Comparative study of pyrolysis characteristics, kinetics and gaseous products between bamboo parenchyma cells and fiber cells

Bamboo parenchyma cells and fiber cells are the two main cell types in bamboo. Differences in their industrial composition and chemical composition lead to different thermal stability. In this study, the focus was on comparing the pyrolysis characteristics of bamboo parenchyma cells and fiber cells. The cells were mechanically separated, and the microstructure of the two cells was observed by scanning electron microscopy. The thermogravimetric analyses (TGA) were conducted at different heating rates (10 degrees C/min, 20 degrees C/min, 30 degrees C/min, and 40 degrees C/min) to examine their thermal stability and pyrolysis behavior. The kinetics of pyrolysis reaction were calculated using the Coats-Redfern (CR) method. Pyrolysis gas chromatography-mass spectrometry (Py - GC/MS) analysis was used to identify and compare the compounds in the pyrolysis vapors of parenchyma cells and fiber cells. The results showed that at a heating rate of 20 degrees C/min, the residual charcoal rate of parenchyma cells was higher (20.91%) compared to the fiber cells (18.20%). However, the maximum mass loss rate and corresponding peak temperature were lower in parenchyma cells, indicating that parenchyma cells are more easily to pyrolysis compared to fiber cells. The CR kinetics indicated that the activation energy of parenchyma cells (69.96 kJ/mol) was lower than that of fiber cells (73.00 kJ/mol) at a heating rate of 20 degrees C/min. Activation energies and preexponential factors for both cell types increased with the heating rate. Ketones, phenols, and aldehydes were identified as the primary constituents in both cell types. Parenchyma cells exhibited a greater variety of ketone compounds compared to fiber cells, while the number of phenolic compounds was lower in parenchyma cells. Overall, this study provides insights into the thermal stability and pyrolysis characteristics of bamboo parenchyma cells and fiber cells. Understanding these differences is important for the comprehensive utilization of bamboo in various industrial applications.