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    • 专利摘要:
    POLYMER COMPOSITES AND MANUFACTURES OF THE SAME. The present invention provides invention provides polymer composites reinforced with high aspect ratio reinforcement filler materials selected from calcium phosphate nanofibers, nanoplates, submicron fibers, submicron plates and combinations thereof. The mechanical and biological properties of inventive composites are significantly enhanced over current polymer composites and they can be used in various biomedical applications, such as dental restorations.
    公开号:BR112013000962B1
    申请号:R112013000962-4
    申请日:2011-07-14
    公开日:2020-06-23
    发明作者:Hao Li；Qingsong Yu；Liang Chen；Meng Chen
    申请人:The Curators Of The University Of Missouri；
    IPC主号:
    专利说明:

    DECLARATION OF CONCESSION
    [0001] Part of this work was supported by (1R21DE018821-01AA) from the National Institute of Health and (CMMI-0846744) from the National Science Foundation. FIELD OF THE INVENTION
    [0002] The present invention generally relates to polymer composites, including a polymeric matrix and reinforcement filler materials selected from nanofibers, nanoplates, submicron fibers, submicron plates and combinations thereof, as well as reinforcement filler materials modified. The mechanical properties, biological properties and / or durability of the polymeric composites described are significantly improved over current polymer composites and are suitable for use in various applications. BACKGROUND OF THE INVENTION
    [0003] Polymer composites have been used in a variety of fields, such as dental restoration and orthopedic implants. Natural biological structures, such as tooth, bone and shell, are composed of nanoscale or submicroscale hard inorganic building blocks (minerals) and soft organic matter (proteins). Metals, however, are the dominant implant materials in the medical markets due to the availability of metals and their mechanical properties. Metal orthopedic implants, however, create significant concerns. Metal implants often need to be removed and even those that are not removed can cause adverse effects, such as excess scar tissue formation, infection, weakened bone and immune sensitivity. Synthetic ceramics, polymers and their composites can provide better biological properties, but their applications have been hampered by inadequate mechanical properties. For example, the compressive and / or tensile strength of hydroxyapatite-collagen (HA / Col) composites is typically much lower than that of cortical bone and metals.
    [0004] In dental applications, amalgam provides an average survival time of 13 years. Resin-based composites typically have an average survival time of 5 to 7 years because of inadequate mechanical properties and poor bonding to the tooth material. Still, polymers are preferred due to safety and aesthetic issues with amalgam.
    [0005] To improve the properties of synthetic polymer composites, fillers have been added to these materials. For example, some polymer composites have been reinforced with silver nano filaments. Some dental composites have used silica or silicate nanoparticles as fillers and some in situ and ex situ orthopedic composites have been reinforced with hydroxyapatite or in the form of short nanofibers and silver nano filaments. However, the mechanical properties of composites reinforced by nanoparticles, short nanofibers, or silver nano filaments show limited improvement in mechanical properties, such as strength and toughness, and may not be sufficient to satisfy the requirements of various applications.
    [0006] Therefore, there is a need to provide a new and improved synthetic composite with enhanced mechanical properties sufficient for biomedical applications. SUMMARY OF THE INVENTION
    [0007] The present invention relates to an improved synthetic polymer composite comprising a polymeric matrix and a reinforcing filler. The reinforcement filler material can be of a variety of materials, as long as it has a high aspect ratio. The fillers are selected from nanofibers, nanoplates, submíeron fibers, submíeron plates and their combinations, as well as modified reinforcement fillers. Reinforcement fillers can be calcium phosphates which are minerals comprising calcium ions (Ca2 +) and a phosphate ion or phosphate ions, such as orthophosphates (PO43-), metaphosphates (PO3 ') or pyrophosphates (P2O74). Polymers comprising the polymeric matrix may be those known and available in the field of biomedical and dental polymers or may be synthesized. Polymers can be of a variety of materials, examples include poly (L-lactide), polyetheretherketone, 2,2-bis [4- (2-hydroxy-3-methacryloyloxypropyl) phenyl] propane (Bis-GMA) and triethylene glycol dimethacrylate.
    [0008] The nanofiber reinforcement fillings, nanoplate, submeron fiber or submeron plate are characterized by a high aspect ratio. The diameter or thickness of the reinforcement filler materials is preferably between about 10 nanometers and about 1 micrometer. The aspect ratios of the filling materials vary from about 10 to about 10,000.
    [0009] In yet another embodiment described herein, a method for making polymer composites is described. The method comprises mixing a polymeric matrix and a reinforcing filler. The method may further comprise a modification step or steps. Modification can be either chemical or mechanical, and can be provided in a polymer, polymer matrix, reinforcement filler materials or polymer composite. In addition, methods of using polymer composites are also described. Polymer composites can be used in orthopedic and dental applications.
    [00010] The polymer composites described here show improved mechanical properties over prior art composites. The polymer composites described here show improved mechanical properties over prior art composites, which include, but are not limited to, strength, stiffness, toughness as well as biological properties. Some modalities have fiber bonding, elongation and removal of fibers that are important reinforcement mechanisms to increase the resistance and toughness of the materials. REFERENCE TO COLORFUL FIGURES
    [00011] The order contains at least one photograph executed in color. Copies of this patent application and the publication with color photographs will be provided by the Office upon request and payment of the necessary fee. BRIEF DESCRIPTION OF THE DRAWINGS
    [00012] FIGS. 1 (a) and (b) are schematic illustrations of composite with diameter or thickness on the nanometric or submicrometric scale. FIG. 1 (a) shows random fillings in a polymer and FIG. 1 (b) shows fillings oriented in one direction.
    [00013] FIGS. 2 (a) to (d) are SEM (Scanning Electron Microscopy) images of HA nanoplates and nanofibers made with different concentrations of gelatin: (a) without gelatin, (b) and (c) 0.4 g / L, and (d) 2 g / L.
    [00014] FIGS. 3 (a) and (b) are SEM images of HA nanofibers made at 100 ° C and with a gelatin concentration (244 bloom) of 1 g / L.
    [00015] FIG. 4 is a graph comparing the flexural strength of poly (L-lactide) (PLA) composites, PLA containing 2% by weight of HA nanofibers and PLA composites containing 2% by weight of HA nanofibers with sonication.
    [00016] FIG. 5 (a) is a graph comparing the biocompatibility between hydroxyapatite nanoparticles (HANP), hydroxyapatite nanofibers (HANF) and TÍ-6AI-4V (Ti, control) at the bottom of the wells using MC3T3-E1 cell line by the MTT assay . HA nanofibers have the best biocompatibility. FIG. 5 (b) is a graph comparing the biocompatibility between HA nanoparticles (HANP), HA nanofibers (HANF), dental composites containing HA nanofibers and silica microparticles (DHS) and dental composites containing silica microparticles (DS) in well bottom using L929 cell lines by MTT assay.
    [00017] FIGS. 6 (a) and (b) are TEM (Transmission Electron Microscopy) images of (a) HA nanofibers as received and (b) HA nanofibers modified by glyoxylic acid.
    [00018] FIG. 7 includes the FT-IR spectra of HA nanofibers as received (HANF) and HA nanofibers modified by glyoxylic acid.
    [00019] FIG. 8 is a graph that compares biaxial flexural strengths between Bis-GMA / TEGDMA dental composites (weight ratio 1: 1) filled with various HA nanofiber mass fractions as received and modified by 0.7 glyoxylic acid and 0.7 silica micrometer in size. The total mass fraction of inorganic filler is 60%.
    [00020] FIGS. 9 (a) and (b) are FT-IR spectra of HA nanofibers as received (HANF) and silanized HA nanofibers.
