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    • 专利摘要:
    Thermoplastic materials reinforced with nanocomposites, their preparation procedure, materials thus obtained and their use. The present invention relates to new thermoplastic materials reinforced with nanocomposites, to their preparation process, as well as to the use of these materials, especially for obtaining three-dimensional objects for biomedical applications and for aerospace and/or aeronautical purposes, for example, the thermoplastic materials reinforced with nanocomposites consisting of polysulfones reinforced with nanocomposites where the reinforcing nanocomposites are nanoparticles of titanium oxide (TiO2) and haloisite nanotubes (Al2 Si2 O5 (OH)4, hydroxylated aluminosilicate) surface modified. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2662933A1
    申请号:ES201700671
    申请日:2017-07-20
    公开日:2018-04-10
    发明作者:Karla Daniela MORA BARRIOS
    申请人:Centro Tecnologico De Nanomateriales Avanzados S L；Centro Tecnologico De Nanomateriales Avanzados SL；
    IPC主号:
    专利说明:

    Thermoplastic materials reinforced with nanocomposites, their preparation procedure, materials thus obtained and their use
    The present invention relates to new thermoplastic materials reinforced with nanocomposites, to its preparation process, as well as to the use of these materials, especially for obtaining three-dimensional objects for biomedical applications and for aerospace and aeronautical purposes, for example.
    More specifically, in a first aspect, the invention relates to thermoplastic materials reinforced with nanocomposites, in particular reinforced polysulfones with nanocomposites, the reinforcing nanocomposites consisting of titanium oxide nanoparticles (Ti0 2) and haloisite nanotubes (AI2Si20 5 (OH) ., hydroxylated aluminosilicate) superficially modified.
    In a second aspect, the invention relates to the process of obtaining said thermoplastic materials reinforced with nanocomposites, in particular polysulfones reinforced with nanocomposites, the reinforcing nanocomposites consisting of titanium oxide nanoparticles (Ti02) and haloisite nanotubes (AhSi20 5 (OH) 4, hydroxylated aluminosilicate) superficially modified. The process of the invention provides an easily scalable preparation route at the industrial level, allowing said process to obtain polymeric materials reinforced with homogeneously distributed nanocomposites and with a controlled particle size, so that the materials obtained are very suitable for the manufacture of intended objects. to the aforementioned applications, for example.
    Finally, in a third aspect, the invention relates to the use of these thermoplastic materials reinforced with nanocomposites, in particular polysulfones reinforced with nanocomposites, the reinforcing nanocomposites consisting of titanium oxide nanoparticles (Ti02) and haloisite nanotubes (AI2Si20 5 ( OH) 4. Hydroxylated aluminosilicate)
    superficially modified, for example, in biomedical, aerospace and / or aeronautical applications.
    Currently, thermoplastic polymers are used in a wide variety of engineering applications due to their unique characteristics, such as their easy processability, optimal specific mechanical properties, excellent resistance to chemical attack and thermostability, since they have unique characteristics such as high adhesive strength and mechanical, stiffness, hardness, elc. However, in many cases these properties can be improved by the incorporation of inorganic additives, such as silica, alumina and glass particles. Thus, in many cases this incorporation allows a significant increase in fracture resistance without sacrificing other of its basic properties. However, more studies are still needed today that allow us to glimpse the causes for which the incorporation of particles modifies certain properties of the pure polymer, for example, the dispersion of particles, the degree of adhesion of the particles to the polymer, the properties of these, morphological and / or structural changes of the polymer due to the presence of particles, etc.
    Most thermoplastic materials, such as polyethylene (PE), polypropylene (PP), polybutylene (PB), polystyrene (PS), polymethylmethacrylate (PMMA), polyvinylchloride (PVC), ethylene polyterephthalate (PET), Teflon (or polytetraOuoroethylene (PTFE), polyamides, etc.) are made up of very long main chains of carbon atoms linked together in a cava lens. Sometimes, nitrogen, oxygen or sulfur atoms are also covalently linked to the main molecular chain. In thermoplastics, the long molecular chains are linked together by intermolecular bonds.
    Depending on the degree of intermolecular forces that occur between the polymeric chains, they can adopt two different types of structures, amorphous structures or crystalline structures, being possible the existence of both structures in the same thermoplastic material.
    In the yellow structure, the polymer chains acquire a structure similar to that of a ball of messy threads, said amorphous structure is directly responsible for the elastic properties of thermoplastic materials.
    In the crystalline structure, the polymer chains acquire an ordered and compact structure, mainly lamellar and micellar structures can be distinguished. Said crystalline structure is directly responsible for the mechanical properties of resistance to stresses or loads, as well as the temperature resistance of thermoplastic materials.
