Standard Historical Last Updated: Aug 23, 2019
ASTM D789-18

Standard Test Method for Determination of Relative Viscosity of Concentrated Polyamide (PA) Solutions

Significance and Use

4.1 These test methods are intended for use as control and acceptance tests. They are also applicable in the partial evaluation of materials for specific end uses and as a means for detecting changes in materials due to specific deteriorating causes.

4.2 The steps involved in running this method are:

4.2.1 Calibration of the viscometers,

4.2.2 Preparation of solutions,

4.2.3 Determination of efflux time,

4.2.4 Calculation of relative viscosity (which requires the following), Determining the density of the polymer/formic acid solution, and Determining the absolute viscosity of the formic acid used.

4.3 Solvents used to prepare concentrated solutions for use in this test method are formic acid ( and m-cresol (

4.4 Solvents used to prepare dilute solutions of various polyamides are designated in ASTM D6779, ISO 16396, and ISO 307. These include:

4.4.1 Formic Acid—PA 6, PA 46, PA 66, PA 69, PA 610, PA MXD6 and corresponding copolyamides

4.4.2 Sulfuric Acid—PA 6, PA 46, PA 66, PA 69, PA 610, PA 612, PA MXD6 and corresponding copolyamides

4.4.3 m-cresol—PA 612, PA1010, PA1012, PA 11, PA 12, PA1212, PA 11/12 copolymers, PA 6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66

4.4.4 Phenol/1,1,2,2-tetrachloroethane (where legal)—PA 6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66, PA 6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 10T PA 6I/6T/66, PPA and copolyamides


1.1 This test method covers the determination of relative viscosity as it applies to concentrated solutions of polyamide (PA).

1.2 This test method does not address measures of viscosity derived from measurements with dilute solutions.

1.3 The values stated in SI units are to be regarded as standard. The values given in brackets are for information only.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

Note 1: This standard and ISO 307 address the same subject, buy the technical content is different.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Book of Standards Volume: 08.01
Developed by Subcommittee: D20.15
Pages: 7
DOI: 10.1520/D0789-18
ICS Code: 83.080.20