Mixing performance Blending

Mixing performance, 306 Blending, 324 Emulsions, 324 Extraction, 324 Gas-liquid contacting, 324 Gas-liquid dispersion, 325 Liquid-liquid dispersion, 325, 326 Mixing vortex, 311 Motionless mixing, see static mixing National Fire Protection Association, 399 Net positive suction head, 160-194 Available from system, 160, 188, 189,... 

Once the analytical method is validated for accuracy at the laboratory scale, it can be used to obtain extensive information on process performance (blend homogeneity, granulation particle size distribution, and moisture content) under various conditions (blender speed, mixing time, drying air temperature, humidity, volume, etc.). Statistical models can then be used to relate the observable variables to other performance attributes (e.g., tablet hardness, content uniformity, and dissolution) in order to determine ranges of measured values that are predictive of acceptable performance. 

The uniformity of a multiphase mixture can be measured by sampling of several regions in the agitated mixture. The time to bring composition or some property within a specified range (say within 95 or 99% of uniformity) or spread in values—which is the blend time—may be taken as a measure of mixing performance. Various kinds of tracer techniques may be employed, for example ... 

MIXING PERFORMANCE OF INLINE MIXERS 4.1. Macromixing (or Blending) Performance... 

The 80%/20% binary blends PE/PS and PP/PS were subjected to F-C reaction for compatibilization performed under nitrogen atmosphere in a Banbury mixer. Different concentrations of catalyst (AICI3) and 0.3% of cocatalyst (styrene) were added to the completely melted and mixed physical blends. The blends and catalyst concentrations are weight based. High MW commercial grades of linear low density polyethylene (LLDPE), and injection-grade polypropylene and polystyrene were used as homopolymers. The compatibilization conditions and MW of the homopolymers are given in Table 20.1. Blend names are listed in nomenclature. 

Polymers are rarely used alone without compounding. Compounding, as used here, refers to melt mixing the blend components and preparing a finished compound from all the components of the blend. The compounding ingredients are of different types, each with a different function to enhance the polymer performance. Table 3.1 shows some of them. 

The emphasis in research and technological development of new products in the polymer industry has changed from synthesis of novel monomers to blending polymers in order to obtain desirable performance properties at a dial-in cost. Polymer blends offer improved performance/cost ratios and flexibility to tailor-make the product to suit customer needs. Polymer blends are intimate mixtures of two or more polymers. The individual components may be melt-mixed, solution blended, co-precipitated, controlled devolatilized, or coagulated before final processing. Finished articles are converted from blends by extrusion or molding processing operations. 

Eor practical reasons, and to facilitate data analysis, single-surfactant systems are normally studied. Importantly, the thermodynamic and kinetic models are easier to handle when compared with multicomponent systems, and there are only a few reliable methods for the unequivocal measurement of mixed systems. However, in real-world applications, mixed and blended surfactants are normally employed for commercial reasons and to improve performance. 

Figure 6-51. An example of the potential effects of regrinding on the performance of an injection-molded TP mixed and blended with virgin material.

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