Improvements in compatibility and properties of biocomposites modified through nanosilica attachment

This novel study provides a strategy for improving the compatibility and properties of lignocellulose fiber-reinforced polymer composites. The nanosilica was loaded on the surface of bamboo fiber by silane coupling agent to prepare a modified bamboo fiber (MBF-Si), and the new composite (MBF-SiP) of MBF-Si and polypropylene (PP) was obtained by compounding and injection molding. The results suggest that, compared to existing composites developed so far, MBF-SiP shows better thermal properties due to its higher crystallization temperature (117.05°C), melting temperature (164.29°C), amount of degradation residue, and degradation temperature at which maximum weight loss occurs. The tight connection between bamboo fiber and nanosilica consumes many polar groups and increases the hydrophobicity of MBF-Si, which affords higher contact angles (> 98°) and lower water absorption (0.26%) of MBF-SiP. Moreover, better flexural strength (60.24 MPa), flexural modulus (3.94 GPa), tensile strength (35.54 MPa) and tensile modulus (0.34 GPa) are obtained in MBF-SiP due to its better interfacial compatibility; whereas MBF-Si addition results in lower elongation and impact strength of neat PP. Interestingly, the stable structure formed by the attachment of nanosilica on bamboo fiber surface restricts PP deformation effectively and MBF-SiP exhibits better stiffness, elasticity and dimensional stability. Graphical abstract