Biodegradability of bioplastic B (53 ± 2% carbon loss) was 4-fold
higher than that of bioplastic A (Table 3) and is comparable to
previously reported values for PLA-based bioplastics. Since the
composition of bioplastic B (5 wt.% PFF, 80 wt.% PLA, 15 wt.%
starch) differed only slightly from the listed composition of bioplastic
A (100% PLA), we expected that the biodegradability values
of the two polymers would be quite similar. These results support
the possibility that the commercially produced bioplastic A may
contain unlisted components that inhibited biodegradation.
Carbon loss from bioplastic C was approximately 40% after
60 days of composting. This value corresponds the combined carbon
content contained in the urea and glycerol portions of this bioplastic
(38% of bioplastic carbon).