Poly (epsilon-caprolactone)-based copolymer toughened polylactic acid composite material as well as preparation method and application thereof

Abstract

The invention provides a poly (epsilon-caprolactone) based copolymer toughened polylactic acid composite material as well as a preparation method and application thereof, and belongs to the technical field of biomedical polymer composite materials. The polylactic acid is used as a main body material, the semi-crystalline thermoplastic polymer polyether-ether-ketone is used as a performance enhancing and modifying material, and the poly (epsilon-caprolactone) based copolymer is used as a toughening agent of a system, so that the obtained composite material shows good mechanical strength and compatibility, is wide in application, and has good economic benefits and practical significance; the method is expected to be further popularized and used in the biomedical field. The result of the embodiment shows that the Young modulus of the poly (epsilon-caprolactone) based copolymer toughened polylactic acid composite material provided by the invention is 834.3-1180.50 MPa, the elongation at break is 3.32-26.21%, and the poly (epsilon-caprolactone) based copolymer toughened polylactic acid composite material has good mechanical properties and flexibility, and meets the application requirements of biomedical materials.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical polymer composites, and particularly relates to a poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material, a preparation method thereof, and an application thereof. Background Art

[0002] As a biodegradable polymer material, polylactic acid can adjust and control its mechanical properties and degradation rate by adjusting its molecular weight, selecting different polymerization methods and forming means to meet different clinical requirements. At present, polylactic acid has been widely used in fields such as surgical sutures, tissue engineering scaffolds, and orthopedic fixation materials. However, due to its inert hydrophobic surface and low free surface energy, it affects the attachment and proliferation of cells on its surface, resulting in reduced biocompatibility. In addition, polylactic acid has high hardness and poor toughness, resulting in high brittleness and easy fracture in application scenarios requiring toughness.

[0003] In order to effectively improve the brittleness of polylactic acid, it needs to be strengthened and toughened. Currently, the modification methods mainly include chemical methods such as copolymerization, crosslinking, and surface modification, as well as physical methods such as blending and plasticization. Among them, the blending modification process is the simplest and most economical, and the blending of biodegradable polymers with polylactic acid has become a very active and important research field in materials science. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material, a preparation method thereof, and an application thereof. The poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material provided by the present invention has good mechanical strength and compatibility.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material, comprising the following raw materials in parts by mass:

[0007] 1-20 parts of poly(ε-caprolactone)-based copolymer;

[0008] 1-30 parts of reinforcing polymer;

[0009] 50-95 parts of polylactic acid.

[0010] Preferably, the poly(ε-caprolactone)-based copolymer comprises a poly(ε-caprolactone)-polylactic acid random copolymer and / or a poly(ε-caprolactone)-polylactic acid block copolymer.

[0011] Preferably, the reinforcing polymer comprises one or more of polyethylene glycol, poly(ε-caprolactone), polyetheretherketone, and polyglycolic acid.

[0012] Preferably, the weight-average molecular weight of the polylactic acid is 100,000 to 130,000.

[0013] Preferably, the method for preparing the poly(ε-caprolactone)-polylactic acid block copolymer comprises the following steps:

[0014] Mix ε-caprolactone monomer, lactide monomer, initiator, catalyst and organic solvent, and carry out ring-opening polymerization reaction to obtain poly(ε-caprolactone)-polylactic acid block copolymer.

[0015] Preferably, the initiator is methoxypolyethylene glycol and the catalyst is stannous octoate.

[0016] The present invention provides a method for preparing the poly(ε-caprolactone) copolymer toughened polylactic acid composite material, comprising the following steps:

[0017] Blend and mold the poly(ε-caprolactone) copolymer, reinforcing polymer and polylactic acid to obtain the poly(ε-caprolactone) copolymer toughened polylactic acid composite material.

[0018] Preferably, the molding method is hot pressing;

[0019] The parameters of the hot pressing include: temperature 140 - 170 °C, pressure 8 - 12 MPa, and holding pressure time 20 - 25 min.

[0020] Preferably, a solvent is further added during blending; the molding method is casting into a film.

[0021] The present invention provides an application of the above poly(ε-caprolactone) copolymer toughened polylactic acid composite material in the field of biomedical applications.

[0022] The present invention provides a poly(ε-caprolactone) copolymer toughened polylactic acid composite material, comprising the following raw materials in parts by mass: 1 - 20 parts of poly(ε-caprolactone) copolymer; 1 - 30 parts of reinforcing polymer; 50 - 95 parts of polylactic acid. The present invention uses polylactic acid as the main material, semi-crystalline thermoplastic polymer or highly crystalline thermoplastic polymer (polyether ether ketone, polyethylene glycol, poly(ε-caprolactone) or polyglycolic acid) as the performance enhancing and modifying material, and poly(ε-caprolactone) copolymer as the toughening agent of the system. The obtained composite material exhibits good mechanical strength and compatibility, has a wide range of uses, good economic benefits and practical significance, and is expected to be further promoted and used in the field of biomedical applications. The results of the examples show that the Young's modulus of the poly(ε-caprolactone) copolymer toughened polylactic acid composite material provided by the present invention is 834.3 - 1180.50 MPa, and the elongation at break is 3.32 - 26.21%.

[0023] The present invention provides a method for preparing the above-mentioned poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material. This method is simple in operation, low in cost, and easy to realize industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the synthesis of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material of the present invention. SPECIFIC EMBODIMENTS

[0025] The present invention provides a poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material, which comprises the following raw materials in parts by mass:

[0026] 1-20 parts of poly(ε-caprolactone)-based copolymer;

[0027] 1-30 parts of reinforcing polymer;

[0028] 50-95 parts of polylactic acid.

[0029] In terms of parts by mass, the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material provided by the present invention comprises 1-20 parts of poly(ε-caprolactone)-based copolymer, preferably 5-15 parts, and more preferably 8-10 parts.

[0030] In the present invention, the poly(ε-caprolactone)-based copolymer preferably comprises poly(ε-caprolactone)-polylactic acid copolymer; further, the poly(ε-caprolactone)-based copolymer preferably comprises poly(ε-caprolactone)-polylactic acid random copolymer and / or poly(ε-caprolactone)-polylactic acid block copolymer. In the present invention, the weight-average molecular weight of the poly(ε-caprolactone)-based copolymer is preferably 50,000-80,000. Poly(ε-caprolactone) is an aliphatic polyester material, which has good biocompatibility and degradability, and strong mechanical properties, but has a low melting point and is rarely used alone. In the present invention, poly(ε-caprolactone) and polylactic acid are copolymerized to combine the respective advantages of the two.

[0031] The present invention has no special requirements on the sources of the poly(ε-caprolactone)-polylactic acid random copolymer and the poly(ε-caprolactone)-polylactic acid block copolymer, and the above copolymers commercially available in the art or self-prepared can be used. When self-preparing, the preparation method of the poly(ε-caprolactone)-polylactic acid block copolymer comprises the following steps:

[0032] Mix ε-caprolactone monomer, lactide monomer, initiator, catalyst and organic solvent, and carry out ring-opening polymerization reaction to obtain poly(ε-caprolactone)-polylactic acid block copolymer.

[0033] In the present invention, the initiator is preferably methoxypolyethylene glycol, and the molecular weight Mn of the methoxypolyethylene glycol is 750 g / mol. In the present invention, the catalyst is preferably stannous octoate, and the organic solvent is preferably toluene.

[0034] In the present invention, the molar ratio of the ε-caprolactone monomer to the lactide monomer is preferably 0.4 to 2.5:1; the molar ratio of the initiator to the catalyst is preferably 1.0 to 1.5:1; in the present invention, the total concentration of the ε-caprolactone monomer and the lactide monomer in the organic solvent is preferably 2.5 to 3.5 mol / L, more preferably 2.8 mol / L.

[0035] In the present invention, the preferred mixing method is as follows: Add the initiator and the organic solvent into a three-necked flask, and dehydrate the reaction system by azeotropic distillation under a dry nitrogen stream. After cooling to room temperature, add the ε-caprolactone monomer, the lactide monomer, and the catalyst.

[0036] In the present invention, the temperature of the ring-opening polymerization reaction is preferably 110 to 140 °C, more preferably 130 °C; the time is preferably 16 to 36 h, more preferably 24 h.

[0037] After the ring-opening polymerization reaction, the present invention preferably performs post-treatment on the obtained ring-opening polymerization reaction product. The post-treatment preferably includes the following steps:

[0038] Add the ring-opening polymerization reaction product to a mixture of n-hexane and diethyl ether to precipitate the copolymer, filter and separate the copolymer from the supernatant, and dissolve it in a dichloromethane solution;

[0039] Concentrate and dry the obtained solution to obtain a poly(ε-caprolactone)-poly(lactic acid) block copolymer solid.

[0040] In the present invention, the concentration is preferably rotary evaporation concentration, and the drying is preferably vacuum drying. In the present invention, the obtained solid is preferably nearly colorless.

[0041] In the present invention, the preparation method of the poly(ε-caprolactone)-poly(lactic acid) random copolymer preferably includes the following steps:

[0042] Add ε-caprolactone and lactide monomers into a three-necked flask, displace nitrogen, stir at 100 to 120 °C for 1 to 2 h, and then add stannous octoate as the catalyst. Raise the temperature to 135 to 160 °C, stop the reaction after 3 to 5 h. Add dichloromethane to dissolve the random copolymer, add ethanol and stir, filter the copolymer until no ethanol drips out. Place it in a blast drying oven and dry for 1 to 2 h, then transfer it to a vacuum drying oven and dry for 7 to 9 h, and then dry it for standby.

[0043] Based on the mass parts of the poly(ε-caprolactone) - based copolymer, the poly(ε-caprolactone) - based copolymer toughened polylactic acid composite material provided by the present invention comprises 1 to 30 parts of a reinforcing polymer, preferably 5 to 20 parts, and more preferably 10 to 15 parts. In the present invention, the reinforcing polymer preferably comprises one or more of polyethylene glycol, poly(ε-caprolactone), polyetheretherketone, and polyglycolic acid.

[0044] In the present invention, the weight-average molecular weight of the reinforcing polymer is preferably 10,000 to 100,000. Specifically, the weight-average molecular weight of the polyethylene glycol is preferably 50,000 to 80,000; the weight-average molecular weight of the poly(ε-caprolactone) is preferably 50,000 to 80,000; the weight-average molecular weight of the polyetheretherketone is preferably 10,000 to 20,000. In the present invention, the source of the reinforcing polymer is preferably commercially available.

[0045] In the present invention, as a crystalline thermoplastic polymer material, polyetheretherketone has high mechanical strength, high temperature resistance, impact resistance, good toughness and rigidity, and can be organically combined with the body, providing a theoretical basis for the application of the composite material in the field of biomedicine in the later stage. Polyethylene glycol has good biocompatibility and biodegradability, can improve the stability and durability of implants, and reduce the rejection reaction to patients. Poly(ε-caprolactone) is a biodegradable polyester material approved by the FDA. Due to its ability to degrade in tissues, it is promising to be used in bone tissue engineering. Polyglycolic acid has good biodegradability and biocompatibility, and is gradually degraded into harmless water and carbon dioxide in the body, and is widely used in fields such as fracture fixation materials and tissue engineering scaffolds.

[0046] Based on the mass parts of the poly(ε-caprolactone) - based copolymer, the poly(ε-caprolactone) - based copolymer toughened polylactic acid composite material provided by the present invention comprises 50 to 95 parts of polylactic acid, preferably 60 to 90 parts, and more preferably 70 to 80 parts. In the present invention, the weight-average molecular weight of the polylactic acid is preferably 100,000 to 130,000; the source of the polylactic acid is preferably commercially available.