    If the lermoplastic material has a high concentration of polymers with amorphous structures, said material will have a poor resistance to loads but an excellent elasticity, if instead the thermoplastic material has a high concentration of polymers with a crystalline structure, the material it will present some resistance properties against loads and efforts, surpassing even thermosetting materials, on the other hand it will present poor elastic properties giving it its characteristic fragility.
    Given the importance of the structure of the thermoplastic material, in the present invention the polysulfones have interesting advantages compared to the conventional thermostable polymers mentioned above. In addition, due to its low density, it is an attractive candidate in structural applications. In this respect, the poJisulfones are formed by chains with repetitive units of phenyl rings joined by a sultana group, which make macromolecular entanglement difficult and favor the existence of strong molecular attractions that provide great hardness and rigidity to this material. On the other hand, the oxygen atoms in the para positions of the benzene ring with respect to the sulfone group provide great stability against oxidation to the polymer. The oxygen atoms between the phenylene rings (ether group) give the chain flexibility and impact resistance
    Thus, in the context of the present invention, the term "polysulfone" refers to any thermoplastic polymer whose repeating units contain the aryl-S02anlo substructure, therefore comprising polyphenylsulfones (abbreviated as PPSU or simply PSU) and polyethersullones (PES).
    This type of thermoplastic polymer, unlike thermosetting resins, does not have cross-links, obtaining its strength and stiffness from the properties inherent to the monomer units and their high molecular weight. This allows a high concentration of lattices in amorphous thermoplastics and a high degree of molecular orientation in crystalline lenses, both with anisotropic properties.
    As mentioned above, reinforced thermoplastic materials are well known. especially with natural or synthetic fibers, for example carbon, glass, wood or metallcas particles. The use of nanofibers or nanoparticles as reinforcement in thermoplastic matrices is also known.
    For example. US20090004460A 1 describes composite materials that include a thermoplastic polymer selected from polyether ketones and polyimides reinforced with carbon nanotubes or nanoparticles, inorganic nanoparticles and clay nanoparticles. US20110260116A1 describes thermoplastic materials that include carbon and graphene nanotubes. Likewise, in the article Mlnfluence of carbonnanotubesonthethermal, electrical and mech an icaI prope rties 01 poly (etherketone) / glassfiberlaminates ", Ana M. Díez · Pascual et al., Carbon, Volume 49, Chapter 8, July 2011, pp. 2817- 2833. Composite materials based on polyether ketones and carbon nanotubes incorporating polysulfones as a compatibilizing agent are compared in comparison to these composite materials without including polysulfones, demonstrating the potential of the former as multifunctional materials in industrial applications
    The figures show the results of tests carried out with samples of the reinforced thermoplastic material of the invention, in the figures: Fig. 1: Thermograms corresponding to the first heating scan for each of the materials studied based on the nanoparticle content of Ti02 : PSU; PSU-l%; PSU-S%; PSU-10%; PSU-20%.
    Fig. 2: Thermograms corresponding to the cooling for each of the materials studied according to the nanoparticles content of Ti02: PSU; PSU-1%; PSU-5%; PSU-10%; PSU-20%.
    Fig. 3: Thermograms corresponding to the second heating scan for each of the materials studied according to the content of Ti02 nanoparticles: PSU; PSU-1%; PSU-5%; PSU-10% and PSU-20%.
    Fig. 4. Thermogravimetric analysis (TGA, 'ThermogravimetricAnalysisH Loss of
    ).
    mass (left) and derivative (right) of the materials studied based on the nanoparticle content of Ti02: PSU; PSU-l%; PSU-5%; PSU-10%; PSU-20%.
    Fig. 5 · Tension curve (in MPa) versus deformation (%) for each of the materials studied according to the nanoparticle content of Ti02: PSU; PSU-1%; PSU-5%; PSU-10%; PSU-20%.
    Fig. 6: Representation of the modulus values of elasticity or Young depending on the composition of the materials studied.
    Fig. 7: Representation of the maximum stress for each of the materials studied according to the nanoparticle content of Ti02: PSU; PSU-1%; PSU-5%; PSU-10%; PSU-20%.
    Representation of the tensile stress for each of the materials studied according to the content of Ti02 nanoparticles: PSU; PSU-1%; PSU-5%; PSU-10%; PSU-20%.
    Fig. 9: Representation of the deformation at break (%) for each of the materials studied according to the nanoparticle content of Ti02: PSU; PSU · l%; PSU · S%; PSU10%; PSU20%.
    5 Fig. 10: Scanning electron microscopy (SEM). Images obtained by SEM of the fraelura surfaces (at 250x): a) PSU; b) PSU-1% TiO "e) PSU-5% TiO" d) PSU10% TiO "e) PSU-20% TiO ,.
