Class 1 1 Introduction PolymerPolymerhistoryPolymerscience AsEarlyasLifeBegan naturalpolymers BIOMACROMOLECULESPolysaccharides DNA RNA starch cellulose chitin etc WhatarePolymers Cellulose Chitin WhatarePolymers AsBroadasinDailyLife syntheticpolymers polystyrene cis polyisoprene poly vinylpyrrolidone WhatarePolymers Polymerpolymerisasubstancecomposedofmoleculeswhichhavelongsequenceofoneormorespeciesofatomsorgroupsofatomslinkedtoeachotherbyprimary usuallycovalentbonds SyntheticPolymers Definition Macromoleculemacromoleculesareformedbylinkingtogethermonomermoleculesthroughchemicalreaction polymerization PolymerandMacromoleculeusedinterchangeably FocusofThisCourse SYNTHETICPOLYMER DifferencesbetweenNaturalPolymersandSyntheticPolymers SyntheticPolymers Definition PolymerderivedfromclassicalGreek Autumn2013 SyntheticPolymers Definition M M M M M M Or M n Poly mersmanyunits Long chain likemoleculesormacromoleculesconsistingofmanyrepeatingunits monomers thatarecovalentlylinked insteadofphysically associatedaggregates Molecularweighthigherthan 10 000g mol differentfromoligomers whichiscomposedofafewrepeatingunits AnExample Polyethylene SomeBasicDefinitions POLYMERAlargemoleculemadeupofsmallbuildingblocksMONOMERSThebuildingblocksHOMOPOLYMERWhatyougetifthebuildingblocksareallthesameCOPOLYMERApolymermadeupofdifferentmonomersBLENDAmixtureofdifferentpolymers Exercise1 Pleaselistthedifferenceofthenaturalpolymerswithsyntheticpolymers atleast2 Exercises2 Considerthefollowingcopolymers whichoftheseisanalternatingcopolymer a A A A A B B B Bb B B B B B A A A A A B B B B B 5 90 5 c A B A A B B A A A B Ad A B A B A B A B Class 2 2 PolymerStructure NomenclatureClassificationPolymerstructureIsomerisminpolymersMolecularweight Polymers FirstOrderStructures Specialtype randomcopolymer Polymers Homopolymers Apolymerderivedfromonespecieofmonomer Conventional basedonsource poly monomer orstructures2 Commercialtradenames TradenamesAlkathene LupolenPropathene NovolenTeflon FluonStyron HostyrenHIPSABS 2 1NomenclatureI TradenamesPerspex Diakon Lucite Oroglass PlexiglasDarvic Welvic Vinoflex Hostalit NomenclatureII TradenamesCarbowaxTerylene Dacron Melinex MylarUltramid6 10 NomenclatureIII 2 2Classification Carbonchainpolymer Carbon OxygenpolymerCarbon SulfurpolymerCarbon Nitrogenpolymer CC polyalkylene CC polyalkenylene CC polyalkynylene CO polyether CS polysulfone CN polyamine O O Autumn2013 Thermoplastic Heatmoldableorprocessible e g plastics fibers linearorbranchedpolymers Thermosetting Heatnon processible e g highlycrosslinkedpolymers Elastomer Polymersthatcanbestretchedtohighextensionsandrapidlyrecovertheiroriginaldimensionswhenthestressisreleased e g lightlycrosslinked chemically vulcanized physically thermoplastic polymers 2 2Classification MoreExamplesofThermoplastics http en wikipedia org wiki Teflon Polymer Autumn2013 ExamplesofThermoplastics Autumn2013 ThermosetMaterials Autumn2013 ThermosetProperties Autumn2013 2 3PolymerStructure LinearPolymerBranchedPolymerCross linkedandNetwork Autumn2013 LinearandBranchedPolymers Linear Branched Whichoftheseismorelikelytocrystallize Autumn2013 LinearandBranchedPolymer BranchedPolymer LinearPolymerCrystallinephase AmorphousphaseAdegreeofcrystallinity Autumn2013 LinearandBranchedPolymer Highdensitypolyethylene HDPE Lowdensitypolyethylene LDPE stronger stiffer butlessopticallyclear greateropticalclarity moreflexible butlessstrong NetworkFormation ReactingTrifunctionalMolecules Yshaped ReactingTetrafunctionalMolecules Xshaped Branchingcanleadtotheformationofdenselyconnectednetworks Networkcanbeformedbyreactingmultifunctionalmolecules Autumn2013 NetworkFormation Anexampleofforminganetworkfromatrifunctionalmoleculeisthereactionofphenolwithformaldehyde PFOligomer PFNetwork Autumn2013 Networks Summary Wecanmakenetworksby Linkingtogethersmallmulti functionalmonomersCross linkingalreadyformedchains Note youcanchangepropertiesdramaticallybychangingthecross linkdensity Cross linkingiscrucialinmakingelastomerswithusefulproperties Autumn2013 Configuration Conformation Configuration 构型 referstotheorderthatisdeterminedbychemicalbonds Theconfigurationofapolymercannotbealteredunlesschemicalbondsarebrokenandreformed Conformation 构象 referstothedifferentarrangementsofatomsandsubstituentsofthepolymerchainarisesfromtherotationofaboutthesinglebonds 2 4IsomerisminPolymers SequenceIsomerismStereoIsomerismStructuralIsomerism Autumn2013 Twomoleculesaresaidtobeisomersiftheyaremadeupofthesamenumberandtypesofatoms butdifferintheconformationoftheseatoms SequenceIsomerism Head H CXY Tail T CH2 Amonomerunitaddstoagrowingchain Autumn2013 SequenceIsomerism partofgrowingchain activesite monomerabouttocollidewithactivesite CH2 CH Polystyrene Autumn2013 SequenceIsomerism Allhead to tailunitsSomehead to headandtail to tailunits CH2 CHF Poly vinylidenefluoride Autumn2013 SequenceIsomerism Autumn2013 StereoIsomerism Isotacticpolymer Syndiotacticpolymer CH2 CHX Autumn2013 StereoIsomerism Polypropylene CH2 CHCH3 Isotactic Syndiotacti