Raw MaterialsRaw Materials
November 8, 2009
5 Min Read
Originally Published MPMN November/December 2009
Click to enlargeA polycarbonate resin has been developed to address demand for a radiation-sterilizable material for thin-wall medical applications. Makrolon Rx2435 combines mechanical strength and toughness with enhanced ease of flow. Potential applications include dialysis components, catheter connectors, surgical instruments, and drug-delivery devices. The resin is supplied in pellet form for injection-molded applications. Gamma-stabilized, it is typically offered in Gamma, an Rx Medical color from the company’s LEDA-compounded color technology range. The material can also be colored using any of the firm’s other biocompatible options. The material meets the requirements of FDA-modified ISO 10993-1 biocompatibility test requirements.
Ultrasoft elastomer with gel-like properties
An ultrasoft elastomer with a feel similar to a firm gel but with greater physical properties can be potted, encapsulated, and molded. MED-4286 is a pliable silicone elastomer designed for applications requiring a Shore 000 durometer, low modulus, and high elongation. Featuring a low, pourable viscosity and a 12-hr work time, the elastomer is easily moldable, providing versatility for a variety of applications. It is also designated as unrestricted and can be considered for use in long-term implants. With a one-to-one mix ratio, the material is packaged in a side-by-side kit for easy use. For short-term implant applications or products that come in contact with skin or body fluid, a restricted version can also be considered.
NuSil Technology LLC
Used to manufacture medical devices, medical instrumentation, and devices for orthopedic trials, a line of medical-grade plastics is suitable for use in surgical instruments and devices, imaging and monitoring equipment, surgical trays, and diagnostic equipment. Products include SustaPEEK MG, Sustason PPSU MG (Radel R), SustaPEI MG (Ultem), and Sustarin C MG acetal. The materials are available as sheets and rods. Certified to a range of standards, including ASTM and USP Class VI, the FDA-compliant supplier also provides lot and batch traceability and ultrasonic testing services.
Röchling Engineering Plastics
Suited for use in medical applications, a line of modified PEEK grades offers enhanced performance characteristics compared with standard PEEK, according to their supplier. Available in eight standard grades that can be injection molded or extruded, the AvaSpire AV-600 series includes three unfilled grades, three 30% glass-reinforced grades, and two 30% carbon-reinforced grades. Featuring improved ductility and toughness, the unfilled grades exhibit 20% higher tensile elongation at yield, with tensile elongation at break values that are at least twice as high as those of comparable PEEK grades, according to the supplier. This feature can benefit interference-fit assemblies and help manage the stress inherent in designs with unavoidably sharp corners. Unfilled grades also offer improved vertical flammability resistance, achieving a UL94 V0 rating of 0.8-mm thickness. The higher thermal performance extends the useful range of PEEK-based compounds above 302°F. The materials also demonstrate higher stiffness between 302° and 374°F. Other features include reduced warpage, tight dimensional tolerances, and chemical resistance and melt viscosities similar to those of standard PEEK.
Solvay Advanced Polymers LLC
Implantable medical fabrics
Employing a variety of materials ranging from biocompatible polymers to metals such as stainless steel, nitinol, platinum, and titanium, a manufacturer produces woven, braided, knitted, and nonwoven implantable textiles. By matching specific medical device applications with the appropriate materials, the supplier can produce fabrics that exhibit optimal mechanical properties for the given application. The fabrics can be engineered from an array of materials, including PEEK, high-performance polyethylenes, bioabsorbable polymers such as polyglycolides and polylactides, radiopaque materials, and low-friction polymers.
Secant Medical LLC
Click to enlargeA thermoplastic elastomer (TPE) can serve as a replacement material for PVC in fluid pathway systems. The K-6100-series TPE material meets USP Class VI guidelines and is certified to ISO 10993-5 and ISO 10003-4 standards. Containing no halogens, plasticizers, or animal derivatives, the material is suited for the fabrication of tubing used to deliver fluids to the body, among other applications. It is autoclavable to 121°C and withstands gamma sterilization. Available with Shore durometer hardnesses of 65A, 75A, and 84A, the material features clarity and a nonstick surface, has nontoxic and nonhemolytic properties, and can be joined by means of heat welding or solvents.
Kent Elastomer Products Inc.
Teflon and stainless-steel composite
Click to enlargeAvailable in thicknesses down to 0.0025 in., a composite diaphragm material provides the chemical resistance properties associated with Teflon combined with an ultrafine stainless-steel cloth substrate. The material was developed to replace regular Teflon film, the thinness and weakness of which has caused deformation issues and premature failure of device components, according to the manufacturer. The thin-film material displays tensile strength, resists the creep and cold-flow problems that can impair ordinary Teflon material, and provides the temperature tolerance, chemical resistance, and reliability needed for critical applications.
For more features and articles on raw materials, go to www.devicelink.com/mpmn/materials.
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