Hydrophobic porous foam, its production process and its uses.

Abstract

Porous foam for the separation of hydrophobic compounds, its production process and uses. The present invention relates to eco-sustainable foams produced from fibrillated cellulose and natural rubber latex that exhibit structural resilience in aqueous media and a high capacity for absorbing non-polar compounds (organic solvents and oils), and can be applied to the separation of mixtures containing such compounds.

Description

1 / 27 Hydrophobic porous foam, its production process and its uses. DESCRIPTION FIELD

[0001] The present description is in the field of the production of macromolecular substances for the production of porous articles or materials. BACKGROUND OF THE INVENTION

[0002] Absorbent materials such as foams, sponges or aerogels can be made up of different chemical substances, from natural or synthetic sources, whose primary function may be to remove impurities and / or contaminants from the environment.

[0003] The choice of raw material for the absorbent material to be applied in the removal of impurities depends on the intrinsic and physicochemical characteristics of the absorbed material. In addition, the operational cost is of utmost importance, currently linked to the sustainability of the process and final product, also taking into account the chemical and structural stability of the absorbent, always aiming for the best performance.

[0004] Many industrial sectors, such as wastewater treatment and environmental remediation, petrochemicals, pulp and paper, and agro-industries, have turned their attention to the need to use sustainable materials that can remove impurities of different kinds (water, soil, and air) and are applicable in various processes. This sustainable character is based on the renewable nature of the raw material, its low toxicity, and high structural and chemical stability. These characteristics should result in low environmental impact, rapid degradation, and excellent performance under the conditions of use, while also having a low production cost, thus increasing their environmental and economic viability. These needs still demand much effort and research to meet these technological challenges. Petition 870260007470, dated 01 / 26 / 2026, page 15 / 78 2 / 27

[0005] Meeting the demands for sustainable technologies, polymers derived from biomass are emerging as favorable alternatives. Among these, cellulose, and its nanostructured derivatives such as micro / nanofibrillated cellulose, have stood out for their self-supporting properties, forming three-dimensional porous structures with high surface area, for example, a property of great importance in absorbent materials. This occurs due to intermolecular interactions of the hydrogen bond type between the hydroxyl groups from the surface of the micro / nanofibrillated cellulose. However, this surface characteristic of the micro / nanofibrils adds a hydrophilic character to the material, decreasing its structural resilience in aqueous media. This deconstruction of the porous structure makes its application in mixtures containing an aqueous phase unfeasible.In this sense, strategies have been applied to reduce the hydrophilic character of cellulose-based porous materials, increasing their structural resilience. Furthermore, due to the hydrophobic, lipophilic, and oleophilic nature of most impurities, surface modifications or the addition of hydrophobic compounds are necessary to achieve better performance and diversify technological applications.

[0006] Among these technological techniques, the functionalization of the cellulose surface (hydrophobization, for example) and / or the addition of compounds that promote physical or chemical interactions between adjacent polymer chains, i.e., cross-linking agents, have been used as effective alternatives in improving the properties of porous materials based on micro / nanofibrillated cellulose, adding greater structural resilience and hydrophobicity to these materials. However, most of these processes require the use of organic or toxic solvents, which can leave residual portions in the material. Petition 870260007470, dated 01 / 26 / 2026, page 16 / 78 3 / 27 final, thus diminishing its sustainable character. STATE OF THE ART

[0007] WO2015012273A1 presents an absorbent with excellent water retention capacity and gel strength. The water absorbent is composed of a polymer of natural origin, for example poly(v-glutamic acid), and nanofibers derived from biomass, for example, cellulose microfibers. The water absorbent can be manufactured by dissolving the polymer in solution, followed by the addition of biomass nanofibers and, subsequently, the addition of a cross-linking agent, promoting the cross-linking of the system into a hydrogel. The described composition includes a synthetic cross-linking agent, which compromises the environmentally friendly nature of this prior art. Another disadvantage is the polar characteristic of this absorbent, unsuitable for certain applications.

[0008] Document US6103790A describes polymer composites of cellulose microfibrils and latex. Polymer / cellulose composites are prepared using individualized cellulose microfibrils with a high aspect ratio and polymeric latex in a stable aqueous suspension. These polymer composites have a wide variety of uses, particularly in paints and nanocomposites. Compositions with cellulose-to-latex percentages below 15% are described, differing from the invention described herein, which has a higher cellulose proportion, thus ensuring greater hydrophobicity.

[0009] Document JP2018188651A presents a foam molding composed of rubber and biomass nanofibers, where the biomass nanofiber content in the rubber foam molding is less than or equal to 10% by mass. Additionally, it presents a method for producing a rubber foam molding comprising obtaining foam from Petition 870260007470, dated 01 / 26 / 2026, page 17 / 78 4 / 27 Rubber by vulcanization. The composition contains a rubber constituent, biomass nanofibers, a vulcanizing agent, and a foaming agent. The process includes the steps of mixing the aqueous latex solution with cellulose nanofibers, stirring, solidification, and simple drying, without specifying freeze-drying.

