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The study of water uptake in degradable polymers by thermally stimulated depolarization currents

Paper ID Volume ID Publish Year Pages File Format Full-Text
13912 941 1998 10 PDF Available
Title
The study of water uptake in degradable polymers by thermally stimulated depolarization currents
Abstract

Poly(DTH succinate) is a new, degradable polymer with potential applications as a medical implant material. This polymer can be classified as an alternating copolymer of succinic acid and desaminotyrosyl-tyrosine hexyl ester (DTH), a diphenolic monomer derived from the natural amino acid L-tyrosine. In this study, the effects of water uptake (hydration) on the secondary relaxations of poly(DTH succinate) were investigated using the technique of thermally stimulated depolarization currents (TDSC). Four relaxation peaks were precisely characterized by means of Gaussian activation energy distributions. Drying and rehydration treatments show that only small amounts of water, at most 0.5% (w/w), are necessary to hydrate two of the four polar moieties in poly(DTH succinate): the pendent chain ester carbonyls and the amide carbonyls in the polymer backbone. Water appeared to be more tightly bound to the amide carbonyl group and more loosely bound to the ester carbonyl group in the pendent chain. Even at a high state of hydration (1.2% w/w), TDSC indicated that no water was associated with the phenyl ester bond in the polymer backbone. This finding may explain the unexpectedly high stability of this polymer toward hydrolysis under physiological conditions. Polymer packing was also affected by hydration. In an intermediate hydration state (water content: 0.5% w/w) polymer packing was less dense than in the wet state (water content: 1.2% w/w). This study represents the first application of the TDSC technique to the study of hydration in a degradable biomedical polymer. The results obtained indicate that the TDSC technique may be useful to assist in the understanding of the mechanisms of hydration and subsequent hydrolytic degradation in degradable biomaterials.

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Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 19, Issue 24, December 1998, Pages 2347-2356
Authors
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us