Oil Remediation using Shaped Polypropylene Fibers
Lisa G. Fuller, Clemson University
Polypropylene (PP) fibers are commonly used as an oil remediation sorbent. The
hydrophobic nature of PP as well as its density (0.90-0.91 g/cc) makes it an excellent candidate for oil sorption of spills on bodies of water. Although conventional PP sorbents already adsorb more oil than other materials, the sorption ratio of grams of oil to grams of material could be increased by replacing the round PP fibers with shaped PP fibers.
The increased surface area of shaped fibers as well as the presence of channels with the individual filament structures would lead to a higher oil sorption as compared to round fibers of the same denier. Commonly used shaped fibers both natural fibers and synthetic fibers.
Natural fibers such as cotton, silk and wool have non-round cross-sections. Cotton has a bean-shaped cross-section as a result of the collapse of the hydrated lumen. Silk has a generally triangular shape that accounts for its unique luster and wool, although mostly round, has scales along the fiber length. The most common synthetic shaped fiber is the hollow fiber.
Melt spun hollow fibers are often used in insulation and wet spun hollow fibers have found a large market in filtering and various separations applications such as hemodialysis, microfiltration, ultrafiltration, reverse osmosis, and gas separation.
The shaped fibers evaluated in this work for oil adsorption were developed by Eastman Chemical Company and Proctor & Gamble for applications in fluid sorption and capture. Some examples of the products developed from these fibers included diapers, sanitary napkins, and bandages as well as in other applications like doll hair, headbands, filters, insulation and liners for microwavable food containers.
Generally, the products developed by these two companies were made from polyester
(PET) fibers. Although using PP instead of PET required some adjustments in the method of fiber extrusion, the change in surface properties made PP a more desirable polymer for this application.