    Fig. 11 'Images obtained by SEM of fracture surfaces (at 1000x): a) 10 PSU; b) PSU · 1% Ti0 2, c} PSU · S% Ti02, d) PSU · 1O% Ti02, e) PSU · 20% Ti0 2.
    Fig. 12: Images obtained by SEM of fracture surfaces (a SOOOx): a) PSU; b) PSU-1% TiO "e) PSU-5% TiO" d) PSU-1 0% TiO "e) PSU-20% TiO ,.
    15 Fig. 13: SEM images of backscattered electrons for the samples: a) PSU + Ti02 1%, b) PSU + Ti02 5%, c) PSU + Ti02 1 0%, d) PSU + Ti02 20%.
    In accordance with the first aspect of the present invention, thermoplastic materials reinforced with nanocomposites are provided, in particular polysulfones reinforced with
    20 nanocomposites, consisting of the reinforcing nanocomposites in titanium oxide nanoparticles (Ti02) and haloisite nanotubes (AI2Si20 s (OH)., Modified hydroxylated aluminosilicate).
    In this regard, in the context of the present invention, the term nanocomposites is
    25 refers to compounds with dimensions below 100 nm. Preferably, the particle size of the titanium dioxide nanoparticles is between 10 nm and less than 100 nm, and the inner diameter of the haloisite nanotubes, as well as their length, ranges between 50 nm and less than 100 nm.
    The titanium dioxide used in the present invention is a biocompatible and non-toxic material, which exhibits oxidation and photocatalytic properties, with antibacterial and anlifüngic properties.
    The use here of titanium dioxide nanoparticles as a reinforcement gives the reinforced thermoplastic material of the invention the characteristics derived from its properties, such as white coloration, self-cleaning ability degrading organic compounds by oxidation or reduction, superhydrophytic character that helps keep surfaces clean. , protection against UV radiation and antibacterial activity.
    Preferably, in the present invention the percentage (%) of titanium dioxide nanoparticles present in the reinforced thermoplastic material of the invention ranges between 0.1% and less than 70% by weight with respect to the weight of the thermoplastic material.
    On the other hand, as nanocomposites in the present invention, haloisite nanotubes are also used together with the titanium dioxide nanoparticles.
    The addition of haloisite nanotubes to the thermoplastic material. The haloisite is constituted by nanotubes of aluminum-silicate. It is a totally natural nanomaterial composed of a double layer of aluminum, silicon, hydrogen and oxygen. They are geometrically very fine tubular particles, curves dimensions are about 50 nm internal diameter and 500 nm to 1.2 IJm approximately long. Among the advantages that these nanotubes have, it is worth highlighting their excellent biocompatibility, natural origin, non-toxicity, they have a large surface area, high capacity for cation exchange and they are economical.In this sense, recent publications show substantial improvements of some properties, for example decrease of the coefficient of thermal expansion (CTE) and increase of the modulus of elasticity ("Thermalstability and flame retardant effects of halloysitenanotubesonpoly (propylener, EuropeanPolymerJournal, Volume 42, June 2006, pp. 1362-1369;" EPDMlmodifiedhalloysltenanocomposites ", Pasbakhsh elScience, Pasbakhsh elScience 48 (2010) 405-413; US2007 / 0106006).
    •
    In the context of the present invention, in contrast to other inorganic nanomaterials used as fillers in polymeric matrices, haloisite nanotubes can be obtained easily and at a lower cost. In addition, its unique crystalline structure, similar to that of CNT carbon nanotubes in terms of geometry, makes these materials 5 potential cheaper substitutes. On the other hand, presenting chemophysical characteristics similar to lamellar clays, they have the advantage that they do not need to be exfoliated so that inside the polymer it offers a potential modifying properties. Finally, the internal diameter of the nanotubes makes haloisite a material with potential applications as encapsulant (host system) of molecules
    10 small such as different types of drugs, these being useful for carrying out controlled release of different types of substances. Taking into account all these characteristics, it seems reasonable to think that haloisite nanotubes are attractive candidates for use as fillers of polymeric matrices in order to improve, among other qualities, their fracture toughness.
    On the other hand, due to the large surface area of these haloisite nanotubes. The dispersion in the polysulfone net during its processing and obtaining the final composite material forms an aggregate and even an agglomerate by favorable interparticle interactions (possibility of hydrogen bond formation between hydroxyl groups).
    Preferably, the percentage (0/0) by weight of haloisite nanotubes present in the reinforced thermoplastic material of the invention is in the range of 0.1 to less than 70% by weight. The percentage varies depending on the final mechanical properties that are required for the creation of three-dimensional objects.
