Fabrication of Polymeric Films by Various Processing Techniques

Polymers have some versatile applications which compete well with metals, alloys, ceramic, etc. such as packaging, textiles, household articles, construction materials, etc. Polymers are used in the form of fibers, films, coatings, foams, or molded and fabricated articles and exhibit a wide range of properties in terms of strength, rigidity, toughness, flexibility, elasticity, resilience, optical clarity, chemical and solvent resistivity, etc.

The calendaring process, is the simplest form, is employed to produce continuous films and sheets.

Die casting is a relatively low cost process which consists of converting a liquid prepolymer to a solid object with a desired shape. Acrylics, epoxies, polyesters, phenolics and urethanes are suitable foe die casting.

Film casting is also used to produce polymeric films. In this technique, the solution in an appropriate concentration of polymer in a suitable solvent is allowed to fall at a pre calculated rate on an endless metallic belt so that a continuous sheet of the polymer solution is thus formed on the surface of the metallic belt.

The injection molding process is having the high production rate. In this technique, a definite quantity of molten thermoplastic material is injected under pressure into a relatively cold mold where it solidifies to the shape of the mold. Pressure is applied through a hydraulically driven piston to push the molten material through a cylinder.

Extrusion is one of the cheapest methods available for producing many common plastic products such as films, filaments, tubes, sheets, pipes, rods, hoses and straps, all in continuous lengths.