Preparation and Characterisation of PBAT-Based Biocomposite Materials Reinforced by Protein Complex Microparticles

In this work, new biodegradable composite materials based on poly (butylene adipate terephthalate) (PBAT) reinforced with zein–TiO2 complex microparticles were prepared and characterised by electron microscopy and tensile and dynamic-mechanical tests. The composite pellets were prepared by solvent casting with different filler contents, namely 0, 5.3, 11.1 and 25 part per hundred resin (phr), to modify and modulate the properties of the final materials. Scanning electron microscopy (SEM) images showed homogeneous dispersion of the filler, without microparticles aggregation or phase separation between filler and matrix, suggesting a good interphase adhesion. According to tensile tests, Young’s modulus showed an improvement in the rigidity and the yield stress presented an increasing trend, with opposite behaviour compared to other composites. Dynamic-mechanical analysis (DMA) results exhibited increasing storage modulus values, confirming a greater rigidity with a higher filler percentage. The glass transition temperature showed a slightly increasing trend, meaning the presence of an interaction between the two phases of the composite materials. Overall, the produced PBAT composites showed similar properties to low-density polyethylene (LDPE), proving to be promising and more sustainable alternatives to traditional polymers commonly adopted in agri-food fields

Preparation and characterisation of PBAT-based biocomposite materials reinforced by protein complex microparticles

In this work we report on the preparation and subsequent mechanical and dynamic-mechanical characterisation of new biodegradable composite materials based on poly (butylene adipate ter-ephthalate) (PBAT) loaded with zein-TiO2 complex microparticles . The masterbatches of the ma-terials were prepared by solvent casting with different filler contents (0 (pure PBAT), 5, 10 and 20 wt%), in order to modify and modulate the properties of the composite. Scanning electron mi-croscopy (SEM) images showed homogeneous dispersion of the filler, without microparticles ag-gregation nor phase separation between filler and matrix, suggesting a good interphase adhesion. Mechanical characterization on dumbbell specimens, obtained by injection moulding, consisted in uniaxial tensile test at constant speed. The Young’s modulus (E) showed an actual improvement of the rigidity with the increase of the filler content. The yield stress (σy) presented a defined in-crease with growing percentage of filler, with opposite behaviour in comparison to the trend gen-erally showed by other composite materials. Dynamic-mechanical analysis results exhibited an in-creasing trend in storage modulus (E’) values, confirming a greater rigidity of the composites with higher filler content. The values of the glass transition temperature (Tg) remained fairly constant, meaning that the thermal stability of the material was not affected by the addition of different amounts of protein complex microparticles. Overall, the produced PBAT composites showed sim-ilar properties to low density polyethylene (LDPE), proving to be promising and more sustainable alternatives to traditional non-biodegradable thermoplastic polymers commonly adopted in food and agricultural fields