    It should be noted that the percentage by weight of nanocomposites present in the thermoplastic material, this is the sum of nanoparticles of titanium dioxide and haloisite nanolubes, does not exceed 70% by weight of the entire reinforced thermoplastic material.
    According to the second aspect, the invention provides a method of producing the thermoplastic reinforced materials described above. The process of the invention provides an easily scalable preparation route at the industrial level, allowing said to obtain polymeric materials reinforced with nanocomposites where
    these are distributed homogeneously in the polymer matrix and with a controlled particle size, the procedure comprising:
    a) Provide titanium dioxide nanoparticles and haloisyl nanotubes; b) In order to improve the dispersion of haloisite nanotubes, mix the
    5 haloisite nanotubes in equipment capable of applying high shear stresses and carrying out a superficial modification thereof by applying ultrasound, in particular homogenizing a wet mixture of the nanotubes and applying ultrasound for 30 minutes to 3 hours at a temperature of 30 to 60 ° C;
    e) Disperse the titanium dioxide nanoparticles and the modified haloisite nanotubes 10 obtained in step b) into a thermoplastic polysulfone material by melt mixing in an extruder.
    In one embodiment of the process of the invention, step c) is carried out by melting the polysulfone terrmoplastic material into an extruder. Preferably, in
    The thermoplastic material, the titanium dioxide nanoparticles and the surface-modified haloisite nanotubes are introduced at the same time as the feed zone of the extruder.
    In a preferred embodiment, this extruder melt mixing is carried out.
    20 at temperatures between 150 ° C and 360 ° C, at a spindle speed between 20 rpm and 800 rpm, and for an estimated time between 1 and 2.5 hours. In yet another preferred embodiment, the extruder employed is a twin screw extruder, for example, a double screw (conical) micro extruder (ThermoElectronCorporation).
    Finally, according to the third aspect, the invention relates to the use of these thermoplastic materials reinforced with nanocomposites, in particular polysulfones reinforced with nanocomposites, the reinforcing nanocomposites consisting of titanium oxide nanoparticles (Ti02) and haloisite nanotubes (AI2Si20s (OHk hydroxylated aluminosilicate) modified, for example in biomedical, aerospace and / or aeronautical applications.
    For use, the thermoplastic materials reinforced with nanocomposites of the invention can be obtained in different forms depending on the geometry of the nozzle of the extruder used, for example tubes, bars, films or plates or even their size can be reduced by suitable systems to achieve them in the form of pellets or dust.
    Likewise, for use the thermoplastic materials reinforced with nanocomposites of the invention can be applied alone or in combination with thermoplastic polysulfone materials that do not include said reinforcing nanocomposites.
    The applications of the reinforced thermoplastic materials of the invention are biocompatible, have high mechanical and abrasion resistance and maintain the optical properties of polysulfone. that is, its translucency. Therefore, they are of special application in the field of biomedical technologies.
    Thus, in a preferred embodiment, the reinforced thermoplastic materials of the invention are used for the production of medical devices, such as bone prostheses, dental prostheses, biomedical implants, dialysis membranes, sterilized trays, dental, medical and surgical instruments, etc. In the case of a biomedical application, a solid dispersion that percolates within the polysulfone matrix is vital, which is biocompatible both in relation to the materials used and the process of obtaining and manufacturing, so that the regulations are complied with sanitary regulators In a particularly preferred embodiment. Dental devices are selected from the group consisting of dental braces, dental implants, dentures, dental aligners, dental crowns, dental veneers, dental covers and dental implants.
    Similarly, the reinforced thermoplastic materials of the invention are used for the manufacture of aerospace and aeronautical devices and elements, in electrical and electronic applications, for example for the manufacture of connectors, reels and coil cores, television components, capacitor film and structural circuit boards, for the manufacture of armored glass, wings in the fuselage, as well as for the manufacture of pipes, pumps, cooling towers, modules and corrosion-resistant filter support plates, etc.
    The reinforced thermoplastic materials of the invention are also used for three-dimensional printing of objects.
    Examples
    Reinforced thermoplastic materials formed by a PSU matrix and a reinforcement of titanium dioxide nanoparticles and haloisite nanotubes were prepared using
    5 different proportions of reinforcements (1%, 5%, 10%, 20% and 30%), as well as a control sample only with PSU and the reinforced material obtained was thermoformed by application of temperature and pressure. As a result, sheets were obtained that were subsequently cut to obtain the corresponding samples in order to perform different tests.
    Sample preparation was performed by dissolving the material and subsequent evaporation of the solvent. For this, chloroform was used as solvent. The mixture was poured into a Petri dish and allowed to stand for 24 hours, the solvent evaporating; the mixture was then taken to a vacuum bell. After 24 hours, the Petri dish was transferred to a stove heated at 20 ° C to 60 ° for 5 days to remove residual solvent.
