Significance and Use
The density of polyethylene is a conveniently measurable property which is frequently useful as a means of following physical changes in a sample, as an indication of uniformity among samples, and as a means of identification.
This test method is designed to yield results with a precision of ±0.08 % or better.
1.1 This test method covers the determination of the density of polyethylene through the utilization of ultrasound equipment.
1.2 This test method is based on the distinct behaviors of the amorphous and crystalline phases of polyethylene in response to ultrasound. Polyethylene shall be viewed as a composite structure where high-density crystalline regions are connected by lower-density amorphous material. The ratio of crystalline to amorphous material determines the final density of the material. The amorphous and crystalline phases exhibit very distinct behaviors with regard to the propagation of sound waves. The propagation characteristics in the composite will depend on the relative amount of the two phases (the degree of crystallinity).
1.3 Inorganic materials increase density as measured by Test Methods D 792 and D 1505, but they have little or no effect on ultrasonic density. The ultrasonic measurement is basically a base resin density.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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.
Note 1—There is no known ISO equivalent to this standard.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D618 Practice for Conditioning Plastics for Testing
D792 Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement
D883 Terminology Relating to Plastics
D1248 Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
D1505 Test Method for Density of Plastics by the Density-Gradient Technique
D3350 Specification for Polyethylene Plastics Pipe and Fittings Materials
D4703 Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets
D4976 Specification for Polyethylene Plastics Molding and Extrusion Materials
E494 Practice for Measuring Ultrasonic Velocity in Materials
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
amorphous; crystalline; density; molded; plaques; polyethylene; sonic; ultrasonic; ultrasound; Density--plastics; Polyethylene (PE); Ultrasound testing ;
ICS Number Code 83.080.20 (Thermoplastic materials)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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