ISO INTERNATIONAL STANDARD 1061 Second edition 1990-11-15 Plastics --- Unplasticized cellulose acetate -- Determination of free acidity Plastiques-Acetate de cellulose non plastifie--- Determination de l'aciditelibre tso Referencenumber ISO1061:1990(E) ISO1061:1990(E) Foreword Iso (the International Organization for Standardization) is a worldwide federationofnationalstandardsbodies(isOmemberbodies).Thework of preparing International Standards is normally carried out through Iso which a technical committee has been established has the right to be represented on that committee.International organizations,govern- mental andnon-governmental,inliaisonwithso,alsotakepartinthe work.iso collaborates closely with the International Electrotechnical Commission (IEC) on all matters ofelectrotechnical standardization. Draft International Standards adopted by the technical committees are circulatedtothememberbodiesforvoting.Publicationas anInter- national Standard requires approval by at least 75% of the member bodies casting a vote. InternationalStandardIso1061waspreparedbyTechnicalCommittee ISO/TC61, Plastics. This ssecond edition cancels and replaces the first edition (Iso 1061:1975), of which it constitutes a minor technical revision. ? ISO1990 orbyanymeans,electronic ormechanical,including photocopyingandmicrofilm,without permission in writing from the publisher. InternatlonalOrganizationforStandardization CasePostale56CH-1211Geneve20·Switzerland Prlnted in Switzerland ISO 1061:1990(E) INTERNATIONAL STANDARD Plastics --- Unplasticized cellulose acetate --- Determination of free acidity WARNING - The use of this International Standard may invoive hazardous materials, operations and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope 3Principle This International Standard specifies a method for A test portion of cellulose acetate is treated with the determination of the amount of free acid in water and the resultant'solution titrated with sodium unplasticized cellulose acetate. hydroxide solution. The free acidity determined by this method includes The free acidity is calculated as the percentage, by acidity extractable by water and acidity due to acidic mass, of free acetic acid in the cellulose acetate. groups directly attached to the cellulose acetate e.g. carboxyl groups. The latter is usually a very small proportion of the total. 4 Reagents This method is not suitable for cellulose acetate During the determination, use only reagents of re- containing any additives which may affect the test. cognized analytical gradeand distilledwater as specified in 4.1. 4.1 Distilled water, freshly boiled to remove carbon 2 Normative references dioxide and cooled. The following standards contain provisions which, 4.2 Sodium hydroxide, standard volumetric sol- throughreferenceinthistext,constituteprovisions of this International Standard. At the time of publi- ution, c(NaOH) = 0,01 mol/l. cation, the editions indicated were valid. All stan- dards are subject to revision, and parties to 4.3 Phenolphthalein, 1 g/l solution in 90 % (V/V) agreements based on this Internationai Standard cthanol. are encouraged to investigate the possibility of ap- plying the most recent.editions of the standards in- dicated below.Members of IEc and Iso maintain registers of currently valid International Standards. 5 Apparatus Iso 565:1990,Test sieves-Metal wire cloth,perfo- 5.1 Glass flask, capacity 250 ml or 300 ml, with rated metal plate and electroformed sheet --. Nominal ground-glass stopper. sizesofopenings. iso585:1990",Plastics Unplasticized cellulose 5.2 Graduated cylinder, capacity 250 ml, graduated acetate -Determination of moisture content. at 2 ml intervals. 1) To be published.