[FTIR and XPS spectroscopic studies of photodegradation of Moso Bamboo (Phyllostachys pubescens Mazel)].

The photodegradation process of bamboo involves very complex chemical reactions. In the present study, surface deterioration of Moso bamboo (Phyllostachys pubescens Mazel) was carried out by a xenon fade meter which can simulate sunlight irradiation, and Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopic (XPS) techniques were used to characterize the resulting changes in the chemical structure and composition of bamboo surface. XPS results showed that light irradiation resulted in significant increases in oxygen (O) content and O/C ratio. Besides, changes were also identified from the detailed C(ls) spectra, with a remarkable decrease in C1 component (C-C) and simultaneous increases in the components of C2 (C-O), C3 (C = O) and C4 (O-C = O), suggesting that the carbon atoms at bamboo surface were highly oxidized. FTIR results showed that lignin was susceptible to light irradiation and was significant degraded after treatment, as indicated by remarkable decreases in the intensity of lignin associated bands (e. g. 1 604, 1 512 and 1 462 cm(-1)). This was accompanied by the formation of new carbonyl compounds as shown by an obvious increase in the intensity of non-conjugated carbonyl group at 1 735 cm(-1), which further indicated the photo-oxidation of bamboo surface. The polysaccharides (cellulose and hemicellulose) components, however, were less influenced by light irradiation, and their relative content at bamboo surface increased significantly due to lignin degradation.