Theproductionof L-lactidefromL-lacticacidinvolvesa substantialformationofmeso-lactideas animpurity,and,uponpolymerizationwiththe industrialcatalysttin octanoate,resultsin poly(L-lacticacid)ofreducedcrystallinitydueto stereoerrorsrandomlydistributedalongthe polymerchains.We describea newapproachwherein,insteadof avoidingstereoerrorsbyremovingthemeso-lactidepriorto polymerization,thestereoerrorsin the polymerare tolerated,by crowdingthemin a stereogradientcopolymer.A zirconiumcomplexof an aminetris(phenolate)ligandis foundtoexhibitveryhighsyndioselectivityin the ringopeningpolymerizationcatalysisofmeso-lactideat roomtemper-ature,and givesrise to stereogradientcopolymersin thepolymerizationof mixturesofmeso-lactide/L-lactideinthemeltat 180°C. Relativeto thestereo-randomcopolymersobtainedwithtin octanoate,thestereo-gradientcopolymersexhibitenhancedcrystallinitiesmanifestedin lowersolubilitiesandhighermeltingtemperaturesand enthalpies.

Stereogradient Poly(Lactic Acid) from meso‐Lactide/L‐Lactide Mixtures

Venditto, Vincenzo
Investigation
;
2022

Abstract

Theproductionof L-lactidefromL-lacticacidinvolvesa substantialformationofmeso-lactideas animpurity,and,uponpolymerizationwiththe industrialcatalysttin octanoate,resultsin poly(L-lacticacid)ofreducedcrystallinitydueto stereoerrorsrandomlydistributedalongthe polymerchains.We describea newapproachwherein,insteadof avoidingstereoerrorsbyremovingthemeso-lactidepriorto polymerization,thestereoerrorsin the polymerare tolerated,by crowdingthemin a stereogradientcopolymer.A zirconiumcomplexof an aminetris(phenolate)ligandis foundtoexhibitveryhighsyndioselectivityin the ringopeningpolymerizationcatalysisofmeso-lactideat roomtemper-ature,and givesrise to stereogradientcopolymersin thepolymerizationof mixturesofmeso-lactide/L-lactideinthemeltat 180°C. Relativeto thestereo-randomcopolymersobtainedwithtin octanoate,thestereo-gradientcopolymersexhibitenhancedcrystallinitiesmanifestedin lowersolubilitiesandhighermeltingtemperaturesand enthalpies.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4808572
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