EN ISO 119:1998

Plastics - Phenol-formaldehyde mouldings - Determination of free phenols - Iodometric method (ISO 119:1977)

A semiquantitative method for the determination of the amount of free phenols in phenolic mouldings. Hot water extraction of free phenols from a powdered test portion, iodination of the water extract and backtitration of the excess of iodine with standard volumetric thiosulfate solution.

Kunststoffe - Phenoplast-Formteile - Bestimmung der freien Phenole - Iodometrisches Verfahren (ISO 119:1977)

Diese Internationale Norm beschreibt ein jodometrisches Verfahren zur halbquantitativen Bestimmung des Gehaltes an freien Phenolen in Phenoplast-Formteilen. ANMERKUNG: Diese Internationale Norm liefert keine Absolutwerte der vorhandenen freien Phenole. Die Menge an freien Phenolen in einem Formteil hängt in hohem Maße vom Grad der Aushärtung ab. Ihre Bestimmung ist ebenfalls von Interesse, wenn mit der Möglichkeit der Verunreinigung von Lebensmitteln oder anderen Gegenständen gerechnet werden muß.

Plastiques - Pièces moulées à base de phénoplastes - Dosage des phénols libres - Méthode iodométrique (ISO 119:1977)

Polimerni materiali - Fenol-formaldehidni oblikovanci - Določevanje prostega fenola - Jodometrična metoda (ISO 119.1977)

General Information

• Status: Published
• Publication Date: 21-Jul-1998
• Withdrawal Date: 30-Jan-1999
• ICS: 83.080.10 - Thermosetting materials
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249/SC 1/WG 13 - Thermosets
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 22-Jul-1998
• Completion Date: 22-Jul-1998
• Ref Project: SIST EN ISO 119:2000 - Plastics - Phenol-formaldehyde mouldings - Determination of free phenols - Iodometric method (ISO 119:1977)

Overview

EN ISO 119:1998 defines a standardized iodometric method for the semi-quantitative determination of free phenols in phenol-formaldehyde plastics mouldings. This international standard, developed by CEN in alignment with ISO 119:1977, is crucial for assessing the chemical composition and safety of phenolic moulded products. The method focuses on extracting free phenols from powdered samples via hot water, followed by iodination and back titration of excess iodine with a volumetric sodium thiosulphate solution. Accurate measurement of free phenol content is essential due to its influence on the degree of cure and potential contamination risks when phenolic plastics contact foodstuffs or other sensitive materials.

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Key Topics

• Scope and Field of Application

  • Suitable for phenol-formaldehyde mouldings made from thermosetting plastics.
  • Provides a semiquantitative measure of free phenols affecting product quality and safety.
  • Important for quality control during manufacturing and for regulatory compliance.

• Method Principle

  • Extraction of free phenols using hot water from powdered test material.
  • Iodination of the aqueous extract in presence of sodium tetraborate.
  • Back titration of unreacted iodine with standard sodium thiosulphate solution using starch as an indicator.
  • Calculation based on the stoichiometric reaction between iodine and phenol molecules.

• Sample Preparation

  • Mouldings reduced to powder by filing, milling, grinding, or drilling, carefully avoiding heating.
  • Sieved to obtain a uniform particle size (nominal aperture of 250 µm).
  • Extraction performed within 1 hour of powder preparation to ensure consistent results.

• Chemical Reagents and Apparatus

  • Reagents include sodium tetraborate, iodine solution (~0.05 N), sulphuric acid (2 N), standard sodium thiosulphate solution, and starch indicator.
  • Typical laboratory glassware and equipment like pipettes, burettes, sieve, flasks, and analytical balance are required.

• Calculation and Reporting

  • Results expressed as percentage by mass of phenol (C6H5OH).
  • Test report must include sample identification, method details, free phenol amount, and date of test.
  • Method influenced by sample powdering approach, which should be agreed upon when used as a referee method.

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Applications

• Quality Control of Phenol-Formaldehyde Mouldings

  • Monitoring curing levels during production to optimize mechanical properties.
  • Ensuring product conformity to safety thresholds for residual free phenols.

• Regulatory Compliance

  • Assessing potential phenol contamination risk in products used for food contact or sensitive applications.

• Material Research

  • Chemical analysis for formulation optimization in thermosetting plastics.
  • Development of improved resin curing processes minimizing free phenol content.

• Industrial and Laboratory Use

  • Routine testing in plastics manufacturing, material certification labs, and regulatory agencies.
  • Reference method for evaluating phenolic materials in forensic or failure analysis contexts.

