Surface characterization of corn stalk superfine powder studied by FTIR and XRD.

Corn stalk superfine powder was ground by a special designed machine. The physical-chemical properties of corn stalk powders with particle sizes of >300, 300-150, 150-74, 74-37 and <15 μm were investigated. The particle size distributions of the powders were: d(90)=362, 147, 74, 40 and 12 μm. The size of corn stalk powders was smaller, the surface area (from 1.188 to 2.432 m(2)/g) and bulk density (from 0.103 to 0.1145 g/ml) were greater. Light microscopy (LM) and scanning electron microscopy (SEM) observations revealed the shape and surface morphology of five types of corn stalk powders. FTIR analysis showed that some position of absorbing peaks was shifted as the powder particle size decreased. X-ray diffraction analyses for corn stalk coarse and superfine powders revealed no evident changes in X-ray pattern. However, the crystallinity, intensity of crystal peaks and crystal size of corn stalk powders with particle sizes from >300 to 300-150 μm dropped, then, as the size of the powders decreased, the crystallinity, intensity of crystal peaks and crystal size increased in some degree.