    [00021] FIG. 10 is a graph that compares the biaxial flexural strengths between Bis-GMA / TEGDMA dental composite (weight ratio 1: 1) filled with several mass fractions of HA nanofibers silanized and modified by glyoxylic acid and silica of 0, 7 micrometer in size. The mass of total inorganic filler is 60%.
    [00022] FIG. 11 is a SEM image of the fracture surface of dental composites containing 5% silanized HA nanofibers and 55% silica particles.
    [00023] FIG. 12 compares the water absorption rate (pL / mm3) between dental composites containing 60% by weight of silica and 2% by weight of silanized HA reinforcement fillers and 58% by weight of silica and 5% by weight of fillers reinforcement of silanized HA after immersion in distilled water.
    [00024] FIG. 13 includes the FT-IR spectra of HA reinforcement fillers as received and reinforcement fillers of HA modified by acrylic acid.
    [00025] FIG. 14 is a graph showing the thermogravimetric analysis of received HA reinforcement fillings received and HA reinforcement fillers modified by acrylic acid.
    [00026] FIG. 15 is a graph comparing biaxial flexural strengths between Bis-GMA / TEGDMA dental composites (weight ratio 2: 1) filled with various mass fractions of HA reinforcement fillers as received and modified by acrylic acid and silica 0.7 micrometer in size. The total mass fraction of inorganic filler is 60%. Filtek Z250 (Z250) from 3M ESPE Company is used as a control.
    [00027] FIG. 16 shows the titration results for the functional portions of reinforcement filler materials. It shows the number of functional surface portions per strip of HA reinforcement fillers after surface modification with 12-aminododecanoic acid, dodecanoic acid and dodecanoic acid.
    [00028] FIG. 17 is a graph showing the X-ray diffraction spectrum of DCPA nanofibers after 9 hours. FIG. 18 is the SEM image of the DCPA and HA reinforcement filler materials.
    [00029] FIG. 19 is a graph showing the biaxial flexural strength of dental composites based on BisGMA / TEGDMA or BisEMA / UDMA containing 2% by weight of DCPA reinforcement fillers and dental composites containing 2% by weight of DCPA reinforcement fillers more 2% by weight of HA reinforcement fillers.
    [00030] FIG. 20 shows the flexural strength (a) and modulus (b) of injection-molded PLA-based composites filled with original HA reinforcing filler materials, modified by glyoxylic acid and silanized with 3-MPS in different mass fractions. Pure PLA (mixed and unmixed) is used as a control.
    [00031] FIG. 21 shows the tensile strength (a) and modulus (b) of injection-molded PLA-based composites filled with original HA reinforcing filler materials, modified by glyoxylic acid and silanized with 3-MPS in different mass fractions. Pure (mixed) PLA is used as a control.
    [00032] FIG. 22 shows a typical stress-strain strain curve for: (a) injection-molded pure PLA and PLA composites containing different amount of original HA reinforcement fillers, (b) injection-molded pure PLA and PLA composites containing quantity different from glyoxylic acid modified HA reinforcement fillers and (c) injection-molded pure PLA and PLA composites containing different amount of 3-MPS silanized HA reinforcement fillers.
    [00033] FIG. 23 is a graph showing deformation by maximum mean stress, elongation, of injection-molded pure PLA and PLA composites containing different amount of original HA reinforcement fillers, modified by glyoxylic acid and modified by 3-MPS. The highest maximum deformation (elongation) also indicates higher toughness and higher resistance to impact and catastrophic failure. DETAILED DESCRIPTION OF THE INVENTION
    [00034] The present invention provides a synthetic polymer composite comprising a polymeric matrix and an amount of reinforcement filler material selected from nanofibers, nanoplates, submicron fibers, submicron plates and combinations thereof, as well as modified fillers. Nano-size or sub-micron size high aspect ratio fibers / plates provide advantages over short fibers and silver filaments providing higher load transfer properties, higher mechanical strength, higher toughness and resistance to catastrophic failures. In addition, these properties can be enhanced through modification. Methods for making and using polymer composites are also described. In addition, the methods have improved biocompatibility over polymeric matrix and polymeric composites containing nanoparticles. 1. Polymer Composites
    [00035] Polymer composites, as used herein, refer to the product of adding the reinforcement filler selected from nanofibers, nanoplates, submicron fibers, submicron plates and their combinations to a polymeric matrix. Polymer composite also refers to this product when additional ingredients are incorporated into the polymer matrix or reinforcement filler. Polymer composite can refer to the cured or dry product, as well as wet mixes. The. Polymer Matrix
    [00036] The polymeric matrix can comprise one or more polymers, as well as additional reagents incorporated in the polymerization of various polymers, such as initiators, catalysts, solvents and the like. Polymers are macromolecules of a monomer or individual monomers. The polymeric matrix can comprise a single polymer or more than one polymer.
    [00037] The polymers incorporated in the matrix can be synthesized or selected from a variety of commercially available polymers. Polymers can include orthopedic polymers or dental polymers. Non-limiting examples of exemplary orthopedic polymers include poly (glycolide) PGA, poly (L-lactide) (PLA), poly (DL-lactide) (DLPLA), poly (dioxanone) (PDO), poly (lactide-co-glycolide) (PLGA), poly (glycolide-co-trimethylene carbonate) (PGA-TMC), poly (e-caprolactone) (PCL), poly (amino acids), polyanhydrides, polyorthoesters, polyetheretherketone (PEEK), polyethylene (PE), collagen, chitosan, gelatin, alginate, poly (methyl methacrylate) (PMMA), polyhydroxyalkanoates (PHAs), polyurethanes (PURs), polyphosphazenes, poly (propylene fumarate) (PPF), poly (1,4-butylene succinate) (PBSu) and poly (a-hydroxy acids). Non-limiting examples of exemplary dental polymers include 2,2-bis [4- (2-hydroxy-3-methacryloyloxypropyl) phenyl] propane (Bis-GMA), bisphenol-A-dimethacrylate ethoxylate (Bis-EMA), 1,6- bis- [2-methacryloyloxyethoxycarbonylamino] -2,4,4-trimethylhexane (UDMA), triethylene glycol dimethacrylate (TEGDMA), tetramethylcrylate urethane, siloxane, 4-epoxycyclohexylmethyl- (3,4- epoxy) cyclohexane (ERL4), cyclohexane (ERL); SSQ) and the like.
    [00038] Polymers can also be synthesized from monomers. A single monomer or a mixture of monomers can be selected for the desired polymer. Monomers include, but are not limited to, glycolide, L-lactide, DL-lactide, dioxanone, trimethylene carbonate, e-caprolactone, amino acids, anhydrides, etherethercetone orthoesters, ethylene, methyl methacrylate, hydroxyalkanoates, urethanes, phosphate propylene fumarate 1 , 4-butylene succinate, o-hydroxy acids and the like.
