Versatile High Viscosity Processes

The high-viscosity processes developed during and after the pioneering period and the applications discovered for high-viscosity machines [8] are as striking as they are varied. 

2 Historical Development of the Co-Rotating Twin Screw [References on page 33] 

Mixing, compounding, kneading, pasting, dissolving Plastics, dyes, fibers, silicon polymer 

Evaporating, releasing, residual degassing Plastics, rubbers, adhesives 

Polymerization, polycondensation, polyaddition and other reactions Thermoplastic polyurethranes, silicone polymers 

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TPs are characterized by low thermal conductivity, high specific heat, and high melt viscosity. Preparation of a uniform homogeneous melt and its delivery at adequate pressure and a constant rate could pose considerable problems if not properly processed (Chapter 3). The principal extruder variants are the single-screw and the twin-screw types. Of these, the single-screw extruder is by far the most versatile and popular in use. 

Technical Application. The experimental finding that with PEO, in contrast to other polymers, many factors have little or no effect on agglomeration is unquestionably the main reason for the great versatility that the agglomeration process offers in the manufacture of SBR latexes. It is noteworthy that the agglomeration result is the same irrespective of whether agglomeration is carried out in a 1-1 beaker or in a 200-m3 reactor, even if base latex viscosity is extremely high as the result of short-time polymerization techniques. 

Block copolymers exhibit unique characteristics in that they are able to self-order to multiphase domain structures of submicron scale with various morphologies because of the relative incompatibility of the different blocks. On the other hand, the liquid crystalline (LC) mesophases provide an additional example of a state of matter characterized by non-crystalline order. The combination of these two different aspects into one single macromolecular architecture leads to block copolymers containing LC blocks (7). These materials can be valuable in elucidating specific aspects of polymer physics and, in addition, may be employed as highly versatile interfacially active additives and viscosity improvers potentially capable of providing enhanced optimization of material processing and performance. 

This is a very versatile process for the polymer chemist, as the polymer can be any one of the three chemical types of anionic, non-ionic or cationic. The polymer molecular weight can vary from low-, through medium-, to high- and cross-Hnking agents can be included in the initial monomer solution, all without changing the nature of the product in the as-sold form. However, the intentional variation of any or aU of these factors will have a substantial effect on the viscosity behaviour of the system when the polymer is eventually used in an aqueous system. 

The viscosity and surface tension of the ink are the most important factors for inkjet printing. Viscosity should not exceed 20 cP for easy, optimum ejection from the nozzle. Surface tension is responsible for the globular shape of the ink droplets applied to the substrate. It is typically in the 28 to 350 mN/m range. There are enough different inks available on the market to render the inkjet process highly versatile. For example, conductive, dielectric, and semiconductive inks are all available for use [24, 28,110]. 

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