    The Petri dish materials were also subjected to a heating between BODe at 120 ° C in an oven for one hour before being subjected to hot pressure in order to obtain sheets or films.
    For this, a FontunePresses press was used, with the following conditions; temperature between 30De and 200oe; pressure between OkNy BOkN, in fragmented times between 2min to 52 min per pressure variance and time as shown in the following tables:
    cycle Pressure (kN)Time (min)
    one ORfifteen
    2 ORfifteen
    3 twenty02
    4 twentytwenty
    5 twentyfifteen
    6 80twenty
    7 8010
    8 twenty10
    cycle Temperature (OC)Time (min)
    one 30twenty
    2 20052
    3 2009
    4 305
    The amount of suitable thermoplastic material calculated from the density of the composite material, the densities of the materials used and the percentage of load for
    5 complete the mold gap. The material is placed in such a way that, as far as possible, phenomena associated with preferential movements do not occur. The upper part of the mold is placed and the mobile plate is adjusted until it is in contact with the mold without pressing.
    10 The samples were then molded in order to obtain probes for mechanical tests in a Microrosystem microinjector, applying the following processing conditions:
    Material Temperature ('C)Re-circulation time (min)Spindle speed (r.p.m)Maximum sample amount (9)
    PSU 3601016010
    PSU + 1% Ti02 3601016010
    PSU + 5% Ti0 2 3601016010
    PSU + 10% Ti02 3601016010
    PSU + 20% TiO, 3601016010
    The extrusion conditions were as follows:
    Sample injection ~ n spindle 'C)ossification unit ('C)in nozzle 'C)in mold 'c)injection pressure (bar)Cooling time and mixing in mold (s)
    PSU 36035035015095030
    PSU + 10% Ti02 36035035015095030
    PSU + 20% Ti02 36035035015095030
    PSU + 5% 36035035015095030
    Ti02 + 30% Nanotubes
    PSU + 30% Nanotubes 36035035015095030
    Tensile test
    5 Tensile tests were performed with a universal Shimadzu AGX test machine, equipped with a 1 kN load cell. The sheets obtained were cut in probes with dimensions according to those established in ISO 527 to determine the tensile properties of polymeric materials. Tensile tests were carried out at a speed of 1 s / 1 mm.
    Thermal Analysis by Differential Scanning Calorimetry (Ose)
    Samples of approximately 5.6 9 of the materials were analyzed by differential scanning calorimetry (DSC) in an equipment of the 8221 Mettler Toledo brand, in an atmosphere of
    15 pure nitrogen 99.99%. The samples were heated from 60 ° C to 2400C above their glass transition temperature, at a rate of 1QoC / min and maintained at this temperature for 15 minutes. thus erasing the thermal history of the material. Subsequently, cooling, heating, enthalpies were determined; crystallization and melting temperatures respectively.
    The process to obtain the different thermograms is briefly described below:
    • Erasing the previous thermal history: The samples are subjected to an average temperature between 60 ° C and 240 ° C above their glass transition temperature and kept at 240 ° C for 15 minutes, at a speed of 10oC / min .
    25 • Cooling from 240 ° C to 60a C at a speed of 1QoC / min. In this way the thermogram of the samples is obtained under cooling conditions.
    • Heating from 60 ° C to 240 ° C. In this way the thermogram of the samples is obtained under heating conditions
    The results are shown in figures 1 to 3,
    According to the analyzes carried out, the effect of the addition of
    5 titanium oxide in the thermal properties of polysulfone. The traces obtained by os for a first heating (ie samples without thermal history erasure) of all the materials under study are shown. Only the temperature range for which a thermal transition is observed has been chosen,
    10 In particular, thermal transitions are observed that we can associate with the characteristic jumps of a vitreous transition process, whose temperature at the inflection point will be called the vitreous transition temperature (Tg) and which appears in all cases at approximately 1BBoe, except for pure polysulfone that shows a change in heat capacity at about 19BoC. The truth is that the trace associated with pure polysulfone
    15 was always very irregular, presenting even another jump at about 50 ° C less. These results have been explained so far. However, it is not an extremely relevant result in relation to the objectives of the invention. In fact, this first scan is carried out in order to eliminate the thermal history of the materials mainly due to its processing.
    In the lermograms associated with the first cooling after having eliminated the corresponding thermal history, in all cases the change in the heat capacity associated with the glass transition from whose inflection point the Tg in the cooling can be extracted can be observed. The corresponding data of T 11 together with the jumps of
    25 heat capacity (C ~), in units of electrical power per unit mass (W / g), are shown in the following table:
    ~ set PSUPSU-1% Ti02PSU-5% Ti02PSU-10% TiO,PSU-20% Ti02
    , ('C) 182.8182.9183.6183.4184.8
    jump C "W / g) 46, 2 x1O "60.2 x10 '40.4 x1O "42.66 x 10 '31.3x1O "'
    In this table it is observed that the T9 of the polysulfone remains practically constant with the particle content. Therefore, it is possible to deduce that the introduction of the particles does not significantly modify the thermal properties of the materials.
