds of chemicals in common use and thousands of less frequently used chemicals that could be used as part of any particular lab experiment or process. Memorizing all the combinations and permutations of potentially incompatible chemicals is not possible. The goal in this section is to learn about some specific incompatible mixtures but more generally to learn about combinations of incompatible chemical groups. Some fundamental chemistry can help you think about the properties and structures of molecules that might predict them as chemicals having incompatible partners. ... 

Much less work has been done on the kinetics of phase separation for PP blends. This is in general quite difficult to study for highly incompatible mixtures, since one cannot get to a well-mixed starting state. Careful studies of the phase separation can only be done for those blends that are just slightly incompatible, which means that again this has to be done on blends of PP with other polyolefins. 

Along this study, we have tried to obtain pol3rmer blends without previous separation of the mixture constituents. For this purpose, we prepared compatibilizers, namely grafted copolymers, for which the effect on incompatible polymers has been known for a long time. It is well known that either diblock, grafted or multiblock copol5Tners, when added in small amormts to incompatible mixtures, improve properties such as ... 

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