Mechanical test methodology for environmental exposure testing of biodegradable polymers

✍ Scribed by W. P. Smutz; A. U. Daniels; K. P. Andriano; E. P. France; J. Heller

• Publisher: Wiley (John Wiley & Sons)
• Year: 1991
• Tongue: English
• Weight: 641 KB
• Volume: 2
• Category: Article
• ISSN: 1045-4861
• DOI: 10.1002/jab.770020103

✦ Synopsis

Abstract

A test methodology was developed for exposing degradable polymer test specimens to a simulated chemical and mechanical body environment and then testing them periodically to detect changes in stress–strain behavior. Poly(ortho ester) specimens were exposed to cyclic loading in aerated tris‐buffered saline (pH = 7.4) at 37°C. Specimens were removed at various time periods and the mechanical properties determined. To determine the effects of cyclic loading alone, additional specimens were cycled in air for the same cyclic periods and tested in the same manner. To determine the effects of a constant load on degradation rate, other specimens were subjected to a static load while exposed to trisbuffered saline. Additional specimens were subjected to immersion in tris‐buffered saline without loading.

Exposure to tris‐buffered saline alone had a small effect on the rate of change of the mechanical properties of the poly(ortho ester) specimens while cyclic loading in air alone had no effect. However a combination of both exposure to tris‐buffered saline and a static load decreased the flexural yield strength by 29% and the modulus of elasticity by 20% after 40 days, and a combination of both exposure to tris‐buffered saline and cyclic loading decreased both the flexural strength and modulus by 75% after 40 days.