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Why degradable polymers undergo surface erosion or bulk erosion

Paper ID Volume ID Publish Year Pages File Format Full-Text
13150 834 2002 11 PDF Available
Title
Why degradable polymers undergo surface erosion or bulk erosion
Abstract

A theoretical model was developed that allows to predict the erosion mechanism of water insoluble biodegradable polymer matrices. The model shows that all degradable polymers can undergo surface erosion or bulk erosion. Which way a polymer matrix erodes after all depends on the diffusivity of water inside the matrix, the degradation rate of the polymer's functional groups and the matrix dimensions. From these parameters the model allows to calculate for an individual polymer matrix a dimensionless ‘erosion number’ ε. The value of ε indicates the mode of erosion. Based on ε, a critical device dimension Lcritical can be calculated. If a matrix is larger than Lcritical it will undergo surface erosion, if not it will be bulk eroding. Lcritical values for polymers were estimated based on literature data. Polyanhydrides were found to be surface eroding down to a size of approximately Lcritical=10−4 m while poly(α-hydroxy esters) matrices need to be larger than Lcritical=10−1 m to lose their bulk erosion properties. To support our theoretical findings it was shown experimentally that poly(α-hydroxy ester) matrices, which are considered classical bulk eroding materials, can also undergo surface erosion.

Keywords
PLA; PLGA; Degradation; Surface erosion; Bulk erosion; Modeling
First Page Preview
Why degradable polymers undergo surface erosion or bulk erosion
Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 23, Issue 21, November 2002, Pages 4221–4231
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering