Subject blend polymer coating

The correlation between quality of a laminar mixture and the total shear strain which the material has undergone applies particularly to blends of polymers. When hard or agglomerated components are being mixed, however, it is necessary to subject such materials to a high shear stress gradient, and special equipment and processes have been developed for such purposes. Tlie rubber and coatings industries in particular abound with examples of such techniques. 

The polymer-blend dispersions of PTFE and fluorinated-pitch with various concentration of fluorinated-pitch have been coated on stainless steel (SUS-304). The various coated polymer-blend were heat-treated at 350 °C 5 °C for 30 minutes. Further, samples were subjected to EB irradiation with a 200keV from EB accelerator (CURETRON , NHV Corporation) up to 1000 kGy at 330 °C 3 °C in nitrogen gas atmosphere. 

While most of the subjects discussed up to this point involve injection molding or extrusion applications, there are a considerable number of other applications where polymer blend technology is and will be employed including adhesives, sealants, coatings, and thermosetting systems, polymeric membranes, and water-based polymers. 

If we study the composition of the surface of a pol)mier solution or a polymer mixture we should expect to find that the composition of the region near the surface is not the same as that of the bulk. The same applies to an interface between such a system and a solid for example a colloidal particle suspended in a polymer solution will often be coated with a layer of polymer, that may well be able to stabilise the colloid, preventing its aggregation. In polymer solutions this phenomena is known as adsorption, if the polymer accumulates at the surface, or depletion, if it is the solvent that is favoured there in polymer blends one often refers to the surface segregation or surface enrichment of one component of the mixture. However, these different names describe what is essentially the same phenomenon, the subject of this chapter. 

The thermodynamic behaviour of polymer solutions has been the subject of extensive study, partly because of the importance of surface coatings such as lacquers and paints, and partly because it is essential to understand the behaviour of polymers in solution in order to quantitatively characterize the polymers and copolymers. Furthermore, it is also not possible to understand the behaviour of polymer-polymer systems (blends and alloys) without some understanding of polymer-solvent systems. There is a close relationship between the way in which amorphous solids mix and the behaviour of polymers in solution polymer solutions are much more amenable to experimental measurements. 

Barrier films of exfoliated clay-polymer composites have been a subject of considerable investigation with some commercial utility (e.g., barrier layer for termis balls).The thin exfoliated clay platelets dispersed in a polymer matrix present a tortuous diffusion path for gas molecules similar to that observed in Figure 12 for biaxially oriented polymer blends. The advantages of exfoliated clay modification for barrier properties are the retention of transparency and low cost. A novel approach utilizing nanocomposites involves dispersion of the exfoliated clay in a water emulsion or suspension and coating a desired substrate. This approach has been commercialized by IntMat for tennis balls, tires, and food packaging applications. For exceptional barrier properties, and where transparency is not required, metalized polymer films or aluminum foil polymer film laminates are usually employed. 

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