Electrical response shape memory PETG invisible orthodontic diaphragm and preparation method thereof

Abstract

The invention belongs to the field of polymer composite materials, and relates to an electrical response shape memory PETG invisible orthodontic membrane and a preparation method thereof. The diaphragm comprises the following raw materials in parts by weight: 10-15 parts of PETG granules, 50-80 parts of an organic solvent and 3-5 parts of a modified conductive filler. The electrical response shape memory PETG invisible orthodontic diaphragm prepared by the invention has a shape memory function, can realize continuous orthodontic treatment by adjusting the shape of a tooth socket, and does not need to be frequently replaced; the shape memory function of the diaphragm is electric response, the shape memory characteristic of the material can be triggered through current, and the response is fast; wherein the modified conductive filler endows the material with local heating capacity, the shape memory effect of the material can be activated only by applying an electric signal to a specific part, the energy utilization efficiency is high, and the shape recovery process is accurate.

Description

Technical Field

[0001] The present invention belongs to the field of polymer composites, and particularly relates to an electro-responsive shape memory PETG invisible orthodontic membrane and a preparation method thereof. Background Art

[0002] Tooth malocclusion is a common oral problem caused by the combined action of genetic and acquired factors, mainly manifested as abnormal tooth arrangement, protrusion, etc.; such problems not only affect facial aesthetics, but may also lead to chewing, swallowing and speech dysfunction, and even affect respiratory function in severe cases. With the increasing attention to oral health, the demand for orthodontics has shown a rapid growth trend.

[0003] Currently, orthodontic treatment mainly relies on orthodontic appliances to adjust the position and movement trajectory of teeth. Among them, invisible orthodontic appliances have gradually become a preferred alternative to traditional fixed orthodontic appliances due to their transparent appearance, convenient wearing, high comfort, and less dietary restrictions. However, since invisible orthodontic appliances are usually made of polymer materials, their mechanical properties are relatively weak, and auxiliary means such as adding attachments are often required when dealing with complex tooth movements. In addition, for patients who require long-term treatment, invisible orthodontic appliances need to be replaced frequently, which increases the time cost and energy cost of treatment.

[0004] PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol ester) is a transparent, non-crystalline copolyester with excellent mechanical properties, high transparency, biocompatibility and chemical resistance. However, its shape is difficult to change after shaping, resulting in frequent replacement during orthodontics, which makes it have certain limitations as an orthodontic appliance material. Therefore, modifying the PETG material to endow it with multifunctionality to meet the requirement of less replacement times is the core content of the present invention. Summary of the Invention

[0005] In view of the above technical problems, the present invention proposes an electro-responsive shape memory PETG invisible orthodontic membrane and a preparation method thereof. The present invention uses PETG as the matrix to prepare a composite material with high performance; this material has an electro-responsive shape memory function and can achieve continuous orthodontics by adjusting the shape of the dental appliance through current, without the need for frequent replacement of the dental appliance.

[0006] To achieve the above object, the present invention adopts the following technical solutions.

[0007] An electro-responsive shape memory PETG invisible orthodontic membrane, comprising the following raw materials in parts by weight: 10 parts to 15 parts of PETG pellets, 50 parts to 80 parts of organic solvent, 3 parts to 5 parts of modified conductive filler.

[0008] Further, the organic solvent is one of dichloromethane (DCM), tetrahydrofuran (THF), chloroform, dimethylformamide (DMF), or dimethyl sulfoxide (DMSO).

[0009] Further, the preparation steps of the modified conductive filler are as follows: Step 1: Add 4 to 6 parts of conductive filler into 15 to 20 parts of mixed acid, ultrasonically disperse for 30 to 40 minutes, then heat to 70°C, magnetically stir and react for 4 hours, wash with deionized water multiple times until the washing liquid is neutral, and vacuum dry at 60°C for 12 hours to obtain a conductive filler with carboxyl groups on the surface; Step 2: Disperse 5 to 10 parts of the conductive filler with carboxyl groups on the surface in an ethanol solution with a concentration of 60%, ultrasonically treat for 30 to 50 minutes to form a uniformly dispersed suspension; Step 3: Add 0.1 to 0.5 part of initiator to the above suspension, stir and heat to 60°C, react for 30 to 50 minutes to form free radicals; slowly dropwise add 3 to 5 parts of graft monomer, keep stirring and reacting at 60°C for 6 to 8 hours, then add ethanol to terminate the reaction to obtain the product; Step 4: Wash the product alternately and repeatedly with ethanol and deionized water to remove unreacted monomers and free graft monomers, vacuum dry at 60°C for 12 hours to obtain the graft-modified conductive filler, that is, the modified conductive filler.

[0010] Further, the conductive filler is one of carbon nanotubes (CNT), carbon black, graphene, polyaniline (PANI), or polypyrrole (PPy).

[0011] Further, the mixed acid is a mixture of two or more of nitric acid, sulfuric acid, phosphoric acid, ferric chloride solution, and chloric acid.

[0012] Further, the initiator is one of sodium persulfate (KPS), hydrogen peroxide, azobisisobutyronitrile (AIBN), potassium persulfate (KPS), or ammonium persulfate (APS).

[0013] Further, the graft monomer is one of methyl methacrylate (MMA), acrylic acid (AA), ethyl methacrylate (EMA), acrylonitrile (AN), styrene (St), or glycidyl methacrylate (GMA).

[0014] A preparation method of an electro-responsive shape memory PETG invisible orthodontic membrane sheet includes the following steps: Step 1: Put PETG pellets into a container containing an organic solvent, stir in a water bath at 35°C to 50°C until the PETG pellets are completely dissolved to obtain a PETG solution; Step 2: Add a small amount of organic solvent to the modified conductive filler and disperse it with an ultrasonic device (ultrasonic power: 200 W - 500 W, time: 30 minutes - 60 minutes). Slowly add the well-dispersed modified conductive filler to the PETG solution to obtain a mixed solution. Step 3: Use an ultrasonic device to ultrasonically treat the mixed solution for 30 minutes - 60 minutes, and continue to stir with a magnetic stirrer for 1 hour - 2 hours to ensure the uniformity of the solution. Step 4: Pour the mixed solution obtained in Step 3 into a flat mold. Place the mold in an oven at 50°C - 60°C for 12 hours - 24 hours to accelerate the evaporation of the solvent. Place the prepared film in a vacuum drying oven and dry it at 60°C for 4 hours - 6 hours. Peel the dried composite material from the mold or glass plate to obtain an electro-responsive shape memory PETG invisible orthodontic film.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0016] 1. The composite material prepared by the present invention has a shape memory function and can achieve continuous orthodontics by adjusting the shape of the dental appliance without frequent replacement.

[0017] 2. The shape memory function of the composite material prepared by the present invention is electro-responsive, and the shape memory characteristics of the material can be triggered by an electric current, with a rapid response.

[0018] 3. The modified conductive filler endows the material with the ability of local heating. By applying an electric signal only to a specific part, the shape memory effect of the material can be activated, with high energy utilization efficiency and a precise shape recovery process. Specific Embodiments

[0019] To facilitate the understanding of the present invention, the technical solutions of the present invention will be comprehensively described below in conjunction with specific embodiments. However, the following described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0020] An electro-responsive shape memory PETG invisible orthodontic film comprises the following raw materials in parts by weight: 10 parts - 15 parts of PETG pellets, 50 parts - 80 parts of organic solvent, and 3 parts - 5 parts of modified conductive filler.

[0021] Further, the organic solvent is one of dichloromethane (DCM), tetrahydrofuran (THF), chloroform, dimethylformamide (DMF), or dimethyl sulfoxide (DMSO).

