Polypropylene/ Malva sylvestris Fiber‐Reinforced Biocomposites: Effect of EBAGMA Compatibilization on Morphology and Properties

This study investigates the potential of Malva sylvestris fibers as sustainable reinforcements for polypropylene (PP)‐based biocomposites. A comprehensive characterization was conducted to evaluate the structural, morphological, thermal, mechanical, rheological, and surface properties of PP biocomposites reinforced with 20 wt% Malva fibers. To enhance the interfacial compatibility between the hydrophobic PP matrix and the hydrophilic fibers, ethylene‐butyl acrylate‐glycidyl methacrylate (EBAGMA) was incorporated at 5 and 10 wt%. Scanning electron microscopy revealed improved fiber/matrix adhesion in the presence of EBAGMA, particularly at 5 wt%. Differential scanning calorimetry showed a significant increase in the degree of crystallinity from 43% for neat PP to 65% for the PP/MF/5EBAGMA biocomposite. Mechanical characterization demonstrated a marked improvement in stiffness, with the tensile modulus increasing from 1445.6 MPa for neat PP to 2058.1 MPa for PP/MF/5EBAGMA. Furthermore, the microhardness increased from 11.5 HV to 45.2 HV, indicating enhanced surface resistance. Rheological measurements indicated a marked increase in complex viscosity at low frequencies (< 0.1 Hz), suggesting a more interconnected microstructure due to enhanced compatibilization between the PP matrix and Malva fibers. Contact‐angle measurements also indicated reduced surface wettability and improved matrix/fiber compatibility. However, using 10 wt% EBAGMA led to lower overall performance than the 5 wt% formulation, likely due to excess compatibilizer, interfacial saturation, and local heterogeneity. Overall, the PP/Malva biocomposites compatibilized with 5 wt% EBAGMA appear to be the most promising formulation for the development of bio‐based structural materials.