Thermal degradation processes of end-capped poly(L-lactide)s in the presence and absence of residual zinc catalyst

Biomacromolecules
Hideki AbeYoshiharu Doi

Abstract

Thermal degradation processes of end-capped poly(L-lactide)s (PLLAs) were investigated by means of several thermoanalytical techniques under both isothermal and nonisothermal conditions. Based on the thermogravimetric analysis, it was found that two distinct processes at temperatures below and above 330 degrees C were existed in the nonisothermal degradation for PLLA samples depending on the amounts of residual zinc compounds from synthesis process. Isothermal degradation experiments at different temperature regions showed that the sample weight of PLLA decreased linearly with time in both cases, whereas the changes in molecular weight revealed different tendency for the temperature. On the basis of characterization of the residual PLLA molecules after isothermal degradation at 330 degrees C, it was confirmed that the omega chain end of the residual molecules was an acrylic ester unit. Majority of volatile products during thermal degradation of PLLA was the lactide regardless of the degradation temperature. From these results, it is concluded that, during the thermal degradation of PLLA samples in the presence of large amounts of residual zinc compounds, the zinc compounds catalyze both the intermolecular transesterification ge...Continue Reading

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Citations

Aug 5, 2010·Journal of the Air & Waste Management Association·Yi-Chi ChienShu-Hua Yang
Mar 29, 2014·Advanced Materials·Zhiwei XieJian Yang
Apr 5, 2014·Angewandte Chemie·Fabian MitschangAndreas Greiner
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Sep 28, 2006·The Journal of Craniofacial Surgery·William S Pietrzak, Barry L Eppley
Feb 2, 2018·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Stéphane W DuchironLuc Avérous
Sep 28, 2017·Bioengineering·Aristotelis KamtsikakisStamatina Vouyiouka
Feb 27, 2021·International Journal of Biological Macromolecules·Francesca SbardellaFabrizio Sarasini
Mar 7, 2021·Polymers·Zachary BrounsteinAndrea Labouriau
May 1, 2021·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Marius MurariuPhilippe Dubois

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