2.2. Preparation of the blends
To prevent any potential hydrolytic degradation of the biodegradable polymers during the melt processing, both the PLA and
PBAT were dried as completely as possible in a vacuum oven at
80C for 8 h before the melt processing. Melt blends were obtained
by using a TSSJ-2533 twin-screw extruder (China). The predetermined weight of PLA, PBAT (weight ratio of PLA/PBAT was fixed at
70/30) and various weight ratios of TBT were fed together under
the screw speed at 90 rpm, and the extruding temperature at various zones was between 165C and 175C. The extrudate passed
through a cooling water bath and were finally pelletized, and then
dried in vacuum over for 24 h at 100C. For comparison, pure PLA
was also extruded under the above same condition.
The blends were abbreviated as LBT-X, wherein X donated the
TBT weight percentage (%) of both PLA and PBAT. For example,
LBT-0.1 represents 0.1 wt.% TBT of the weight of PLA and PBAT.