[0047] The present invention provides a preparation method of the above poly(ε-caprolactone) - based copolymer toughened polylactic acid composite material, comprising the following steps:

[0048] Blend and mold the poly(ε-caprolactone) - based copolymer, the reinforcing polymer, and the polylactic acid to obtain the poly(ε-caprolactone) - based copolymer toughened polylactic acid composite material.

[0049] As an embodiment of the present invention, there are no special requirements for the blending method of the present invention. The above components can be mixed evenly by using the blending methods well-known to those skilled in the art; the forming method is preferably hot pressing; the parameters of the hot pressing preferably include: the temperature is preferably 140-170°C, more preferably 150-160°C; the pressure is preferably 8-12 MPa, more preferably 10 MPa; the holding time is preferably 20-25 min, more preferably 22-24 min.

[0050] As an embodiment of the present invention, an organic solvent is also added during the blending to obtain a mixed solution; the organic solvent is preferably dichloromethane; the mass ratio of the poly(ε-caprolactone)-based copolymer to the organic solvent is preferably 1.5-3:1. In the present invention, the forming method is preferably casting into a film. The present invention preferably performs casting into a film in a polytetrafluoroethylene mold. The temperature of the casting into a film is preferably room temperature, and the time is preferably 24 h.

[0051] In the present invention, when the forming method is casting into a film, the thickness of the obtained poly(ε-caprolactone)-based copolymer toughened polylactic acid composite film material is preferably 0.1-0.3 mm, more preferably 0.2 mm.

[0052] In the present invention, the synthesis schematic diagram of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material is as Figure 1 shown.

[0053] The present invention provides the application of the above poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material in the field of biomedicine. In the present invention, the field of biomedicine is preferably orthopedics, stomatology or maxillofacial surgery. Specifically, the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material is preferably used as a bone repair material, bone tissue engineering or 3D printing material.

[0054] The following examples will be used to illustrate in detail the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material provided by the present invention, its preparation method and application, but they should not be construed as limiting the protection scope of the present invention.

[0055] In the following examples, the reinforcing polymer polyetheretherketone used was purchased from Jiangsu Junhua Special Engineering Plastic Products Co., Ltd., and the model was 7600G.

[0056] Example 1

[0057] The preparation method of the poly(ε-caprolactone)-polylactic acid block copolymer comprises the following steps:

[0058] S1. Add 0.012 g of methoxypolyethylene glycol (Mn = 750 g / mol) and 75 mL of toluene into a three-necked flask. Dehydrate the reaction system by azeotropic distillation, and under a dry nitrogen stream, distill until the final volume is 40 mL. After cooling to room temperature, add 3.5 g of ε-caprolactone, 4.5 g of lactide monomer, and 0.2 mL of stannous octoate solution (0.1 M in anhydrous toluene).

[0059] S2. After stirring and reacting at 130 °C for 24 h, pour the resulting mixture into a mixture of n-hexane and diethyl ether (v / v = 4 / 1) to precipitate the polymer. Filter and separate the polymer from the supernatant, and dissolve it in dichloromethane solution. The resulting polymer solution is concentrated by rotary evaporation and then dried in vacuo to obtain a polymer in a nearly colorless state, which is the poly(ε-caprolactone)-poly(lactic acid) block copolymer with a molecular weight of 60,000 - 80,000.

[0060] Example 2

[0061] The preparation method of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite film material is as follows:

[0062] Add 2 parts of the poly(ε-caprolactone)-poly(lactic acid) block copolymer obtained in Example 1 and 5 parts of polyetheretherketone into 93 parts of polylactic acid matrix. Add dichloromethane as a solvent into a beaker, stir the mixture at room temperature for 6 h. When it becomes relatively viscous, pour it into a polytetrafluoroethylene mold and dry it at room temperature for 24 h to obtain the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite film material with a thickness of 0.106 mm.