[0010] The article by Kargarzadeh et al. (2018) discusses the versatility of nanocellulose applications, such as its use as a reinforcing agent in composites and nanocomposites, due to its good intrinsic properties, such as stiffness and a certain degree of crystallinity, in addition to its biodegradability and renewable source. These are important characteristics for the development of new materials. This review elucidates recent developments in this area, including the production, characterization, properties, and range of applications of biodegradable composites, thermoplastics, and porous nanocomposites based on cellulose. The unique properties of nanocellulose and its various preparation techniques are highlighted, and its applicability as a reinforcing agent in various biodegradable polymeric matrices such as starch, proteins, alginate, chitosan, and gelatin is described.Subsequently, the effects of nanocellulose on the properties of thermoplastic polymers, such as polyamides, polysulfone, polypropylene, and polyacronitrile, are reported. The article concludes with a presentation of new findings and cutting-edge studies on nanocellulose foam and aerogel composites. Three different types of aerogels are discussed, i.e., nanocellulose-based aerogels, modified nanocellulose-based aerogels, and nanocellulose-based porous templates, as well as their preparation techniques and properties. In the case of foam composites, the research focus has been on two main preparation techniques, namely foaming / foam mixing and melt mixing, their respective challenges, and the properties of the final composites. Petition 870260007470, dated 01 / 26 / 2026, page 18 / 78 5 / 27

[0011] In the work of Kargarzadeh and colleagues (2018), a comparative study was carried out between cellulose nanocrystals and biodegradable polymers, nanoplastics, and biodegradable thermoplastics reinforced with cellulose nanofibers. Considering the vast amount of research on cellulose-based composites, special emphasis is given to such composites at the end of the review. The document does not disclose a composite comprising mixtures of cellulose nano- and microfibers with natural rubber latex.

[0012] Given the above, no hydrophobic porous foam with an environmentally friendly composition comprising cellulose microfibers and natural rubber latex was found in the state of the art.

[0013] The addition of natural rubber latex to the composition of micro / nanofibrillated cellulose porous foams overcomes several disadvantages of previous techniques, as its intrinsic and unique characteristics (many related to the composition of the latex) added hydrophobic properties, without the need for a subsequent step to hydrophobize the material. Surprisingly, the latex provided structural integrity to the foams, maintaining stable porous structures when added to water, an advantage achieved due to the anchoring of the cellulose micro / nanofibrils by latex particles, adding hydrophobicity and structural resilience to the final material when exposed to aqueous media.

[0014] Furthermore, in the present invention, the aforementioned foam composed of micro / nanofibrillated cellulose and latex is environmentally sustainable. This advantage is related to the fact that the entire dispersion is carried out in an aqueous medium, being free of toxic and / or environmentally aggressive solvents. This foam allows the removal of different oleophilic and hydrophobic compounds and has great potential to replace the materials currently used. Petition 870260007470, dated 01 / 26 / 2026, page 19 / 78 6 / 27 for the removal of contaminants, which may involve the use of organic solvents at some stage of production, or may have a high manufacturing cost. BRIEF DESCRIPTION OF THE INVENTION

[0015] The present invention relates to an eco-sustainable foam produced from fibrillated cellulose (preferably micro / nanofibrillated) and natural rubber latex, which has a high absorption capacity of non-polar compounds (oils, organic solvents, for example) and can be applied to separate mixtures containing such compounds.

[0016] In one embodiment, the foam-based materials contain cellulose and natural rubber latex characterized by comprising cellulose in micrometric dimensions.

[0017] In one embodiment, the foam-based materials contain cellulose and natural rubber latex characterized by comprising cellulose in nanometric dimensions.

[0018] In one embodiment, the foam based on materials containing cellulose and natural rubber latex characterized by comprising a cellulose concentration by dry mass between 10 and 90%;

[0019] In one embodiment, the foam based on materials containing cellulose and natural rubber latex is characterized by comprising a concentration of natural rubber latex by dry mass between 20 and 90%;

[0020] In one embodiment, the foam based on materials contains cellulose and natural rubber latex characterized by comprising a porosity greater than 70%.

[0021] In one embodiment, the foam-based materials contain cellulose and natural rubber latex characterized by being hydrophobic.

[0022] In one embodiment, foam-based materials contain cellulose and Petition 870260007470, dated 01 / 26 / 2026, page 20 / 78 7 / 27 natural rubber latex characterized by exhibiting structural integrity in an aqueous medium.

[0023] The present invention also relates to a process for producing foam based on materials containing cellulose and natural rubber latex, characterized by comprising: adding homogenized micro and nanofibrillar cellulose to a dispersion of natural rubber latex; stirring to homogenize the mixture; filling molds with the mixture; cooling and freezing filled molds; freeze-drying to remove water.

[0024] In one embodiment, the process is characterized by comprising a mold with at least one of its walls having thermal conductivity different from the others.

[0025] The present invention also relates to the use of foam based on materials containing cellulose and natural rubber latex, for separating mixtures containing at least one hydrophobic component.