[0022] Further, the preparation steps of the modified conductive filler are as follows: Step 1: Add 4 to 6 parts of conductive filler into 15 to 20 parts of mixed acid, ultrasonically disperse for 30 to 40 minutes, then heat to 70 °C, magnetically stir and react for 4 hours, wash with deionized water multiple times until the washing liquid is neutral, and vacuum dry at 60 °C for 12 hours to obtain a conductive filler with carboxyl groups on the surface; Step 2: Disperse 5 to 10 parts of the conductive filler with carboxyl groups on the surface in an ethanol solution with a concentration of 60%, and ultrasonically treat for 30 to 50 minutes to form a uniformly dispersed suspension; Step 3: Add 0.1 to 0.5 part of initiator into the above suspension, stir and heat to 60 °C, react for 30 to 50 minutes to form free radicals; slowly dropwise add 3 to 5 parts of graft monomer, keep stirring and reacting at 60 °C for 6 to 8 hours, then add ethanol to terminate the reaction to obtain a product; Step 4: Wash the product alternately and repeatedly with ethanol and deionized water to remove unreacted monomers and free graft monomers, and vacuum dry at 60 °C for 12 hours to obtain a graft-modified conductive filler, that is, the modified conductive filler.

[0023] Further, the conductive filler is one of carbon nanotubes (CNT), carbon black, graphene, polyaniline (PANI), or polypyrrole (PPy).

[0024] Further, the mixed acid is a mixture of two or more of nitric acid, sulfuric acid, phosphoric acid, ferric chloride solution, and chloric acid.

[0025] Further, the initiator is one of sodium persulfate (KPS), hydrogen peroxide, azobisisobutyronitrile (AIBN), potassium persulfate (KPS), or ammonium persulfate (APS).

[0026] Further, the graft monomer is one of methyl methacrylate (MMA), acrylic acid (AA), ethyl methacrylate (EMA), acrylonitrile (AN), styrene (St), or glycidyl methacrylate (GMA).

[0027] A preparation method of an electro-responsive shape memory PETG invisible orthodontic membrane sheet includes the following steps: Step 1: Put PETG pellets into a container filled with an organic solvent, stir in a water bath at 35 °C to 50 °C until the PETG pellets are completely dissolved to obtain a PETG solution; Step 2: Add a small amount of organic solvent to the modified conductive filler, and disperse it with an ultrasonic device (ultrasonic power is 200 W - 500 W, time is 30 minutes - 60 minutes), slowly add the dispersed modified conductive filler into the PETG solution, and stir simultaneously to prevent the filler from agglomerating to obtain a mixed solution; Step 3: Use an ultrasonic device to ultrasonically treat the mixed solution for 30 to 60 minutes to ensure the uniform dispersion of the conductive filler in the PETG solution, and continue to stir with a magnetic stirrer for 1 to 2 hours to ensure the uniformity of the solution; Step 4: Pour the solution mixed in Step 3 into a flat mold, place the mold in an oven at 50°C - 60°C for 12 - 24 hours to accelerate the solvent evaporation, place the prepared film in a vacuum drying oven, dry at 60°C for 4 - 6 hours, and peel the dried composite material from the mold or glass plate to obtain an electro-responsive shape memory PETG invisible orthodontic film.

[0028] Example 1.

[0029] Preparation of modified conductive filler: Add 4 parts of conductive filler to 15 parts of a mixed acid of nitric acid and sulfuric acid, ultrasonically disperse for 30 minutes, then heat to 70°C, magnetically stir and react for 4 hours, wash with deionized water multiple times until the washing liquid is neutral, and vacuum dry at 60°C for 12 hours to obtain a conductive filler with carboxyl groups on the surface. Disperse 5 parts of the conductive filler with carboxyl groups on the surface in an ethanol solution with a concentration of 60%, ultrasonically treat for 30 minutes to form a uniformly dispersed suspension. Add 0.1 part of initiator to the suspension, stir and heat to 60°C, and react for 30 minutes to form free radicals; slowly dropwise add 3 parts of graft monomers, keep stirring and reacting at 60°C for 6 hours, then add ethanol to terminate the reaction. Wash the product alternately with ethanol and deionized water repeatedly to remove unreacted monomers and free graft monomers, and vacuum dry at 60°C for 12 hours to obtain the modified conductive filler.

