Modification of Diss Fibers for Biocomposites Based on Recycled Low-Density Polyethylene and Polypropylene Blends

The aim of this work is the valorization of diss fibers with recycled and regenerated low-density polyethylene (rLDPE) for the development of biocomposites based on blends of rLDPE polypropylene (PP) and diss fibers. The diss fibers were characterized by laser granulometer and FTIR spectroscopy. Two PP/rLDPE blends of different compositions (50/50 and 75/25) were prepared. These polymer blends were reinforced by nano-Si particles and compatibilizers which were investigated using three compatibilizers: maleic anhydride functionalized ethylene copolymer rubber (MAC), maleic anhydride functionalized ethylene copolymer rubber/SiO2 (MAC/SiO2), and maleic anhydride functionalized ethylene copolymer rubber/SiO2/ionic liquid (MAC/SiO2/IL). The thermal properties of the blends were studied using differential scanning calorimetry and thermogravimetric analysis. Their crystallinity was investigated by X-ray diffraction and their morphology by scanning electron microscopy, while mechanical properties were evaluated by tensile testing. The best tensile properties were obtained for the PP/rLDPE (75/25) blend. A significant increase of the Young's modulus, stress at break, and elongation at break was obtained with the three compatibilizers. MAC acted as a compatibilizer of both polymers, resulting in improved interfacial adhesion which increased tensile properties. Finally, the effect of diss fiber surface modification on the properties of PP/rLDPE blends was considered. The results showed a modification of tensile properties and a satisfactory interfacial adhesion between diss fibers and polymer blends. Furthermore, thermal stability was not significantly decreased by the addition of 5 wt% diss fibers.