Why does polypropylene absorb oil

Case studies. Aerospace and Defence. Electrical Market. Food and Beverage. Mass Transit. Process Industry. Renewable Energy. Customer Support. Technical Support. New products. Subscribe to our e-Newsletter. Why should I use meltblown polypropylene sorbents? Why does polypropylene float and repel water? The resin is fed into an extruder where it is heated and melted to the appropriate temperature and viscosity required for fiber formation.

The extruder feeds molten polymer through a distribution die which enforces the polymer through fine holes in a spinnerette which is attached to the discharge end of the distribution die. As the resin strands emerge from the spinnerette, high velocity hot air is discharged along both sides of the spinnerette.

This stream of hot air attenuates the polymer strands into a blast of microfibers which are frozen by the surrounding ambient atmosphere before being propelled onto the web former. If surfactants and dispersants are presents in the water then the surface tension changes in the sorbent, resulting in the sorbent then absorbing water and other liquids.

The surfactant will cling to the polypropylene fibers resulting in the changing of the fibers surface tension. For further explanations on surface tensions, see chapter "Why does a polypropylene sorbent float and repel water". There are several scientific characteristics of meltblown polypropylene that cause it to repel water and float. A dyne is a metric unit of force.

This large difference is what causes polypropylene to be water repellent or hydrophobic. Then there is the specific gravity as defined as the density of polypropylene relative to the density of fresh water. The specific gravity of fresh water is 1. This simply means that polypropylene is lighter than water and will float. Salt water's density is higher than the density of fresh water. In salt water the meltblown polypropylene will be even more buoyant.

The "pronounced buoyancy" of meltblown polypropylene is a result not only of the surface energy and the specific gravity but also of the air that is trapped between the fibers of the sorbent. The fiber packing is so dense that the surface energy of the sorbent will not allow water to replace the air that naturally exists between the fibers, thus the sorbent will not become water-logged.

The net result is that an oil sorbent will float indefinitely. The only thing that may cause polypropylene to float lower than the water line is the presence of a contaminant such as a surfactant or emulsifier in the water. Such contaminants might include soap, detergent, alcohol or chemical dispersant. The presence of these surfactant materials would cause the oil to be at least partially soluble in the surrounding water and would change the surface energy enough to allow water to penetrate between the fibers.

The polypropylene will not sink as to the bottom but it can hold some water in the presence of the surfactants. For the polypropylene to sink to the bottom, it would need to be weighted sand, rock, debris, or heavier than water type liquid to offset the buoyancy of polypropylene. In open water conditions, polypropylene will float indefinitely, even if fully saturated with oil.

Take Note: Sorbents do not alter the characteristics of the chemical liquid absorbed! For your safety the SPC chemical sorbents are colored green. The outcomes from this research are believed to provide an essential reference in the practical application of polypropylene and lignin blend sponges in oil spill management. Three different oils, namely engine oil, soybean oil, and lubricating oil, were used. Every test was repeated three times to obtain an average value. The properties of the studied oils are reported in Table 1.

The sponge was immersed with acetone and subsequently dried under vacuum. The general protocol for the procedure for the fabrication of sponge is illustrated in Fig. For SEM observation, samples were cut, then fixed on double tape, and after that plated with a thin film of gold before measurement. The absorption ability was studied by weighing the samples before W i and after W t immersing them in oils soybean, engine as percent weight gain Q [ 38 , 39 ].

The ability to reuse the sorbents for oil sorption was studied using soybean oil, the sorbents with oil were squeezed, and then squeezed sorbent was again used with the same procedure as described above. The sorption—squeezing process was repeated many times under identical conditions to evaluate the reusability of the sorbent. In all tested samples, the three-dimensional interconnected porous structures were investigated by SEM, as depicted in Fig.

This is explained to the phase separation of the polymer solution during the cooling process, in which polymer-rich regions contributed to the formation of skeletons.

The porous structures provided sufficiently storage space to capture the oil. The pore volume decreased by squeezing the sorbent, causing the recovery of the absorbed oil. The figure revealed the characterization of blend sponge that lignin achieved incorporation in the PP blend successfully [ 41 ]. It is clearly obvious that pure polypropylene had a smooth surface, as shown in Fig. PP showed a hydrophobic feature with a contact angle around The obtained results may be attributed to the contribution of the several free polar groups from lignin [ 43 ].

These sorbents also have hydrophobic features. On the another side to indicate lipophilic feature for sorbents, it was obviously noticed that tested sorbents immediately absorbed oil droplets, as shown in Fig. Engine oil dyed in red and water dyed in blue with methylene blue were spotted on the surface of the sorbent. It can be observed from a typical FTIR spectrum of added lignin in polypropylene that the composition of the bonds did change but increased the intensity of the peaks.

