Effect of microwave irradiation on the microfibril orientation in Phyllostachys iridescens bamboo

Taking small-diameter Phyllostachys iridescens bamboo as the research subject, the morphology of bamboo fiber cell walls was observed using scanning electron microscopy, atomic force microscopy, and polarized light microscopy, and a qualitative analysis was performed. X-ray diffraction, synchrotron radiation wide-angle X-ray scattering, and small-angle X-ray scattering were used to quantitatively study changes in the microfibril orientation angle and orientation degree of bamboo, revealing the changes in the bamboo fiber wall morphology and microfibril orientation before and after microwave irradiation treatment. The results showed that the cell wall surface of the samples became smoother and more even after microwave irradiation treatment. Before treatment, the microfibril angle of the samples was 15.87°, with an orientation degree of 0.94 and an average micropore length of 29.3 mm. After treatment, the microfibril angle decreased to 13.18°, the orientation degree increased to 0.97, and the average micropore length increased to 59.7 mm. The microfibril angle decreased by 2.68°, the orientation degree of samples increased by 0.03, and the average micropore length increased by 30.4 mm after microwave irradiation treatment. These results indicate that microwave irradiation treatment reduces the microfibril angle and increases the orientation degree in small-diameter bamboo. This provides a theoretical foundation for the rational and efficient utilization of Phyllostachys iridescens bamboo.