Polymeric composite, process for preparing a polymeric composite, and use of the polymeric composite

Abstract

The present invention pertains to the fields of materials engineering and nanotechnology. More specifically, the invention discloses a polymeric composite comprising the incorporation of niobium species and a process for preparing same. The composite of the invention exhibits outstanding properties, such as, for example, enhanced mechanical and thermal properties, as well as, for example, antioxidant activity, ultraviolet (UV) radiation-absorbing capacity, and ultraviolet (UV) radiation-protective functionality. In addition to the specific composition, the process for preparing the composite also significantly influences the properties of the prepared composite.

Description

Polymer Composite, Process for Preparing a Polymer Composite and Use of Polymer Composite Descriptive Report of Invention Patent Field of Invention

[0001] The present invention is situated in the field of materials engineering and nanotechnology. More specifically, the invention discloses a polymer composite comprising the incorporation of niobium species and a process for its preparation. The composite of the invention exhibits remarkable properties, such as enhanced mechanical and thermal properties, as well as, for example, antioxidant, ultraviolet (UV) radiation absorbing and UV radiation protection effects. Background of the Invention

[0002] Nanotechnology is a rapidly expanding science that has generated much expectation due to the unusual properties of nanoparticles made from various materials. However, its large-scale use still faces multiple limitations, beginning with the unavailability of nanoparticle preparations with high concentration, purity, and precise particle size distribution.

[0003] Particularly in the field of polymers, the use of nanoparticles is not typically the subject of studies or technologies, partly due to the limitations indicated above and partly due to their molecular structure, which is completely different from that of metals.

[0004] These and other reasons contribute to the fact that no polymer doped with nanoparticles with a particle size distribution of choice and entirely in the nanometer range is yet available on an industrial scale. The present invention solves these problems.

[0005] In the search for the state of the art in scientific and patent literature, the following documents related to the topic were found:

[0006] Patent application WO2022036427, with inventors in common with the The present invention discloses a niobium nanoparticle preparation obtained by a top-down approach. Said preparation also possesses the following technical characteristics: particles entirely within the nanometer granulometric range; high purity; industrial scale production, with a cost suitable for economic viability. Said nanometric powder preparation has very high purity, since the process does not add impurities or lead to the formation of reaction products, as is the case with state-of-the-art bottom-up (or synthesis) processes. On the other hand, WO2022036427 does not mention a polymeric composite as disclosed in the present patent application.

[0007] Patent document US20070116976A1 refers to how to offer a composition that combines improved impact resistance with effective corona resistance. As a solution, US20070116976A1 discloses a nanocomposite comprising a polymeric composition and nanoparticles with an average major dimension less than or equal to about 500 nanometers. However, US20070116976A1 does not mention a polymeric composite as disclosed in the present patent application.

[0008] Patent document CN110229412 refers to solving the compatibility problems of nanomaterials with polymers so that mechanical properties such as hardness are not affected. Thus, CN1 10229412 discloses a nanocomposite with increased strength and hardness obtained by "melt blending" of a premix. The premix comprises: a) a nanomaterial which can be metal oxides, transition metals and rare earths, b) a liquid medium which can be water and other solvents, c) polypropylene and, preferably, to increase the amount of liquid medium to which the nanomaterial is bound, an auxiliary agent can also be added. However, it does not mention a polymeric composite as disclosed in the present patent application.

[0009] The article by Hajduk et al. (2021) (Thermal and optical properties of PMMA firns reinforced with Nb2Ü5 nanoparticles) reveals the effect of nanoparticles of Niobium pentoxide alters the thermal and physical properties of polymethyl methacrylate (PMMA). On the other hand, Hajduk et al. (2021) does not mention a polymeric composite as disclosed in the present patent application.

[0010] Patent document US2009226711A1 discloses a biaxially oriented nanocomposite film formed by a process comprising mixing a nanofiller and a polymeric composition to form a nanocomposite; extruding the nanocomposite as a melt to form a molten tube; expanding the tube biaxially by means of mechanical force and air pressure to form a bubble; and collapsing the bubble to form at least one sheet of a biaxially oriented nanocomposite film, wherein the biaxially oriented nanocomposite film has a tensile strength (dielectric strength) of at least 300 V / micrometer. Conversely, US2009226711A1 does not mention a polymeric composite as disclosed in the present patent application.