[0026] In one embodiment, the use of foams for absorption and separation of mixtures is characterized by the hydrophobic component absorbed being selected from the group comprising organic solvents, silicones, vegetable oils and / or synthetic oils, aromatic compounds and mixtures thereof.

[0027] In one embodiment, the use of foams is characterized by being applied for environmental decontamination or river remediation. BRIEF DESCRIPTION OF THE FIGURES

[0028] The present description will be illustrated in some embodiments represented in the following drawings.

[0029] Figure 1(a) is a digital photograph of a foam composed mainly of cellulose nanofibrils (CNF) and natural rubber latex (LBN) in a mass ratio of LBN20 / CNF80, respectively, of an embodiment of the present invention. Petition 870260007470, dated 01 / 26 / 2026, page 21 / 78 8 / 27

[0030] Figure 1(b) is a photograph of CNF and LNB foam in a mass ratio of 80 / 20 on the surface of a Taraxacum sp. inflorescence, demonstrating its low density.

[0031] Figure 2(a) is a photograph of micro / nanofibrillated cellulose (CNF) foams embedded with natural rubber latex (LBN), of an embodiment of the present invention, immersed in oil (top), demonstrating their hydrophobicity, and CNF foams immersed in water (bottom), demonstrating their hydrophilicity.

[0032] Figure 2(b) is a photograph of CNF foams embedded with latex (LBN20 / CNF80), in a wettability test with oil (orange) and water (black).

[0033] Figure 3 is a series of photographs of a structural resilience test of foams in liquids, testing a micro / nanofibrillated cellulose (CNF) foam incorporated with natural rubber latex (LBN), of an embodiment of the present invention (left column); and a CNF foam in water (right column).

[0034] Figures 4(a) to 4(d) are a series of photographs of a structural resilience test of CNF foams incorporated with natural rubber latex (LBN20 / CNF80), of an embodiment of the present invention, tested in three different solvents: THF, Chloroform, and Toluene. Figure 4(a) is a digital photograph of the LBN20 / CNF80 foams after immersion in the different organic solvents. Figure 4(b) is a digital photograph of the LBN20 / CNF80 foams immediately immersed. Figure 4(c) is a digital photograph of the LBN20 / CNF80 foams after 48 hours of immersion. Figure 4(d) is a digital photograph of the LBN20 / CNF80 foams after solvent evaporation and weighing. Values ​​indicated as a percentage show the decrease in mass after immersion. Petition 870260007470, dated 01 / 26 / 2026, page 22 / 78 9 / 27

[0035] Figures 5(a) to 5(g) are a series of photographs of a procedure for reusing LBN20 / CNF80 foams, of an embodiment of the present invention, for absorbing diesel oil in water. Figure 5(a) is an example of the absorption cycles. Figure 5(b) is an absorption cycle comprising immersion of the LBN20 / CNF80 foam for 30 min. Figure 5(c) is a squeezing process, in which the liquid is expelled from the foam by mechanical compression. Figure 5(d) represents the oil separation efficiency after ten absorption and squeezing cycles, while Figure 5(e) represents twenty cycles. Figure 5(f) shows the oleophilic affinity of the LBN20 / CNF80 foam in the diesel / water mixture. Figure 5(g) demonstrates the effect of foam shape recovery after zero, ten and twenty cycles, respectively, the scale being given in centimeters. DETAILED DESCRIPTION OF THE INVENTION

[0036] This description presents the formulation of a foam based on materials containing cellulose and latex, characterized by comprising: cellulose in micro and nanofibrillar form; colloidal dispersion of natural rubber latex; and high porosity.

[0037] In one embodiment, porosity is selected from a group comprising: isotropically oriented porosity, randomly distributed porosity, cellular-shaped porosity, honeycomb-shaped porosity, or combinations thereof.

[0038] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by comprising cellulose in micrometric dimensions.

[0039] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by comprising cellulose in nanometric dimensions. Petition 870260007470, dated 01 / 26 / 2026, page 23 / 78 10 / 27

[0040] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by comprising a cellulose concentration by dry mass between 10 and 90%;

[0041] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by comprising a concentration of natural rubber latex by dry mass between 20 and 90%;

[0042] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by comprising a porosity greater than 70%.

[0043] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by being hydrophobic.

[0044] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized as being oleophilic.

[0045] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized as being lipophilic.

[0046] In one embodiment, foam based on materials containing cellulose and natural rubber latex is characterized by exhibiting structural resilience in an aqueous medium.

[0047] The present description also presents a process for producing said foam based on materials containing cellulose and natural rubber latex, characterized by comprising: adding homogenized fibrillar cellulose to a colloidal dispersion of natural rubber latex; stirring to homogenize the mixture; filling a mold with the mixture; cooling and freezing the mixture in the filled molds; lyophilizing the mixture.

[0048] In one embodiment, the process is characterized by comprising a mold with at least one of its walls having thermal conductivity different from the others. Petition 870260007470, dated 01 / 26 / 2026, page 24 / 78 11 / 27

[0049] This description also presents uses of said foam based on materials containing cellulose and natural rubber latex, for separating mixtures containing at least one hydrophobic component.

