Study On Rheological Properties Of Plant Fiber Pulp Of Buffering Material

Environmental protection and green trade barrier bring new request to packaging material, while people pay more attention to green buffering packaging material. In the production process of plant fiber buffering packaging material, the rheological property is an important parameter of fibre pulp. Knowledge of the rheological properties of fibre pulp is helpful in technics melioration, quality control and equipment selection.In this paper, the rheological properties of fibre suspension, including liquid-solid two-phase and gas-liquid-solid there-phase flow, were studied by a Brookfield DV-â…¢ULTRA rheometer, and their rheological mechanisms were analysed. We can draw the following results:First, the rheological properties of liquid-solid two-phase fibre suspensions were measured. From the experimental results, the two-phase pulp containing fir fibre behaved as non-Newtonian and fitted well to the Casson model, and it was pseudoplastic and exhibited a typical shear-thinning behavior. It was found that all of the factors such as fibre concentration, temperature and fibre axial ratio could influence the flow equations. And It was concluded that the plastic viscosity and yield stress increased when raising the pulp concentration or enlarging the axial ratio, the effect of concentration on plastic viscosity could be described by exponential equations. And when raising the temperature, the plastic viscosity and yield stress decreased, the effect of temperature on plastic viscosity could be described by Arrhenius equation.At the same time, the rheological properties of gas-liquid-solid there-phase fibre suspensions, added anionic surfactant, were investigated. It was found that fibre foaming system was non-Newtonian fluid and pseudoplastic. The apparent viscosity strongly depended on the shear rate, and their relationship fitted well to the Casson model. The factors such as fibre concentration, temperature and gas-liquid ratio could influence the flow equations. and it was concluded that the plastic viscosity and yield stress increased when raising the pulp concentration or enlarging the gas-liquid ratio, the plastic viscosity is exponential increasing with fibre concentration. The effect of temperature on plastic viscosity could be described by Arrhenius equation, when raising the temperature, the plastic viscosity decreased, but yield stress increased. The activation energy of viscous flow became higher at higher concentration, and it was more sensitive to temperature.In this paper, the effects of each factor including fibre concentration, fibre axial ratio, temperature, gas-liquid ratio and shear rate on the rheological behavior had been opened out, and analysed their rheological mechanism. The results must be helpful in production and exploitation of plant fibre suspension, selection of the equipment, and development of fibre suspension rheology.