    [00039] The polymeric matrix can include a single polymer or a series of polymers. In some embodiments, the polymeric matrix will have only a single polymer, while other embodiments may require mixtures of two or more polymers to give the most advantageous properties for the particular application. In embodiments in which there are two or more polymers, the polymers can probably be combined in any proportion, without any limitation. In some embodiments, the polymers may be present in the polymeric matrix in an approximately equal amount and in other embodiments the amounts of each polymer may vary from about 1 to about 99% of the matrix. For example, in a polymeric matrix comprising two polymers, the amount of each polymer can be about 50% or, alternatively, a polymer can be about 75% or about 90% of the compound. In a polymeric matrix comprising more than two polymers, the polymers can be supplied in approximately equal ratios or with an excess of one or more of the polymers. B. Reinforcement filling materials
    [00040] Suitable reinforcement fillers are selected from nanofibers, nanoplates, submicron fibers, submicron plates and their combinations, as well as modified fillers and can be synthesized or purchased when commercially available. Reinforcement fillers can be characterized as nanofibers, nanoplates, submicron fibers or submicron plates. The reinforcement fillings will, on average, be of size and diameter featuring nanofibers, nanoplates, submicron fibers or submicron plates. Nanofiber and submicron fiber fillers are generally fiber-shaped and can be characterized by a diameter and a length. The cross section of a fiber can be round, oval, triangular, rectangular, square, pentagonal, hexagonal or similar, with the largest diameter / side similar in size to the diameter / small side. Nanofibers have a diameter less than 100 nm. Sub-micron fibers have a diameter of more than 100 nm and less than 1 micron. Nanoplates and submicron plates are characterized by a rectangular (non-square), oval (non-round) cross section, or similar shape with the largest diameter / side (width) much larger than the smallest diameter / side (thickness). The plates can be characterized by the length of their longest side, the width of the cross section of the longest side and the thickness of the plate as the shortest dimension of the plate. Sub-micron plates have a thickness of more than 100 nm and less than 1 micron. Nanoplates are less than 100 nm thick. More preferably, the diameter and thickness of the fillers are between about 10 nm and about 1 micrometer. The length of the fibers and plates can and will vary. In some embodiments, the length will be about 100 to about 900 times the thickness or diameter. In other embodiments, the length will be 50,000 times the diameter.
    [00041] Reinforcement fillers are also characterized by a high aspect ratio. The aspect ratio characterizes the longest dimension of a given object over its shortest dimension. A high aspect ratio, as used here, is an aspect ratio above about 10. For fibers, the aspect ratio is the length divided by the diameter and for plates the aspect ratio is the length divided by the thickness of the plate . It should be understood that each nanofiber, nanoplate, submicron fiber or submicron plate does not need to be within a particular aspect ratio, but instead, the reinforcing filler material can be characterized by a high aspect ratio when the filler components reinforcement, on average, have a high aspect ratio. Reinforcement fillings have an average aspect ratio above about 10. In other embodiments, reinforcement fillings vary between about 1,000 and about 50,000. In other embodiments, the average aspect ratio varies between about from 100 to about 500, or from about 400 to about 900, or from about 800 to about 10. 000. As would be appreciated by a person skilled in the art, bundled fillers would have a lower aspect ratio if the diameter or thickness of the entire beam were used as the shortest dimension.
    [00042] Reinforcement fillers can be of a single filament, bundles or mixtures of filaments and bundles. In some embodiments, the reinforcement fillers are filamented and the bundle thickness is, on average, less than about 5 micrometers, on average, less than about 4 micrometers, on average, less than about 3 micrometers, on average, or less than about 2 micrometers on average. In other embodiments, the reinforcement fillers are substantially single filament. Reinforcement fillers can be in any orientation. Reinforcement fillers can be randomly dispersed in the polymer matrix, or substantially oriented in a single direction. Some guidelines can improve strength, stiffness, toughness, cushioning, wear resistance and other properties.
    [00043] Reinforcement fillers comprise various calcium phosphates. Calcium phosphates are the main mineral phase in teeth and bones and can be used to improve the biocompatibility of a polymer composite. Furthermore, calcium phosphates have been shown to prevent tooth decay (or tooth decay) due to its ability to generate calcium ions. Calcium phosphates, as used herein, comprise calcium ions (Ca2 +) together with one or more ions containing phosphate. Phosphate ions include phosphate-containing molecules including orthophosphates (PO43-), metaphosphates (POs') and pyrophosphates (P2O74). Calcium phosphates can further comprise one or more additional anions. Non-limiting examples include hydroxide ions (OH-), carbonate ions (CO32-), fluorine ions (F '), chlorine ions (Cl), sulfate ions (SO42) and their combinations. Calcium phosphates may also contain one or more cations, including, by way of non-limiting example, hydrogen ions (H +), sodium ions (Na +), potassium ions (K +), magnesium ions (Mg2 +), ions silver (Ag +) and their combinations. Calcium phosphates can also be stabilized by an anion (X), preferably (OH-), (CO32), (F), (Cl-) or mixtures thereof. Hydroxyapatite (HA) is the compound of the formula Ca5 (PO4) 3X, where X "is substantially (OH). Other examples of suitable reinforcement filler materials include Ca3 (PO4) 3 tricalcium phosphate, including amorphous, oep phase; tetracalcium phosphate Ca4 (PO4) 2O; Ca mono-calcium phosphate (H2PO4) 2i Mono-calcium phosphate Ca (H2PO) 2. H2O; Hydrogen calcium phosphate, anhydrous CaHPCU, DCPA, Monetite, carbonated hydroxyapatite, Caio (P04) and (C03) x ( OH) 2-2x, where x varies from 0 to 1, CHA, dicalcium phosphate dihydrate CaHPCU. 2H2O, Brushite, ocataccal phosphate CasíHPCUXPCUXOH); calcium deficient hydroxyapatite Ca ^ HPCUMPCUXOH, CDHA and the like.
    [00044] In some aspects of the invention, the reinforcing filler material further comprises a gelatin-like coating on the surface of the fillers. The gelatin coating is a likely result of the synthesis of reinforcement fillings. The coating was considered to contain both amine and carboxylic acid radicals. These portions can be loaded or unloaded, depending on the pH.
    [00045] Modification of polymer composites, polymer matrix or reinforcement filler materials can enhance certain properties of the resulting polymer composite. Some modifications can provide improved dispersion or promote mechanisms, such as enhanced fiber bonding or fiber removal, which increases the strength of composites. In addition, modifications can decrease the shrinkage of the resulting polymer composite, decrease the water absorption of the polymer composite, or improve the thermal stability of the polymer composite. The modifications can be chemical or mechanical.
    [00046] Chemical modifications result in fixing different portions to the surface of the reinforcement filler. Depending on the polymer composite, different chemical modifications to the surface of the reinforcement filler may be possible. For example, amine surface portions may be desired when epoxy, collagen, chitosan and gelatin are used as the polymeric matrices. Carboxylic acid and hydroxyl fractions can be useful for polymer composites when collagen, chitosan and gelatin are used as the polymeric matrices. The alkyl groups on the filling surfaces can be useful to improve dispersion in non-polar polymers.
    [00047] Reinforcement fillers can be modified by carboxylic acids. The resulting surface portion can comprise the formula -NH (CRiR2) nCOOH, where Ri and R2 are independently chosen from hydrogen, hydrocarbyl, or substituted hydrocarb en is an integer between 1 and 20. In Reaction Scheme 1 below, the glycolic acid is the carboxylic acid reagent and the resulting reinforcement filler material comprises a surface of portions -NH (CRiR2) nCOOH, where R1 and R2 are hydrogen and n is 1. In other embodiments, the resulting reinforcement filler can comprise a -NHCOR8 portion surface, where Rs is selected from hydrogen, hydrocarbyl and substituted hydrocarbyl. The carboxylic acid fractions of the modified polymers can exist as ions or as neutral groups, depending on the pH. Reaction Scheme 1
    [00048] Reinforcement fillers can also be modified by amine reagents. Amine reagents can react with various groups in the filler. In some embodiments, the amine reagent reacts with the carboxylic acid fractions on the surface of the reinforcement filler. The resulting substitution in carboxylic acid can be a -CONR3R4 fraction, as shown in Reaction Scheme 2, in which R3 and R4 are independently chosen from hydrogen, hydrocarbyl or substituted hydrocarbyl groups. Reaction with an amine gas can result in various amine functionalities, including charged species, on the surface of the reinforcement filler. Reaction Scheme 2
    [00049] Reinforcement fillers can also comprise silane surface modifications. Silanes can react with hydroxyl fractions on the surface of the reinforcement filler. The hydroxyl portions may be of the gelatin-like composition on the surface of the reinforcing filler material or of hydroxyl portions of calcium phosphate. Silanes covalently bond to the oxygen atoms in the filler. A silane molecule can bond with one to three hydroxyl portions of the reinforcement filler depending on the replacement of the silane Si atom. When the Si atom is replaced by leaving groups, the leaving groups can be replaced by a bond to hydroxyl groups in the reinforcement filler. In some embodiments, silanes have the formula of SiRs (LG) 3, where Rs is independently chosen from hydrogen, hydrocarbyl or substituted hydrocarbyl, LG is a selected leaving group of hydroxy, alkoxy or halogen and the modified reinforcement filler The resulting silane can have up to three bonds with the hydroxyl group of the filler, as shown in Reaction Scheme 3. Reaction Scheme 3
    [00050] In alternative modalities, silane can bond to one hydroxyl or two hydroxyl groups to form the surface modifications shown below. Reaction Scheme 4
    [00051] A further modification of the surface may be alkylation. Alkylation can be provided in several portions of the reinforcement filler. The alkylation of an amine moiety results in an alkyl amine moiety -NHRg, where Rg is hydrocarbyl or substituted hydrocarbyl. Alkylation of a carboxylic acid can result in an alkyl ester-COOR10 as the surface modification, where R10 is a hydrocarbyl or substituted hydrocarbyl. Other modifications include peroxidation, where a peroxide can be incorporated into the surface of the reinforcement filler.
