ISO 24698-2-2018 PDF

Full title and description

Rubber, raw — Determination of bound acrylonitrile content in acrylonitrile-butadiene rubber (NBR) — Part 2: Kjeldahl method. This international standard specifies an analytical procedure using an automatic Kjeldahl analyser for quantifying the bound acrylonitrile fraction in NBR and related rubbers (including XNBR, NBIR and NBR latex).

Abstract

This document specifies a method for the determination of the bound acrylonitrile content in acrylonitrile-butadiene rubber (NBR) by an automatic analyser which uses the Kjeldahl method. The method is also applicable to carboxylic acrylonitrile-butadiene rubber (XNBR), acrylonitrile-butadiene-isoprene rubber (NBIR) and NBR latex. Note: ISO 24698-2 and ISO 24698-1 (the Dumas/combustion method) can give different results on the same rubber sample.

General information

• Status: Published (confirmed)
• Publication date: 3 October 2018
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 83.040.10 — Latexes and raw rubber
• Edition / version: Edition 2 (2018)
• Number of pages: 11

Scope

Specifies a laboratory method for determining the bound acrylonitrile content in raw acrylonitrile-butadiene rubber (NBR) and related materials by digestion and Kjeldahl analysis using an automatic analyser. The standard defines required apparatus, reagents, sample preparation, analytical procedure, calculation of results and reporting. It is intended for use in quality control, research and conformity testing where measurement of bound acrylonitrile is required.

Key topics and requirements

• Definition of scope, terms and units relevant to bound acrylonitrile in rubber.
• Requirements for sample preparation and representative sampling of NBR and NBR latex.
• Details of digestion and distillation steps adapted for the Kjeldahl methodology and use of automatic Kjeldahl analysers.
• Specification of reagents, apparatus calibration, blank determinations and quality controls.
• Calculation methods to report bound acrylonitrile content (expression of results and significant figures).
• Precision, repeatability and reproducibility considerations and reporting of uncertainty where applicable.
• Health, safety and waste-handling notes relevant to Kjeldahl digestion and chemical reagents.
• Statement that results may differ from those obtained using the alternative combustion (Dumas) method (ISO 24698‑1).

Typical use and users

Used by rubber manufacturers, incoming raw-material inspection labs, independent testing laboratories, R&D departments, and compliance teams to quantify bound acrylonitrile in NBR grades and related rubbers. Typical applications include quality control of raw rubber, formulation verification, acceptance testing, and research into polymer composition and processing effects.

Related standards

Key related documents include ISO 24698-1 (Part 1: Combustion/Dumas method for bound acrylonitrile), ISO 1795 (sampling and preparative procedures for raw rubber), and other analytical standards addressing nitrogen determination and sample handling in rubber testing (for example ISO 19051 series and standards on solvent extract and related measurements).

Keywords

acrylonitrile, bound acrylonitrile, NBR, XNBR, NBIR, Kjeldahl method, automatic Kjeldahl analyser, rubber testing, analytical method, ISO 24698-2, raw rubber, quality control

FAQ

Q: What is this standard?

A: ISO 24698-2:2018 is an international standard that specifies a Kjeldahl-based analytical method for determining the bound acrylonitrile content in acrylonitrile-butadiene rubber (NBR) and closely related materials.

Q: What does it cover?

A: It covers apparatus and reagent requirements, sample preparation, digestion and analysis using an automatic Kjeldahl analyser, calculation and expression of results, precision considerations and safety guidance for the method.

Q: Who typically uses it?

A: Rubber producers, quality-control and analytical laboratories, independent testing services, research groups working with NBR and materials engineers concerned with polymer composition and compliance.

Q: Is it current or superseded?

A: The document was published as Edition 2 on 3 October 2018. It replaces earlier editions; users should check their national standards body for confirmation of current status and any national adoption or amendments.

Q: Is it part of a series?

A: Yes. It is Part 2 of the ISO 24698 series on determination of bound acrylonitrile in NBR. Part 1 (ISO 24698-1) describes the combustion (Dumas) method; both parts are alternate analytical approaches and can give different numerical results for the same sample.

Q: What are the key keywords?

A: acrylonitrile, bound acrylonitrile, NBR, Kjeldahl, analytical method, rubber testing, ISO 24698-2.