[0030] Put 10 parts of PETG pellets into a beaker containing 50 parts of organic solvent, stir in a water bath at 35°C until completely dissolved; add 10 parts of organic solvent to 3 parts of modified conductive filler, disperse with an ultrasonic device (ultrasonic power: 200W, time: 30 minutes), slowly add the dispersed conductive filler to the PETG solution while stirring to prevent filler agglomeration; use an ultrasonic device to ultrasonically treat the mixed solution for 30 minutes to ensure the uniform dispersion of the conductive filler in the PETG solution; continue to stir with a magnetic stirrer for 1 hour to ensure the uniformity of the solution; pour the mixed PETG and modified conductive filler solution into a flat mold, place the mold in an oven at 50°C for 12 hours to accelerate the solvent evaporation. Place the prepared film in a vacuum drying oven, dry at 60°C for 4 hours, and peel the dried composite material from the mold or glass plate to obtain a uniform electro-responsive shape memory PETG invisible orthodontic film.

[0031] Example 2.

[0032] Preparation of modified conductive filler: Add 5 parts of conductive filler into 18 parts of mixed acid of nitric acid and sulfuric acid. After ultrasonic dispersion for 35 minutes, heat it to 70 °C and stir magnetically for 4 hours. Wash it with deionized water for multiple times until the washing liquid is neutral, and then dry it in vacuum at 60 °C for 12 hours to obtain conductive filler with carboxyl groups on the surface. Disperse 5 parts of conductive filler with carboxyl groups on the surface in an ethanol solution with a concentration of 60%, and perform ultrasonic treatment for 30 minutes to form a uniformly dispersed suspension. Add 0.1 part of initiator into the suspension, stir and heat it to 60 °C, and react for 30 minutes to form free radicals; slowly dropwise add 3 parts of graft monomers, keep stirring and reacting at 60 °C for 6 hours, then add ethanol to terminate the reaction. Wash the obtained product with ethanol and deionized water alternately and repeatedly to remove unreacted monomers and free graft monomers, and then dry it in vacuum at 60 °C for 12 hours to obtain modified conductive filler.

[0033] Put 15 parts of PETG pellets into a beaker containing 60 parts of organic solvent, stir in a water bath at 50 °C until completely dissolved; add 12 parts of organic solvent to 5 parts of modified conductive filler, and disperse it with an ultrasonic device (ultrasonic power is 500 W, time is 60 minutes). Slowly add the dispersed conductive filler into the PETG solution while stirring to prevent the filler from agglomerating; use the ultrasonic device to perform ultrasonic treatment on the mixed solution for 60 minutes to ensure the uniform dispersion of the conductive filler in the PETG solution. Continue to stir with a magnetic stirrer for 2 hours to ensure the uniformity of the solution; pour the mixed PETG and modified conductive filler solution into a flat mold, and place the mold in an oven at 60 °C for 24 hours to accelerate the volatilization of the solvent. Place the prepared film in a vacuum drying oven and dry it at 60 °C for 6 hours. Peel the dried composite material from the mold or glass plate to obtain a uniform electro-responsive shape memory PETG invisible orthodontic film.

[0034] Example 3.

[0035] Preparation of modified conductive filler: Add 6 parts of conductive filler into 20 parts of mixed acid of nitric acid and sulfuric acid. After ultrasonic dispersion for 40 minutes, heat it to 70 °C and stir magnetically for 4 hours. Wash it with deionized water for multiple times until the washing liquid is neutral, and then dry it in vacuum at 60 °C for 12 hours to obtain conductive filler with carboxyl groups on the surface. Disperse 5 parts of conductive filler with carboxyl groups on the surface in an ethanol solution with a concentration of 60%, and perform ultrasonic treatment for 30 minutes to form a uniformly dispersed suspension. Add 0.1 part of initiator into the suspension, stir and heat it to 60 °C, and react for 30 minutes to form free radicals; slowly dropwise add 3 parts of graft monomers, keep stirring and reacting at 60 °C for 6 hours, then add ethanol to terminate the reaction. Wash the obtained product with ethanol and deionized water alternately and repeatedly to remove unreacted monomers and free graft monomers, and then dry it in vacuum at 60 °C for 12 hours to obtain modified conductive filler.

