effects of photopolymerizable prepolymer architecture on thermomechanical properties ·...
TRANSCRIPT
EffectsofPhotopolymerizablePrepolymerArchitectureonThermomechanicalProperties
ByJonScholteandAllanGuymonChemicalandBiochemicalEngineering
UniversityofIowa
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• LineargradientshavebeenshowntoinfluencetheresoluBonandsizeofpolymerblendmorphology.
Guoetal.J.Poly.Sci.B.2015,53,860-868 2
• LineargradientshavebeenshowntoinfluencetheresoluBonandsizeofpolymerblendmorphology.
Guoetal.J.Poly.Sci.B.2015,53,860-868 3
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Initiator Mediating Radical
SG-1
• •
I
Heat >50 oC
kc
Alkoxyamines
RAFT
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• NitroxideMediatedPolymerizaBonrequires2subsequentfeedstosynthesizeanendfuncBonalizedprepolymer
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• EndfuncBonalizedspeciescanbesynthesizedwithasinglefeedandgrowsfromtheinsideout
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• BothNitroxideandRAFTmethodsallowforthesynthesisofrandomlyreacBveprepolymersfromasimpleonepotmethod
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Polymer Mn PDI Func4onality
N-End 11,000 1.4 8
N-Random 15,000 1.4 8
R-End 12,000 1.2 8
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0.5%wtDMPA10mW/cm26min
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EndfuncBonalformulaBonsshowlargeglasstransiBonforbutylacrylatebackboneandsecondforhddadomain
0.5%wtDMPA10mW/cm26min
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ConBnuousharddomainimprovesmodulusofendfunc4onalizedformulaBons
0.5%wtDMPA10mW/cm26min
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ConBnuousharddomainsinendfunc4onalmaterialsincreasesresistancetosuddenstress
0.5%wtDMPA10mW/cm26min
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1MPa
• RearrangementaroundTrithiocarbonatebondwillallowforbothrelaxaBonandagreaterdistribuBonofso^segmentsthroughoutthenetwork
• Ifrearrangementsareoccurring,theywouldcompetewithpropagaBonandthusalterreacBonkineBcs
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RAFTrearrangementretardsthepolymerizaBonathighprepolymerconcentaBons
0.5%wtDMPA10mW/cm215min
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NetworkrearrangementpreventscompletecureinRAFTformulaBons
0.5%wtDMPA10mW/cm215min
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RearrangementaroundRAFTgroupdiminishesphaseseparaBonandleadstogradualdecreasesinstoragemoduli
0.5%wtDMPA10mW/cm215min
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RAFTrearrangementdiminishesprimarybutylacrylateglasstransiBon
0.5%wtDMPA10mW/cm215min
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0.5%wtDMPA10mW/cm215min
• RAFTrelievesstressandcreatessmallerso^domain
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Greatercon4nuityofharddomainsfurtherincreasesresistancetosuddenstress
0.5%wtDMPA10mW/cm215min
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1MPa
0.5%wtDMPA10mW/cm26min
Transferinrandomsystemsproducesextremelyrobustfilmsallowingforfurthertuningofthesystems.
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• NitroxideandRAFTprocessescanbeusedtomakefuncBonalPrepolymers.
• Architectureofprepolymermoleculesdirectlyeffectsmorphology
• RAFTprocessesallowssmallerso^domainsandnetworkrelaxaBonproducingtoughermorerobustfilms
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• GuymonGroup
• TheUnversityofIowa• IUCRC
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• NitroxideandRAFTprocessescanbeusedtomakefuncBonalPrepolymers.
• Architectureofprepolymermoleculesdirectlyeffectsmorphology
• RAFTprocessesallowssmallerso^domainsandnetworkrelaxaBonproducingtoughermorerobustfilms
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