Polyether ester type polyurethane with shape memory characteristic and preparation method thereof

Abstract

The invention discloses polyether ester type polyurethane with a shape memory characteristic and a preparation method of the polyether ester type polyurethane, and belongs to the field of high polymer materials. The preparation method comprises the following steps: firstly, using an epoxy compound and a cyclic lactone compound as comonomers, carrying out ring opening polymerization by using a cheap and easily available commercial catalyst to synthesize polyether ester polyol, and introducing a small amount of ester groups into a polyether structural unit as ester exchange sites, so that the compatibility of the polyester structural unit and the polyether structural unit is improved; the polyether ester random copolymer with uniform and controllable performance is prepared; then introducing an isocyanate compound, a chain extender and a branching agent into a reaction system to synthesize polyether ester polyurethane with a long-chain branched structure. The polyether ester type polyurethane is prepared through a one-pot method, the method is simple in route, low in cost and environmentally friendly, the obtained polymer has the shape memory characteristic, the performance of the polymer can be regulated and controlled by adjusting copolymerization components, and the method has the prospect and potential of large-scale production.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and in particular relates to a polyether ester type polyurethane with shape memory properties and a preparation method thereof. Background Art

[0002] Polyurethane is known as the "fifth plastic". It is a polymer formed by the addition polymerization of polyisocyanates, chain extenders and polyols. Due to its excellent performance, it is widely used in light industry, chemical industry, electronics, textiles, medical treatment, construction, building materials, automobiles and other fields. In the polyurethane molecular chain, the structure and performance of polyols often determine the performance and application scenarios of polyurethane. According to the differences in the structure of polyols, it can be divided into three categories: polyester polyurethane, polyether polyurethane and polyether ester polyurethane. In the polyurethane industry, polyester polyurethane and polyether polyurethane are the most widely used, but polyester polyurethane and polyether polyurethane each have certain advantages and disadvantages. For polyester polyurethane, its advantages are good mechanical properties and degradability, but poor hydrolysis resistance; for polyether polyurethane, its advantages are good hydrolysis resistance and low temperature resistance, but poor mechanical properties and heat resistance. Polyether ester polyurethane can combine the advantages of both, and achieve overall performance regulation by regulating components, thereby improving the designability of materials. However, the uneven performance of polyether ester polyols often has a negative impact on the performance of polyether ester polyurethane materials, resulting in poor shape memory of the material and limited application. At present, the main methods for preparing polyether-ester polyols are blending, melt polycondensation and ring-opening polymerization. Among them, the ring-opening polymerization method has the advantages of relatively mild reaction conditions and controllable material structure, but it often requires the development of new catalysts, which is costly, and it is difficult to prepare polyether-polyester random copolymers due to the large difference in ring tension between alkylene oxide and cyclic lactone. At the same time, the current preparation route of shape memory polyurethane materials often involves the preparation and post-treatment of oligomer polyols, chain extension reaction, casting, solvent removal and curing molding, etc. The route is complicated and environmentally friendly. Summary of the invention

[0003] In view of the deficiencies of the prior art, the present invention provides a polyether ester type polyurethane with shape memory property and a preparation method thereof.

[0004] To achieve the above object, the present invention adopts the following technical solution: A polyether-ester type polyurethane with shape memory properties, which is a long-chain branched structure copolymer having a polyether structural unit and a polyester structural unit; the preparation method thereof comprises the following steps: (1) adding an epoxy compound, a cyclic lactone compound, an acid anhydride compound, a catalyst 1, a catalyst 2 and an initiator into a reactor for a primary reaction; (2) After the pressure in the reactor drops to 0, the temperature is raised to carry out a secondary reaction to obtain a polyether ester diol; (3) adding an isocyanate compound dissolved in an organic solvent dropwise into a reactor to carry out three reactions; (4) A mixed solution containing an isocyanate compound, a chain extender and a branching agent is added dropwise into a reactor to carry out four reactions to obtain a polyetherester polyurethane with a long-chain branched structure.

[0005] Furthermore, the epoxy compound in step (1) is any one of ethylene oxide, propylene oxide, epichlorohydrin and butylene oxide; its structural formula is as follows: .

[0006] Furthermore, the cyclic lactone compound in step (1) is any one of glycolide, levorotatory lactide, dextrorotatory lactide, racemic lactide, valerolactone or caprolactone, and its structural formula is as follows; its molar ratio to the epoxy compound is 1:0.1-9; .

[0007] Furthermore, the acid anhydride compound in step (1) is any one of succinic anhydride, methylsuccinic anhydride or glutaric anhydride; and the molar ratio of the acid anhydride to the epoxy compound is 1:10-100.

[0008] Furthermore, the catalyst 1 in step (1) is zinc-cobalt double metal cyanide complex (DMCC); the mass ratio of the catalyst 1 to the epoxy compound is 1:100-10000.

[0009] Furthermore, the catalyst 2 in step (1) is an organic carboxylate or oxide containing any one of metal titanium, tin, antimony and germanium; and the mass ratio of the organic carboxylate or oxide to the cyclic lactone compound is 1:100-1000.