    [00052] The modification level of the reinforcement filler material may vary depending on the application. In some embodiments, the reinforcement filler can be modified to the degree that the modifying reagent forms an outer layer of the filler. In other embodiments, the modifications may be more dispersed, leaving gelatin-like coating or the surface of reinforcing filler material as the outermost layer in some areas. The titration of the functional groups is shown in FIG. 16 and shows the number of surface functionalities in a polymer composite after modification with various reagents.
    [00053] The high aspect ratio of reinforcement fillers shows high levels of biocompatibility. Biocompatibility is a measure of a material's suitability for biological uses and is important for medical and dental applications. Biocompatible materials are non-toxic, cause little or no immune response when placed in a biological system, and do not cause high levels of cell death in the surrounding tissues. The biocompatibility of the polymer composites described here was tested by MTT analysis which showed a high level of biocompatibility compared to other fillers. ç. Compositions
    [00054] Polymer composites comprise the polymer matrix and reinforcement fillers. The reinforcement fillers can be of a single type or a mixture of reinforcement fillings. Reinforcement fillers can be present in a range of weight percentages of the polymer composite, also called loading rate. Loading rates can vary widely in different polymeric matrices. The stiffness of a polymer composite generally increases with the loading rate, however, there is also a point at which additional loading causes decreases in the mechanical properties of the polymer composite. In some embodiments, the amount varies from about 0.5 to 80% by weight of the polymeric compound. In alternative embodiments, the amount of reinforcement filler material can vary from about 1 to 50% by weight of the polymeric composite. In yet another embodiment, the amount of filler material ranges from about 20% by weight to about 60% by weight and, in yet another aspect of the invention, the amount of filler material varies from about 3% by weight to about 15% by weight.
    [00055] Composites may also contain additional fillers. Additional fillers can provide additional mechanical properties for polymeric composites. Additional fillers can be any acceptable filler known in the art. The additional fillers can also be polymeric, such as calcium phosphates, strontium glass, barium glass, quartz, borosilicate glass, ceramic, silica, silicon nitride, silicon carbide, zirconia, medical grade ceramic, poly (L-lactide), poly (e-caprolactone), poly (lactide-co-glycolide), chitosan, cellulose, collagen, gelatin, chitosan, cellulose, collagen, gelatin and other medical polymers. The additional filler material can be of various shapes, such as particle, rod or fiber. Additional filling materials can be of various sizes on the gauge, submicrometric and micrometric scales.
    [00056] Additional filler materials can be of various sizes in the nanometric, submicrometric and micrometric scales. The amount of additional filler material present in the composite can vary widely depending on the application. In some embodiments, the amount of additional filler material can vary from 0 to 80% by weight of the polymeric composite. In an alternative embodiment, the additional filler material can vary between about 50 and about 70% by weight of the polymeric composite. In a preferred embodiment, the amount of additional filler material can be about 60% by weight of the polymeric composite.
    [00057] Polymer composites or individual components can be further modified mechanically by means of a variety of methods described in Part II. Mechanical modifications can provide better dispersion of various ingredients in the polymer composite. In particular, mechanical modifications can provide better dispersion of the reinforcement filler material through the polymer matrix as seen in both Scanning Electron Microscopy and Transmission Electron Microscopy.
    [00058] In some embodiments, mixed polymer composites can be a highly viscous liquid. Polymer composites are transformed into solids through the curing or molding process. Cured or molded polymer composites have the advantageous properties of biocompatibility, strength and water absorption described here.
    [00059] The polymer composites described may additionally exhibit high levels of biaxial flexural strength, flexural strength, tensile strength, elongation, etc. Strength is a measure of a material's ability to resist deformation under stress. Polymer composites advantageously provide mechanical properties over the same polymers without fillers. In one embodiment, adding high-aspect ratio calcium phosphate filler materials increases the biaxial strength of polymers in an amount ranging from about 2% improvement to about 100% improvement. II. Method of Manufacturing Polymer Composites
    [00060] Another aspect of the present invention provides a method of making polymer composites. The method comprises mixing a high aspect ratio reinforcement filler material selected from nanofiber, nanoplate, submeron fiber, submeron plate and their combinations, in a polymeric matrix. The method can also comprise several modifications. The. Polymer Matrix
    [00061] The polymeric matrix can be provided either as a commercially available polymer, polymer mixture or can be synthesized.
    [00062] The synthesis of polymers can be carried out by any method known in the art. Acceptable monomers include, but are not limited to, monomers listed in Part 1 (a). Polymer synthesis may require the use of an acceptable solvent and / or catalyst or initiator. Polymerization solvents include any solvent acceptable for the polymerization reaction, including acetone, alcohols, chloroform, 1,2-dichloroethane, dioxane, ethyl acetate, hexanes, methyl ethyl ketone, water and mixtures thereof. Non-limiting examples of suitable polymerization initiators include ketones, peroxides, amino and vinyl initiators or catalysts. Specific examples of initiators or catalysts include, but are not limited to, camphorquinone (CQ), phenylpropanedione, lucirin, ethyl-4-dimethylaminobenzoate (E4), 2,2'-azobis (2-methylpropionitrile), benzoyl peroxide and the like. Catalysts and initiators can be added for any reason sufficient to give polymerization. Typically, the initiators or catalysts are supplied to the reaction in 1 to 10% by weight for the weight of the polymer.
    [00063] The matrix can also comprise a mixture of two or more polymers. The polymers can be mixed by any method including by manual mixing, grinding, sonication and the like. A solvent can be used to facilitate mixing by temporarily reducing the viscosity of the polymers. Preferably, the solvent will be evaporated from the polymer and not included in the polymeric matrix in any substantial amount.
    [00064] Mechanical modifications can be provided to polymers or polymeric matrices, as described below in Part II (c). B. Reinforcement filling materials
    [00065] Reinforcement filler materials can be purchased or synthesized. Synthesis of unmodified calcium phosphate reinforcement fillers can be performed by any method known in the art. For example, hydroxyapatite reinforcing filler materials are synthesized by combining calcium nitrate with phosphate salt in the presence of gelatin and urea and heating at a temperature of about 60 ° C to about 100 ° C for 1 to 5 days. In a preferred embodiment, calcium nitrate is (Ca (NOs) 2), dihydrogen phosphate, sodium phosphate (NaHhPCU), gelatin and urea are dissolved in water and the concentrations of calcium nitrate (Ca (NO3) 2), dihydrogen phosphate sodium (NaHhPCU), gelatin and urea are, respectively, 0.02 mol / L (mol / liter), 0.02 mol / L, 0.2 g / L (gram / liter) and 0.04 mol / L. The solution can be mixed, then heated to 95 ° C and maintained at 95 ° C for 72 hours. The concentration of reagents can influence the formation of fillers.
