Porous Structures of C-Shaped Polypropylene Fibers and Oil-Absorbing Performance of Their Spun-Bond Non-woven Fabrics

Spun-bond non-woven fabrics (NWFs) made of porous C-shaped polypropylene fibers were applied in rapid oil absorption and effective on-line oil spillage monitoring. It is of great interest to further optimize the absorption properties of these materials by tuning their preparation parameters as well as characterize them with theoretical models. In this paper, effects of die shape, diluent composition (mixtures of dibutyl and dioctyl phthalate), and drawing speed on their porous structure and oil-absorbing performance were systematically investigated and characterized based on two novel concepts, i.e., the equivalent capillary tube pore radius and the kinetic pore tortuosity (barrier to access) derived from the simplest capillary tube liquid-filling model. The use of higher dibutyl phthalate fractions under faster drawing speeds resulted in the formation of larger and more connected inner filament sub-micron pores. Three stages of tube filling relating to inter-filament large pores, medium pores close to bonding points, and inner filament small pores were observed in the spun-bond NWFs. Continuous oil recovery rates of 986 L·m⁻²·h⁻¹ with an oil/water selectivity of 6.4 were achieved in dynamic skimming experiments using simulated spilled oil.

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