[0063] Example 3

[0064] The preparation method of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite film material is as follows:

[0065] Add 3 parts of the poly(ε-caprolactone)-poly(lactic acid) block copolymer obtained in Example 1 and 8 parts of polyetheretherketone into 89 parts of polylactic acid matrix. Add dichloromethane as a solvent into a beaker, stir the mixture at room temperature for 6 h, and then pour it into a polytetrafluoroethylene mold and dry it at room temperature for 24 h to obtain the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite film material with a thickness of 0.198 mm.

[0066] Example 4

[0067] The preparation method of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite film material is as follows:

[0068] 4 parts of the poly(ε-caprolactone)-poly(lactic acid) block copolymer obtained in Example 1 and 8 parts of polyetheretherketone were added to 88 parts of a polylactic acid matrix. Dichloromethane was added as a solvent in a beaker, and the mixture was stirred at room temperature for 6 h. When it became relatively viscous, it was poured into a polytetrafluoroethylene mold and dried at room temperature for 24 h to obtain a poly(ε-caprolactone) copolymer toughened polylactic acid composite film material with a thickness of 0.254 mm.

[0069] Example 5

[0070] The preparation method of the poly(ε-caprolactone) copolymer toughened polylactic acid composite film material is as follows:

[0071] 5 parts of the poly(ε-caprolactone)-poly(lactic acid) block copolymer obtained in Example 1 and 10 parts of polyetheretherketone were added to 85 parts of a polylactic acid matrix. Dichloromethane was added as a solvent in a beaker, and the mixture was stirred at room temperature for 6 h. When it became relatively viscous, it was poured into a polytetrafluoroethylene mold and dried at room temperature for 24 h to obtain a poly(ε-caprolactone) copolymer toughened polylactic acid composite film material with a thickness of 0.189 mm.

[0072] Example 6

[0073] The preparation method of the poly(ε-caprolactone) copolymer toughened polylactic acid composite film material is as follows:

[0074] 5 parts of the poly(ε-caprolactone)-poly(lactic acid) block copolymer obtained in Example 1 and 5 parts of polyglycolic acid were added to 90 parts of a polylactic acid matrix. Dichloromethane was added as a solvent in a beaker, and the mixture was stirred at room temperature for 6 h. When it became relatively viscous, it was poured into a polytetrafluoroethylene mold and dried at room temperature for 24 h to obtain a poly(ε-caprolactone) copolymer toughened polylactic acid composite film material with a thickness of 0.255 mm.

[0075] Example 7

[0076] On the basis of Example 5, the content of polyetheretherketone was reduced, and the method was as follows:

[0077] 5 parts of the poly(ε-caprolactone)-poly(lactic acid) block copolymer and 5 parts of polyetheretherketone were added to 90 parts of a polylactic acid matrix. Dichloromethane was added as a solvent in a beaker, and the mixture was stirred at room temperature for 6 h. When it became relatively viscous, it was poured into a polytetrafluoroethylene mold and dried at room temperature for 24 h to obtain a polylactic acid composite film material with a thickness of 0.223 mm.

[0078] Comparative Example 1

[0079] 5 parts of poly(ε-caprolactone)-poly(lactic acid) block copolymer were added to 95 parts of polylactic acid matrix. Dichloromethane was added as a solvent in a beaker. The mixture was stirred at room temperature for 6 h. When it became relatively viscous, it was poured into a polytetrafluoroethylene mold and dried at room temperature for 24 h to obtain a polylactic acid composite film material with a thickness of 0.289 mm.

[0080] Performance testing

[0081] The mechanical properties of the composite film materials obtained in the examples and comparative examples were tested, and the test standard referred to the national standard GB / T 1040.3-2006. The obtained results are shown in Table 1.