[0050] In one embodiment, the use of foams is characterized by the hydrophobic component of the mixture being classified as aromatic compounds, organic solvents, silicones, vegetable oils and / or synthetic oils.

[0051] In one embodiment, the use of foams is characterized by being applied for environmental decontamination and remediation. EXAMPLE 1: ABSORPTION CAPACITY OF SUNFLOWER AND SOYBEAN VEGETABLE OILS FOR DIFFERENT FOAM COMPOSITIONS.

[0052] In this example, the versatility of absorption of the foams of the present invention for different types of oils was exemplified by absorption tests for four distinct foam compositions containing natural rubber latex (LBN) and micro / nanofibrillated cellulose (CNF).

[0053] For the compositions, an aqueous dispersion of LBN (pH = 7 and 62.6% solids content), extracted from the species Hevea brasilienses, and CNF (3.8% w / w), which was obtained from eucalyptus, was used.

[0054] The foams of the present invention were obtained by mixing homogenized CNF (previously sonified in ultrasound with an amplitude of 40% for 5 min under an ice bath) and dispersing LBN. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were duly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples. The composition of each of the foams is organized in Table 1. Petition 870260007470, dated 01 / 26 / 2026, page 25 / 78 12 / 27 Table 1: Composition of foams based on cellulose micro / nanofibrils and natural rubber latex. Cellulose concentration (micro / nanofibers) by dry mass Natural rubber concentration by dry mass (%) (%) 50 50 70 30 80 20 90 10

[0055] The foams of the present invention are highly porous (total porosity of 90%) and have demonstrated structural integrity, as visualized in figure 1(a). Figure 1(b) demonstrates the very low density of the foams, resulting from the high degree of porosity of the material produced.

[0056] The structural stability, as well as the hydrophobic characteristics of the foams of the present invention, is exemplified in Figures 2 and 3. Given that absorption of the foams of the present invention requires hydrophobic properties (low affinity for water), it is necessary that they exhibit affinity for non-polar compounds, such as oils and organic solvents. Figure 2(a) illustrates the hydrophobicity when latex is added to the foam composition. In the mixture of two immiscible phases (water and oil), the foam containing only CNF localizes in water, while in the case of the foam with 20% LBN the foam interacts strongly with the oleophilic phase. The wettability (ability to allow a liquid to spread over its solid surface) of the foam of the present invention is shown from the formation of angles of the liquid on the surface of the material in Figure 2(b).The hydrophobic surface of CNF foams incorporated with LBN can be verified by the formation of a water droplet, as seen in figure 2(b), in black, on the surface. Petition 870260007470, dated 01 / 26 / 2026, p. 26 / 78 13 / 27 while the oil droplet, seen in figure 2(b), in orange, spread across the entire surface.

[0057] For better absorption and subsequent reuse, it is required that there are no structural changes when the foam is introduced into the mixture (water / oil) to be separated. Figure 3 illustrates the greater structural stability, that is, the ability of the foam to remain intact when immersed in a liquid medium. In this case, the test was performed for foams made only of CNF (LBN0 / CNF100) immersed in water and CNF incorporated with LBN (LBN20 / CNF80) immersed in oil for 24 hours. The CNF dispersed completely in water after 5 hours (right column), while the CNF foam incorporated with latex remained stable in oil (see Figure 3 - left column). These results indicated that the foam of the present invention is a good candidate for the decontamination of oils and / or non-polar compounds and water.

[0058] The absorption capacity of oils is exemplified here by absorption tests, which were carried out at a temperature of 25 °C. The previously weighed foams (m0) were immersed in 10 mL of two types of vegetable oils: sunflower and soybean. The foams were removed after a 5-minute interval, which proved sufficient to absorb the entire quantity of oil. The absorption capacity (Qt) was calculated from the following equation:

[0059] Qt=(mt-m0) / m0

[0060] where m0 and mt are the masses of the foams before and after absorption, respectively.

[0061] Table 2 presents the results of the absorption tests (after an equilibrium time of 5 min) for sunflower and soybean vegetable oils, obtained at room temperature. Table 2: Absorption capacity (Qt) of sunflower and soybean oil after five minutes of equilibration. Petition 870260007470, dated 01 / 26 / 2026, page 27 / 78 14 / 27 Cellulose concentration (micro / nanofibrils) (% w / w) Latex concentration (% w / w) Sunflower oil quantity (g / g) Soybean oil quantity (g / g) 50 50 19 ± 1 16 ± 5 70 30 22 ± 2 17 ± 2 80 20 43 ± 3 48 ± 4 90 10 25 ± 5 33 ± 1

[0062] Among the prepared foam compositions, the one that presented the best absorption values ​​was the foam with 20% w / w LBN and 80% w / w CNF, this improvement being correlated to the increase in specific surface area resulting from the increase in porosity and pore diameter. EXAMPLE 2: PREPARATION OF FOAMS FOR ABSORPTION OF GASOLINE, DIESEL OR PUMP OIL

[0063] In these examples, compositions based on an aqueous dispersion of LBN (pH = 7 and 62.6% solids content), extracted from the species Hevea brasilienses, and CNF (3.8% w / w), which was obtained from eucalyptus, were used.

