Effect of pro‐oxidants on the aerobic biodegradation, disintegration, and physio‐mechanical properties of compostable polymers

Biodegradable polymers are gaining momentum to resolve the globally acknowledged plastic waste problem. Understanding, characterizing, and developing new generations of biodegradable plastics is crucial to provide industries with alternative green materials that can fully satisfy biodegradation rates and lifetime specifications. This study evaluates the influence of metal pro‐oxidant additives on the degradation properties of various biodegradable polymer systems. For this purpose, iron (III) stearate (FeSt3) and bismuth oxide (Bi2O3), as oxidant agents, were incorporated into poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), poly(butylene adipate‐co‐terephthalate) (PBAT), cellulose acetate (CA), poly(lactic acid) (PLA), and thermoplastic starch (TPS) bioplastics. The material performances and biodegradability properties due to the additives on the resulting bioplastic formulations were investigated. A mechanism was proposed in which both pro‐oxidant additives can accelerate the thermo‐oxidation processes under composting conditions and cleave the polymer chains into smaller fragments to stimulate the biodegradation rate through microorganisms' activity. The study revealed that both pro‐oxidant additives, FeSt3 and Bi2O3, effectively improved the biodegradation process for all tested polymers except TPS, which already had a very high biodegradation rate. The observed change in the barrier and mechanical properties due to the additives were within tolerable limits of corresponding neat polymers. Pro‐oxidants promote biodegradation and disintegration.