1、Designation:D 2455 89(Reapproved 1996)e1Standard Test Method forIdentification of Carboxylic Acids in Alkyd Resins1This standard is issued under the fixed designation D 2455;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of
2、 last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.e1NOTEEditorial changes were made throughout in November 1996.1.Scope1.1 This test method covers the qualitative determination ofthe
3、 carboxylic acids in alkyd resins,including resin-modifiedalkyds.It may be used for analyzing polyesters but additionalpeaks may appear from monomers such as styrene.1.2 The constituents of three resin samples have beencorrectly identified in collaborative work by three laboratories.It is apparent t
4、hat quantities as low as 1%can readily bedetected.1.3 The values stated in inch-pound units are to be regardedas the standard.The values given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is therespon
5、sibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For a specifichazard statement,see Section 7.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 2245 Test
6、 Method for Identification of Oils and OilAcidsin Solvent-Reducible Paints33.Summary of Test Method3.1 The resin specimen is subjected to rapid transesterifica-tion with lithium methoxide to form methyl esters that areseparated by programmed temperature gas-liquid chromatog-raphy on polar and nonpol
7、ar columns,then identified by theirretention relative to a standard.If the presence of maleic orfumaric acids is indicated,an alternative transesterificationwith boron trifluoride is necessary.4.Significance and Use4.1 The presence of carboxylic acids in alkyd resins has adirect effect on the crossl
8、inking capability of the resin.This testmethod helps the user determine the reactivity of the resin.5.Apparatus5.1 LinearProgrammedTemperatureGasChromatographAny instrument with programming featuresshould be suitable if equipped with a hot-wire type of detectorand adaptable to the following operatin
9、g conditions:Detector cell temperature,C300Detector cell current,mA150Injection port temperature,C330Helium flow at exit,cm3/min85Programmed temperature details:Approximate column heating rate,/min4.0Starting column temperature,C:Polyester-Carbowax 20M125Silicone grease,DC-1175Finishing column tempe
10、rature,C:Polyester-Carbowax 20M225Silicone grease,DC-112505.2 Columns:5.2.1 PolarBend a 6-ft(1.8-m)length of14-in.(6.4-mm)copper tubing into a U-shape and fill one side with 20%polyethylene glycol 20M4on acid-washed 60 to 80-meshwhite,flux-calcined diatomite,(USP code S1A)5and fill theother side wit
11、h 20%diethylene glycol succinate on the samesolid support.Maintain constant vibration during the filling andadd small amounts of the packing material alternately to eachside.Condition at 225C until“bleeding”reaches a minimum.Mount this column so that the sample passes first through thepolyester sect
12、ion.Two 3-ft(0.9-m)sections,packed separatelyand joined together may be used if preferred.5.2.2 NonpolarPack a 6-ft(1.8-m)length of14-in.(6.4-mm)copper tubing with 20%silicone grease on acid-washed60 to 80-mesh Chromosorb W.5Condition at 250C until“bleeding”reaches a minimum.5.3 Syringe,having a fix
13、ed needle,10-L capacity.5.4 Separatory Funnel,250 mL.1This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.33 on Polymers and Resins.Current edition approved April 28,1989.Publishe
14、d June 1989.Originallypublished as D 2455 66.Last previous edition D 2455 69(1981)e1.2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 06.01.4The sole source of supply of the polyethylene glycol,Carbowax 20M known tothe committee at this time is Union Carbide Corp.,39 Old R
15、idgebury Rd.,Danbury,CT 06817.If you are aware of alternative suppliers,please provide this informationto ASTM Headquarters.Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.5The sole source of supply of white,flux-calcined diat
16、omite,Chromosorb Wknown to the committee at this time is Celite Corp.,P.O.Box 5108,Denver,CO80217-5108.If you are aware of alternative suppliers,please provide this informa-tion to ASTM Headquarters.Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTM5.5 Steam Bath.6.Reagents6.
