ASTM D2765-16
Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics

Standard No.

ASTM D2765-16

Release Date

2016

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D2765-16(2024)

Latest

ASTM D2765-16(2024)

Scope

5.1 Many important properties of crosslinked ethylene plastics vary with the gel content. Hence, determination of the gel content provides a means of both controlling the process and rating the quality of finished products.

5.2 Extraction tests permit verification of the proper gel content of any given crosslinked ethylene plastic and they also permit comparison between different crosslinked ethylene plastics, including those containing fillers, provided that, for the latter, the following conditions are met:

5.2.1 The filler is not soluble in either decahydronaphthalene or xylenes at the extraction temperature.

5.2.2 The amount of filler present in the compound either is known or will be determined by other means.

5.2.3 Sufficient crosslinking has been achieved to prevent migration of filler during the extraction. Usually it has been found that, at extraction levels up to 508201;%, the extractant remains clear and free of filler.

5.3 A suitable antioxidant is added to the extractant to inhibit possible oxidative degradation at the extraction temperatures.

5.4 Before proceeding with this test method, reference shall be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or a combination thereof, covered in the materials specification shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions apply.

1.1 The gel content (insoluble fraction) produced in ethylene plastics by crosslinking is determined by extracting with solvents such as decahydronaphthalene or xylenes. The methods described herein are applicable to crosslinked ethylene plastics of all densities, including those containing fillers, and all provide corrections for the inert fillers present in some of those compounds.

1.2 Test Method A, which permits most complete extraction in least time, is to be used for referee tests, but two alternative nonreferee Test Methods B and C are also described. Test Method B differs from the referee test method only in sample preparation; that is, it requires use of shavings taken at selected points in cable insulation, for example, rather than the ground sample required by the referee test method. Because the shaved particles are larger, less total surface per sample is exposed to the extractant, so this test method ordinarily yields extraction values about 1 to 28201;% lower than the referee method. Test Method C requires that a specimen in one piece be extracted in xylenes at a constant temperature of 110°C. At this temperature and with a one-piece specimen, even less extraction occurs (from 3 to 98201;% less than the referee test method), this method permits swell ratio (a measure of the degree of crosslinking in the gel phase) be determined.

1.3 Extraction tests are made on articles of any shape. They have been particularly useful for electrical insulations since specimen......

ASTM D2765-16 Referenced Document

• ASTM D1603 Standard Test Method for Carbon Black In Olefin Plastics
• ASTM D1998 Standard Specification for Polyethylene Upright Storage Tanks
• ASTM D297 Standard Test Methods for Rubber Products-Chemical Analysis
• ASTM D3351 Standard Test Method for Gel Count of Plastic Film
• ASTM D618 Standard Practice for Conditioning Plastics for Testing
• ASTM D883 Standard Terminology Relating to Plastics
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ISO 10147 Pipes and fittings made of crosslinked polyethylene (PE-X) - Estimation of the degree of crosslinking by determination of the gel content

ASTM D2765-16 history

• 2024 ASTM D2765-16(2024) Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
• 2016 ASTM D2765-16 Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
• 2011 ASTM D2765-11 Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
• 2001 ASTM D2765-01(2006) Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
• 2001 ASTM D2765-01 Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
• 2001 ASTM D2765-95 Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics