Thermoplastic starch (TPS) has attracted significant
attention
as an alternative to fossil-fuel-derived plastics owing to its abundance
and biodegradability. However, its high hydrophilicity impedes its
utilization in packaging applications because of issues such as moisture
uptake and inferior barrier properties. In particular, the hydrophilicity
of TPS hampers its ability to be compatible with hydrophobic biodegradable
polymers such as poly(butylene adipate-co-terephthalate)
(PBAT). Herein, we report a TPS/PBAT blend with enhanced compatibility,
mechanical properties, and water resistance, achieved by using in
situ reactive compatibilization. We synthesized a reactive compatibilizer,
styrene glycidyl methacrylate copolymer (SG), and prepared TPS/PBAT
blends (50/50) with varying SG contents (0, 1, 3, 5, and 7 parts per
hundred resin [phr]). The tensile strength of the TPS/PBAT blend increased,
and the size of the TPS domains dispersed in the PBAT matrix decreased
when an optimal amount of SG (3 phr) was incorporated into the blend.
The complex viscosity, storage modulus, and loss modulus also increased
as the SG content increased, likely due to enhanced compatibility
between TPS and PBAT. Furthermore, the water resistance improved upon
incorporating SG into the blend, as evidenced by the significant increases
in the contact angle and water vapor barrier properties. Overall,
these findings underscore the potential of in situ reactive compatibilization
to improve the intercomponent compatibility and water resistance of
the TPS/PBAT blends while maintaining their biodegradability and sustainability.