Foam precursor and foam with biodegradable copolymer and methods thereof

A method, comprising:

• inputting unmodified starch, polybutylene adipate-co-therephthalate (PBAT), and water into an extruder to form a mixture that propagates through a plurality of temperature-controlled zones of the extruder;
• outputting an extrudate from the extruder, the extrudate corresponding to the mixture processed by the extruder;
• and
• chopping the extrudate into a plurality of granules, wherein a PBAT weight percent representative of the PBAT included in the plurality of granules is from 10% to 40%, wherein a starch weight percent representative of the unmodified starch included in the plurality of granules is greater than the PBAT weight percent, wherein a water weight percent representative of the water included in the plurality of granules is 20% or less, wherein the PBAT weight percent is greater than the water weight percent, and wherein a density of individual granules included in the plurality of granules extrudate is from 400 kg/m3 to 1500 kg/m3.