ASTM F2695-12(R2020) pdf free download
ASTM F2695-12(R2020) pdf free download.Standard Specification for Ultra-High Molecular Weight Polyethylene Powder Blended With Alpha-Tocopherol (Vitamin E) and Fabricated Forms for Surgical Implant Applications
1. Scope
1.1 This specification covers ultra-high molecular weight polyethylene (UHMWPE) powder blended with alpha- tocopherol (Vitamin E) intended for use in surgical implants. 1.2 The requirements of this specification apply to alpha- tocopherol-containing UHMWPE in two forms. One is virgin polymer powder blended with alpha-tocopherol prior to con- solidation (Section 4). The second is any form fabricated from this blended, alpha-tocopherol-containing powder from which a finished product is subsequently produced (Section 5). This specification does not apply to finished or semi-finished products that are doped with Vitamin E after consolidation. 1.3 Aside from blending with alpha-tocopherol, the provi- sions ofSpecifications F648 and D4020 apply. Special require- ments detailed in this specification are added to describe powders containing alpha-tocopherol that will be used in surgical implants. This specification addresses material char- acteristics and does not apply to the packaged and sterilized finished implant. This specification also does not apply to UHMWPE materials extensively crosslinked by gamma and electron beam sources of ionizing radiation. 1.4 The following precautionary caveat pertains only to the fabricated forms portion, Section 5, of this specification. This standard does not purport to address all ofthe safety concerns, ifany, associated with its use. It is the responsibility ofthe user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 crosslinking—the process by which ionizing irradia- tion produces chemical bonds between UHMWPE molecules. 3.1.2 extensively crosslinked UHMWPE—UHMWPE mate- rial that has been subjected to total doses of gamma and/or electron beam ionizing irradiation greater than 40 kGy. 3.1.3 fabricated form—any bulk shape of UHMWPE, fab- ricated from the virgin polymer powder, used during the process of fabricating surgical implants prior to crosslinking, packaging, and sterilization. A fabricated form includes a semi-finished rod or sheet as well as a direct compression molded component. 3.1.4 generic property—that property which is determined solely by the chemical composition and structure of the virgin polymer. 3.1.5 ionizing irradiation—gamma ray or high-energy elec- tron irradiation sources. 3.1.6 virgin polymer powder—the initially delivered form of the polymer as synthesized from its monomers prior to any processing or fabrication into a medical device. The provided resin is typically in the form ofpellets, granules, or powder and is the material from which fibers, tubes, rods, slabs, sheets, films, or specific parts and devices are fabricated. Specifically, it is the form of UHMWPE as obtained from the powder manufacturer and prior to blending and fabrication into a bulk shape.
Alpha-tocopherol is a biocompatible stabilizer of polyolefins (1-6) and is intended to reduce oxidative degrada- tion during processing, radiation processing, shelf life storage, and in-vivo exposure of UHMWPE. Several laboratory studies have demonstrated that alpha-tocopherol will stabilize irradi- ated UHMWPE from accelerated aging conditions intended to simulate a variety of severe oxidative challenges (7-12). Human clinical use of implants fabricated from alpha- tocopherol blended UHMWPE is reported to have begun in 2004. At present, the extent to which alpha-tocopherol will help stabilize UHMWPE implants from in-vivo oxidation has not yet been determined.
This specification is intended to describe the proper- ties required and the procedures to be followed in testing unirradiated raw materials of UHMWPE blended with alpha- tocopherol for medical implant applications. This specification does not purport to address the testing that is needed for implants that are fabricated from the raw materials specified herein.
