Effect of Nano-hydroxyapatite Modification of Bamboo Fiber on the Properties of Bamboo Fiber/Polylactic Acid Composites

An investigation was conducted of the modification of bamboo fibers (BF) by nano-hydroxyapatite (N-HA) and its impact on the mechanical and thermal properties of BF/PLA composites. The functional groups, and crystallinity of the N-HA modified BF were investigated with Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), respectively. The effects of different N-HA contents on the properties of the BF/PLA composites were evaluated using mechanical testing (bending, tensile, and impact properties), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that the most suitable N-HA content was 7.5 wt.%. Treating BF with an optimum concentration of N-HA decreased the polarity of the bamboo fiber, while maintaining the crystal structure of the cellulose. Compared with the control group, the mechanical properties and the crystallinity of the modified BF/PLA composites were improved, and the flexural, tensile, and impact strengths increased by 10.2%, 11.6%, and 28.1%, respectively. The thermogravimetric analysis results indicated modified BF/PLA composites has higher thermal stability.