[0011] Based on the literature reviewed, no documents were found that anticipated or suggested the teachings of the present invention. Summary of the Invention

[0012] The present invention enables modulation of the physical and chemical properties of a polymeric material, such as, but not limited to, polypropylene, comprising improvements in tensile strength, elongation, melt flow index, melting temperature, and enthalpy of fusion. In addition to the specific composition, the composite preparation process also significantly influences the properties of the prepared composite.

[0013] Furthermore, the composite of the present invention exhibits other notable properties such as, for example, antioxidant effect, ultraviolet (UV) radiation absorber, and protection against ultraviolet (UV) radiation.

[0014] In a first object, the present invention defines a polymer composite comprising a thermoplastic polymer matrix and a mass quantity of Niobium species, wherein said quantity in The mass of niobium species comprises an amortization level of at least 19%.

[0015] In a second object, the present invention defines a process for preparing a polymer composite comprising at least one step of dispersing a bulk quantity of Niobium species in a molten thermoplastic polymer matrix.

[0016] In a third object, the present invention defines the use of said polymeric composite as an antioxidant, as an absorber of ultraviolet (UV) radiation, or as a protector against ultraviolet (UV) radiation, or combinations thereof.

[0017] These and other objects of the invention will be immediately appreciated by those skilled in the art and will be described in detail below. Brief Description of the Figures

[0018] The following figures are presented:

[0019] Figure 1 presents a comparative analysis of Differential Scanning Calorimetry (DSC) curves for samples of the polymer composite produced in the present invention.

[0020] Figure 2 presents a comparative analysis of the melting temperatures for samples of the polymer composite produced in the present invention.

[0021] Figure 3 presents a comparative analysis of the enthalpies of fusion for samples of the polymer composite produced in the present invention.

[0022] Figure 4 presents a comparative analysis of melt flow indices (MFI) for samples of the polymer composite produced in the present invention.

[0023] Figure 5 presents a comparative analysis of tensile strength at rupture for samples of the polymer composite produced in the present invention.

[0024] Figure 6 presents a comparative analysis of the elongation for samples of the polymer composite produced in the present invention.

[0025] Figure 7 shows the results of the tensile strength tests of the samples tested.

[0026] Figure 8 shows the results of the elongation at break tests of the tested samples.

[0027] Figure 9 shows the melt flow index results for the samples tested.

[0028] Figure 10 shows the melting point results for the tested samples.

[0029] Figure 11 shows the results of the enthalpy of fusion of the tested samples. Detailed Description of the Invention

[0030] The present invention enables modulation of the physical and chemical properties of a polymeric material, such as, but not limited to, polypropylene, comprising improvements in tensile strength, elongation, melt flow index, melting temperature, and enthalpy of fusion. In addition to the specific composition, the composite preparation process also significantly influences the properties of the prepared composite.

[0031] Furthermore, the composite of the present invention exhibits other notable properties such as, for example, antioxidant effect, ultraviolet (UV) radiation absorber, and protection against ultraviolet (UV) radiation.

[0032] In the context of the present invention, the expression "Niobium species" encompasses various chemical entities containing Niobium, including metallic Niobium, oxides, hydrates, hydrides, carbides, or nitrides of Niobium, iron Niobium or Niobium alloyed with other metals or transition metals, or combinations thereof. It also includes Niobium pentoxide (Nb2O5), NbC, NbO, Niobium oxalate, niobic acid, and FeNb. It may be a mass quantity of microparticles, submicroparticles, nanoparticles, or combinations thereof.

[0033] In a first object, the present invention defines a polymer composite comprising a thermoplastic polymer matrix and a mass quantity of Niobium species, wherein said quantity in The mass of niobium species comprises an amortization level of at least 19%.

[0034] In the context of the present invention, the expression "degree of amortization" should be understood as the extent to which a material exhibits a predominantly disordered phase, in contrast to predominantly monocrystalline and polycrystalline phases. "Amortization" can be understood as a process of loss of long-range order of atoms, molecules or ions in the crystalline structure of a given material, and may also exhibit short-range order.