[0036] Put 12 parts of PETG pellets into a beaker containing 60 parts of organic solvent, stir in a water bath at 50 °C until completely dissolved; add 15 parts of organic solvent to 4 parts of modified conductive filler, and disperse it with an ultrasonic device (ultrasonic power is 200 W, time is about 60 minutes). Slowly add the dispersed conductive filler into the PETG solution while stirring to prevent the filler from agglomerating; use the ultrasonic device to ultrasonically treat the mixed solution for 30 minutes to ensure the uniform dispersion of the conductive filler in the PETG solution; continue to stir with a magnetic stirrer for 2 hours to ensure the uniformity of the solution; pour the mixed PETG and modified conductive filler solution into a flat mold, and place the mold in an oven at 60 °C for 24 hours to accelerate the evaporation of the solvent; place the prepared film in a vacuum drying oven and dry it at 60 °C for 4 hours. Peel the dried composite material from the mold or glass plate to obtain a uniform electro-responsive shape memory PETG invisible orthodontic film.

[0037] Comparative Example 1.

[0038] Put 10 parts of PETG pellets into a beaker containing 50 parts of organic solvent, stir in a water bath at 35 °C until completely dissolved; add a small amount of organic solvent to 3 parts of unmodified conductive filler, and disperse it with an ultrasonic device (ultrasonic power is 200 W, time is about 30 minutes). Slowly add the dispersed conductive filler into the PETG solution while stirring to prevent the filler from agglomerating; use the ultrasonic device to ultrasonically treat the mixed solution for 30 minutes to ensure the uniform dispersion of the conductive filler in the PETG solution; continue to stir with a magnetic stirrer for 1 hour to ensure the uniformity of the solution; pour the mixed PETG and conductive filler solution into a flat mold, and place the mold in an oven at 50 °C for 12 hours to accelerate the evaporation of the solvent. Place the prepared film in a vacuum drying oven and dry it at 60 °C for 4 hours. Peel the dried composite material from the mold or glass plate to obtain a PETG invisible orthodontic film.

[0039] Comparative Example 2.

[0040] Put 10 parts of PETG pellets into a beaker containing 50 parts of organic solvent, stir in a water bath at 35 °C until completely dissolved; pour the mixed PETG solution into a flat mold, and place the mold in an oven at 50 °C for 12 hours to accelerate the evaporation of the solvent; place the prepared film in a vacuum drying oven and dry it at 60 °C for 4 hours. Peel the dried composite material from the mold or glass plate to obtain a uniform PETG film.

[0041] Comparative Example 3.

[0042] Preparation of modified conductive filler: Add 6 parts of conductive filler to 20 parts of a mixed acid of nitric acid and sulfuric acid. After ultrasonic dispersion for 40 minutes, heat it to 70 °C and stir magnetically for 4 hours. Wash it with deionized water multiple times until the washing liquid is neutral, and then dry it in a vacuum at 60 °C for 12 hours to obtain a conductive filler with carboxyl groups on its surface. Disperse 5 parts of the conductive filler with carboxyl groups on its surface in an ethanol solution with a concentration of 60%, and perform ultrasonic treatment for 30 minutes to form a uniformly dispersed suspension. Add 0.1 part of initiator to the suspension, stir and heat it to 60 °C, and react for 30 minutes to form free radicals; slowly dropwise add 3 parts of graft monomer, keep stirring and reacting at 60 °C for 6 hours, then add ethanol to terminate the reaction. Wash the obtained product alternately with ethanol and deionized water repeatedly to remove unreacted monomers and free graft monomers, and then dry it in a vacuum at 60 °C for 12 hours to obtain the modified conductive filler.

[0043] Put 10 parts of PETG pellets into a beaker containing 50 parts of organic solvent, and stir in a water bath at 35 °C until completely dissolved; slowly add 3 parts of the modified conductive filler to the PETG solution, pour the mixed PETG and conductive filler solution into a flat mold, and place the mold in an oven at 50 °C for 12 hours to accelerate the volatilization of the solvent; place the prepared film in a vacuum drying oven and dry it at 50 °C for 4 hours, then peel the dried composite material from the mold or glass plate to obtain a uniform electro-responsive shape memory PETG invisible orthodontic film.

