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1、外文文献原稿和译文SodiumPolyacrylate:Alsoknownassuper-absorbentor“SAP”(superabsorbentpolymer),KimberlyClarkusedtocallitSAM(superabsorbentmaterial).Itistypicallyusedinfinegranularform(liketablesalt).Ithelpsimprovecapacityforbetterretentioninadisposablediaper,allowingtheproducttobet
2、hinnerwithimprovedperformanceandlessusageofpinefluffpulp.Themolecularstructureofthepolyacrylatehassodiumcarboxylategroupshangingoffthemainchain.Whenitcomesincontactwithwater,thesodiumdetachesitself,leavingonlycarboxylions.Beingnegativelycharged,theseionsrepeloneanothersot
3、hatthepolymeralsohascross-links,whicheffectivelyleadstoathree-dimensionalstructure.Ithashigemolecularweightofmorethanamillion;thus,insteadofgettingdissolved,itsolidifiesintoagel.TheHydrogeninthewater(H-O-H)istrappedbytheacrylateduetotheatomicbondsassociatedwiththepolarity
4、forcesbetweentheatoms.Electrolytesintheliquid,suchassaltminerals(urinecontains0.9%ofminerals),reducepolarity,therebyaffectingsuperabsorbentproperties,especiallywithregardtothesuperabsorbentcapacityforliquidretention.ThisisthemainreasonwhydiaperscontainingSAPshouldneverbet
5、estedwithplainwater.Linearmolecularconfigurationshavelesstotalcapacitythannon-linearmoleculesbut,ontheotherhand,retentionofliquidinalinearmoleculeishigherthaninanon-linearmolecule,duetoimprovedpolarity.ForalistofSAPsuppliers,pleaseusethislink:SAP,thesuperabsorbentcanbedes
6、ignedtoabsorbhigheramountsofliquids(withlessretention)orveryhighretentions(butlowercapacity).Inaddition,asurfacecrosslinkercanbeaddedtothesuperabsorbentparticletohelpitmoveliquidswhileitissaturated.Thishelpsavoidformationof"gelblocks",thephenomenonthatdescribestheimpossib
7、ilityofmovingliquidsonceaSAPparticlegetssaturated.HistoryofSuperAbsorbentPolymerChemistryUntilthe1980’s,waterabsorbingmaterialswerecellulosicorfiber-basedproducts.Choicesweretissuepaper,cotton,sponge,andfluffpulp.Thewaterretentioncapacityofthesetypesofmaterialsisonly20tim
8、estheirweight–atmost.Intheearly1960s,theUnitedStatesDepartmentofAgriculture(USDA)wasconductingwo
