Significance and Use

This test method is designed to produce data indicative of the degree of crosslinking in ultra high molecular weight polyethylene that has been crosslinked chemically or by ionizing radiation.

The results are sensitive to the test temperature, solvent, and method used. For the comparison of data between institutions, care must be taken to have the same test conditions and reagents.

The data can be used for dose uniformity analysis, fundamental research, and quality assurance testing.

1. Scope

1.1 This test method describes how the crosslink density, molecular weight between crosslinks, and number of repeat units between crosslinks in ultra-high molecular weight polyethylene (UHMWPE) crosslinked by ionizing radiation or by chemical means can be determined by measuring the swelling ratio of samples immersed in o-xylene. Examples of experimental techniques used to make these measurements are discussed herein.

1.2 The test method reported here measures the change in height of a sample specimen while it is immersed in the solvent. Volumetric swell ratios assume that the sample is crosslinked isotropically, and that the change in dimension will be uniform in all directions. This technique avoids uncertainty induced by solvent evaporation or temperature change.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D2765 Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics

E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Keywords

crosslink density; molecular weight; network; swelling; UHMWPE; Crosslink density; In-situ inspection/analysis; Linear variable displacement transducers (LVDTs); Mechanical measurement; Molecular weight; Network parameters; Ultra-high molecular-weight polyethylene (UHMWPE); Volumetric measurement--medical/surgical applications;

ICS Code

ICS Number Code 83.080.01 (Plastics in general)

DOI: 10.1520/F2214-02R08

ASTM International is a member of CrossRef.

ASTM F2214