[0082] Table 1 Mechanical properties of the composite film materials

[0083] Young's modulus (MPa) Elongation at break (%) Example 2 845.19±55.20 26.21±4.32 Example 3 859.78±36.90 24.33±5.68 Example 4 952.01±29.75 10.21±5.24 Example 5 1146.08±45.59 5.52±0.34 Example 6 834.30±21.54 25.16±6.21 Example 7 1180.50±10.24 3.32±3.50 Comparative Example 1 749.02±3.56 5.45±6.78

[0084] As can be seen from Table 1, in the present invention, poly(ε-caprolactone)-poly(lactic acid) block copolymer was added to the system as a toughening agent, which improved the compatibility of the composite material, and the improvement of compatibility was also beneficial to the enhancement of the toughness of the material. In addition, polyetheretherketone, as a crystalline thermoplastic polymer material, has high mechanical strength, high temperature resistance, impact resistance, good toughness and rigidity, and can be organically combined with the body, providing a theoretical basis for the application of the composite material in the field of biomedicine in the later stage. Compared with Examples 2-5, in the system of Comparative Example 1, the mass fraction of the reinforcing polymer polyetheretherketone was reduced, so the amount of polylactic acid matrix increased accordingly. From the experimental results, the elongation at break of Comparative Example 7 increased and the Young's modulus decreased; while in the system of Comparative Example 1, only poly(ε-caprolactone) copolymer and polylactic acid matrix were contained, which was in contrast to the previous examples, and the mechanical properties were all reduced.

[0085] In summary, the poly(ε-caprolactone) copolymer toughened polylactic acid composite material prepared by the present invention has both good mechanical properties and flexibility, meeting the application requirements of biomedical materials.

[0086] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material, comprising the following raw materials in parts by mass: 1 to 20 parts of poly(ε-caprolactone)-based copolymer; 1 to 30 parts of reinforcing polymer; 50 to 95 parts of polylactic acid.

2. The polycaprolactone-based copolymer toughened polylactic acid composite material according to claim 1, wherein The poly(ε-caprolactone)-based copolymer comprises a poly(ε-caprolactone)-polylactic acid random copolymer and / or a poly(ε-caprolactone)-polylactic acid block copolymer.

3. The polycaprolactone-based copolymer toughened polylactic acid composite material according to claim 1, wherein The reinforcing polymer comprises one or more of polyethylene glycol, poly(ε-caprolactone), polyetheretherketone and polyglycolic acid.

4. The polycaprolactone-based copolymer toughened polylactic acid composite material according to claim 1, wherein The polylactic acid has a weight-average molecular weight of 100,000 to 130,000.

5. The polycaprolactone-based copolymer toughened polylactic acid composite material according to claim 2, wherein The preparation method of the poly(ε-caprolactone)-polylactic acid block copolymer comprises the following steps: Mix ε-caprolactone monomer, lactide monomer, initiator, catalyst and organic solvent, and carry out ring-opening polymerization reaction to obtain poly(ε-caprolactone)-polylactic acid block copolymer.

6. The preparation method according to claim 5, wherein The initiator is methoxypolyethylene glycol, and the catalyst is stannous octanoate.

7. The preparation method of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material according to any one of claims 1 to 6, comprising the following steps: Blend and mold the poly(ε-caprolactone)-based copolymer, reinforcing polymer and polylactic acid to obtain a poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material.

8. The preparation method according to claim 7, characterized in that, The molding method is hot pressing; The parameters of the hot pressing include: temperature 140 to 170 °C, pressure 8 to 12 MPa, and holding pressure time 20 to 25 min.

9. The preparation method according to claim 7, wherein A solvent is also added during the blending; the molding method is casting into a film.

10. The application of the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material according to any one of claims 1 to 6 or the poly(ε-caprolactone)-based copolymer toughened polylactic acid composite material prepared by the preparation method according to any one of claims 7 to 9 in the biomedical field.

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