Application of a catechol-polyamine co-deposition method for silane grafting of bamboo fiber for improved interface compatibility with poly (lactic acid) matrix

Abstract

In this work, we enhanced the hydrophobicity of bamboo fiber (BF) surface using a mussel-inspired method. The surface of the BF was coated by a thin layer of polymerized catechol/polyamine, which was then used as a platform to carry out the grafting of three silane coupling agents (KH550, KH560 and KH570) using two commonly used silane modification methods (surface spraying method and immersion stirring method). Then the modified BF was used as a reinforcement of Poly-lactic acid (PLA) matrix to prepare a fully biodegradable composite. Composites made of BF modified by immersion stirring modification method showed better mechanical results compared to those made of BF modified by surface spraying method for the three silane coupling agents. Moreover, the impregnation stirring method/KH570 combination showed the best mechanical and thermal results. Furthermore, an appropriate amount of silane coupling agent KH570 can effectively improve the mechanical properties of the composites. With the increase of KH570 dosage, the mechanical properties of the composite showed a trend of first increasing and then decreasing. When the KH570 dosage was 1%, the tensile test and modulus, the bending test and modulus, and the impact strength reached their maximum values of 90.96 MPa, 5743 MPa, 74.96 MPa, 3822 MPa and 11.33 MPa respectively, which is 7.4%, 6.7%, 9.5%, 10.6% and 7.8% higher compared to the composite without KH570. This indicates that the grafting of KH570 onto the surface of the BF had significantly enhanced the interfacial adhesion between the BF and the PLA matrix.