[0035] In one embodiment of the composite, the said mass quantity of Niobium species preferably comprises a depreciation rate of at least 20%, more preferably at least 25%, more preferably at least 30%, more preferably at least 35%, more preferably at least 39%, more preferably at least 40%, more preferably at least 45%, more preferably at least 50%, more preferably a depreciation rate of at least 55%, more preferably at least 60%, more preferably at least 65%, and even more preferably a depreciation rate of at least 70%. In one embodiment, the depreciation rate is at least 71%, more preferably at least 72%, more preferably at least 73%. In a non-limiting embodiment, the depreciation rate is 74%.

[0036] In one embodiment of the composite, the aforementioned mass quantity of Niobium species comprises a depreciation rate of at least 39%, preferably a depreciation rate of at least 55%, and even more preferably a depreciation rate of at least 70%.

[0037] In one embodiment of the composite, the aforementioned niobium species are composed of NbO, NbC, Nb2U5, niobic acid, niobium oxalate, FeNb, or combinations thereof. In one embodiment of the composite, the aforementioned niobium species are composed of Nb2U5.

[0038] In one embodiment of the composite, the aforementioned mass quantity The mass quantity of niobium species ranges from 1 to 500 ppm relative to the polymer composite. In one embodiment, the mass quantity of niobium species is 1 ppm relative to the polymer composite. In one embodiment, the mass quantity of niobium species is 50 ppm relative to the polymer composite. In one embodiment, the mass quantity of niobium species is 100 ppm relative to the polymer composite. In one embodiment, the mass quantity of niobium species is 250 ppm relative to the polymer composite. In one embodiment, the mass quantity of niobium species is 500 ppm relative to the polymer composite.

[0039] In one embodiment, the composite is additionally graphitized with acrylic acid, methacrylic acid, glycidyl methacrylate, maleic anhydride, silanes, peroxides, or combinations thereof.

[0040] In one embodiment, said thermoplastic polymer is a matrix of polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyamide and its derivatives (PA), polyacetal (POM), thermoplastic polyesters and their derivatives (PET and / or PBT), styrene-butadiene-acrylonitrile copolymer (ABS) and blends thereof. In one embodiment, said thermoplastic polymer is a polypropylene (PP) matrix.

[0041] In one embodiment, the composite further comprises a dispersing agent. In one embodiment, said dispersing agent is Triton-Xl OO.

[0042] In a second object, the present invention defines a process for preparing a polymer composite comprising at least one step of dispersing a bulk quantity of Niobium species in a molten thermoplastic polymer matrix.

[0043] In one embodiment, the dispersion step is carried out in a processing step in the molten state or in solution, or by special thermoplastic transformation processes; other thermoplastic transformation processes.

[0044] In one embodiment, the processing is carried out in an extruder.

[0045] In one embodiment, the process further comprises the administration of a bulk quantity of a graphitizing agent, a dispersing agent, or a plasticizer.

[0046] In one embodiment, the graphitizing agent is acrylic acid, methacrylic acid, glycidyl methacrylate, maleic anhydride, silanes, peroxides, or combinations thereof. In one embodiment, the dispersing agent is Triton-X100. In one embodiment, the plasticizer is selected from mineral oils, paraffinic oils, naphthenic oils, their derivatives, and / or blends thereof.

[0047] In one embodiment, the process further comprises the administration of a bulk quantity of a graphitizing agent, wherein said graphitizing agent is acrylic acid, methacrylic acid, glycidyl methacrylate, maleic anhydride, silanes, peroxides, or combinations thereof.

[0048] In one embodiment of the process, the heating in the extruder is in the range of 120 to 230 °C. In another embodiment of the process, the heating in the extruder is in the range of 120 to 200 °C.

[0049] In one embodiment of the process, the extruder is a co-rotating twin-screw extruder.

[0050] In a third object, the present invention defines the use of said polymeric composite as an antioxidant, as an absorber of ultraviolet (UV) radiation, or as a protector against ultraviolet (UV) radiation, or combinations thereof.

[0051] Examples

[0052] The examples shown here are intended only to illustrate some of the various ways of carrying out the invention, without limiting its scope.

