ASTM D6556-21 rus PDF

Full title and description

ASTM D6556-21 — Standard Test Method for Carbon Black — Total and External Surface Area by Nitrogen Adsorption. This test method defines procedures to measure the total surface area (NSA, by multipoint B.E.T. nitrogen adsorption) and the external surface area (STSA) of carbon black, reporting values primarily in SI units and including guidance on instrumentation, sample preparation and reporting.

Abstract

This standard specifies multipoint nitrogen adsorption measurements at cryogenic temperature to determine (1) the total specific surface area using the Brunauer–Emmett–Teller (B.E.T.) NSA approach and (2) the external (rubber-accessible) surface area using the statistical thickness surface area (STSA) method. It replaces earlier editions and provides the basis for reporting NSA and STSA values for carbon black quality control, specification and research. The standard notes the relationship between STSA and older CTAB values and includes safety and unit conventions.

General information

• Status: Active standard (current edition D6556-21).
• Publication date: 1 May 2021 (designation: D6556-21).
• Publisher: ASTM International (formerly American Society for Testing and Materials).
• ICS / categories: 71.060.10 (chemical elements / surface area measurement).
• Edition / version: D6556-21 (current revision; supersedes earlier D6556 editions).
• Number of pages: 6 pages.

Scope

The standard covers determination of total surface area by multipoint B.E.T. nitrogen adsorption (NSA) and determination of external surface area by the statistical thickness surface area (STSA) method for carbon blacks. It specifies units (SI preferred), apparatus types, sample degassing and preparation, measurement conditions and reporting formats, and includes safety and applicability notes. The document is intended for laboratories performing carbon black surface-area determinations and does not address all laboratory safety requirements.

Key topics and requirements

• Principle: multipoint nitrogen adsorption at liquid-nitrogen temperature and analysis by the B.E.T. NSA theory to obtain total surface area (NSA).
• External surface area (STSA): statistical thickness method to report rubber-accessible surface area; STSA is used for correlation with rubber properties.
• Relation to CTAB method: CTAB (formerly Test Method D3765) has been withdrawn as preferred STSA is used; the standard provides an empirical relation to estimate CTAB from STSA when needed.
• Apparatus and sample preparation: requirements for multipoint static-volumetric adsorption apparatus, sample cells, degassing (typical degassing temperatures around 300 ± 10 °C) and high-purity gases.
• Reporting: units (m2/g), number of points used for BET fit, STSA reporting, and notes on precision and uncertainty (use of reference blacks and control charts recommended via related guides).

Typical use and users

Used by carbon black manufacturers, quality control and R&D laboratories, rubber and tire industry formulators, materials scientists and testing service providers for product specification, batch release, comparative testing and research into filler–rubber interactions. Laboratories that perform these measurements typically follow ASTM apparatus and reference-black practices and use statistical monitoring to validate ongoing precision.

Related standards

Key related documents include the withdrawn CTAB method (ASTM D3765), guides for test validation and laboratory control (ASTM D4821), morphological characterization methods (ASTM D3849), and international BET-method standards such as ISO 9277 (Determination of specific surface area by gas adsorption — BET method). These standards and guides are commonly used together to ensure traceable, comparable surface-area determinations and laboratory quality control.

Keywords

carbon black; surface area; B.E.T.; NSA; STSA; nitrogen adsorption; multipoint adsorption; CTAB (historic); reference blacks; sample degassing; m2/g.

FAQ

Q: What is this standard?

A: ASTM D6556-21 is a test method that defines procedures to measure the total (NSA) and external (STSA) surface area of carbon black using multipoint nitrogen adsorption and B.E.T.-based evaluation.

Q: What does it cover?

A: It covers instrument and apparatus requirements, sample preparation (including degassing), multipoint adsorption measurement and calculation of B.E.T. NSA and STSA values, units and reporting conventions, and notes on safety and applicability.

Q: Who typically uses it?

A: Carbon black producers, QA/QC and R&D labs, rubber and tire compounders, independent testing laboratories and materials research groups use the standard for specification, product control and research.

Q: Is it current or superseded?

A: The D6556-21 edition (published 1 May 2021) is the current ASTM edition as of this publication; it supersedes prior D6556 revisions. Users should check ASTM records for any amendments or later revisions.

Q: Is it part of a series?

A: It is part of the ASTM D24 committee’s body of carbon-black test methods and is used alongside related standards and guides (for example D3765 historically for CTAB, D4821 for validation/precision, D3849 for morphology). It is also consistent in principle with international BET standards such as ISO 9277.

Q: What are the key keywords?

A: B.E.T., NSA, STSA, nitrogen adsorption, carbon black, surface area, CTAB (historic), multipoint adsorption, reference blacks.