[0064] The foams were obtained by mixing homogenized CNF (previously sonified in ultrasound with a 40% amplitude for 5 min under an ice bath) and dispersing LBN. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were properly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples. In this example, foams were prepared with an LBN concentration of 20% w / w and CNF of 80%. Petition 870260007470, dated 01 / 26 / 2026, page 28 / 78 15 / 27 mm.

[0065] The oil absorption capacity is exemplified here by absorption tests, which were carried out at a temperature of 25 °C. The previously weighed foams (m0) were immersed in 10 mL of two types of oil (diesel and pump oil) and gasoline. The foams were removed after a 5-minute interval, which proved sufficient to absorb the entire quantity of oil. The adsorption capacity (Qt) was calculated from the following equation:

[0066] Qt=(mt-m0) / m0

[0067] where m0 and mt are the masses of the foams before and after absorption, respectively.

[0068] Table 3 presents the results of the foam absorption tests with 20% LBN and 80% CNF, for gasoline, diesel oil and pump oil, after 5 minutes of equilibration in 10 mL of the oils or gasoline. Table 3: Absorption capacity of 20% w / w natural rubber latex foam and micro / nanofibrillated cellulose (80% w / w). Qt Qt Qt gasoline diesel oil pump oil (g / g) (g / g) (g / g) 22 ± 2 29 ± 1 43 ± 1 EXAMPLE 3: PREPARATION OF FOAMS FOR ABSORPTION OF ORGANIC SOLVENTS: TETRAHYDROFURAN (THF), TOLUENE AND CHLOROFORM.

[0069] In these examples, compositions based on an aqueous dispersion of LBN (pH = 7 and 62.6% solids content), extracted from the species Hevea brasilienses, and CNF (3.8% w / w), which was obtained from eucalyptus biomass, were used.

[0070] The foams were obtained by mixing homogenized CNF (previously sonified in ultrasound with an amplitude of 40% for 5 min under Petition 870260007470, dated 01 / 26 / 2026, page 29 / 78 16 / 27 ice bath) and the LBN dispersion previously dialyzed for 24h. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were duly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples.

[0071] Absorption tests were performed at room temperature. The foams were previously weighed (m0) and then immersed in 10 ml of organic solvents. The absorption capacity (Qt) can be calculated from the following equation:

[0072] Qt=(mt-m0) / m0

[0073] where m0 and mt are the masses of the foams before and after solvent absorption, at a time of 5 minutes, respectively.

[0074] Table 4 presents the results of the absorption tests for the foam with 80% nanocellulose and 20% latex, for the solvents tetrahydrofuran (THF), toluene and chloroform, at room temperature, after 5 min of equilibrium, in 10 mL of the respective solvents. Table 4: Absorption capacity (Qt) of natural rubber latex foam (20% w / w) and micro / nanofibrillated cellulose (80% w / w) for a time of 5 minutes until absorption equilibrium. Qt Qt Qt THF Toluene Chloroform (g / g) (g / g) (g / g) 23 ± 3 22 ± 1 42 ± 1

[0075] After testing, it can be observed that the foam containing 80% nanocellulose and 20% latex showed good absorption capacity for the Petition 870260007470, dated 01 / 26 / 2026, page 30 / 78 17 / 27 chloroform, and lower for toluene and tetrahydrofuran (THF). EXAMPLE 4: PREPARATION OF FOAMS FOR KINETIC TESTS IN OILS AND SOLVENTS

[0076] In this example, only one foam concentration containing 80% nanocellulose and 20% latex was prepared for kinetic testing in different oils and solvents. Another important parameter tested to evaluate the quality and efficiency of the foam was the equilibrium kinetics of the foam with the organic oils and solvents.

[0077] For the compositions, an aqueous dispersion of LBN (pH = 7 and 62.6% solids content) extracted from the Hevea brasiliensis species was used. CNF (3.8% w / w) was obtained from cellulose extracted from eucalyptus biomass.

[0078] The foams were obtained by mixing homogenized CNF (previously sonified in ultrasound with a 40% amplitude for 5 min under an ice bath) and dispersing LBN. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were properly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples.

[0079] The test consisted of immersing the foam in 15 ml of oils or organic solvents in two protocols: measurements of the change in foam mass at equal intervals during the first ten seconds, and from then on, at ten-second intervals until approximately 100 minutes. The absorption capacity was then calculated from the following equation:

[0080] Qt=(mt-m0) / m0

[0081] where m0 and mt are the masses of the foams, respectively Petition 870260007470, dated 01 / 26 / 2026, page 31 / 78 18 / 27

[0082] Table 5 below presents the results of kinetic tests on different oils and organic solvents. For soybean oil and sunflower oil, the time required to reach equilibrium is 3 s, demonstrating high efficiency and speed of application. For gasoline and diesel oil, equilibrium is reached in the first second, showing good performance and rapid absorption equilibrium. For pump oil, equilibrium was reached in 5 s, showing good efficiency and demonstrating the high versatility of application for oil decontamination in water.