[0053] Example 1 - Process for obtaining niobium pentoxide nanoparticles

[0054] A Labstar LS01 ball mill (Netzsch) was fed with micrometric particles of niobium pentoxide. (Referred to...) The process involved high-energy wet milling. The particle suspension was 17.7 wt%, consisting of approximately 3500 g of milli-Q water + 10 M NaOH and 750 g of the solid sample, which was prepared and stabilized in the mill's mixing tank at pH 9 and titrated with 10 M NaOH. The milling spheres used were yttria-stabilized zirconia, 400 µm in diameter. The milling chamber was filled to 80% vol., and the suspension temperature was below 40 °C. The mill rotation speed was set to 3000 rpm, and milling was conducted for 8 hours. To stabilize the suspension at pH 9, 10 M NaOH was added during milling, with samplings taken periodically and particle sizes measured.

[0055] In this example, several embodiments of niobium pentoxide nanoparticle preparations were obtained, with a purity greater than 99%. Commercial niobium pentoxide, with the particle size distribution described in Table 1, was pre-comminuted in a high-energy mill containing yttria-stabilized zirconia spheres with a diameter of 400 µm, in liquid medium and the pH adjusted to 6.6. The mill rotation speed was 3500 rpm and the particle grinding was conducted at a temperature below 40 °C. Table 4 shows the particle size distribution (PSD) of niobium pentoxide input (commercial product) and output from a pre-comminution step.

[0056] Table 1 - Input DTP (commercial product) and output DTP after pre-comminution.

[0057] The average specific surface area S (m 2 The mass of the particles after the pre-comminution step was 0.32 m / g. 2 / g.

[0058] In one embodiment, the pre-comminuted particles were then fed into a high-energy mill, where conditions similar to those described above were applied, but with 200 µm Zr spheres and milled for different times, until each nanoparticle preparation was obtained. Three different nanoparticle preparations were obtained, each with a defined particle size distribution as described in Table 2.

[0059] Table 2 - Particle size distribution of three different preparations (C, D and E) of niobium pentoxide nanoparticles.

[0060] Further details on the process for obtaining the nanoparticles can be found in patent application BR112023003019 of the inventors of the present application. In the examples of the present application, samples were used that were subjected to 12 hours of grinding.

[0061] Without intending to be bound by theory, it is understood that the samples subjected to 12 hours of grinding, which exhibit a higher degree of amortization (74%), contribute to the surprising effects presented.

[0062] Example 2 - Samples tested in the present invention

[0063] Seven products were produced and tested in the present invention. The characteristics of each product are described in Table 3 below:

[0064] Table 3 - Composition and processing of each sample tested

[0065] Sample (A) corresponds to the PP HS503 HS polypropylene matrix processed in a single-screw extruder. Samples (B) and (C) were produced in a single-screw extruder under a simple dispersion process, in both cases a dispersing agent (Triton-Xl OO) was used, with sample (C) comprising a quantity of Nb2Ü5 nanoparticles of 500 ppm. Samples (D), (E), (D') and (E') were produced by a reactive extrusion graphitization process in the presence of acrylic acid as a graphitization agent. In addition to the matrix and graphitizing agent, samples (E) and (E') comprise a quantity of Nb2Ü5 nanoparticles of 500 ppm, with samples (D) and (E) being produced on a single-screw extruder and samples (D') and (E') being produced on a co-rotating twin-screw extruder.

[0066] A slight yellowing of the samples was observed in the presence of acrylic acid.

[0067] The temperature profile along the tested extruders can be seen below in Table 4. The processing speed of the extruders was 100 RPM.

[0068] Table 4 - Temperature profile of the extruders

[0069] In addition to the 500 ppm quantity for nanoparticles (NPs), quantities of 250 ppm, 100 ppm, and 50 ppm were tested to evaluate the influence of particle concentration on the samples.

[0070] Example 3 - Thermal analysis of samples of the composite produced in the present invention.

[0071] Thermal analysis by Differential Scanning Calorimetry (DSC) was performed on a Netzsch Polyma DSC214 instrument with a thermal routine. (atm N2): • Heating from 25 to 300 °C, at 10 °C / min; • Cooling from 300 to 25 °C, at 20 °C / min.

[0072] The DSC results are shown in Figure 1.

[0073] Figure 2 presents a comparative analysis of the melting temperatures for samples of the polymer composite produced as described above.

[0074] Figure 3 presents a comparative analysis of the enthalpies of fusion for samples of the polymer composite produced as described above.

