1、Designation:D 2456 91(Reapproved 1997)e1Standard Test Method forIdentification of Polyhydric Alcohols in Alkyd Resins1This standard is issued under the fixed designation D 2456;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year
2、 of 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.e1NOTEFootnotes were changed editorially in September 1997.1.Scope1.1 This test method covers the qualitative determination ofthe
3、 polyols in alkyd resins,including resin-modified alkyds.Itmay be used for analyzing polyesters,but additional peaks mayappear from monomers such as styrene.1.2 The constituents of three resin samples have beencorrectly identified in collaborative work by five laboratories.Quantities as low as 1%,ob
4、tained by blending samples ofknown composition,were readily detected.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the app
5、lica-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 Water23.Summary of Test Method3.1 The resin specimen is subjected to aminolysis to formamides of the carboxylic acids and to relea
6、se the polyolspresent,followed by direct acetylation with acetic anhydride.The acetates are extracted and then separated by application ofprogrammed temperature gas chromatography.4.Significance and Use4.1 The types of polyhydric alcohols used in the synthesis ofalkyd resins has a direct effect on c
7、rosslinking capabilities ofthe resin.This test method helps determine the reactivity of theresin.5.Apparatus5.1 LinearProgrammedTemperatureGasChromatographAny instrument with programming featuresshould be suitable if equipped with a thermal conductivitydetector(TCD)3and adaptable to the following op
8、eratingconditions:Detector cell temperature,C300Detector cell current,mA150Injection port temperature,C330Helium flow at exit,cm3/min60Programmed temperature details:Approximate column heating rate,deg/min7.9Starting column temperature,C50Finishing column temperature,C2255.2 Columns(Note 1)A 4-ft(1.
9、2-m)length of14-in.(6.4-mm)outside diameter copper tubing packed with 10weight%of polyethylene glycol,20M4on 60 to 80 mesh acidwashed,white flux-calcined diatomite(UPS Code S1A),andconditioned at 240C until“bleeding”reaches a minimum.NOTE1Commercially available columns may be selected and usedprovid
10、ed they are capable of performing operations equivalent to thecolumns specified in this test method.5.3 Syringe,having a fixed needle,10-L capacity.6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall confo
11、rm to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the d
12、etermination.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Type IV of Specification D 1193.1This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and Applications and is the di
13、rect responsibility ofSubcommittee D01.33 on Polymers and Resins.Current edition approved Jan.8,1991.Published February 1991.Originallypublished as D 2456 66.Last previous edition D 2456 89.2Annual Book of ASTM Standards,Vol 11.01.3Thermal conductivity detector is adequate within the scope of this t
14、est method.However,a flame ionization detector(FID)may be used if desired withoutcompromising results of the analysis.4The sole source of supply of the Carbowax 20M known to the committee at thistime is Union Carbide Corp.,39 Old Ridgebury Rd.,Danbury,CT 06817.If you areaware of alternative supplier
15、s,please provide this information to ASTM Headquar-ters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.5Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the
16、testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.6.3 Acetic Anhydride.6.4 n-Butylamine,boiling point 76 to 78C.6.5 Chloroform.7.Hazards7.1 The reagents and samples used in this test method may,under some conditions,be ha
