Significance and Use

The crystallinity of UHMWPE will influence its mechanical properties, such as creep and stiffness. The reported crystallinity will depend on the integration range used to determine the heat of fusion, and the theoretical heat of fusion of 100 % crystalline polyethylene used to calculate the percent crystallinity in an unknown specimen. Differential scanning calorimetry is an effective means of accurately measuring both heat of fusion and melting temperature.

This test method is useful for both process control and research.

1. Scope

1.1 This test method discusses the measurement of the heat of fusion and the melting point of ultra-high-molecular weight polyethylene (UHMWPE), and the subsequent calculation of the percentage of crystallinity.

1.2 This test method can be used for UHMWPE in powder form, consolidated form, finished product, or a used product. It can also be used for irradiated or chemically-crosslinked UHMWPE.

1.3 This test method does not suggest a desired range of crystallinity or melting points for specific applications.

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.

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

D3418 Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry

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

E793 Test Method for Enthalpies of Fusion and Crystallization by Differential Scanning Calorimetry

E967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers

E968 Practice for Heat Flow Calibration of Differential Scanning Calorimeters

E1953 Practice for Description of Thermal Analysis and Rheology Apparatus

Keywords

crystallinity; differential scanning calorimetry; heat of fusion; melting temperature; thermal analysis; UHMWPE;

ICS Code

ICS Number Code 07.030 (Physics. Chemistry); 17.200.10 (Heat. Calorimetry)

DOI: 10.1520/F2625-10

ASTM International is a member of CrossRef.

ASTM F2625