Properties and structure of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/wood fiber biodegradable composites modified with maleic anhydride

Abstract

In this study, the green biodegradable composites were prepared by common industrial solid wastes poplar wood fibers (Populus tomentosa) and biopolymer poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) via hot pressing process, and the maleic anhydride (MAH) was added as the coupling agent to increase the interfacial adhesion. The morphological, crystalline, thermo-mechanical and mechanical properties of the bio-composites were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA) and mechanical property analysis. Results showed that the mechanical properties of the composites were increased and the Young's modulus decreased continuously with the addition of MAH. New bonds were formed between the P34HB and wood fibers due to add MAH, the interfacial adhesion of the composites was improved for the enhanced wettability of wood fibers. Additionally, the thermal stability of composites increased with the degree of the structural perfection increasing. The storage modulus of the composites was increased and the dynamic stiffness was better than static stiffness. Moreover, it was also found that the optimal condition of coupling agent dosage was 0.5%.