[0075] Without wishing to be bound by theory, it is understood that the increase in the enthalpy of fusion of the sample (E') produced with the co-rotating twin-screw extruder, compared to the PP of sample (A), may be related to a better mixing of the formulation of nucleation points around the nanoparticle organizing the PP chains, increasing the crystallinity.

[0076] Example 4 - Comparative analysis of the melt flow index

[0077] Melt flow index tests were performed according to ASTM D1238 using a MAQTEST plastometer. The tests were performed in quintuplicate.

[0078] Figure 4 presents a comparative analysis of the melt flow indices for samples of the polymer composite produced in the present invention.

[0079] Changes in the melt flow index were observed depending on the type of processing: • Single screw extruder: 73% increase; • Twin-screw extruder: 21% increase.

[0080] Co-rotating twin-screw extruders generally provide a more intensive and distributive degree of mixing compared to single-screw extrusion.

[0081] This intensive mixing process can lead to a more efficient interaction between the polymer (PP) and acrylic acid, decreasing the melt flow index (MFI).

[0082] Example 5 - Comparative analysis of mechanical properties

[0083] The test specimens for the mechanical tests were produced for each sample by melting the sample, transferring the molten resin to the reservoir of an AX mini injection molding machine, and injecting the test specimens under the following conditions: • Pressure: 8 bar; • Mold temperature: 50 °C; • Cooling: 1 min.

[0084] The mechanical properties of tensile strength at break (in MPa) and elongation at break (%) were evaluated according to ASTM D638 using a MAQTEST dynamometer. The tests were performed in quintuplicate (at least).

[0085] Figure 5 presents a comparative analysis of tensile strength at rupture for samples of the polymer composite produced in the present invention.

[0086] No significant variation was observed in tensile strength compared to sample (A), so it is understood that the nanoparticles did not significantly affect the tensile strength of PP.

[0087] Figure 6 presents a comparative analysis of the elongation for samples of the polymer composite produced in the present invention.

[0088] Regarding elongation, a 50% increase in elongation was observed in sample (E') compared to sample (A), indicating that the nanoparticles significantly increased the elongation capacity of PP, resulting in significant advantages for the material.

[0089] Based on the results discussed above, it was observed that, regarding the constituents, the samples graphitized with acrylic acid containing Nb2Ü5 nanoparticles (NPs) demonstrated an intensification of the elongation property and melt flow index, proving highly desirable properties for the products.

[0090] Regarding processing, it was observed that the type of extrusion can directly influence the properties of the polymer composite. Production The process of manufacturing composites via reactive extrusion using a co-rotating twin screw is considered ideal because it results in a more homogeneous and stable material.

[0091] Example 6 - Samples tested in the present invention with Niobium species

[0092] Niobium species were added to thermoplastic matrices directly through molten processing, by extrusion, injection, extrusion-blow molding, stretch-blow molding processes; in solution; dispersion in masterbatch; special thermoplastic transformation processes; and other thermoplastic transformation processes.

[0093] Samples were prepared using a co-rotating twin-screw extruder with L / D=40, and raw material addition was controlled by gravimetric dosers. Polypropylene samples with niobium species concentrations between 50 ppm and 1000 ppm by mass were prepared. The antioxidant and UV absorber effects of niobium species were verified using only niobium species and with blends containing primary and secondary antioxidants (HALS) for thermoplastics, to evaluate the synergy between the systems. The polypropylene used was PP H301 (obtained from Braskem).

[0094] The temperature profile along the tested extruders can be seen below in Table 5. The processing speed of the extruders was 100 RPM.

[0095] Table 5 - Temperature profile of the extruders

[0096] Commercial antioxidants used for comparison with niobium pentoxide and synergy between the two: Chimassorb 944 and Tinuvin 622 (obtained from BASF). Both are HALS (UV light stabilizer) type antioxidants. Sterically hindered amine compounds) exhibit synergy among themselves, increasing weather protection for polyolefins (PP, PE, EVA and their blends), PVC and its blends, polyamides and their different species and blends, polyurethanes and their blends.

[0097] From the compositions prepared by extrusion, test specimens were injected to evaluate the following mechanical properties: tensile strength (ASTM D638), IZOD impact strength (ASTM D256), and flexural strength (ASTM D790). The mechanical properties were characterized before and after the accelerated aging processes. Test specimens were also prepared by injection molding, in a flat plate geometry.

