Method Blending dispersion

The degree of dispersion of the minor phase plays a crucial role. Important factors here are the blend composition, the interfacial tension between both components, the melt-viscosity of both components, the processing device and mixing conditions, the blend preparation method, etc. 

Polyethylene and polypropylene are mutually incompatible and the blend prepared from the melt of a mixture of the two polymers is, to a certain extent, hetmrgeneous. The transition of the original crystal structure of polyethylene into a pseudobexagonal modification depends on the irradiation dose, the dispersion method, and the conditions of the orientation of the macrcmudecule in the sample. Pseudobexagonal modification exists from S to 10 K over the melting temperature of a parent crystalline structure of polyethylene. 

Conducting electronic polymers, their blends and conventional polymers are fabricated into nanofibers by a nonmechanical, electrostatic dispersion method. 

Two dispersion methods will be considered. In the first case, the effect of dry blending conditions on dispersion in resultant mouldings is examined. 

Blends of polyester with cotton (qv) or viscose are first dyed with disperse dyes, then with sulfur dyes (see Fibers, polyester Fibers, regenerated CELLULOSics). Disperse and sulfur dyes can also be appHed simultaneously in a pad—dry—thermofix/chemical reduction pad—steam sequence. In this case, the sulfur dyes cannot be used in thein reduced form because of the effect of the sodium sulfide on the disperse dye. Therefore, this method is confined to the solubilized sulfur dyes or sulfur dyes in the dispersed form. 

Thermal Fixation Properties of Disperse Dyes on Polyester—Gotton. This method assesses the fixation properties of disperse dyes as a function of the time, temperature, dyestuff concentration, or presence and amount of auxiUary agents. The polyester—cotton fabric is padded and dried, the cotton dissolved in sulfuric acid and washed out of the blend, and the amount of dye on the polyester component assessed by either reflectance or measuring the optical density of a solution of dye obtained by extracting the dye with boiling chloroben2ene solvent. 

Chlorination was found (172) to be the most suitable and effective method for decolori2ing and reducing the COD of waste dyebaths containing a2o dyes. These findings have been substantiated for chlorination and biochemical purification (173). A study (174) has been done on the technical and economic feasibiUty of a chlorination dye wastewater reclamation system for treating effluent that is suitable for reuse in dyeing of polyester/cotton blends with disperse and direct dyes. 

Scale-up techniques for using the results of pilot plant or bench scale test w ork to establish the equivalent process results for a commercial or large scale plant mixing system design require careful specialized considerations and usually are best handled by the mixer manufacturer s specialist. The methods to accomplish scale-up will vary considerably, depending on whether the actual operation is one of blending, chemical reaction tvith product concentrations, gas dispersions, heat transfer, solids suspensions, or others. 

Another processing method has been termed the solventless. process. In this method, a premix is made from NC fibers plus liquid NG and minor ingredients dispersed in water. The paste is centrifuged and air-dried. The remaining ingredients are tumble-blended and then calender-rolled into sheets called carpet rolls . These are then extruded into finished pellets or cylinders... 

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