[0083] It was found that, for the more viscous oils and solvents, the kinetic equilibrium of absorption was faster compared to the less viscous oils / solvents. Table 5: Absorption kinetics of different oils and solvents for the same composition of natural rubber latex foam and micro / nanofibrillated cellulose (20 / 80 m / m). Time(s) Silicone oil Soybean oil Sunflower oil Gasoline Diesel oil 1 5.09 21.25 15.78 18.86 31.77 6.92 2 17.41 43.10 35.07 20.40 31.50 18.48 3 24.69 51.10 41.45 20.74 31.92 29.33 4 28.21 52.04 42.37 19.98 30.72 38.42 5 36.88 53.05 43.05 20.40 30.16 42.00 6 42.54 53.52 42.16 20.05 31.08 42.43 7 43.09 53.31 42.82 19.73 32.21 43.04 8 45.97 53.27 41.77 20.67 31.97 43.92 9 48.06 53.12 42.17 19.77 31.62 43.20 Petition 870260007470, dated 01 / 26 / 2026, page 32 / 78 19 / 27 10 47.79 53.42 42.61 20.61 30.72 42.26 20 49.57 53.21 43.68 19.91 30.45 42.40 30 49.65 54.20 43.27 20.16 30.64 43.63 40 50.32 52.98 42.62 19.30 31.22 42.24 50 50.14 53.25 42.20 19.48 31.36 41.88 60 51.02 52.84 43.10 19.86 31.78 41.47 EXAMPLE 5: PREPARATION OF CNF FOAMS INCORPORATED WITH LATEX (LBN20 / CNF80) FOR ABSORPTION, REUSE AND STRUCTURAL RESILIENCE IN ORGANIC SOLVENTS: TETRAHYDROFURAN (THF), TOLUENE AND CHLOROFORM.

[0084] In these examples, compositions based on an aqueous dispersion of LBN (pH = 7 and 62.6% solids content), extracted from the species Hevea brasilienses, and CNF (3.8% w / w), which was obtained from eucalyptus biomass, were used.

[0085] The foams were obtained by mixing homogenized CNF (previously sonified in ultrasound with a 40% amplitude for 5 min under an ice bath) and LBN dispersion previously dialyzed for 24 h. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were duly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples.

[0086] Structural resilience was evaluated for CNF foams incorporated with LBN20 / CNF80 latex (with 20% LBN and 80% CNF by dry mass), immersed for 48 hours in three different organic solvents, as shown in Figures 4(a) to 4(c). The foams were dried and their mass Petition 870260007470, dated 01 / 26 / 2026, page 33 / 78 20 / 27 measured again, showing a loss of less than 5% of the initial mass, as seen in figure 4(d). This indicates structural resilience and no mass loss after a long period immersed in organic solvents.

[0087] Absorption tests were performed at room temperature. The foams were previously weighed (m0) and then immersed in 10 ml of the organic solvents: THF, Chloroform, and Toluene. The absorption capacity (Qt) can be calculated from the following equation:

[0088] Qt=(mt-m0) / m0

[0089] where m0 and mt are the masses of the foams before and after solvent absorption, at a time of 5 minutes, respectively. Reuse was evaluated by repeating this procedure twenty times for each foam. Between each cycle, the foams were placed in an oven (70 °C) for 1 hour for complete solvent evaporation.

[0090] Table 6 presents the results of the absorption tests for the foam with 80% nanocellulose and 20% latex, for the solvents tetrahydrofuran, toluene and chloroform, at room temperature, for twenty absorption cycles in 10 mL of the respective solvents. Table 6: Reuse tests of latex-incorporated CNF foams (LBN20 / CNF80) in three different solvents: THF, Chloroform, and Toluene. Reuse tests Absorption capacity (Qt) [g-g'1] Cycles ___________________________________________________ Chloroform Toluene 1 31.8±5.1a 12.4±4.4a 2 32.5±5.2a 12.7±3.8a 3 32.5±6.2a 12.9±3.8a Petition 870260007470, dated 01 / 26 / 2026, page 34 / 78 21 / 27 4 32.1±5.7y 12.7±3.7y 5 32.1±5.4y 12.5±3.6y 6 31.3±5.8y 13.0±3.8y 7 31.1±4.9y 12.8±3.9y 8 31.1±4.1y 11.9±2.6y 9 30.3±4.1a 12.1±4.3a 10 30.4±4.8a 12.0±3.6a 11 29.3±3.1a 11.5±3.9a 12 30.2±3.8a 12.4±3.6a 13 30.1±4.9a 12.2±3.5a 14 29.7±3.9y 11.8±3.5y 15 29.9±4.9y 11.5±3.7y 16 29.8±4.8y 11.8±3.8y 17 29.6±4.8y 11.9±3.3y 18 30.6±5.8y 12.2±3.8y 19 29.7±3.8y 11.7±3.7y 20 26.3±5.6y 11.6±4.0y

[0091] A statistical treatment using ANOVA and Tukey's test with 95% significance was performed to verify significant differences between the mean values. Values ​​in the same column that display the same letter (a) are statistically equal (p<0.05).