    [00066] Reinforcement filler materials can also be chemically modified. Chemical modifications can be achieved by wet chemistry methods, as well as by plasma treatment. Using wet chemistry to modify the reinforcement filler materials, the modification reagent is added to a diluted solution of the reinforcement filler. A solvent can be provided in about 100 to about 1,000% by weight for the weight of the reinforcement filler materials. Reinforcement fillers are generally dispersed in the solvent before adding the modifying reagent.
    [00067] The amount of modification reagent added to the reaction depends on the type of modification being carried out, the method of carrying out the modification and the reinforcement filler material being modified. The amount of modifying agent provided can vary from about 5% by weight to about 300% by weight for the amount of reinforcement filler. The amount of time required for the modification reaction can also vary widely. Modification reactions can occur over a period of 10 minutes to 2 days.
    [00068] In some embodiments, chemical modification is facilitated by plasma treatment. Plasma treatment can be performed in a number of ways and is within the scope of the invention. A typical plasma treatment can be carried out by placing the reinforcement filler in a glass reactor under vacuum. The reactor provides a gas flow stream as well as a high energy plasma source. Plasma facilitates the reaction between gaseous reagents and the reinforcement filler to achieve a change in the surface through gas reactions. Various volatile reagents can be used to provide the desired functionality. For plasma treatment, gaseous reagents can be supplied with an inert gas to lower the gas concentration of the gaseous reagent.
    [00069] Modification reagents for both wet chemistry and plasma chemistry methods are chosen from amines, alkyl groups, carboxylic acids, peroxides and silanes. Exemplary amine reagents are ammonia and alkyl amines. Examples of carboxylic acid reagents are acrylic acid, citric acid, 12-aminododecanoic acid, dodecanoic acid, dodecanedioic acid, glycolic acid, glycoxyl acid, lactic acid, methacrylic acid and the like. Examples of silane reagents include 3-methacryloxypropyltrimethoxy silane (3-MPS) and hexamethyldisiloxane (HMDSO), (trimethoxysilyl) propylamine, 3-aminopropyltriethoxysilane, 4-aminobutyltriethoxysilane, 3-aminopropyltri (methoxyethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy-ethoxy) N- (2-aminoethyl) -3-aminopro-piltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyltriethoxysilane. Other exemplary reagents include methane, carbon dioxide, O2 and unsaturated and saturated hydrocarbons where the number of carbon atoms ranges from 1 to 20. Gaseous or volatile reagents are suitable for plasma chemistry, although liquid reagents are suitable for wet chemistry.
    [00070] Chemical modifications may also require the addition of several additional reagents to facilitate the reaction. For example, the modification can be carried out with additional reagents to facilitate the reaction, such as catalysts, cleaners or acids or bases. For example, modification of acrylic acid is known to be facilitated by a catalyst present in about 1 to 10% by weight of the reinforcement filler. An exemplary catalyst for the reaction is sodium cyanoborohydride.
    [00071] Mechanical modifications can be provided for reinforcement filler materials, as described below in Part ll (c). ç. Mixture
    [00072] The method comprises mixing the reinforcement filler materials in the polymeric matrix to give the polymeric composite. The mixture can be supplied either to liquid polymers or to dry polymers. The mixture can be supplied by any acceptable means, including through manual and automated methods. Mixing can additionally be facilitated by a method of mechanical modification described herein.
    [00073] The mixing step may additionally comprise a solvent. The solvent can provide high mixing by temporarily reducing the viscosity of the materials. The solvent can be chosen from a range of suitable solvents including acetone, alcohols, chloroform, 1,2-dichloroethane, dioxane, ethyl acetate, hexanes, methyl ethyl ketone, water and mixtures thereof. Preferably, the solvent evaporates from the composition, such that the solvent is not incorporated in the final composite in any substantial amount. The amount of solvent used can vary depending on the desired viscosity from about 1% by weight of the polymer composite to about 50% by weight of the polymer composite. d. Additional Steps
    [00074] The process may further comprise an additional step or steps, including mechanical modifications and / or curing.
    [00075] Mechanical modification can further increase the mixture to achieve the desired dispersion or beam size. Mechanical modifications can be provided for the reinforcement filler materials, the polymer matrix or the polymer composite. Examples of methods of mechanical modification are sonication, melt mixing, grinding and the like.
    [00076] Sonication involves applying sound to shake a sample. Sonication can increase the dispersion of reinforcement fillers in the polymer matrix and can also reduce the level of grouping in the reinforcement fill materials. Sonication can be performed by a commercial sonicator, using an ultrasonic horn, or by any available means. The amount of time that a reinforcing filler material, polymer matrix or mixture must be subjected to sonication depends on the level of dispersion or the size of the desired bundles. Longer sonication times result in more dispersion and smaller beams. In one embodiment, sonication is provided for a period of time ranging from 20 minutes to 2 days. In another embodiment, sonication is provided for a period of time ranging from 1 hour to 10 hours. In a preferred embodiment, sonication is provided for 6 hours.
    [00077] Fusion mixture can also be used to facilitate dispersion. Melt blending can be obtained by mixing the dry matrix polymers with dry reinforcement fillers. The melt blending can also be achieved using a compost or micro-compost. Rotation speeds and residence times can be varied for ideal conditions and are within the scope of the invention.
    [00078] The method can also comprise a milling step that mixes both reinforcement fillers and the polymeric matrix and increases the dispersion of the reinforcement fillings in the polymeric matrix. Various commercial grinders are available and grinding can also be carried out manually, providing strength during mixing of the polymer matrix and fillers. Grinding can be supplied in different granulation sizes and at various speeds and is within the scope of the invention.
    [00079] The method can also comprise a healing stage. Polymer composites can be cured by any method known in the art including, but not limited to, the addition of chemical curing additives, UV radiation, light, electron beam, heat or by exposure to environmental conditions.
    [00080] The method may comprise hot pressing. In this process, the polymeric composites are elevated at elevated temperatures and then maintained at high pressure to form composites. The method may additionally comprise injection molding and / or machining. In this process, the polymer composites are molded using an injection molding machine. Composites can be formed in different ways depending on the application.
    [00081] Composites can also be machined, for example, using a lathe machine to have a particular shape for various applications. III. Method of Using Polymer Composites
    [00082] In another embodiment, the polymer composites described here can be used in dental and biomedical applications.
    [00083] Polymer composites can be used as a dental restorative material. Dental restoration may be necessary to provide reinforcement for a tooth that is structurally damaged. In the case of damage caused by decay, the decayed portion of the tooth is first removed, which can cause additional structural damage. The polymer composite is then used to fill the removed or missing area due to decay or damage. The polymer composite has the effect of sealing the fallen region of additional decay and / or reinforcing the tooth structure.
    [00084] The polymeric composites described here can be applied in a manner similar to that of other dental fillers. Polymeric composites are supplied in a moist (soft) state on the surface of the tooth being restored. The polymer composite can be applied using standard dental equipment, such as tweezers. The polymer composite can be shaped to suit any particular purpose or while wet by removing or forming the wet polymer composite or after the polymer composite has been cured by polishing and molding.
    [00085] The polymeric composites described here can be applied to make other dental components, such as crown and composite-based veneers, and then applied.
    [00086] Polymer composites can also be used in orthopedic applications. Orthopedic uses of polymeric composites aim to remedy weaknesses in bone structure. In some applications, the polymer composite can be molded into internal bone fixation devices, such as bone screws, plates, pins and rods that guide healing or provide reinforcement to the bone structure. The fixing devices are formed by injection molding and hot pressing. Polymer composites formed in a fixation device can be placed on the bone structure or by open or closed surgery, depending on the application.
