PBAT

PBAT, or poly(butylene adipate-co-terephthalate), is a biodegradable aliphatic–aromatic co-polyester designed for flexible, compostable plastics. It comprises repeating units derived from 1,4-butanediol, adipic acid and terephthalic acid (or their derivatives), forming a random copolyester. The material is intended to combine toughness and processability with biodegradability.

PBAT is produced by polycondensation, often via ester interchange followed by polycondensation, using diol and diacid or diester feedstocks and metallic catalysts. The resulting polymer is typically used in blends and formulations to tune mechanical properties and degradation rate.

In terms of properties, PBAT is known for high elongation and impact resistance, low brittleness, and good processability on conventional extrusion equipment. Its crystallinity is moderate and its physical properties depend strongly on composition and blending. Because of its softness, it is commonly blended with other biodegradable polymers such as polylactic acid (PLA), starch blends, or polyhydroxyalkanoates to produce films and molded parts with a balance of strength and flexibility.

Applications include compostable packaging films, bags for shopping and produce, mulch films for agriculture, and disposable tableware or coatings for packaging laminates. PBAT is valued for enabling flexible, compostable solutions that disintegrate in industrial composting environments.

Biodegradation occurs through enzymatic and microbial hydrolysis of ester bonds and is accelerated under industrial composting conditions. Standards such as EN 13432 and ASTM D6400 specify compostability criteria. In noncomposting environments, degradation rates are slower and depend on environmental conditions and formulation.