[0092] Reuse tests indicated significant efficiency and consistency of absorption of organic solvents even after twenty cycles. The resilience test illustrated in Figure 4 also verified that immersion of LBN20 / CNF80 foam () in organic solvents does not structurally affect the foam, and its mass loss was below 5% w / w, indicating that the incorporated latex is not dissolved in the solvent. Petition 870260007470, dated 01 / 26 / 2026, page 35 / 78 22 / 27

[0093] In these examples, compositions based on an aqueous dispersion of LBN (pH= 7 and 62.6% w / w solids content), extracted from the species Hevea brasilienses, and CNF (3.8% w / w), which was obtained from eucalyptus, were used.

[0094] The foams were obtained by mixing homogenized CNF (previously sonified in ultrasound with a 40% amplitude for 5 min under an ice bath) and dispersing LBN. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were properly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples. In this example, foams were prepared with an LBN concentration of 20% w / w and CNF of 80% w / w.

[0095] The reuse test based on oil absorption capacity cycles is exemplified here by absorption tests performed twenty times for two distinct systems: diesel oil and a diesel oil / water mixture; which were carried out at a temperature of 25 °C. For the first test, the previously weighed foams (m0) were immersed in 10 mL of diesel oil. The foams were removed after a 5-minute interval, which proved sufficient to absorb the entire quantity of oil. The adsorption capacity (Qt) was calculated from the following equation:

[0096] Qt=(mt-m0) / m0

[0097] where m0 and mt are the masses of the foams before and after absorption, respectively. Between each absorption cycle, mechanical compressions were performed in order to release (squeezing) the amount of Petition 870260007470, dated 01 / 26 / 2026, page 36 / 78 23 / 27 oil absorbed. This process is shown in Figure 5. For the case of the reuse test of a diesel / water oil system, the demonstration is illustrated in Figure 5. For the first test, the previously weighed foams (m0) were immersed in 10 mL of diesel oil. The foams were removed after a 5-minute interval, which proved sufficient to absorb the entire amount of oil. The adsorption capacity (Qt) was calculated from the following equation:

[0098] Qt=(mt-m0) / m0

[0099] where m0 and mt are the masses of the foams before and after absorption, respectively. Between cycles, i.e., after weighing, the same squeezing processes were performed to release the amount of oil absorbed.

[0100] Table 7 presents the results of foam reuse tests with 20% LBN and 80% CNF, for two distinct systems: diesel oil and a diesel oil / water mixture.

[0101] The unique reuse and structural recovery property of cellulose and natural rubber latex foams (LBN20 / CNF80) was also verified for diesel oil. Despite the decrease in absorption after the first cycle, the absorbed oil values ​​remained constant until the twentieth cycle. The oleophilic affinity and reuse capacity were verified for LBN20 / CNF80 foams immersed in a diesel oil / water mixture. It was found that its hydrophobic character allowed the sequestration of all the oil mass added to the surface of the mixture, effectively separating the oil from the water, and the number of cycles of this separation was around twenty, indicating another interesting characteristic for materials: their reuse without loss of performance. Table 7: Reuse tests of latex-incorporated CNF foams (LBN20 / CNF80) in diesel oil and in diesel / water mixture. Petition 870260007470, dated 01 / 26 / 2026, page 37 / 78 24 / 27 Reuse tests Cycles Absorption capacity (Qt) [g^g-1] Chloroform Toluene 1 31.8±5.1a 12.4±4.4a 2 32.5±5.2a 12.7±3.8a 3 32.5±6.2a 12.9±3.8a 4 32.1±5.7a 12.7±3.7a 5 10 30.4±4.8a 12.0±3.6a 11 29.3±3.1a 11.5±3.9a 12 30.2±3.8a 12.4±3.6a 13 30.1±4.9a 12.2±3.5a 14 29.7±3.9a 11.8±3.5a 15 29.9±4.9y 11.5±3.7y 16 29.8±4.8y 11.8±3.8y 17 29.6±4.8y 11.9±3.3y 18 30.6±5.8y 12.2±3.8y 19 29.7±3.8y 11.7±3.7a 20 26.3±5.6a 11.6±4.0a

[0102] A statistical treatment using ANOVA and Tukey's test with 95% significance was performed to verify significant differences between the mean values. Values ​​in the same column that display the same letter are statistically equal (p<0.05). Petition 870260007470, dated 01 / 26 / 2026, page 38 / 78 25 / 27 EXAMPLE 7: PREPARATION OF CNF FOAMS INCORPORATED WITH LATEX (LBN20 / CNF80) FOR FILTRATION OF DIESEL OIL MIXTURE WITH WATER.

