{"id":10626,"date":"2025-11-18T08:51:58","date_gmt":"2025-11-18T07:51:58","guid":{"rendered":"https:\/\/endolab.org\/?post_type=mt-polymer-analysis&p=10626"},"modified":"2025-11-19T17:49:37","modified_gmt":"2025-11-19T16:49:37","slug":"astm-f2381","status":"publish","type":"mt-polymer-analysis","link":"https:\/\/endolab.org\/de\/mt-polymer-analysis\/astm-f2381\/","title":{"rendered":"ASTM F2381"},"content":{"rendered":"

ASTM F2381:<\/strong> Standard Test Method for Evaluating Trans-Vinylene Yield in Irradiated Ultra-High Molecular Weight Polyethylene Fabricated Forms Intended for Surgical Implants by Infrared Spectroscopy<\/p>\n\n\n\n

<\/p>\n\n\n\n

Purpose<\/strong><\/h3>\n\n\n\n

This test method describes how to quantify trans-vinylene groups in ultra-high molecular weight polyethylene (UHMWPE) components intended for surgical implants using infrared (IR) spectroscopy. The resulting trans-vinylene index<\/em> (TVI) is used as an internal indicator of radiation dose and crosslinking produced during ionizing radiation treatment (e.g., gamma or electron beam sterilization\/crosslinking).<\/p>\n\n\n\n

<\/p>\n\n\n\n

Typical Application<\/strong><\/h3>\n\n\n\n
    \n
  • Orthopedic UHMWPE components (e.g., joint replacement inserts) or test coupons that have been irradiated for crosslinking or sterilization.<\/li>\n\n\n\n
  • Verification and mapping of radiation dose uniformity and crosslinking through the thickness of a component or preform.<\/li>\n\n\n\n
  • Supporting process development or quality control where irradiation conditions (source, dose, temperature, oxygen level) are critical.<\/li>\n<\/ul>\n\n\n\n

    General Test Description<\/strong><\/h3>\n\n\n\n
      \n
    • A thin slice (~200 \u00b5m) is cut from the UHMWPE component perpendicular to the articular (or other surface of interest) using a microtome.<\/li>\n\n\n\n
    • The slice is analyzed in a calibrated FTIR spectrometer. Spectra are collected in small steps (typically matching a ~200 \u00b5m aperture) from the surface of interest across the thickness, generating a depth profile.<\/li>\n\n\n\n
    • For each location, the area of the trans-vinylene absorption peak at ~965 cm-1 is measured and normalized by the area of the CH peak at ~1370 cm-1 to yield the TVI (ratio of peak areas). This normalization compensates for minor variations in the thickness of the specimen slice.<\/li>\n\n\n\n
    • A \u201cdepth locator\u201d (DL) is calculated from aperture size and step size to map each TVI value back to its distance from the articular surface, resulting in a TVI-versus-depth profile.<\/li>\n\n\n\n
    • Surface roughening of the film is used to reduce Fourier rippling artifacts without changing the true absorption peaks.<\/li>\n<\/ul>\n\n\n\n

      <\/p>\n\n\n\n

      What the Test Demonstrates<\/strong><\/h3>\n\n\n\n
        \n
      • Relative level of radiation-induced trans-vinylene unsaturation (and thus crosslinking) at different depths in the UHMWPE.<\/li>\n\n\n\n
      • Uniformity of received radiation dose and crosslinking within a component or preform, assuming an appropriate calibration curve between TVI and dose has been established for the specific irradiation conditions.<\/li>\n<\/ul>\n\n\n\n

        <\/p>\n\n\n\n

        Key Points for Device Developers<\/strong><\/h3>\n\n\n\n
          \n
        • The output is a TVI depth profile<\/em>, not a direct mechanical property; separate testing is needed for wear or strength.<\/li>\n\n\n\n
        • Calibration to actual dose is material- and process-specific and requires external dosimetry; F2381 itself does not define target TVI values or \u201cacceptable\u201d ranges.<\/li>\n\n\n\n
        • Test reports should document resin and lot, consolidation and post-treatments, sample geometry, film preparation, spectrometer setup, and analysis method (manual vs software).<\/li>\n<\/ul>\n\n\n\n

          <\/p>","protected":false},"featured_media":0,"parent":0,"template":"","meta":{"_acf_changed":false,"_uag_custom_page_level_css":""},"class_list":["post-10626","mt-polymer-analysis","type-mt-polymer-analysis","status-publish","hentry"],"acf":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"trp-custom-language-flag":false},"uagb_author_info":{"display_name":"Simon Kaddick","author_link":"https:\/\/endolab.org\/de\/author\/"},"uagb_comment_info":0,"uagb_excerpt":"ASTM F2381: Standard Test Method for Evaluating Trans-Vinylene Yield in Irradiated Ultra-High Molecular Weight Polyethylene Fabricated Forms Intended for Surgical Implants by Infrared Spectroscopy Purpose This test method describes how to quantify trans-vinylene groups in ultra-high molecular weight polyethylene (UHMWPE) components intended for surgical implants using infrared (IR) spectroscopy. The resulting trans-vinylene index (TVI) is…","_links":{"self":[{"href":"https:\/\/endolab.org\/de\/wp-json\/wp\/v2\/mt-polymer-analysis\/10626","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/endolab.org\/de\/wp-json\/wp\/v2\/mt-polymer-analysis"}],"about":[{"href":"https:\/\/endolab.org\/de\/wp-json\/wp\/v2\/types\/mt-polymer-analysis"}],"wp:attachment":[{"href":"https:\/\/endolab.org\/de\/wp-json\/wp\/v2\/media?parent=10626"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}