Abstract
A poly(L-lactic acid) scaffold prepared by a combination of freeze-extraction and porogen-leaching methods was submitted
to static degradation in a phosphate-buffered saline solution at pH 7.4 and 37C for up to 12 months. After 6 months of degradation,
the scaffold maintained its integrity, although noticeable changes in its permeability and pore size were recorded. After 12
months, scanning electron microscopy pictures showed that most of the trabeculae were broken, and the sample disaggregated under
minimum loading. Neither weight loss nor crystallinity changes in the first heating calorimetric scan were observed during the degradation
experiment. However, after 12 months, a rise in the crystallinity from 13 to 38% and a drop in the glass-transition temperature
from 58 to 54C were measured in the second heating scan. The onset of thermal degradation moved from 300 to 210C after
12 months. Although the elastic modulus suffered only a very slight reduction with degradation time, the aggregate modulus
decreased 44% after 6 months.
