Preparation of Poly(Butylene Succinate)/Soy Protein Isolate Bio-Composites by Reactive Compatibilization with Peroxide and Acrylate

Poly(butylene succinate) (PBS)/soy protein isolate (SPI) bio-composites were reactive compatibilized by adding dibenzoyl peroxide (BPO) and hexanediol diacrylate (HDDA) via melt blending in an internal mixer. The structure and properties of composites were studied by scanning electron microscopy, Fourier transform infrared spectroscopy, dynamic mechanical analyses, rheological tests, contact angle measurements, thermogravimetric analyses, differential scanning calorimetry, wide-angle X-ray diffraction, tensile tests and water absorption tests. The results showed that a branched graft copolymer (SPI-g-HDDA-g-PBS) was produced with the aid of BPO and HDDA via melt blending, which served as a compatibilizer. It improved the compatibility and enhanced the adhesion between PBS matrix and SPI phase by forming a network structure in the composites. The grafts contents in the composites were determined by Soxhlet extraction. The crystal structure of PBS was not changed in the composites. The melt viscosity and elasticity, hydrophobicity, thermal stability and crystallinity of PBS/SPI-HDDA/BPO composites were improved. The tensile strength and Young’s modulus increased 46% and 55%, while the water absorption decreased ~ 20% for PBS/SPI-HDDA/SPI (80/20/0.1) composite in comparison with PBS/SPI (80/20) composite. The potential usage of the bio-composites is household and industrial products and disposable packaging and items.