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Related Standards

• ISO 565 - Test sieves for particle size standardization, applicable to sample preparation.
• ISO/R 385 - Requirements for precision laboratory burettes used in volumetric analysis.
• ISO 648 - Laboratory glassware specifications, including single-mark pipettes essential to this procedure.
• ISO/TC 61 - Technical Committee on plastics responsible for developing related plastics testing standards.

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Keywords: phenol-formaldehyde mouldings, free phenols determination, iodometric method, phenolic plastics testing, CEN standard, ISO 119:1977, thermosetting plastics, chemical analysis, volumetric titration, phenol content testing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2000
3ROLPHUQLPDWHULDOL)HQROIRUPDOGHKLGQLREOLNRYDQFL'RORþHYDQMHSURVWHJD
IHQROD-RGRPHWULþQDPHWRGD,62
Plastics - Phenol-formaldehyde mouldings - Determination of free phenols - Iodometric
method (ISO 119:1977)
Kunststoffe - Phenoplast-Formteile - Bestimmung der freien Phenole - Iodometrisches
Verfahren (ISO 119:1977)
Plastiques - Pieces moulées a base de phénoplastes - Dosage des phénols libres -
Méthode iodométrique (ISO 119:1977)
Ta slovenski standard je istoveten z: EN ISO 119:1998
ICS:
83.080.10 Duromeri Thermosetting materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL STANDARD -
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l EXAYHAPO,QHAII OPTAHW3AUIMX IlO CTAHLI[APTW3AUWU.ORGANISATION INTERNATIONALE DE NORMALISATION
Plastics - Phenol-formaldehyde mouldings - Determination
of free phenols -
lodometric method
Plastiques - Pikes moukes a’ base de phknoplastes - Dosage des phknols libres - Me’thode iodome’trique
First edition - 1977-10-01
UDC 678.632 : 547.56 : 543.8 Ref. No. IS0 119-1977 (E)
Descriptors : plastics, phenol formaldehyde, mouldings, chemical analysis, determination of content, phenols, volumetric analysis.
Price based on 2 pages
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 member bodies). The work of developing
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 119 was developed by Technical Committee ISO/TC 61,
Plastics, and was circulated to the member bodies in November 1975.
It has been approved by the member bodies of the following countries :
Australia India Romania
Belgium
I ran South Africa, Rep. of
Brazil
Israel Spain
Chile
Italy Sweden
Czechoslovakia
Japan Switzerland
Egypt, Arab Rep. of Mexico Turkey
Finland
Netherlands United Kingdom
France
New Zealand U.S.A.
Germany
Peru U.S.S.R.
Hungary
Poland
No member body expressed disapproval of the document.
This International Standard cancels and replaces IS0 Recommendation R 119-1959,
of which it constitutes a technical revision.
0 International Organization for Standardization, 1977 l
Printed in Switzerland
IS0 119-1977 (E)
INTERNATIONAL STANDARD
Plastics - Phenol-formaldehyde mouldings - Determination
lodometric method
of free phenols -
1 SCOPE AND FIELD OF APPLICATION 4.2 Sulphuric acid, 2 N solution.
This International Standard specifies an iodometric method
4.3 Iodine, about 0,05 N solution.
for the semi-quantitative determination of the amount of
free phenols in phenol-formaldehyde mouldings.
Dissolve 6,35 g of iodine in approximately 40 ml of a
500 g/l solution of potassium iodide and dilute to I 000 ml
NOTE - This International Standard does not provide an absolute
with water.
measure of the free phenols present.
The amount of free phenols in a moulded article is
4.4 Sodium thiosulphate, 0,05 N standard volumetric
influenced to a major extent by the degree of cure. Its
solution.
evaluation is also of interest where the possibility of conta-
mination of foodstuffs or other materials in contact with
4.5 Starch, approximately 2,5 g/l solution.
the article has to be considered.
2 REFERENCES
5 APPARATUS
ISO/R 385, Burettes.
Ordinary laboratory apparatus and
Woven metal wire cloth and
IS0 565, Test sieves -
5.1 Means for reducing the mouldings to a powder.
Nominal sizes of apertures.
perforated plate -
IS0 648, Laboratory glassware - One-mark pipettes.1 )
5.2 Sieve, with nominal apertures of 250pm, complying
with the requirements of IS0 565.
3 PRINCIPLE
5.3 Balance, accurate to 0,OI g.
Hot aqueous extraction of free phenols from a powdered
Iodination of the aqueous extract b
...