Compared to GTA and DPGDB, GTB has benzene ring structure, it may reduce PA chain mobility.
In summary, by considering thermal properties including [T.sub.g], [T.sub.m], [T.sub.cc], and [DELTA][H.sup.2.sub.m], it is possible that the plasticizing efficiency for PLA is in a sequence: DPGDB > GTA > GTB.
The parameter [bar.k] for the three plasticizers is various and presents an upward tendency in a sequence: GTA > DPGDB > GTB.
The elongation of PLA plasticized by GTA, DPGDB, and GTB significantly increase with plasticizer content, which is in well accordance with [T.sub.g] reduction in DSC thermogram.
However, the amorphous state is still observed for PLA plasticized with DPGDB and GTB after 75 days' storage, because slow crystallization does not undergo during storage period.
The thermal degradation of three plasticizers increases in a sequence: GTA (120[degrees]C)< DPGDB (192[degrees]C) < GTB (241[degrees]C), which is consistent for the thermal degradation sequence: PLA/GTA-25 (185[degrees]C)< PLA/DPGDB-25 (250[degrees]C) < PLA/GTB-25 (272[degrees]C).
Plasticizing effect of GTB, DPGDB, and GTA on poly (lactic acid) is studied.