Injection molded and extruded plastics are available in the widest array of materials and properties. They can be custom compounded in almost endless combinations. When choosing a material, a good rule is to use a plastic that is readily available with proven biocom-patibility appropriate for its use, and that meets the mechanical design and assembly requirements. Most mechanical plastics available in shapes for machining that are thermoplastics are available in injection molding pellet form.
The injection molding process will accommodate virtually any thermoplastic. Extrusion for catheters is usually done from the more flexible plastics such as Pebax®, polyurethane, polyvinylchloride (PVC) nylon, thermoplastic elastomers (TPEs), and flourinated ethylene propylene (FEP). Extrusion from rigid plastics such as PEEK (polyetheretherketone) is available where more pushability and torqueability of a catheter is required. Flexibility in these stiffer plastics in extrusions is achieved by use of thinner wall sections.
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