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Plas%csAddi%vesandGreenChemistry
EvanBeach
14thAnnualGreenChemistry&EngineeringConference
Addi%ves
1tonne=1000kg
106 ton
nes/yrprodu
ced
About5%(wt.)ofallplas%cisaddi%ves
Plas%cizersaccountfor>50%ofaddi%ves
Flameretardantsaccountforabout25%
Consequences
persistence,bioaccumula1on,toxicity
DOTP(akaDEHP)
PBDEs
Solu%onsandstrategies• Small‐molecule,drop‐inreplacementsforDOTP,PBDEsetc.
• Higher‐MWaddi%vesforreducedmigra%on
• Designingpolymerswithinherentlydesirableproper%es
&
greendesignprinciples
Solu%onsandstrategies• Small‐molecule,drop‐inreplacementsforDOTP,PBDEsetc.
• Higher‐MWaddi%vesforreducedmigra%on
• Designingpolymerswithinherentlydesirableproper%es
&
greendesignprinciples
ImpactsofPVC
PVCaccountsfor80%ofplas%cizeruse;theplas%cizermarketis75‐85%phthalates
0%plas%cizer 85%plas%cizer
PVCconsump1onisnotexpectedtodecreaseintheshortterm
PVCisonlypartofthechallenge
Biopolymersbasedoncellulose,starch,andwheatglutenwillconsumeplas%cizers
Poly(lac%cacid)(Tg=55°C)isbri_lelikePVC(Tg=82°C)andrequiresaddi%vesifitistobeusedasaflexibleplas%c
Smallmoleculealterna%vestoDOTPTheliteratureaboundswithexamples.Manyalterna%vesbelongtothephthalateclass(e.g.DINP).Manyarealsoproblema%c(e.g.mellitateesters).
Certainbio‐basedfeedstocksmightbeexpectedtoresultinlesshazardousproducts.
sorbitolderivedfromglucose tuneproper%esvia
choiceoffa_yacid
C8diestershowsDOTP‐likeperformance
TerVeld,M.G.R.etal.Agric.FoodChem.2006,54,4407‐4416.vanHaveren,J.etal.inFeedstocksfortheFuture.AmericanChemicalSociety:Washington,DC,2006.
Isosorbideestersofalkanoicacidsarefullybiodegradableandpassedtestsforacutetoxicity,sensi%za%on,mutagenicity,&estrogenicity
FlameretardancyisawidespreadneedDemandisexpectedtoincrease5%/yr
M.Chanda,S.K.Roy.IndustrialPolymers,SpecialtyPolymers,andTheirApplica1ons
Limi'ngOxygenIndices(LOI)ofcommonpolymers
Non‐self‐ex%nguishingpolymer
LOI Self‐ex%nguishingpolymer
LOI
polyoxymethylene 16 polycarbonate 27
polyethylene 17 polyarylate 34
polypropylene 18 polyethersulfone 38
polystyrene 18 PEEK 40
PMMA 18 PVC 42
naturalrubber 18 polyamide‐imide 43
ABS 18 poly(phenylenesulfide) 44
Nylon‐6,6 24 polyether‐imide 47
PETE 25 poly(vinylidenechloride) 60
polychloroprene 26 PTFE 95
TheLOIforself‐ex%nguishingisusuallytakenas27,not21(thevolume%ofO2inair)tocorrectforlackofconvec%vehea%nginthetestmethod.
Flameretardants
Source:SRIConsul%ng/h_p://www.flameretardants‐online.com
Goal:compa%blewithplas%cs,effec%veatreasonablelevels,non‐leaching,non‐toxic
Non‐halogenatedflameretardants
• 2007AddConconference:nopapersonhalogenatedchemicals,althoughflameretardantsmadeuponeofthelargestgroupofsubmissions
• Governmentandindustrygroupshaveconductedextensivereviews,e.g.h_p://www.nonhalogenated‐flameretardants.com
• Fewerexamplesfrombio‐organicfeedstocks
• Solu%onsareolenbasedonmechanismsspecifictoapolymer
MolecularHeatEater®• Powderorgelbasedoncarbonateandphosphatesaltsandbenignorganic
acids– citric
– glutaric
– succinic
– oxalic
– formic
– ace%c
– stearic
Someareagriculturalwasteproducts
Sub‐micronpar1clesrequireastrongendothermicreac1ontodecompose
MHEinac%onuntreated treated
Solu%onsandstrategies• Small‐molecule,drop‐inreplacementsforDOTP,PBDEsetc.
