聚丙烯酰胺聚合工艺外文翻译.pdf

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1、PolymerBulletin5,39-45(1981)PolymerBulletin9Springer-Verlag1981ThermalStabilityofPolyacrylamideSolutions:EffectofResidualImpuritiesintheMolecular-weight-degradationProcessuponHeatingGuyMullerLaboratoiredeChimieMacromol~culaire,ERA471,Facult~desScience

2、sdeI'Universit~deRouen,76130Mont-Saint-Aignan,FranceSUM~ARYWehaveinvestigatedtheeffectoftemperatureonthechemical(hydrolysis)andthermal(molecularweight)stabilityofpurifiedpolyacrylamidesolution.Fromviscosityandlightscatteringdataweshowthatnopolymerdegra

3、dationduetooxygencontaminationresultsfromheatingpolymersolutionsalthoughhighertemperatureisresponsibleforhydrolysisofamidegroups.INTRODUCTIONAqueoussolutionsofcommercialpolyacrylamideswhichcontainoxygenoftenlostagreatpartoftheirinitialviscositywhenstor

4、edatmoderate(60~andhigher(90~temperatureforextendedperiodsoftime(i).Theviscositylossinsaltsolutionofheatedpolymerscanbeduetoincreaseintheioniccharacterofpolymers(hydrolysisofamidegroups)and/ortomolecularweightdegradation.Wehaveshownthatmolecularweightd

5、egradationcanoccurintemperature(60~andpH(7-9)conditionswherethehydrolysisincreaseisfoundnegligible(2).Commercialpolymersalwayscontainsmallamountsofresidualimpurities(e.g.residualpolymerizationcatalysts,...)whicharethoughttohaveanadverseeffectonpolymerd

6、egradationinsolutionwhenoxygenisnotexcludedfromthesystem(freeradicalmecha-nism).Excludingand/orscavengingoxygenisapossiblewaytoreducedegradation(3).Anothersolutionistoremoveresidualimpuritiesduringpreparationandrecoveryofpolymersorbytreatingtheaqueousp

7、olymersolutionsbythewayofadequateseparationmethods(dialysis,percolationthroughionicexchangeresins,ultrafiltration).Herewepresentresultsconcerningthethermalstabi-lityofpurifiedpolyacrylamideswhicharenotfromcommercialorigin.Inallexperiencesoxygenwasnotex

8、cludednorscavenged.Weshowthatpurified0170-0839/8110005100391501.4040polyacrylamidesolutionsexhibitnomolecularweightdegradationattemperaturesbetween60andI00~althoughhydrolysisextentsareincreaseduponheating.Thegoodthermalstabilityisattrib