Abstract: Through the melt blending method, the three-dimensional hydrogen bonding network of biomass filler was constructed to enhance the filler matrix interaction among chitin, tannic acid and PHBV, and the bending and impact properties of chitin-tannic acid/PHBV composites were greatly improved. The changes of characteristic peaks of PHBV matrix before and after adding chitin and tannic acid were studied by infrared spectroscopy,the formation of three-dimensional hydrogen bonding network was discussed, and whether the hydrogen bonding successfully interacted between matrix and filler was verified. The test results of mechanical properties show that PHBV composites have excellent bending and impact properties. After introducing three-dimensional hydrogen bonding network, its bending modulus increases to 833 MPa, which is about 1.79 times of the pure sample. The bending strength increases from 28.7 MPa to 42.5 MPa, which is increased by 48%. The impact strength reaches 2 851 J/m², which is 68.3% higher than that of the pure sample. SEM was used to observe the microstructure of the bending section and the dispersion of fillers. The results show that chitin, tannic acid and polymer matrix were well mixed, and the interfacial interaction between the two phases was further enhanced. WAXD and DSC were used to investigate the crystallinity. The results show that the three-dimensional hydrogen bonding network destroyed the regularity of macromolecular chain to a certain extent, restricted the movement of molecular chain, and led to the decrease of crystallinity to a certain extent.

Key words: PHBV, hydrogen bonding network, biodegradable, mechanical properties, composites