# ISO 21257:2018 — Withdrawn and superseded ISO standards

For ISO 21257:2018, item title is Plastics — Polymer polyols for use in the production of polyurethane — Determination of the residual acrylonitrile and styrene monomer content by gas chromatography; status code is 9599; successor is ISO 21257:2024; withdrawn / published date is 2018-10-03, recorded from its source on 2026-08-05.

- **Identifier:** ISO 21257:2018 _(verified: appears in the quote below)_
- **Item title:** Plastics — Polymer polyols for use in the production of polyurethane — Determination of the residual acrylonitrile and styrene monomer content by gas chromatography _(verified: appears in the quote below)_
- **Status code:** 9599 _(verified: appears in the quote below)_
- **Successor:** ISO 21257:2024
- **Withdrawn / published date:** 2018-10-03 _(verified: appears in the quote below)_

## What the source says

> 70271,IS,,ISO 21257:2018,Plastics — Polymer polyols for use in the production of polyurethane — Determination of the residual acrylonitrile and styrene monomer content by gas chromatography,Titre manque,2018-10-03,1,['83.080.10'],ISO/TC 61/SC 12,9599,,[89578],['en'],15,<p>This document specifies a method for the determination of the residual acrylonitrile monomer and styrene monomer in polymer polyols by gas chromatography.</p>

## Source

- https://isopublicstorageprod.blob.core.windows.net/opendata/_latest/iso_deliverables_metadata/csv/iso_deliverables_metadata.csv

Last verified: 2026-08-05. Review by: 2027-02-01.
Part of [Withdrawn and superseded ISO standards](https://referencesource.org/iso-standard-supersessions/).