Open‐cell polypropylene/polyolefin elastomer blend foams fabricated for reusable oil‐sorption materials

Abstract

The fabrication of high-performance oil sorbents is of great significance for oil spill cleanup. The main objective of this study was to prepare open-cell polypropylene/polyolefin elastomer (PP/POE) blend foams for fabrication of reusable sorbents for oil sorption. Open-cell PP/POE blend foams were prepared via continuous-extrusion foaming using supercritical carbon dioxide as the blowing agent. The interconnected open-cell structure was characterized by scanning electron microscopy. The hydrophobicity and lipophilicity of PP/POE open-cell foams were revealed by tests of contact-angle measurement, water and cyclohexane sorption on the foam surface, CCl 4 and cyclohexane sorption in water, and oil/water separation. Further, the sorption tests indicated that PP/POE blend foams showed larger oil-uptake capacities than pure PP foams. In addition, cyclic compression tests showed that PP/POE open-cell foams had excellent ductility and significantly improved recoverability compared to pure PP foams. In cyclic sorptiondesorption tests, the sorption kinetics was studied in terms of capacity and saturation time, showing that PP/POE foams kept larger sorption capacities for 10 cycles, with larger sorption rates and good reusability. Based on the high open-cell content, the good hydrophobic and oleophilic properties, the high oil-sorption capacity, the improved recoverability, the large sorption rate, and the good reusability in cyclic oil-sorption performance, the PP/POE open-cell foams have shown promise as potential oil sorbents in applications for oil spill cleanup.

Strategy for the preparation of lightweight polypropylene/polyethylene‐octene elastomer composite foams with different phase morphologies using supercritical carbon dioxide

“…[48][49][50][51][52][53][54] Researchers have studied the sc-CO 2 foaming of the PP/POE system, finding that the addition of POE increased the cell density via heterogeneous nucleation, which is beneficial to cell opening. In practical applications, polyethyleneoctene elastomer (POE) is often blended with PP to improve the toughness of PP.…”

Kinetics study of oil sorption with open‐cell polypropylene/polyolefin elastomer blend foams prepared via continuous extrusion foaming

“…Furthermore, POE can also work as the soft regions on the cell walls, and during gas expansion after the polymer melts are extruded out from the die, the soft regions can be broken to interconnect the adjacent cells, thus further increasing cell opening. The strategies to increase cell opening can be found in the previous literature . By controlling the temperature of the second extruder, we obtained open‐cell PP/POE foams of different densities and different cell structures, including different expansion ratios, different void fractions, and different open‐cell contents.…”

“…The volume expansion of EPDM during CO 2 saturation at higher temperatures changes the phase structure from a sea‐island structure to a bicontinuous structure, making it possible to form interconnected cell structures during foaming, ie, open‐cell foams. According to recently reported studies, open‐cell PP‐based foams show good oil sorption performance, such as good hydrophobic properties, large sorption capacities, and good reusability, which indicate their potential as oil sorbents in the future. However, the kinetics of the oil sorption of PP‐based foams of different cell structures has not yet been reported.…”

“…PP fabrics are easy to fabricate and show good hydrophobic properties and high sorption rates; however, they have low sorption capacities, which is a drawback for their application as oil sorbents . In the very recent years, open‐cell PP‐based foams have been fabricated to solve the problem of low capacities of PP fabrics . Rizvi et al prepared open‐cell PP foams with PP copolymers via continuous extrusion foaming with scCO 2 as the foaming agent, and the foams show large capacities and good reusability.…”

“…Rizvi et al prepared open‐cell PP foams with PP copolymers via continuous extrusion foaming with scCO 2 as the foaming agent, and the foams show large capacities and good reusability. Our previous study demonstrated the fabrication of high open‐cell PP/polyolefin elastomer (POE) blend foams prepared via continuous extrusion foaming with scCO 2 as the foaming agent, and the foams exhibit a good oil sorption performance. Xu et al prepared open‐cell PP/starch foams via continuous extrusion foaming with water as the foaming agent and starch as the water carrier.…”