    [00087] In some aspects of the invention, the fixtures are intended to be permanent and in other aspects of the invention the polymer composite fixtures degrade over time.
    [00088] As another example of orthopedic applications, polymer composites can be applied to bone in a moist or partially cured (soft) format, such as in the form of bone cements. The soft or wet composite material can be used to support bone and to reinforce an internal fixation device. DEFINITIONS
    [00089] As used herein alkyl means a hydrocarbyl or a substituted hydrocarbyl which can be cyclic or straight chain. Unless otherwise indicated, these portions preferably comprise 1 to 20 carbon atoms.
    [00090] As used herein, calcium phosphates include calcium ions (Ca2 +) in conjunction with one or more ions containing phosphate. Phosphate ions include phosphate-containing molecules, including orthophosphates (PO ’), metaphosphates (PCs’) and pyrophosphates (P2O74). Calcium phosphates can further comprise one or more additional anions. Non-limiting examples include hydroxide ions (OH), carbonate ions (CO32), fluorine ions (F), chlorine ions (Cl), sulfate ions (SO ) And their combinations. Calcium phosphates can also contain one or more cations including, by way of non-limiting example, hydrogen ions (H +), sodium ions (Na +), potassium ions (K +), magnesium ions (Mg2 +), silver ions (Ag +) and their combinations. Calcium phosphates can be further stabilized by an anion (X '), preferably (OH'), (COs2 '), (F'), (Cl ') or mixtures thereof.
    [00091] As used herein, hydrocarbyl means organic compounds or ions consisting exclusively of the elements of carbon and hydrogen. These portions include alkyl, alkenyl, alkynyl and aryl. They can be cyclic or linear. Unless otherwise indicated, these portions preferably comprise 1 to 20 carbon atoms.
    [00092] As used herein substituted hydrocarbyl means hydrocarbyl moieties which are replaced by at least one other atom other than carbon and hydrogen. These atoms can be nitrogen, oxygen, silicon, sulfur, phosphorus, boron or a halogen. They can be cyclic or straight-chain. Unless otherwise indicated, these portions preferably comprise 1 to 20 carbon atoms.
    [00093] As used here, nanofiber means a fiber with a diameter less than 100 nm.
    [00094] As used herein, nanoparticle means a plate where all three dimensions of the particle are less than 100 nm.
    [00095] As used herein, nanoplate means a plate where the thickness of the plate is less than 100 nm.
    [00096] Silver nano filament, as used herein, means bundles with a diameter less than 100 nm and is also characterized by a small aspect ratio, typically less than 5.
    [00097] Sub-micron fiber as used herein, means a fiber with a diameter greater than 100 nm, but less than 1 pm.
    [00098] As used here, submicron plate means a plate where the plate thickness is above 100 nm, but less than 1 pm.
    [00099] As used herein, silica is a material substantially comprised of silica oxides, SiOx, where X is any integer. EXAMPLES
    [000100] The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those skilled in the art that the techniques disclosed in the examples represent techniques discovered by the inventors to work well in the practice of the invention. Those skilled in the art, however, should, in the light of this disclosure, appreciate that many changes can be made to the specific modalities that are revealed and still obtain an equal or similar result without deviating from the spirit and scope of the invention, therefore, all the established matter will be interpreted as illustrative and not in a limiting sense. Example 1. Synthesis of Hydroxyapatite Nanofiber (HA)
    [000101] HA reinforcing filler materials were manufactured by dissolving Ca (NOs) 2, sodium hydrogen phosphate NaH2PO4, gelatin and urea in water. The concentrations of calcium nitrate (Ca (NO3) 2), sodium dihydrogen phosphate (NaH2PO4), gelatin and urea are respectively 0.02 mol / L (mol / liter), 0.02 mol / L, 0.2 g / L (g / liter) and 0.04 mol / L. The mixed solution was then warmed up from room temperature to 80 to 100 ° C and maintained between 80 and 100 ° C for 72 hours. The resulting filler materials were then filtered, washed with deionized water and dried at room temperature. The synthesis parameters have been optimized to provide reinforcing filler materials with a high aspect ratio. FIGs. 2 (a) to (d) are SEM images of samples made with different gelatin concentrations (75 bloom). The reaction temperature was 80 ° C for all three experiments; the gelatin concentration was varied between 0 and 2 g / L, and the experiments lasted approximately 24 hours. Without any gelatin, most HA crystals have a plaque-like structure (FIG. 2a). The average length, width and thickness of HA materials are about 30 pm, 4 pm and 100 pm, respectively, and such HA materials are HA nanoplates and HA submicroplates. By adding 0.4 g / L of gelatin, growth in the width direction was significantly impeded and more nanofibers were observed. The average width has shrunk to 0.50 at 2 pm and the thickness has been about 250 nm. When more (2 g / L) gelatin was added to the solution, more nanofibers were formed. The average diameter was about 200 to 300 nm. No significant length changes were observed for the three conditions with different concentrations of gelatin. Gelatin has confined the growth of hydroxyapatite fibers, especially in the width direction in solutions. High-strength gelatin gel (225 bloom) had similar effects on the growth of hydroxyapatite as those of low-strength gelatin gel (75 Bloom). FIGs. 3 (a) and (b) are SEM images of HA fillings grown at 100 ° C for 72 hours. The average length was about 60 pm, twice the length of samples taken at 80 ° C. The average diameter was smaller, around 100 nm. These conditions yield longer and thinner HA fillings. Some HA nanofibers grown at 100 ° C are not well dispersed, but primarily bundles. Example 2. Improvement in flexural strength of PLA composites and modification
    [000102] FIG. 4 shows the effects of modification on a variety of poly (L-lactide) (PLA) composites. FIG. 4 shows the flexural strength (in MPa) of unmodified PLA composites, PLA composites with 2% by weight of HA reinforcement fillers as received, PLA composites with 2% by weight of HA reinforcement fillers with sonication , and PLA composites with 5% by weight of HA reinforcement fillers with sonication. Example 3. Biocompatibility of Filling Materials and Composites
    [000103] Cell studies were performed with the MC3T2-EI cell line (American Type Culture Collection, VA). The cells were maintained in minimal modified alpha-essensical medium (a-MEM) without ascorbic acid supplemented with 10% fetal bovine serum (FBS) and incubated in a humidified atmosphere of 37 ° C at 5% CO2. MTT (3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide) was applied to assess cell vitality and proliferation. Living cell mitochondrial dehydrogenases reduce the tetrazolium ring, resulting in a blue formazan product that can be measured spectrophotometrically. The amount of formazine present is proportional to the number of viable cells present.
    [000104] Using Ti as a control, the biocompatibilities of HA nanofiber filler materials and HA nanoparticle filler materials were tested. FIG. 5 (a) shows the average of several MTT tests. The MTT results indicate that HA nanofibers are significantly more biocompatible in terms of cell vitality and proliferation than HA nanoparticles. In addition, the MTT results show the advantages over titanium.