[0098] The samples were subjected to accelerated aging in a forced-air oven, according to ISO 188:2023, at a temperature of 70°C, for a period of 168 hours. The mechanical properties of these samples were evaluated after these aging cycles.

[0099] The flat plates were subjected to aging in CUV, according to ASTM G154-23 - cycles 1 and 2. After aging, the color variation of the samples was calculated by spectrophotometry, according to the procedures of ASTM D2244-23.

[0100] Based on the results discussed above, it was observed that, regarding the constituents, the samples graphitized with acrylic acid containing Nb2Ü5 nanoparticles (NPs) demonstrated an intensification of the elongation property and melt flow index, proving highly desirable properties for the products.

[0101] Changes in the melt flow index were observed depending on the type of processing: • Single screw extruder: 73% increase; • Twin-screw extruder: 21% increase.

[0102] Co-rotating twin-screw extruders generally provide a more intensive and distributive degree of mixing compared to single-screw extrusion.

[0103] This intensive mixing process can lead to a more efficient interaction between the polymer (PP) and acrylic acid, decreasing the melt flow index (MFI).

[0104] Regarding processing, it was observed that the type of extrusion can directly influence the properties of the polymer composite. The production of composites via co-rotating twin-screw reactive extrusion is considered ideal because it results in a more homogeneous and stable material.

[0105] Niobium species were added to thermoplastic matrices directly by molten processing, using extrusion processes.

[0106] During the extrusion of composites, other fillers such as talc, calcium carbonate, mica, kaolin, titanium dioxide, or combinations thereof, with different particle sizes, can be added in order to mitigate shrinkage problems when these composites are transformed by the injection molding process.

[0107] In the formulation of the thermoplastic composite, plasticizers such as mineral oils, paraffinic oils, naphthenic oils, their derivatives and / or blends thereof, and other plasticizers of a nonpolar and polar nature may also be added.

[0108] The thermoplastic composite formulation may also contain primary and secondary antioxidants, UV inhibitors, and UV absorbers, depending on the final application. Niobium species may be added to the formulation as a UV absorber and crystallization nucleating agent.

[0109] From the compositions prepared by extrusion, test specimens were injected to evaluate the following mechanical properties: tensile strength (ASTM D638), IZOD impact strength (ASTM D256), and flexural strength (ASTM D790). The pellets of the prepared composites were evaluated theologically, through melt flow index, according to ASTM D1238 standard.

[0110] Example 7 - Comparison of graphitized samples

[0111] The composition of the samples tested can be seen in Table 6 below.

[0112] Table 6

[0113] Table 7 - Temperature profile of the co-rotating twin screw extruder

[0114] The processing speed was 100 rpm.

[0115] The samples described in Table 6 were tested for mechanical properties (tensile strength, elongation at break, melt flow index) and thermal properties (melting temperature and enthalpy of fusion).

[0116] Figure 7 shows the results of the tensile strength tests of the samples tested.

[0117] Figure 8 shows the results of the elongation at break tests of the tested samples.

[0118] Figure 9 shows the melt flow index results for the samples tested.

[0119] Figure 10 shows the melting point results for the tested samples.

[0120] Figure 11 shows the results of the enthalpy of fusion of the tested samples.

[0121] Regarding thermal properties, the reference sample, which corresponds to polypropylene processed only in a twin-screw extruder, shows a slightly higher melting temperature among the samples, which is expected for unmodified PP.

[0122] The decrease in melting point observed in the samples is due to the graphitization process of the PP chains, whose functionalizing agents can disrupt the crystallinity and molecular order of the PP, leading to melting at slightly lower temperatures.

[0123] The insertion of 50 ppm of Nb2Ü5 nanoparticles resulted in a decrease of 1.24 °C in the melting point of graphitized PP with glycidyl methacrylate (GM) and, conversely, in an increase of 2.17 °C in graphitization with acrylic acid (AA).

[0124] The reference sample, which corresponds to polypropylene processed only in a twin-screw extruder, shows a slightly higher melting temperature among the samples, which is expected for unmodified PP, indicating greater crystallinity and regularity of the polymer chains, which therefore require more energy to melt.