[0103] In these examples, compositions based on an aqueous dispersion of LBN (pH= 7 and 62.6% w / w solids content), extracted from the species Hevea brasilienses, and CNF (3.8% w / w), which was obtained from eucalyptus, were used.

[0104] The foams were obtained by mixing homogenized CNF (previously sonified in ultrasound with an amplitude of 40% for 5 min under an ice bath) and dispersing LBN. The final dispersion (2% w / w solid) was subjected to magnetic stirring for 30 min at a temperature of 25 °C. This amount of solids resulted in a viscosity suitable for filling rectangular and cylindrical polyethylene molds. The filled molds were duly placed in a freezer for 24 hours at -10 °C, and subsequently subjected to a lyophilization process for 24 hours for complete sublimation of the ice contained in the samples. In this example, foams were prepared with an LBN concentration of 20% w / w and CNF of 80% w / w.

[0105] In summary, the filtration test was performed as follows: a 1:1 w / w mixture of diesel / water was previously stirred to obtain an emulsion. During stirring, a 20% w / w LBN foam and an 80% w / w CNF foam with a previously measured mass (m0) was placed in a funnel, so that the preferential passage of the liquid would be through the foam and its porous structure. The diesel / water mixture was poured into the funnel. The separation process consisted of decantation (due to the difference in densities, water being denser than diesel) and subsequent filtration with the foam to absorb any possible droplets and micro-droplets of oil remaining after decantation. In Petition 870260007470, dated 01 / 26 / 2026, page 39 / 78 During the first 26 / 27 minutes, the mass of water separated was measured. After that, other water mass values ​​were acquired every 30 or 60 minutes during 2 hours of testing. With this data, a separation efficiency table was constructed over time. From this, it was shown that the separation efficiency after 120 minutes was approximately 87%. Table 8: Amount of water separated in a diesel oil / water emulsion over time. Time (min) Filtered H2O Mass (g) Separation Efficiency (%) 0 0 0 1 0.15 1.71 2 0.68 7.72 3 1.18 13.40 4 1.69 19.20 5 2.2 25.10 6 2.38 27.05 7 2.53 28.75 8 2.7 30.68 9 2.87 32.61 10 3.04 34.55 11 3.19 36.25 12 3.31 37.61 13 3.41 38.75 14 3.56 40.45 15 3.71 42.15 16 3.84 43.63 17 3.98 45.22 Petition 870260007470, dated 01 / 26 / 2026, page 40 / 78 27 / 27 18 4.1 46.59 19 4.23 48.07 20 4.42 50.23 30 5.97 67.84 40 7.46 84.77 50 7.57 86.03 60 7.61 86.48 90 7.7 87.51 120 7.91 89.88

[0106] The filtration test demonstrated another application of cellulose and natural rubber latex foams (LBN20 / CNF80): hydrophobic filter membranes. The decantation-driven separation process was improved with the addition of the foam, which prevented the passage of any oil. The separation efficiency is also noteworthy, considering that around 90% of the water in the mixture was recovered. Petition 870260007470, dated 01 / 26 / 2026, page 41 / 78

Claims

1 / 2 CLAIMS 1. Hydrophobic porous foam, characterized by comprising: nanofibrillated cellulose (CNF); and natural rubber latex (LBN), wherein: the concentration of said cellulose is between 20 and 80% by dry mass; and the concentration of said natural rubber latex is between 20 and 80% by dry mass.

2. Foam, according to claim 1, characterized by comprising cellulose in micrometric dimensions.

3. Foam, according to claim 1, characterized by comprising cellulose in nanometric dimensions.

4. Foam, according to any one of claims 1 to 3, characterized by comprising porosity greater than 70% of its volume.

5. Foam, according to any one of claims 1 to 4, characterized by comprising porosity selected from the group comprising isotropically oriented porosity, randomly distributed porosity, cellular porosity, honeycomb porosity, or combinations thereof.

6. Foam, according to any one of claims 1 to 5, characterized by exhibiting structural resilience in an aqueous medium.

7. Foam production process of claims 1 to 6, characterized by comprising adding homogenized fibrillar cellulose to a dispersion of natural rubber latex; stirring to homogenize the mixture; filling a mold with the mixture; cooling and freezing the mixture in the filled mold; and freeze-drying the mixture. Petition 870260077168, dated 03 / 08 / 2026, page 11 / 14 2 / 2 8. Process, according to claim 7, characterized by comprising a mold with at least one of its walls having thermal conductivity different from the others.

9. Use of foam as described in claims 1 to 6, characterized in that it is for separating mixtures containing at least one hydrophobic component.

10. Use of foam, according to claim 9, characterized in that the hydrophobic component of the mixture is selected from the group comprising aromatic compounds, organic solvents, silicones, vegetable oils, synthetic oils and mixtures thereof.

11. Use of foam, according to any of claims 9 to 10, characterized by being for environmental decontamination and remediation. Petition 870260077168, dated 03 / 08 / 2026, p. 12 / 14

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