    [000105] FIG. 5 (b) shows the average of several MTT tests using L929 cell lines. The MTT results indicate that HA nanofibers have better biocompatibility than HA nanoparticles and adding HA nanofibers to dental composites also improves biocompatibility. Example 4. Modification by Glyoxylic Acid
    [000106] Modification by glyoxylic acid was carried out by dissolving 5g of hydroxyapatite nanofibers as received in 150ml of deionized water. 0.39 g of glyoxylic acid was then added and the solution was stirred for 30 minutes. During stirring, 0.28 g of sodium cyanoborohydride was added dropwise. After stirring for 24 hours, the fibers were filtered and rinsed with deionized water 5 times to remove any residual catalyst. Then, HA nanofibers were air-dried at room temperature. FIG. 6 (b) shows the TEM (Transmission Electron Microscopy) of HA nanofibers with significantly improved dispersion. FIG. 7 shows the FT-IR spectra of HA nanofibers as received and HA nanofibers modified by glyoxylic acid. FT-IR shows that, compared to the HA nanofibers as received, the peak intensities for C = O (about 1640 cm-1), CH (about 2918, 2850, 1470 cm1) and OH (about 3457 cm-1) are significantly higher. These results indicate that there are more C = O, C-H and OH portions in the modified sample. Example 5. Resistance to biaxial flexion
    [000107] Several HA nanofibers and silanized silica particles of 0.7 micrometer size were tested in a polymeric matrix. The polymeric matrix contained 49.5% by weight of Bis-GMA and 49.5% by weight of TEGDMA comonomer, camphorquinone (0.5% by weight) and ethyl-4-dimethylaminobenzoate (0.5% by weight). HA nanofibers were added in mass fractions of 2% by weight, 3% by weight, 5% by weight, 7% by weight and 10% by weight, 60% by weight with silanized silica particles of size were also tested as a control. The desired reinforcement fillers were added to vials with Bis-GMA and TEGDMA and acetone. An ultrasound horn was used to disperse the filling materials in the polymeric matrix. Camphorquinone and ethyl-4-dimethylaminobenzoate were added as initiators and the flask was covered with aluminum foil. After mixing thoroughly, the solutions were added to a Teflon® mold (diameter 12 mm, thickness 1.5 mm) covered by a glass slide. The samples were cured.
    [000108] An SMS TA HDPIus Texture Analyzer was centered on the disk model. A 100 kg load cell was used to apply the load and the samples were supported by three ball bearings positioned 120 ° from each other in a circle. SMS TA HDPIus recorded the load applied as a function of time. Resistance to biaxial flexion was calculated according to a method commonly used and reported by Skrtic and Antonucci (2004). FIG. 8 shows an average of several experiments. Fig. 8 shows the improvement of HA nanofibers modified by glyoxylic acid over HA nanofibers as received. The biaxial flexural strength for polymer composites was highest at 3% by weight of HANF and 5% of HANF. HA nanofibers as received at 3% by weight had a biaxial flexural strength of 124.2 ± 3.5 MPa, 29% higher than the control, and HA fibers modified by 3% by weight of glyoxylic acid had a biaxial flexural strength of 134.5 ± 3.4 MPa, 40% higher than the control. Example 6. Silanization and strength of the composite
    [000109] The silanization process was carried out on 5g of hydroxyapatite reinforcing filler. 15 ml of 3-methacryloxypropyltrimethoxy silane was added to a mixture of 300 ml of acetone and water (70/30). The solution was heated at 40 ° C for 3 hours under constant magnetic stirring followed by subsequent treatment at 60 ° C for 5 hours. Then, the mixture was filtered and washed with acetone and water at least twice and then transferred to an oven at 120 ° C for 2 hours to remove excess water and solvent. FIGs. 9 (a) and (b) are the high resolution FT-IR spectra of HA reinforcing filler materials before and after the silanization treatment. In addition to the characteristic peaks of HA and gelatin, the characteristic absorbance bands of silane (3-methacryloxypropyltrimethoxy silane), including the C = O methacrylate stretching vibration (approximately 1. 720 cm1) and symmetric Si-O-Si H (approximately 2004 cm-1), were identified in the FT-IR spectra. Sample making and mechanical testing were similar to Example 5. Water absorption from dental composites containing silanized HA reinforcement fillers was investigated based on the American Dental Association protocol (ADA, 1993).
    [000110] The results of biaxial flexural strength test are included in FIG. 10. As shown in FIG. 10, the addition of HA reinforcing filler materials as received without fillers did not significantly improve the biaxial flexural strength over the control. The addition of HA modified by glyoxylic acid and silanized HA significantly improved the mechanical strength.
    [000111] FIG. 11 is the SEM (Scanning Electron Microscopy) image of the surface of dental composites reinforced by 5% by weight of silanized HA reinforcement fillers in 55% by weight of silica microparticles. As shown in FIG. 11, the individual beam size was typically less than 1 micrometer, much smaller than the bundles in HA reinforcement fillers as received. FIG. 11 also shows the removal of fibers in the composite.
    [000112] The composites were also immersed in distilled water for 7 days. FIG. 12 compares the water absorption rate of the composites. As shown in FIG. 12, both composites reinforced with 2% silanized HA and composites reinforced with 5% silanized HA have a lower water absorption rate (35 pg / mirr3 and 36 pg / mirr3, respectively) than that of the ADA standard (40 pg / mirr3). Example 7. Treatment of acrylic acid and composite strength
    [000113] The modification of a hydroxyapatite reinforcing fiber was also carried out using acrylic acid. 1.00 g of HA reinforcement fillers as received was added to the acetone and sonicated by a Sonifier® 450 (Branson, Inc.) for 20 minutes. 3.00 g of acrylic acid were added to the mixture and homogenized by Sonifier® for 15 minutes. The suspension was magnetically stirred at 50 ° C for 12 hours. Then, the suspension was washed to remove unbound acrylic acid. HA nanofibers modified by acrylic acid were dried and stored under ambient conditions for later use.
    [000114] Acrylic acid modified HA reinforcement filler materials were added to a Bis-GMA polymer matrix : EG MA 2: 1. A mixture of the polymers, the nanofibers of HA modified by acrylic acid and the silica particles was stirred magnetically with 5 ml of acetone for 30 minutes. The mixture was then sonicated on the Sonifer® 450 for 10 minutes. The mixture was magnetically stirred for an additional 2 hours at 50 ° C. Camphorquinone and ethyl 4-dimethylamino-benzoate were added to the solution, while the reactor was completely covered with aluminum foil to prevent curing. The mixture was cooled to 4 ° C for 1 hour.
    [000115] The mixture was placed in a round mold covered with glass slides. The mechanical properties were tested using the protocol of Example 5. The dry fibers as received and the reinforcement fillers of HA modified by acrylic acid were characterized by FT-IR. FT-IR confirmed the modification of the surface. As shown in FIG. 13, the carbonyl portion (C = O, 1710 cm1) and the hydroxyl portion (OH, 2900 to 3450 crrr1) were observed for HA reinforcement fillers modified by acrylic acid.
    [000116] Thermogravimetric analysis (TGA) was performed for received HA reinforcement filler materials and acrylic acid modified HA fillers with a Q-5000-IR (TA Instruments, Inc.) and weight loss was measured by Universal Analysis 2000. Nitrogen (10.0 mL / min) was used as the equilibrium gas. Measurements were performed at 30 ° C to 1,000 ° C. As shown in FIG. 14, two different steps of weight loss were found in reinforcement fillers of HA modified by acrylic acid in the range of 162 to 235 ° C and 374 to 452 ° C, compared to HA fill materials as received.
    [000117] Biaxial flexural strengths were also measured against a 3M Filtek Z25® as a control (only consists of silica particle fillers). FIG. 15 shows, compared to the 3M Filtek Z250 product, that both acrylic acid modified HA reinforcement fillers have a higher / better reinforcement effect than just silica. Example 8. Surface modification of HA reinforcement filler materials with different modifications
    [000118] The HA reinforcing filler was modified on the surface with three reagents, 12-aminododecanoic acid, dodecanoic acid and dodecanedioic acid, respectively. Surface functional group titration was used to characterize the surface modification. The result is shown in FIG. 16. All modifications were made at 95 ° C to determine the extent of functionalization. The result of the titration of the surface carboxyl group has twice the portions of carboxylic acid on the reinforcement filler surface modified by dodecanedioic acid and twice the amino portions on the surface of HA reinforcing fibers modified by 12-aminododecanoic acid. Example 9. Synthesis of DCPA Reinforcement Filler Materials and Dental Composites with DCPA Reinforcement Filler Materials.