Claims

1. An electrically responsive shape memory PETG invisible orthodontic diaphragm, characterized in that: The invention comprises the following raw materials in parts by weight: 10 to 15 parts of PETG pellets, 50 to 80 parts of organic solvents, and 3 to 5 parts of modified conductive fillers.

2. The electrically responsive shape memory PETG invisible orthodontic diaphragm according to claim 1, characterized in that: The organic solvent is one of dichloromethane, tetrahydrofuran, chloroform, dimethylformamide or dimethyl sulfoxide.

3. The electrically responsive shape memory PETG invisible orthodontic diaphragm according to claim 1, characterized in that: The preparation steps of the modified conductive filler are: Step 1, add 4 to 6 parts of conductive filler to 15 to 20 parts of mixed acid, ultrasonically disperse for 30 to 40 minutes, heat to 70°C, react for 4 hours with magnetic stirring, wash with deionized water several times until the washing liquid is neutral, and vacuum dry at 60°C for 12 hours to obtain a conductive filler containing carboxyl groups on the surface; Step 2, dispersing 5 to 10 parts of a conductive filler having a carboxyl group on its surface in a 60% ethanol solution, and ultrasonically treating the solution for 30 to 50 minutes to form a uniformly dispersed suspension; Step 3, add 0.1 to 0.5 parts of initiator to the above suspension, stir and heat to 60°C, react for 30 to 50 minutes to form free radicals; slowly dropwise add 3 to 5 parts of grafting monomer, keep stirring at 60°C for 6 to 8 hours, then add ethanol to terminate the reaction to obtain a product; Step 4: The product is washed repeatedly with ethanol and deionized water alternately to remove unreacted monomers and free grafted monomers, and vacuum dried at 60° C. for 12 hours to obtain a grafted modified conductive filler, i.e., a modified conductive filler.

4. The electrically responsive shape memory PETG invisible orthodontic diaphragm according to claim 3, characterized in that: The conductive filler is one of carbon nanotubes, carbon black, graphene, polyaniline or polypyrrole.

5. The electrically responsive shape memory PETG invisible orthodontic diaphragm according to claim 3, characterized in that: The mixed acid is a mixture of two or more of nitric acid, sulfuric acid, phosphoric acid, ferric chloride solution and chloric acid.

6. The electrically responsive shape memory PETG invisible orthodontic diaphragm according to claim 3, characterized in that: The initiator is one of sodium persulfate, hydrogen peroxide, azobisisobutyronitrile, potassium persulfate or ammonium persulfate.

7. The electrically responsive shape memory PETG invisible orthodontic diaphragm according to claim 3, characterized in that: The grafting monomer is one of methyl methacrylate, acrylic acid, ethyl methacrylate, acrylonitrile, styrene or glycidyl methacrylate.

8. A method for preparing an electrically responsive shape memory PETG invisible orthodontic membrane, characterized in that: The steps include: Step 1, put the PETG pellets into a container filled with an organic solvent, stir in a water bath at 35°C-50°C until the PETG pellets are completely dissolved to obtain a PETG solution; Step 2, adding a small amount of organic solvent to the modified conductive filler, dispersing it with an ultrasonic device, and slowly adding the dispersed modified conductive filler to the PETG solution to obtain a mixed solution; Step 3, using an ultrasonic device to perform ultrasonic treatment on the mixed solution for 30 minutes to 60 minutes, and continuing to stir with a magnetic stirrer for 1 hour to 2 hours to ensure that the solution is uniform; Step 4: Pour the mixed solution in step 3 into a flat-bottomed mold, place the mold in an oven at 50°C-60°C for 12-24 hours to accelerate the volatilization of the solvent, place the prepared membrane in a vacuum drying oven, and dry it at 60°C for 4-6 hours. The dried composite material is peeled off from the mold or glass plate to obtain an electrically responsive shape memory PETG invisible orthodontic membrane.