    5 After the cooling scan, a new sample heating scan is performed. When performing this second heating scan, it is observed that a simple curve is not obtained in the thermograms (as in the case of cooling), but rather they have an overlapping peak with the change in the heat capacity of the material. These types of peaks are usually attributed to heats due to molecular relaxation and are usually known
    10 as enthalpy relaxation.
    From the thermograms obtained, the glass transition temperature, Tg (calculated from the inflection point of the curve) and the temperature corresponding to the maximum of the enthalpy relaxation (Thma ~) were determined. Likewise, the changes in the
    15 heat capacity associated with the glass transition temperature (expressed in W / g) and the heat associated with enthalpy relaxation (J / g) for each of the systems studied. The data is collected in the following table.
    Compound PSUPSU-1% Ti02PSU-5% TiO,PS U-l 0% TiO,PSU-20% TiO,
    , ('C) 188.1188.5188.8187.9189.1
    ~ high (Cp, W / g) 44, 2x1O "60.2x l 0 "42.9xl0'Y40.3xl0 '"29.4x1O "'
    h, ma ~ (OC) 190.6190190, 9190.2191, 2
    Relaxation 0.410, 4140.5150.4450.337
    ntalpica (Jlg)
    It is observed that the Tg of the pure polysulfone differs by 1 ° C with respect to the Tg of the material with 20% TiO particles:;>, so it is possible to conclude that the introduction of the particles does not modify significantly the thermal properties of the materials obtained. There are also no significant differences in the temperature at which
    25 produces enthalpy relaxation.
    Thermogravimetric Analysis (TGA)
    A thermogravimetric analyzer was used, capable of measuring changes in weight based on temperature and time. Frequently this type of analysis is used to identify the components of a mixture based on the thermal stability of each of them, registering the loss of weight of the sample with respect to the temperature. Samples of 5-7 mg of the mixtures and their components were taken and heated at 10 ° C / min from 50 ° C to 900 ° C. The tests were performed on a STA600 thermogravimetric scale from PerkinElmer under a nitrogen atmosphere. In this way the decomposition temperature ranges of the mixtures were determined.
    The results obtained from the thermogravimetric study of the samples studied correspond to the loss of mass (expressed in%) as a function of the temperature for the samples according to the Ti02 particle content (PSU: PSU-1%: PSU-5%: PSU -10%; PSU-20%). In all cases, two significant mass losses are observed. The initial loss of mass at temperatures below 200 ° C is usually attributed to the removal of small amounts of water present in these materials.
    The most significant mass loss occurs at very high temperatures (between 45050QoC). The thermal degradation of the samples starts from 450 ° C. Degradation processes are stabilized at temperatures above 650 ° C, observing that in no case a zero residue is reached, even in the case of pure polymer (PSU). This result is in agreement with the results observed by other authors. In the case of reinforced materials, it is also necessary to take into account the solid residue, which is caused by the presence of TI02 particles.
    The curve corresponding to the first derivative of the thermogram shown on the left side of Figure 4, that is, the differential thermogram (or DTGA, differentialthermogravimetricanalysis) is of great help in identifying temperatures that are not readily detectable in a thermogram For example, From these curves it is possible to identify the temperature at which the degradation rate of the samples is maximum, which is around 530 ° C. In addition, it is also possible to identify the starting temperatures of the degradation process of the sample or the end of the degradation process.
    Mechanical properties
    Samples were tested to obtain tensile curves (strain in MPa vs. strain in%), Young E modulus values, stress to breakage or (MPa), maximum strength (EMPa) and elastic limit (E ), The results are shown in the following table and in figures 5 to 9.
