Preparation and properties of compatible polybutylene adipate‐co‐terephthalate composites with high rice husk content

Abstract To deal with the severe issue of non‐degradable “white pollution”, it is essential to use cheap and readily available biomass fillers and biodegradable polymers to prepare green plastics with good compatibility and excellent comprehensive properties. In this work, polybutylene adipate‐co‐terephthalate (PBAT) as the matrix, and polycaprolactone‐based polyurethane prepolymers (PCLPU) as compatibilizer were used to prepare bio‐composite materials with a high husk powder content. SEM results indicated that a compatible interface structure had been successfully established. The compatibility of the composite materials was achieved through novel interface structures with physical crosslinking and urethane bonds. Furthermore, compared with the control without compatibilizer, a significant increase in elongation at break from 2.01% to 31.98% was demonstrated, indicating a nearly 15‐fold improvement. A notable increase in impact strength from 3.33 to 11.67 KJ/m² was observed, suggesting that the toughness and strength were enhanced by adding polyurethane prepolymer. Furthermore, it was revealed through thermogravimetric and water resistance tests that the addition of PCLPU enhanced the thermal stability and hydrophobicity of the composite material. The biomass content of composite materials can reach as high as 80%, significantly reducing their cost. Highlights The rice husk powder as a filler can be up to 80%, significantly reducing the cost of the composite materials. Both strength at break and elongation at break of the biocompsite were improved obviously with PCLPU as compatibilizer. The thermal stability and hydrophobicity of composite materials enhanced with the adding of PCLPU. The compatibility of the composites was achieved through innovative interfacial structures, including physical crosslinking and urethane bonds. The high‐biomass rice husk powder/PBAT composites showed excellent mechanical properties for its good compatibility.