Studies on the nanostructure of the cell wall of bamboo using X-ray scattering

The relationship between the nanostructure of Moso bamboo (Phyllostachys edulis (Carr.) H. De Lehaie) and the radial distance from the lacuna and the age of the culm was studied using X-ray scattering and electron microscopy. The size of cellulose crystallites and the crystallinity increased, and the mean microfibril angle decreased from about 40A(0) in the inner part to about 10A(0) in the outer part of the culm showing that bamboo is a functionally graded material at the nanoscale. The mean thickness and length of crystallites in the 4.5-year-old sample from the inner to outer part of the culm were 29.6 +/- A 1.0 , 30.7 +/- A 0.5 , 31.6 +/- A 0.5 , and 247 +/- A 10 , 303 +/- A 10 , 328 +/- A 10 , respectively. The length of crystallites in the inner part of 0.5-year-old bamboo and in the outer part of 10.5-year-old bamboo was 30-40 lower than in the corresponding parts of the 4.5-year-old sample. The crystallinity and the thickness of crystallites showed no age-dependence.