    Sample E (GPa)O'rOlur¡¡ (MPa), (% 100)
    PSU 2.0 ± 0.147.1 ± 7.23.4 ± 0.8
    PSU + 1% TiO " 2.0 ± 0.254.8 ± 7.23.4 ± 0.2
    PSU + 5% TiO " 2.1 ± 0.250.1 ± 4.22.8 ± 0.5
    PSU + 10% TiO " 2.4 ± 0.250.1 ± 8.82.6 ± 0.6
    PSU + 20% TiO " 2.9 ± 0.342.3 ± 2.81.7 ± 0.5
    AG -X Shimadzu Universal Machine
    From the figures it follows that in no case is the plastic deformation observed clandestinely, so it can be concluded that, in all cases, under the conditions of the test, all materials exhibit a relatively fragile behavior. On the other hand, it can be seen how the tensile strength increases with the Ti02 particle content, although the materials become less stubborn in terms of traction, since their maximum deformation is reduced. Both these assessments and the rigidity of the materials improve in quantitative terms from the parameters that characterize them. Regardless of the error, it is observed that Young's modulus increases with the particle content. These results therefore suggest that the stiffness of potisulfone increases with the content of Ti02 nanoparticles and haloisite nanotubes. In order to better visualize what happens in mechanical terms in the polysulfone thermoplastic material by adding Ti02 nanoparticles and haloisite nanolubes,
    .
    they show the values associated with the different mechanical parameters studied according to the composition of the materials.
    Values of the modulus of elasticity or Young depending on the composition of the materials studied: it can be observed that with up to 10% by weight of nanoparticles 5 Young's modulus has a tendency to increase; however, for 20% by weight the trend changes and there is a clear increase in the rigidity of the material.
    Maximum effort or maximum tensile strength: it is observed that the sample begins to deform even before the application of smaller loads. It is clearly observed that the smaller the amount of titanium dioxide, the greater its maximum effort.
    Breaking stress: it can be seen that the breaking strength barely shows variations depending on the concentration of Ti02, at least up to 20% by weight of nanoload.
    Deformation of rupture: in show the values associated to said deformation without considering the elastic recovery. As expected by adding nanoparticles of a very rigid ceramic material, the polymer matrix becomes less ductile, since it is possible that the interfaces of the nanoparticles with the polymer matrix are regions of concentration
    20 of tensions where the beginning of cracks is favored that finally give rise to mechanical failure.
    As shown in the following table, a significant increase in mechanical properties is observed.
    R € c: umen of results V results by adding nanotubes ée haloisita to the polysulfone polymer matrix plus titanium dioxide ·
    Mechanical Testing
    Resistance to ration mPa ft'length a
    ration (%) Raction module Flexible force
    mPa Module dE
    lection
    ~
    PSU
    72 10 2551 103 2689
    PSU + 1 0%Ti02
    83534481313448
    PSU + 20%Ti02
    2-3
    PSU + 5% T10 2 + 30% halootite nanotubes
    131 1.7 11722 172 9653
    PSU + 10% haloisite nanotubes
    1242110321869653
    PSU + 10% Ti02 + 20% haloisite nanotubes
    138 1.2 20685 193 12411 PSU + 30%
    haloislta nanotubes
    155one2413224119306
    ASTM TEST 0638 0638 0638 0790 0790
    Scanning electron microscopy (SEM)
    Figures 10 to 13 present the images obtained by scanning electron microscopy (SEM) corresponding to the fracture surfaces of each of the materials studied. The images reveal that the fracture surface
    5 changes significantly with the particulate content. In general, by increasing the nanoparticles content of titanium dioxide and haloisite nanotubes, it is observed that the fracture surface is more rough.
    Figure 10 a), corresponding to pure polysulfone, shows how in the area of
    A fracture has formed a step that could be associated with a localized deformation process during the tensile test. Except for the presence of this step, the fracture surface is quite smooth. The incorporation of 1% Ti02 particles and haloisite nanotubes (Figure 10b) significantly modifies the fracture surface, observing an increase in roughness with the particle content.
    Figure 11 shows the images obtained by SEM corresponding to the fracture surfaces of composite materials at 1000 magnifications. Again we observe changes in roughness with particle content. The samples with lower particle content (Figure 11 a, corresponding to 1% Ti02 ynanotubes and Figure 20 11 b, corresponding to 5% Ti02 and nanotubes) have some smooth areas compatible with the fracture associated with polysulfone. In the case of samples with higher particle content, the fracture surface is quite rough. The images reveal that the fracture surface changes significantly with the particle content. In general, increasing the particle content shows that the fracture surface is
    25 more rugged, confirming the above.
    Figure 12 shows the Images obtained by SEM at 5000 magnifications corresponding to the fracture surfaces of each of the materials studied. With the exception of the sample corresponding to the polymer matrix (pure PSU), the remaining 30 samples have two distinct regions. A smoother region, compatible with areas rich in polysulfone and a more rugged one, which could be assigned to zones
    With high concentration in particles. This fact would be indicative of the presence of agglomerates in the composite material, which is usually detrimental to the improvement in mechanical properties. However, in order to confirm these observations, micrographs were performed using the scattered electron detector.
