ISSN:
0021-9304
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Medizin
,
Technik allgemein
Notizen:
This article reports the morphological observations on the surface changes of poly(glycolic acid) sutures which have been exposed to various dosages of γ irradiation (0, 2.5, 5.0, 10, 20, and 40 Mrad) and duration of immersion (0, 7, 14, 28, 48, 60, and 90 days) in a physiological saline buffer. The most important gross morphological characteristics of PGA suture hydrolytic degradation is the formation of surface cracks on the filaments. The regularity of the surface cracks increased with an increase in the γ irradiation and the duration of hydrolysis. Surface cracks were not observed in irradiated sutures that had not been subjected to hydrolytic degradation. The arrangement of the surface cracks, their orientation on the filaments, and the direction of crack propagation provide very useful information for depicting the mechanism of hydrolytic degradation in this class of fibrous material. The microfibrillar model of fiber structure has been used as the basis for the proposed degradation mechanism of PGA in vitro. It is believed that hydrolysis occurs initially in the amorphous regions sandwiched between two crystalline zones, as tie-chain segments, free chain ends, and chain folds in these regions degrade into fragments. As degradation proceeds, the size of the fragments reaches the stage at which they can be dissolved into the buffer medium. This dissolution removes the fragments from the amorphous regions, and surface cracks appeared.
Zusätzliches Material:
8 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jbm.820160410
Permalink
