*2.2. Polymer Composite Preparation*

Starch, rice husk, PBS, and PBAT were dried at 70 ◦C overnight before use. TPS was prepared using a Haake internal mixer at 100 ◦C with a rotor speed of 50 rpm by mixing 75 wt% starch with 23 wt% glycerol. TPRH was also prepared by mixing 90.0 wt% rice husk with 9.1 wt% glycerol using a Haake internal mixer at 100 ◦C with a rotor speed of 50 rpm. The PBS, PBAT, maleic anhydride (MA), dicumyl peroxide (DCP), calcium stearate, and TPRH/TPS (with the amount shown in Table 2) were physically mixed in the Haake internal mixer at 160 ◦C with a rotor speed of 50 rpm for 15 min. Subsequently, the samples were fabricated by a compression molding machine at 160 ◦C for 6 min preheating

time, 3 min heating time, and 2 min cooling time into 140 mm × 180 mm × 0.5 mm sheets. The compositions of the melt-blended specimens are summarized in Table 2.

**Table 2.** The compositions of the PBAT/PBS/TPS and PBAT/PBS/TPRH for the fabrication of biodegradable polymers.


CS: calcium stearate, MA: maleic anhydride, DCP: Dicumyl peroxide, PBS: polybutylene succinate, TPS: thermoplastic starch, TPRH: thermoplastic rice husk.
