Abstract: Variation pattern of pore structure of wheat straw fiber during recycling process with N₂ adsorption-desorption method under low temperature was investigated with transmission electron microscopy during different recycling times. The results showed that the pore size distribution of wheat straw fiber was complicated with numerous micropores and middle-size pores except large pores. After the first recycle, the pore volumes of micropores was decreased 3.2×10^-5cm³/g and the average pore volume of middle-size pore was reduced 1.67×10^-5cm³/g. After the second recycle, the pore volumes of micropores and middle-size pores were decreased 9.2×10^-5cm³/gand 2.77×10^-5cm³/gseparately compared with the first recycle. After the third recycle, the average pore volumes of middled-size pore decreased 5.81×10^-5cm³/g compared with the second recycle, but the micropores disappeared, while pore distribution was changed insignificently.The average pore size and the surface area of fiber had a trend of drop during the recycling process. It was also found that after recycling and remoistening, the lumen of fiber had irreversible collapse and distortion, and there was lots of pleats that changed the shape and size of pores.

Key words: wheat straw fiber, pore structure, wheat straw pulp, recycling, configuration of pores