Motionless mixer blending

Motionless Mixer Blending of Styrene/ Acrylonitrile Copolymer and Nitrile Rubber to Form ABS... 

This study (3) was done to produce an ABS type resin by dry and melt blending SAN and a nitrile rubber in a motionless mixer. In polyblends of two semicompatible polymers, the particle size of the dispersed phase is an important factor concerning final properties, particularly if a rubber is dispersed to improve impact strength. Motionless mixers should give precise control over the final particle size since for laminar flow the number of fluid layers and the striation thickness can be predicted mathematically. The hypothesis that the impact strength should peak out at a precise number of mixing elements was thus investigated. 

Distribution of components in a mixture through laminar shear mixing frequently occurs in a disordered manner, although motionless mixers are designed to blend in a more regular way through a process of repeated stream splitting and material combination. 

The results for blending for motionless mixers can be correlated by plotting coefficient of variation reduction CoVr versus L/D. In laminar flow there is no effect of viscosity, flow rate or initial CoV on these correlations. CoVr is usually found to correlate with the L/D in an exponential form. 

Mixing, as a term, is generally used in three different senses i. It corresponds to the blending of two or more components, i.e. it is a unit operation carried out to unify two or more material streams or charges into one. a. Mixing is the synonym of agitation or stirring, i.e. it is an action carried out e.g. by stirrers or motionless mixers to induce relative displacements of various parts of the treated material by convection, shear, dispersion, random movements, turbulence, etc. 

Blending equipment is available with zero, one or two principal moving parts. The former are motionless mixers in which fluids are pumped through... 

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