    [000119] DCPA reinforcing filler materials were manufactured by dissolving Ca (NOs) 2, sodium hydrogen phosphate NaH2PO4, gelatin and urea in concentrations of 0.02 mol / L (mole / liter), 0.02 mol / L, 0.2 g / L (grams / liter) and 0.04 mol / L, respectively. The mixed solution was then warmed up from room temperature to 95 ° C and maintained at 95 ° C for 1 to 9 hours. The resulting reinforcement fillers were then filtered, washed with deionized water and dried at room temperature to give dry reinforcement fillings. X-ray diffraction (XRD) in FIG. 17 showed the characteristic peaks of DCPA in regions 20 of 26.5 °, 30.1 ° and 30.3 °, respectively. Figure 18 shows SEM images of DCPA nanofibers.
    [000120] 2,2-Bis [4- (2-hydroxy-3-methacryloyloxypropyl) phenyl] propane / T triethylene glycol and bisphenol-A-dimethacrylate ethoxylate / 1,6-bis- [2- methacryloyloxyethoxycarbonylamino] -2,4,4-trimethylhexane containing DCPA reinforcement fillers and the combination of DCPA and HA reinforcement fillers were fabricated and biaxial flexural strengths were measured. FIG. 19 shows that dental composites containing 2% by weight of DCPA have significantly higher biaxial flexural strength than the control (~ 100 MPa, dental composites containing only silica particles). Example 12. Preparation of injection-molded PLA composites with HA reinforcing filler materials
    [000121] Injection molding was used to make HA reinforcing filler materials in PLA matrices. PLA resin (Purac) was stored at 15 ° C to prevent degradation. In order to obtain a good dispersion and mixing effect, the PLA pellets were ground to small particles in a mixer (Blentec) for 3 minutes and 20 seconds at the highest speed. Then, the ground PLA particles and reinforcement fillers were mixed into a dough and the mixtures were ground for 90 seconds and stored in plastic bags at 15 ° C until the machine was ready for injection molding. A mini-ejector 45 model was used for injection molding of pure PLA and PLA / HA samples. 25 grams of PLA / HA were heated to 232 ° C inside the injection cylinder for 5 minutes. Thereafter, the samples were injection molded into ASTM standard aluminum mold (ASTM D638 and ASTM D5934 standard IV test sample) at 95 psi of pressure, 6 seconds of injection time and 232 ° C nozzle temperature. After the injection molding process, the samples were removed from the mold and stored in a desiccator for mechanical testing. Both the tensile test (ASTM D638) and the flexion test (ASTM D5934) were performed with an Instron model 3600 in the corresponding ASTM standard.
    [000122] As shown in FIG. 20 (a), the addition of reinforcement fillers can significantly improve the flexural strength of the polymeric matrix. The incorporation of 5% by weight of silanized reinforcement fillers increased the flexural strength by 49.8% compared to pure mixed PLA. In addition, surface modifications increased flexural strength. FIG. 20 (b) shows the flexural modulus up to 29.6% compared to pure mixed PLA. The tensile strength and module are shown in FIG. 21. Tensile strength was increased significantly from 54.1 ± 4.5 MPa to 73.6 ± 2.3 MPa, with the addition of 5% by weight of silanized HA reinforcement fillers, which is 36.1% . The drive module has also been substantially improved.
    [000123] FIG. 22 shows the typical stress-strain curve for PLA and PLA composites containing original unmodified HA reinforcement fillers, glyoxylic acid modified HA reinforcement fillers and silanized HA reinforcement fillers. FIG. 23 shows the maximum deformation of different samples. In all cases, the maximum deformation at the point of failure increases with the addition of HA nanofibers as received or modified on the surface from ~ 1.7% to 2.3% to 2.6%. Maximum deformation was also referred to as elongation, which characterizes how much the materials could be elongated in a tensile test at break. Higher elongation indicates higher toughness and higher impact resistance.
    [000124] It is understood that the previous detailed description and the accompanying examples are merely illustrative and should not be taken as limitations on the scope of the invention, which is defined only by the attached claims and their equivalents. Several changes and modifications to the revealed modalities will be evident for the technicians versed in the subject. Such changes and modifications, including, without limitation, those related to the chemical structures, formulations, or methods of using the invention can be made without departing from its spirit and scope.
    权利要求:
    Claims (11)
    [0001]
    Polymer composite, characterized by the fact that it comprises: a polymer matrix and a reinforcement filler material in which the reinforcement filler material comprises calcium phosphate nanofibers, submicron fibers, or combinations thereof, in which the reinforcement material The reinforcement filler has a gelatin-coated surface comprising portions of amine, portions of carboxylic acid, or combinations thereof, and wherein the reinforcement filler material has a diameter or thickness ranging from about 10 nm to about 1 pm and an aspect ratio ranging from about 50 to about 000 and present in an amount ranging from about 0.6% by weight to about 15% by weight.
    [0002]
    Polymer composite according to claim 1, characterized in that portions of amine, portions of carboxylic acid, or combination thereof on the gelatin-coated surface are modified with a reagent selected from the group consisting of alkyls, amines, acids carboxylics, peroxides and silanes.
    [0003]
    Polymer composite according to claim 1, characterized in that the reinforcing filler material is present in an amount ranging from about 0.6% by weight to about 6% by weight.
    [0004]
    Polymer composite according to claim 1, characterized in that the reinforcing filler material is in bundles.
    [0005]
    Polymer composite according to claim 1, characterized in that the diameter or thickness of the reinforcement filler material is between about 50 nm and about 500 nm.
    [0006]
    Polymer composite according to claim 1, characterized by the fact that the aspect ratio is between about 100 and about
    [0007]
    Polymer composite according to claim 1, characterized in that the polymeric matrix comprises a mixture of bisphenol A glycidyl methacrylate and triethylene glycol dimethacrylate.
    [0008]
    Polymer composite according to claim 1, characterized in that the polymer matrix comprises poly (L-lactide).
    [0009]
    Polymer composite according to claim 4, characterized in that the bundles have a diameter less than about 5 pm.
    [0010]
    Polymer composite according to claim 4, characterized by the fact that the bundles have a diameter less than about 2 pm.
    [0011]
    Polymer composite according to claim 1, characterized in that the polymer composite further comprises an additional filler material selected from the group consisting of calcium phosphates, strontium glass, barium glass, quartz, borosilicate glass , ceramics, silica, silicon nitride, silicon carbide, zirconia, medical grade ceramics, poly (L-lactide), poly (e-caprolactone), poly (lactide-coglycolide), chitosan, cellulose, collagen, gelatin and mixtures of the same.
    类似技术:
    公开号 | 公开日 | 专利标题
    BR112013000962B1|2020-06-23|POLYMER COMPOSITE
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    同族专利:
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    JP2018149346A|2018-09-27|
    CN107778528A|2018-03-09|
    JP2017048393A|2017-03-09|
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    BR112013000962A2|2016-05-17|
    WO2012009555A3|2012-03-29|
    CN103096840A|2013-05-08|
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    法律状态:
    2018-12-26| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-09-03| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-04-14| B15K| Others concerning applications: alteration of classification|Free format text: A CLASSIFICACAO ANTERIOR ERA: A61F 2/28 Ipc: A61L 27/46 (2006.01), C08K 7/08 (2006.01) |
    2020-04-22| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2020-06-23| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 14/07/2011, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    US39958010P| true| 2010-07-14|2010-07-14|
    US61/399,580|2010-07-14|
    PCT/US2011/044040|WO2012009555A2|2010-07-14|2011-07-14|Polymer composites and fabrications thereof|
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