As seen from Table 6, the organic carbon content of the
PBAT sample before degradationwas 63.3%, and the oxygen
atom content was 30.0%. After degradation the organic
carbon content of the residual samples was 59.1%, and the
oxygen atom content was 34.6%. The organic carbon content
of the PBAT/PLA sample before degradationwas 56.4%,
and the oxygen atom content was 37.5%. The organic carbon
content of residual samples after degradation was
55.0%, and the oxygen atom content was 39.1%. For the PLA
sample, the organic carbon content before degradationwas
50.5%, and the content of oxygen atoms was 44.0%. The
organic carbon content of the residual samples after
degradation was 47.0%, and the oxygen atom content was
47.3%. Comparing the samples before and after degradation,
it is clear that the organic carbon contents in the residual
samples decreased, while the oxygen atom contents
increased. The increase in the content of oxygen atoms may
be due to the increase of the carboxyl group numbers in the
molecular structure, which in turn causes an increase in the
oxygen atom content. This also shows that the degradation
of PLA in soil conditions does occur, a result that differs
from reports in the literature that illustrate that PLA slowly
degrades under soil conditions