Preparation and Properties of Poly (Butylene Adipate‐co‐Terephthalate)/Soybean Protein Composites Compatibilized With Different Types of Poly (ε‐Caprolactone)‐Based Polyurethane Prepolymer

This study is to report the synthesis and characterization of a new type of biodegradable composites that is made of soybean protein (SP), poly(butylene adipate-co-terephthalate) (PBAT) and different types of poly(ε-caprolactone)-based polyurethane prepolymer (PUP). The influence of PUP containing aromatic and aliphatic hard segments as a compatibilizer on the interface structure and properties of PBAT/SP composites was studied. The results show that the compatibilization effect of PUP with an aromatic hard segment structure on the PBAT/SP composite material is better than that of PUP with an aliphatic hard segment structure as the modifier. For example, adding 10 wt% of MPU (PUP with MDI as the hard segment) can increase the tensile strength (14.8 MPa), elongation at break (37%) and impact strength (16.5 kJ m−2) of PBAT/SP composites. These values were significantly higher than the mechanical properties (10.1 MPa, 16.3%, and 9.6 kJ m−2) of the composites prepared with IPU (IPDI as the hard segment) as the modifier, increasing by 47%, 127%, and 72%, respectively. Meanwhile, the prepared composite materials have good biodegradability, and the thermal stability and hydrophobicity of the materials have also been improved. Therefore, this research result provides an important reference for the interface design and performance regulation of PBAT/SP composites.