In this case, it was observed through the experimental test that the adsorption process speed is slower, which indicates the presence of large holes and small macropores. That increase in absorbed oil into a tested sample is a vital key for the fast removal of spilled oils.

Figure 5 b, c, and e shows the weight gain of sorbents in the oil—water system. This result corroborates the contact angle results. Even that still PP15L and PP20L showed an improvement in sorption capacity compared to the blank one for both systems, it was seen that there is an increase in oil sorption with increased addition of lignin content. All polymer modified by lignin had to show the positive impact of lignin on oil sorption in the system.

Lignin slightly reduced the hydrophobic character of the polymer matrix due to the polar groups in the structure.

Still, it also has aromatic groups obtained from benzene, which can favor the sorption of organic compounds [ 49 ]. High oil retention ability is an essential feature to keep oil encapsulated in the sorbent so that the sorbent can be relocated from the water to a nominated area without losing the oil into the surrounding so that it avoids the second contaminant.

The oil retention after 24 h dripping for tested sorbents was measured as the values listed in Table 3. The engine oil retention of these sorbents indicates a similar tendency, that is And lubricating oil retention of these sorbents indicates a similar tendency, that is Generally speaking, it was noted that tested samples absorbed a higher amount of soybean oil than the engine oil and lubricating oil. This could be attributed to the fact that soybean oil is heavier than engine oil within the same unit volume.

On the other hand, soybean oil was more ready to drip out from tested sorbents than engine oil. The draining takes place when the capillary pressure is insufficient to capture the weight of oils.

The heavy nature of soybean oil combined with its lower viscosity than engine oil was favorable for the dipping process [ 50 ]. Figure 6 a shows a mixture of oil and water, in which the colorless transparent part is water and the colored part is oil. As shown in Fig. Once contacted, the floating oil drop is quickly and selectively collected inside the blend material. The adsorbed oil gathered easily by hand squeezing, as shown in Fig.

After repeating the process several times in water and oil, the oil was successfully separated. The sponge could be easily reused by washing and dried subsequently, as shown in Fig.

As described above, the excellent absorption properties make sponge a recyclable oil sorbent for large-scale oil spill cleanup. The absorption and recycling process of soybean oil oil dyed with red color and the recovery of the PP 10L sponge by washing and drying in the air.

Temperature is a significant parameter in the oily wastewater research since the temperature differs due to areas and seasons [ 51 ]. The results of the experiments were presented, as shown in Fig. It was shown the oil temperature effect on the weight gain of tested samples.

This indicates that oil viscosity is directly related to the temperature, which can be explained to the random motion of particles increase, which supports the opportunity of oil droplets to be attached on the sorbent surface and penetrate the pores.

Effect of temperature on oil absorption capacities of sponges a soybean oil, b engine oil, c lubricating oil. In this study, novel porous sponges based on economically and commercially available PP and lignin were successfully fabricated using the low-cost, simple process, eco-friendly, so-called thermally induced phase separation method TIPS.

Phase separation using the TIPS method was achieved in a short time, which shows a great advantage for the cleanup of a sudden oil spill accident.

SEM showed sponges with a three-dimensional interconnected porous structure and showed lignin mixed with polypropylene. FTIR analysis revealed the successful blend of polypropylene and lignin together. Sponges showed good adsorption ability to oils. The absorbed oils were easily recycled by squeezing the sorbents manually. Considering oil absorbency of sponge, as well as the template-free and versatile fabrication method, this research presented a method for the design and fabrication of blend porous materials from polypropylene and lignin.

J Clean Prod — Google Scholar. Mar Pollut Bull 1 —9. Desalination — Sep Purif Technol — Biores Technol — Sep Purif Technol Fuel — Chem Eng J — Proc Chem Chem Chem Eng — To achieve this high number, the fibres must have a large amount of air space loft between them to retain as much fluid as possible. A higher loft mat can absorb more product quickly but will be structurally weaker than a dense laminated product — it is important therefore to select the right combination of size, weight and construction to optimize your performance.

Spill Solutions Canada can work with you to develop optimal solution. Cellulose fibres are less effective for oil based spills or outdoor applications as they must be adapted to repell water Meltblown polypropylene fibres are chemically very stable and can adsorb virtually all liquids — making polypropylene based sorbents the only choice for unknown or hazardous HazMat materials Meltblown is resistant to high heat and will melt before it burns while cellulose will not melt — although one must be aware that any sorbent can be forced to burn meltblown or cellulose because the sorbent will take on the physical or hazourdous attributes of the absorbed liquids Sorbent Selection Guide.