    The images obtained by SEM with the backscattered electron detector corresponding to the same samples in the same area and at 5000 magnifications are shown in Figure 13. The use of the backscattered electron detector allows to see differences in contrast due to the presence of elements of different atomic numbers, which should
    10 to identify if there are regions with a higher concentration of particles than others. However, practically no large differences in contrast are observed. This result could be due to the proximity of the atomic number of sulfur (present in polysulfone) and of lithium and nano tubes.
    Example .. of use of the reinforced lermoplastic of the invention
    For the three-dimensional printing of objects with the reinforced thermoplastic material of the invention, said compound, in the molten state, is injected by the printing nozzles of a 3D printer, The production of three-dimensional objects from a printer in
    20 30 (F m.l) allows you to obtain a desired object, with its respective applications and use, allowing you to customize the object to measure or to the letter depending on the needs.
    权利要求:
    Claims (14)
    [1]
    one. Thermoplastic material reinforced with nanocomposites, in particular polysulfones reinforced with nanocomposites, the reinforcing nanocomposites consisting of titanium oxide nanoparticles and surface-modified haloisite nanotubes.
    [2]
    2. Thermoplastic material reinforced with nanocomposites according to claim 1, characterized in that the percentage by weight of nanocomposites present in the thermoplastic material does not exceed 70% by weight of the entire reinforced thermoplastic material.
    [3]
    3. Thermoplastic material reinforced with nanocomposites according to claim 1, characterized in that the percentage of titanium dioxide nanoparticles present in the reinforced thermoplastic material ranges between 0.1% and less than 70% by weight with respect to the weight of the thermoplastic material.
    [4]
    Four. Thermoplastic material reinforced with nanocomposites according to claim 1, characterized in that the percentage by weight of haloisite nanotubes present in the reinforced thermoplastic material is in the range of 0.1 to less than 70% by weight.
    [5]
    5. Thermoplastic material reinforced with nanocomposites according to claim 1, characterized in that the particle size of the titanium dioxide nanoparticles is between 10 nm and less than 100 nm.
    [6]
    6. Thermoplastic material reinforced with nanocomposites according to claim 1, characterized in that the inner diameter of the haloisite nanotubes, as well as their length, ranges between 50 nm and less than 100 nm.
    [7]
    7. Method of producing a thermoplastic material according to claims 1 to 6, the process comprising the steps of:
    a) Provide nano particles of titanium dioxide and haloisite nanotubes;
    b) In order to improve the dispersion of the haloisite nanotubes, mix the haloisite nanotubes in equipment capable of applying high shear stresses and carry out a superficial modification of them using ultrasound;
    c) Disperse the titanium dioxide nanoparticles and the modified haloisite nanotubes obtained in step b) into a thermoplastic polysulfone material by melt mixing in an extruder.
    [8]
    8. Method according to claim 7, characterized in that the surface nesting of step b) is carried out by homogenizing a wet mixture of the haloisite nanotubes and applying ultrasound to the wet mixture for 30 minutes to 3 hours, at a temperature of 30 to 600C .
    [9]
    9. Method according to claim 7, characterized in that step c) is carried out by means of a fusion of the thermoplastic polysulfone material in an extruder, preferably with simultaneous addition of the titanium dioxide nanoparticles and the surface-modified haloisite nanotubes.
    [10]
    10. Method according to claim 7, characterized in that, in step c), the extruder used is a twin screw extruder.
    [11]
    eleven. Method according to claim 7, characterized in that stage c) is carried out at temperatures between 150 ° C and 360 ° C, at a spindle speed between 20 rpm and 800 rpm, and for an estimated time between 1 and 2.5 hours .
    [12]
    12. Use of a thermoplastic material reinforced with nanocomposites according to any of claims 1 to 6, in biomedical applications, for the production of medical or dental devices, in aerospace and / or aeronautical applications, in electrical and electronic applications, as well as in three-dimensional printing of objects .
    [13]
    13. Use according to claim 11, characterized in that the dental devices are selected from the group consisting of dental brackets, dental implants, dental prostheses, dental aligners, dental crowns, dental veneers, dental sleeves and dental implants.
    [14]
    14. Use according to claim 11, characterized in that the medical devices are selected from the group consisting of bone prostheses, biomedical implants, dialysis membranes, sterilized trays, dental instruments. Medical and surgical.
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    同族专利:
    公开号 | 公开日
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20020132875A1|2000-12-29|2002-09-19|Dental Technologies, Inc.|Solid nanocomposites and their use in dental applications|
    WO2014186460A1|2013-05-14|2014-11-20|Eaton Corporation|Multi additive multifunctional composite for use in a non-metallic fuel conveyance system|
    法律状态:
    2018-07-31| FA2A| Application withdrawn|Effective date: 20180725 |
    优先权:
    申请号 | 申请日 | 专利标题
    ES201600802|2016-09-27|
    ES201600802|2016-09-27|
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