[0125] The insertion of Nb2Ü5 nanoparticles caused a decrease in the enthalpy of fusion in all cases: the sample graphitized with methacrylic acid (AMA) and 50 ppm of Nb2Ü5, the sample graphitized with glycidyl methacrylate (GM) and 50 ppm of Nb2Ü5, and the sample graphitized with acrylic acid (AA) and 50 ppm of Nb2Ü5. The decrease was most pronounced in the sample graphitized with methacrylic acid (AMA) and 50 ppm of Nb2Ü5. The nanoparticles likely act as points of perturbation. in the polymer network that hinders crystallization.

[0126] Regarding the melt flow index, considering the processed PP sample as a reference for comparative analysis, we verified the influence of both the type of functionalizing agent used in the graphitization and the insertion of Nb2Ü5 nanoparticles.

[0127] Regarding mechanical properties, the reference sample exhibits lower elongation at break, indicating lower deformability before failure.

[0128] Regarding the effect of graphitization, the graphitized samples showed an increase in elongation at break compared to the reference sample.

[0129] Samples graphitized with glycidyl methacrylate (GM) and 50 ppm Nb2U5 and graphitized with acrylic acid (AA) and 50 ppm Nb2U5 show a greater elongation at break than their counterparts without nanoparticles, indicating that the addition of Nb2U5 improves the ductility of PP.

[0130] The sample graphitized with methacrylic acid (AMA) and 50 ppm Nb2Ü5 shows that the insertion of NPs reduces elongation compared to the counterpart graphitized only with AMA. This sample presented a lower enthalpy of fusion value and, therefore, lower crystallinity, which can result in a more brittle polymer matrix or one with less plastic deformation capacity, resulting in lower elongation at break.

[0131] The PP sample graphitized with glycidyl methacrylate (GM) and 50 ppm Nb2U5 showed the greatest elongation at break, indicating that the combination of functionalization with glycidyl methacrylate and the addition of Nb2U5 nanoparticles results in the greatest increase in PP flexibility.

[0132] This substantial increase in deformation capacity before rupture may be due to the synergy between the malleability provided by GM and the distribution of nanoparticles within the PP matrix, which possibly prevents or hinders crack propagation, contributing to energy absorption during deformation.

[0133] Example 8 - General comparison between the graphitized samples containing niobium pentoxide nanoparticles

[0134] In light of the results found:

[0135] 1) Graphitized PP with acrylic acid + 100 ppm Nb2U5 stood out in terms of ductility, due to the significant increase in elongation at break (403%) compared to PP. This improvement suggests that the addition of Nb2U5 in moderate concentrations can result in materials with substantially greater deformation capacity without sacrificing mechanical strength, evidenced by a tensile strength of 33 MPa (PP = 34.2 MPa). This combination may be particularly advantageous for applications where flexibility and structural integrity are critical.

[0136] 2) PP graphitized with methacrylic acid + 250 ppm Nb2U5 presents itself as a balanced composition, providing both enhanced strength and flexibility. The tensile strength remains at a satisfactory level of 33 MPa, accompanied by an improved elongation at break of 162% compared to PP. These data indicate that such a composition could be favorable for industrial applications that demand a material with optimized mechanical properties.

[0137] 3) PP graphitized with glycidyl methacrylate + 250 ppm Nb2U5 resulted in samples with a significant increase in ductility, particularly at the 250 ppm concentration, where the elongation at break reached an increase of 352% compared to PP. This result points to a considerable improvement in the material's ability to absorb energy before failure, a highly desirable attribute for components subjected to dynamic loads or impacts.

[0138] 4) Regarding PP graphitized with glycidyl methacrylate + 50 ppm Nb2O5, when compared to the reference PP, all graphitized samples showed an increase in elongation at break. The sample graphitized with glycidyl methacrylate containing 50 ppm Nb2O5 showed the highest tensile strength value (37.9 MPa) in the comparative study, accompanied by a considerable elongation at break (74.2%) - Reference: PP 34.2 MPa / 28.5%. This combination suggests promising potential for applications requiring materials that can withstand stress without undergoing premature permanent deformation.

[0139] 5) Regarding niobium pentoxide nanoparticles, based on the experiments performed, it is understood that the ideal concentration is around 100 ppm. The comparative analysis of the set of results presented indicates that 100 ppm of Nb2Ü5 can be considered an ideal concentration to maximize ductility, reflected in elongation at break, while simultaneously maintaining good tensile strength. This concentration appears to be an inflection point where the benefits of the nanoparticles are maximized without apparent disadvantages in strength.

