Effects of slushing process on the pore structure and crystallinity in old corrugated container cellulose fibre

Variation in the pore structure and the crystalline of old corrugated container cellulose fibre during slushing was investigated using low-temperature nitrogen adsorption, Fourier transform infrared spectroscopy and fractal geometry. With increasing slushing time, the fibre bundles decrease gradually, and become single fibre finally, meanwhile some fibres are cut off. The Brunauer–Emmett–Teller surface area of the fibres increased to 18% after 20 min comparing with 5 min, and the Barrett–Joyner–Halendar (BJH) pore volume of the fibres increased to 31% after 15 min and then to 17.5% after 20 min comparing with 5 min, but the BJH average pore size of the fibres changed little. The fractal dimensions, the crystallinity and the hydrogen bonding strength of the fibre cellulose increased first and then decreased with increasing slushing time. No new chemical group appeared during slushing. With increasing slushing time, the water retention value (WRV) of the fibres increased. The increase of WRV was due to the change of the fractal dimension and crystallinity of the fibres.