Functionalpolymersaremacromoleculestowhichchemicallyfunctionalgroupsareattached;theyhavethepotentialadvantagesofsmallmoleculeswiththesamefunctionalgroups.Theirusefulnessisrelatedbothtothefunctionalgroupsandtothenatureofthepolymerswhosecharacteristicpropertiesdependmainlyontheextraordinarilylargesizeofmolecules.Theattachmentoffunctionalgroupstoapolymerisfrequentlythefirststeptowardsthepreparationofafunctionalpolymerforaspecificuse.However,theproperchoiceofthepolymerisanimportantfactorforsuccessfulapplication.Inadditiontothesyntheticaliphaticandaromaticpolymers,awiderangeofnaturalpolymershavealsobeenfunctionalizedandusedasreactivematerials.Inorganicpolymershavealsobeenmodifiedwithreactivefunctionalgroupsandusedinprocessesrequiringsevereserviceconditions.Inprinciple,thereactivegroupsmaybepartofthepolymerbackboneorlinkedtoasidechainasapendantgroupeitherdirectlyorviaaspacergroup.Arequiredactivefunctionalgroupcanbeintroducedontoapolymericsupportchain(1)byincorporationduringthesynthesisofthesupportitselfthroughpolymerizationandcopolymerizationofmomonmerscontainingthedesiredfunctionalgroups,(2)bychemicalmodificationofanon-functionalizedperformedsupportmatrixand(3)byacombinationof(1)and(2).Eachofthetwoapproacheshasitsownadvantagesanddisadvantages,andoneapproachmaybepreferredforthepreparationofaparticularfunctionalpolymerwhentheotherwouldbetotallyimpractical.Thechoicebetweenthetwowaystothesynthesisoffunctionalizedpolymersdependsmainlyontherequiredchemicalandphysicalpropertiesofthethoroughlyexaminedinordertotakefulladvantageofeachofthepreparativetechniques.Rapidprogressintheutikizationoffunctionalizedpolymericmaterialshasbeennotedintherecentpast.Interestinthefieldisbeingenhancedduetothepossibilityofcreatingsystemsthatcombinetheunuiquepropertiesofconventionalactivemoietiesandthoseofhighmolecularweightpolymers.Thesuccessfulutilizationofthesepolymersarebasedonthephysicalformsolvationbehavior,porosity,chemicalreactivityandstabilityofthepolymers.Thevarioustypesoffunctionalizedpolymerscoverabroadrangeofchemicalapplications,incldingthepolymericreactants,catalysts,carriers,surfactants,stabiliz-ers,ion-exchangeresins,etc.Inavarietyofbiologicalandbiomedicalfields,suchasthepharmaceutical,agriculture,foodindustryandthelike,theyhavebecomeindispensablematerials,especiallyincontrolledreleaseformulationofdrugsandagrochemicals.Besides,thesepolymersareextensivelyusedastheantioxidants,flameretardants,corrosioninhibitors,flocculatingagents,antistaticagentsandtheothertechnologicalapplications.Inaddition,thefunctionalpolymerspossessbroadapplicationprospectsinthe
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