| 摘要 |
PROBLEM TO BE SOLVED: To provide medical devices and methods for their fabrication.SOLUTION: Biodegradable endoprostheses are formed from amorphous polymers having desirable biodegradation characteristics. The strength of such amorphous polymers is enhanced by annealing to increase crystallinity without substantially increasing the biodegradation time. The crystallinity of a highly amorphous polymer is below 10% prior to modification. After modification, the crystallinity is usually increased by at least 20% of the original crystallinity of an amorphous material, preferably by at least 100% of the original crystallinity of the amorphous material and more preferably by at least 1,000% of the original crystallinity of the amorphous material. Presently preferred polymer materials have a crystallinity in the range from 10% to 20% after modification. |
