Citric acid cross-linking modification of magnesium oxysulfate whiskers and bamboo flour and the enhanced performance of PP composites

In present work, citric acid was used as a cross-linking agent to perform surface hydrophobization of magnesium oxysulfate (MOS) whiskers and bamboo flour (BF), producing PP/MOS/BF ternary composites via melt extrusion and injection molding processes. The results show that MOS increase the crystallization temperature, melting temperature, and degree of crystallinity of the composites, acting as heterogeneous nucleation agents. BF inhibits the crystallization process of PP, but when compounded with MOS, it enhances the crystallization performance of the ternary composites, leading to an increase in crystallinity. Additionally, the rigidity of MOS and the flexibility of BF synergistically enhance the adhesion between PP and the filler, thereby improving the mechanical properties of the ternary composites. Furthermore, the storage modulus and loss modulus of the ternary composites increase, while the loss factor and bonding factor decrease, with no significant change in the glass transition temperature. The good compatibility and bonding strength generated between MOS whiskers, BF, and PP result in optimal dynamic mechanics. For the M-B-30-3:1 sample, its tensile performance reaches 33.74 MPa, as well as bending strength and notched impact strength of 28.87 MPa and 9.77 kJ/m 2 , respectively.