• Higher‐MWaddi%vesforreducedmigra%on
• Designingpolymerswithinherentlydesirableproper%es
&
greendesignprinciples
HighMWplas%cizers
• Limitmobilityinpolymermatrix
• Preventtransportacrossbiologicalmembranes
• Degrada%onproductsmustbeconsidered
1,3‐propanediolfromglucoseviaglycerol(engineeredE.coli)
Adipicacidfromglucose(engineeredmicrobes)
MW1500‐2500Da
isabe_erplas%cizerforPLAthan:
MW371
Mar%no,V.P.;Jimenez,A.;Ruseckaite,R.A.J.Appl.Polym.Sci.2009,112,2010‐2018.
Strategiesforhigh‐MWflameretardants• Copolymeriza%onwithspecialmonomers,gralingreac%veaddi%vestobackbone
– Flameretardancyis“permanent”
– Lessdisrup%onofpolymerproper%es
– Effec%veatlowerloadingsthanlow‐MWaddi%ves
Lu,S.‐Y.;Hamerton,I.Prog.Polym.Sci.2002,27,1661‐1712.
Mul%‐wallcarbonnanotubes
max.heatreleaserate~800kW/m2
max.heatreleaserate~500kW/m2
2%nanotubes
• Effec%veinpolycarbonate,polyamide,polyethylene,polypropylene,polystyrene
• Cannotstandalone–butpromising
• Nohalogens,metals,orphosphorus
Schartel,B.etal.Polym.Eng.andSci.2008,48,149‐158.
Solu%onsandstrategies• Small‐molecule,drop‐inreplacementsforDOTP,PBDEsetc.
• Higher‐MWaddi%vesforreducedmigra%on
• Designingpolymerswithinherentlydesirableproper%es
&
greendesignprinciples
Plas%citywithoutaddi%ves:thermoplas%celastomers(TPEs)
• Metallocene‐catalyzedpolyolefins:“thethreattoflexiblePVC”– 1millionlbpolymer/1lbcatalyst/1hr
– JournalofVinylandAddi1veTechnology,1998:poten%altocapture50%oftheflexiblePVCmarket(30‐40%plas%cized)
Wilson,R.B.,Jr.J.VinylAddit.Technol.1998,4,84‐86.
TPEsfromBiobasedMaterials
• Polyethers
• Polyamidesbasedoncanola,castoroil
• Polyurethanesfromvegetableoil
Mizuno’s2009runningshoemodelscontainPebax®Rnew,abio‐basedTPE(upto94%renewablecarbon)
Markarian,J.Plas1csAddi1ves&Compounding2008,10,38‐43.
InherentlyFireRetardantPolymers
Self‐ex'nguishingpolymer
LOI
polycarbonate 27
polyarylate 34
polyethersulfone 38
PEEK 40
PVC 42
polyamide‐imide 43
poly(phenylenesulfide) 44
polyether‐imide 47
poly(vinylidenechloride) 60
PTFE 95
Zhang,H.U.S.DepartmentofTransporta%on,FederalAvia%onAdministra%on,OfficeofAvia%onResearch,2004.
poly(hydroxyamide) poly(benzoxazole)
Challenges• Cost,mechanicalperformance,processingdifficul%es
• Mechanis%cunderstanding– Heteroatoms(N,O,P,S,halogens)
– Aroma%crings
– Heteroatomicrings
– Pro‐crosslinkingorpro‐cycliza%onchemicalgroups
Kevlar®(paralinkages)
Nomex®(metalinkages)
Whysuchasignificantdifferenceinheatrelease?
Zhang,H.U.S.DepartmentofTransporta%on,FederalAvia%onAdministra%on,OfficeofAvia%onResearch,2004.
Inspira%onfromnature:woolWoolfoamsratherthanburns.Igni%ontemperatureis570‐600°C(higherthanrayon,nylon,polyester)
Aneffectofmicrostructure?Chemicalcomposi%on?Both?
Be_erunderstandingofnaturallyflameretardantmaterialswillleadtoinnova%oninfire‐safe,bio‐basedplas%cs
CSIRO,FlameResistanceofWool
Solu%onsandstrategies• Small‐molecule,drop‐inreplacementsforDOTP,PBDEsetc.
• Higher‐MWaddi%vesforreducedmigra%on
• Designingpolymerswithinherentlydesirableproper%es
&
greendesignprinciples
Reducinghazard(atalllifecyclestages)
Useofrenewableresourcesistobeencouraged,butitcannotbetheonlymetric
Conclusions
• Func%onalalterna%vestoDEHPandPBDEsareabundant
• Bio‐basedchemicalplaxormsare(andwillbe)asourceofinnova%on
• Allgreenprinciplesshouldbemetbynewmaterials,toavoidtheproblemsofthepast