[0140] 6) Regarding PP graphitized with methacrylic acid + 100 / 250 / 500 ppm Nb2U5, the MFI provides an indication of the PP's processability. Methacrylic acid with 100, 250, or 500 ppm Nb2U5 showed an adequate MFI (2.2 g / 1 μm), which is slightly higher than that of PP (2.0 g / 1 μm), suggesting that there is no significant compromise in processability resulting from the graphitization process and / or the insertion of nanoparticles.

[0141] 7) The melting temperature remains relatively stable across the different samples, with marginal variations that do not indicate drastic changes in the thermal stability of PP resulting from the graphitization process and / or the insertion of nanoparticles.

[0142] In conclusion, the desired properties of the material should guide the choice of graphitizing agent and the concentration of Nb2Ü5.

[0143] There is evidence suggesting that acrylic acid is the most effective graphitizing agent in terms of improving the ductility of PP, especially at a concentration of 100 ppm of Nb2U5. This formulation provides a favorable balance between ductility and tensile strength.

[0144] High concentrations of Nb2Ü5 (250 and 500 ppm) show that the effect on mechanical properties is less beneficial than at lower concentrations, indicating that there is a limit beyond which the addition of NPs may not be effective. Further improvements may even be detrimental.

[0145] Those skilled in the art will appreciate the knowledge presented here and will be able to reproduce the invention in the forms presented and in other variants and alternatives covered by the scope of the following claims.

Claims

Claims 1. Polymer composite characterized by comprising a thermoplastic polymer matrix and a mass quantity of niobium species, wherein said mass quantity of niobium species comprises an amortization degree of at least 19%.

2. Polymer composite according to claim 1 characterized by the said mass quantity of Niobium species comprising a degree of amortization of at least 39%, preferably a degree of amortization of at least 59% and even more preferably a degree of amortization of at least 74%.

3. Polymer composite according to claim 1 characterized in that said niobium species are composed of NbO, NbC, Nb2O5, niobic acid, niobium oxalate, FeNb or combinations thereof.

4. Polymer composite according to claim 3 characterized in that said niobium species are composed of Nb2Ü5.

5. Polymer composite according to claim 1 characterized by being additionally graphitized with acrylic acid, methacrylic acid, glycidyl methacrylate, maleic anhydride, silanes, peroxides or combinations thereof.

6. Polymer composite according to claim 1 characterized in that the thermoplastic polymer is polypropylene.

7. Polymer composite according to claim 1 characterized in that the amount of niobium species by mass is from 1 to 500 ppm relative to the polymer composite.

8. A process for preparing a polymer composite characterized by comprising at least one step of dispersing a bulk quantity of niobium species in a molten thermoplastic polymer matrix.

9. Process for preparing a polymer composite according to claim 8, characterized in that the dispersion step is carried out in a molten state or solution processing step.

10. Process for preparing a polymer composite according to Claim 9 is characterized by the processing being carried out in an extruder.

11. Process for preparing a polymer composite according to claim 8, characterized by further comprising the administration by mass of a graphitizing agent, a dispersing agent or a plasticizer.

12. Process for preparing a polymeric composite according to claim 11, characterized by comprising the administration by mass of a graphitizing agent, wherein said graphitizing agent is acrylic acid, methacrylic acid, glycidyl methacrylate, maleic anhydride, silanes, peroxides or combinations thereof, wherein the dispersing agent is Triton-XlOO and wherein the plasticizer is mineral oils, paraffinic oils, naphthenic oils, their derivatives and / or blends thereof.

13. Process for preparing a polymer composite according to claim 8, characterized in that the thermoplastic polymer is polypropylene.

14. Process for preparing a polymer composite according to claim 10, characterized by the heating in the extruder being in a range of 120 to 230 °C.

15. Process for preparing a polymer composite according to claim 10, characterized in that the extruder is a co-rotating twin-screw extruder.

16. Use of the polymeric composite as defined in claim 1, characterized by being an antioxidant, an absorber of ultraviolet (UV) radiation, or a protector against ultraviolet (UV) radiation, or combinations thereof.

Images