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Polymers 2014, 6(4), 1232-1250; doi:10.3390/polym6041232
Article

Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers

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Received: 27 December 2013; in revised form: 12 March 2014 / Accepted: 8 April 2014 / Published: 22 April 2014
(This article belongs to the Special Issue Polymers from Biomass)
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Abstract: In order to reduce the effects of hydrolytic degradation and to maintain sufficient viscosity during processing of biomass based poly(l-lactic acid) (PLLA), various epoxy functional reactive oligomers have been characterized and incorporated into the degraded fragments as chain extenders. The molecular weight of PLLA increased with the increase in functionality of the reactive oligomers. No further increase in molecular weight was observed for oligomers with functionality of greater than five. Under our experimental conditions, no gelation was found even when the highest functionality reactive oligomers were used. This is attributed to the preferential reaction of the carboxylic acid versus the negligible reactivity of the hydroxyl groups, present at the two ends of the degraded PLLA chains, with the epoxy groups. The study provides a clear understanding of the degradation and chain extension reaction of poly(lactic acid) (PLA) with epoxy functional reactive oligomers. It is also shown that a higher functionality and concentration of the reactive oligomers is needed, to bring about a sufficient increase in the molecular weight and hence the hydrolytic stability in circumstances when PLA chains suffer significant degradation during processing.
Keywords: (lactic acid); degradation; epoxy; multifunctional (lactic acid); degradation; epoxy; multifunctional
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Rathi, S.R.; Coughlin, E.B.; Hsu, S.L.; Golub, C.S.; Ling, G.H.; Tzivanis, M.J. Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers. Polymers 2014, 6, 1232-1250.

AMA Style

Rathi SR, Coughlin EB, Hsu SL, Golub CS, Ling GH, Tzivanis MJ. Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers. Polymers. 2014; 6(4):1232-1250.

Chicago/Turabian Style

Rathi, Sahas R.; Coughlin, Edward B.; Hsu, Shaw L.; Golub, Charles S.; Ling, Gerald H.; Tzivanis, Michael J. 2014. "Maintaining Structural Stability of Poly(lactic acid): Effects of Multifunctional Epoxy based Reactive Oligomers." Polymers 6, no. 4: 1232-1250.


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