Homogeneous blend

Poly(ethyl methacrylate) (PEMA) yields truly compatible blends with poly(vinyl acetate) up to 20% PEMA concentration (133). Synergistic improvement in material properties was observed. Poly(ethylene oxide) forms compatible homogeneous blends with poly(vinyl acetate) (134). The T of the blends and the crystaUizabiUty of the PEO depend on the composition. The miscibility window of poly(vinyl acetate) and its copolymers with alkyl acrylates can be broadened through the incorporation of acryUc acid as a third component (135). A description of compatible and incompatible blends of poly(vinyl acetate) and other copolymers has been compiled (136). Blends of poly(vinyl acetate) copolymers with urethanes can provide improved heat resistance to the product providing reduced creep rates in adhesives used for vinyl laminating (137). 

Compatibility. Clear definition of compatibility is rather difficult. Compatibility has been defined as the ability of two or more materials to exist in close and permanent association for an indefinite period without phase separation and without adverse effect of one on the other [28]. On the other hand, compatibility is easily recognized in solvent-borne adhesives as a homogeneous blend of materials without phase separation. Normally, compatibility is understood as a clear transparent mixture of a resin with a given polymer. But, compatibility is a more complex thermodynamic phenomenon which can be evaluated from specific... 

Powder coating is a solventless coating system that is not dependent upon a sacrificial medium such as a solvent, but is based on the performance constituents of solid TP or TS plastics. It can be a homogeneous blend of the plastic with fillers and additives in the form of a dry, fine-particle-size compound similar to flour. The three basic methods are the fluidized bed, electrostatic spray, and electrostatic fluidized bed processes (9). 

For homogeneous blends, % < 0 and consequently the presence of another noncrystallizable polymer depresses the melting point of a polymer. 

It is mainly used as a homogeneous blend with polystyrene (see Sect. 5.5). 

As already mentioned two-phase blends show two glass transition temperatures, which can be ascribed to the components. However, homogeneous blends only have an intermediate glass transition temperature, between those of the components, depending on the composition. 

Due to light scattering, crystalline polymers mostly yield turbid films.Their blends with other polymers are always demixed because polymers are not able to form mixed crystals. Consequently, crystallizable polymers only yield homogeneous blends above their melting point. As soon as crystallization sets in, the components will separate. 

A pyrotechnic composition will usually contain a small percentage of an organic polymer that functions as a binder, holding all of the components together in a homogeneous blend. These binders, being organic compounds, will also serve as fuels in the mixture. 

In the plating process it is essential to guarantee a homogenous blending besides homogenous addition/distribution of the liquid material. The liquid feeding can be carried out by inlet lances, injectors or nozzles, while agglomeration of the plated powder material has to be suppressed by a chopper or cutter. 

The antistatic agent is uniformly incorporated into the copolymer by conventional melt blending techniques. For example, the antistatic agent is blended with molten copolymer in a manner to form a homogeneous blend, using for example an extruder. 

In impact tests the order was the same except that Tritonal/D-2 95/5 and Picratol 52/48 were reversed Addnl work was conducted on the use of surfactants for reducing the interfacial tension between TNT and paraffin waxes. Refs 98 100 report results of tests using the n-octadecyl, n-hexa-decyl, n-dodecyl and n-hexyl esters of 2,4,6-trinitrobenzoic acid to permit stable homogeneous blends of paraffin waxes in molten TNT. It is reported that all these materials act as surfactants and that the interfacial activity increases as a linear function of the alkyl chain length of the ester. N-octadecyl 2,4,6-trinitrobenzoic acid also acts as a surfactant for the beeswax/TNT system. It was concluded, however, that the degree of reduction in the interfacial tension of... 

NS is proposed as an ignition compn for elec blasting caps) 155)C. A.Woodbury,USP 2118533 (1938) CA 32,5632(1938) (Blasting caps contg a homogeneous blend of BkPdr ground smokeless proplnt) 156)R.F.3.Cox,USP 2125221(1938) ... 

Here n is the average refractive index, k is Boltzman s constant, and T is absolute temperature (13). If a polyblend were to form a homogeneous network, the stress would be distributed equally between network chains of different composition. Assuming that the size of the statistical segments of the component polymers remains unaffected by the mixing process, the stress-optical coefficient would simply be additive by composition. Since the stress-optical coefficient of butadiene-styrene copolymers, at constant vinyl content, is a linear function of composition (Figure 9), a homogeneous blend of such polymers would be expected to exhibit the same stress-optical coefficient as a copolymer of the same styrene content. Actually, all blends examined show an elevation of Ka which increases with the breadth of the composition distribution (Table III). Such an elevation can be justified if the blends have a two- or multiphase domain structure in which the phases differ in modulus. If we consider the domains to be coupled either in series or in parallel (the true situation will be intermediate), then it is easily shown that... 

Hill and Barham [133] showed by transmission electron microscopy that blends of high and low molar mass polyethylene melts were homogeneous with no detectable phase separation. The blends were prepared by solution mixing to obtain an initially homogeneous blend before the thermal treatment in the melt. It should be realised that the mechanical mixing of high and low molar mass linear polyethylenes to obtain a homogeneous melt may require considerable work and time. 

Polymers of different structures do not form homogeneous blends. Mixture of polymers that differ in structure and polarity are compatible with one another only to a very limited extent. They separate in the melt or at the latest after cooling in the solid state, as a result of weak interfaces between the components and local stress concentrations. Therefore, they cannot be... 

The foams were prepared by first mixing the bark and the isocyanate, the other components (catalyst, surfactant, and blowing agent) were pre-mixed and added to this bark - isocyanate mix, and the mixing was continued to yield a homogeneous blend which began to rise and yield a foam product. The rate of foaming was a function of the catalyst used. 

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