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Hydrolysis of polylactide in aqueous media
Author(s) -
Rodriguez Edwin J.,
Marcos Bernard,
Huneault Michel A.
Publication year - 2016
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.44152
Subject(s) - hydrolysis , autocatalysis , crystallinity , aqueous solution , induction period , chemistry , molar mass distribution , kinetics , alkaline hydrolysis , aqueous medium , polymer chemistry , materials science , chemical engineering , organic chemistry , polymer , catalysis , physics , quantum mechanics , crystallography , engineering
In this study, two commercial polylactide (PLA) grades with different d ‐lactate contents were subjected to hydrolysis in neutral, acidic, and alkaline aqueous media at temperatures above the glass transition. We monitored the hydrolysis process by means of tracking the changes in the molecular weight distribution, weight loss, water uptake, and PLA crystallinity as a function of time. In both, neutral and acidic media, hydrolysis showed an initial induction period over which no weight loss was observed, whereas the average molecular weight dropped drastically. After this initial period, the weight loss increased rapidly, whereas the molecular weight decreased slowly. Additionally, in alkaline media, hydrolysis occurred mainly through a surface‐erosion process; this resulted in a simultaneous molecular weight decrease and weight loss without a noticeable induction period. An autocatalytic mechanism was assumed in neutral and acidic media to describe the hydrolysis kinetics. The measured molecular weight decrease over time was successfully described by a two‐stage exponential model. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 44152.