[0010] Furthermore, the initiator in step (1) is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, polyethylene glycol 200, polyethylene glycol 400, polypropylene glycol 200, and polypropylene glycol 400; and the molar ratio of the initiator to the epoxy compound is 1:1~200.

[0011] Furthermore, the temperature of the primary reaction in step (1) is 60-120°C and the time is 0.5-3h.

[0012] Furthermore, the temperature of the secondary reaction in step (2) is 70-150°C and the time is 2-6 h.

[0013] Furthermore, the organic solvent in step (3) is any one of dichloromethane, chloroform and tetrahydrofuran.

[0014] Furthermore, the temperature of the three reactions in step (3) is 40-100°C and the time is 3-12h.

[0015] Furthermore, the isocyanate compounds in steps (3) and (4) are independently selected from any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate or dicyclohexylmethane-4,4'-diisocyanate.

[0016] Furthermore, the molar ratio of the isocyanate compound to the initiator used in step (3) is 1:0.9-1.2.

[0017] Furthermore, the molar ratio of the isocyanate compound to the chain extender used in step (4) is 1:0.9-1.2.

[0018] Furthermore, the chain extender in step (4) is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol or 1,4-cyclohexanedimethanol; and the molar ratio of the chain extender to the initiator in step (1) is 1:0.1-9.

[0019] Furthermore, the branching agent in step (4) is any one of propylene glycol, pentaerythritol or dipentaerythritol; and the molar ratio of the branching agent to the chain extender is 1:1-100.

[0020] Furthermore, the mixed solution in step (4) uses any one of dichloromethane, chloroform and tetrahydrofuran as a solvent.

[0021] Furthermore, the temperature of the four reactions in step (4) is 40-100°C and the time is 3-12h.

[0022] The invention firstly uses epoxy compounds and cyclic lactones as comonomers to prepare a polyether ester random copolymer with uniform and controllable properties, and then further introduces isocyanate compounds, chain extenders and branching agents into the reaction system to synthesize a long-chain branched structure polyether ester type polyurethane. The synthesized polymer has shape memory properties, and the material properties can be regulated by adjusting the copolymer components. The molecular weight regulation range is 10000-200000 g / mol, wherein the molar content of the polyether ester is regulated in the range of 5-95 mol%; and the shape memory transition temperature regulation range is -60-50°C.

[0023] The beneficial effects of the present invention are (1) The polyether ester diol in the polyether ester type polyurethane with shape memory properties obtained by the present invention is prepared using epoxy compounds and cyclic lactones as raw materials. By adjusting the feed ratio, the glass transition temperature or melting point thereof can be adjusted within a range of -60 to 50 °C.

[0024] (2) Compared with linear polyether ester polyurethane, the polyether ester polyurethane obtained in the present invention has a higher molecular weight and better shape memory properties, a higher shape memory recovery rate, and the material properties can be regulated by adjusting the copolymer components. The shape memory transition temperature can be regulated in the range of -60 to 50 °C, and the shape recovery rate is above 90%.

[0025] (3) The polyetherester polyurethane of the present invention is prepared by a "one-pot method", which has a simple route, low cost, green and environmentally friendly, and has the prospect and potential for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the GPC spectrum of the sample prepared in Example 1.

[0027] Figure 2 The sample prepared in Example 1 1 H NMR spectrum.

[0028] Figure 3 This is the DSC spectrum of the sample prepared in Example 1.

[0029] Figure 4 This is the GPC spectrum of the sample prepared in Example 2.

[0030] Figure 5 The sample prepared in Example 2 1 H NMR spectrum.

[0031] Figure 6 This is the DSC spectrum of the sample prepared in Example 2.

[0032] Figure 7 This is the GPC spectrum of the sample prepared in Example 3.

[0033] Figure 8 The sample prepared in Example 3 1 H NMR spectrum.

[0034] Fig. 9 This is the DSC spectrum of the sample prepared in Example 3.

[0035] Fig.10 This is the GPC spectrum of the sample prepared in Example 4.

[0036] Fig.11 The sample prepared in Example 4 1 H NMR spectrum.

[0037] Fig.12 This is the DSC spectrum of the sample prepared in Example 4.

[0038] Fig.13 This is the GPC spectrum of the sample prepared in Example 5.

[0039] Fig.14 The sample prepared in Example 5 1 H NMR spectrum.

[0040] Fig.15 This is the DSC spectrum of the sample prepared in Example 5.

[0041] Fig.16 The GPC spectrum of the sample prepared in the comparative example.

[0042] Fig.17 The samples prepared for the comparative example 1 H NMR spectrum.

[0043] Fig.18 The DSC spectrum of the sample prepared in the comparative example. DETAILED DESCRIPTION

[0044] A polyetherester polyurethane with shape memory properties, the preparation method of which comprises the following steps: (1) Add the epoxy compound, cyclic lactone compound, acid anhydride compound, catalyst 1, catalyst 2 and initiator into a reactor and react at 60-120 °C for 0.5-3 h; (2) After the pressure in the reactor drops to 0, the temperature is raised to 70-150 °C and the reaction is carried out for 2-6 hours to obtain polyether ester diol; (3) Add the isocyanate compound dissolved in the organic solvent dropwise into the reactor and react at 40-100 °C for 3-12 h; (4) Add a mixed solution containing an isocyanate compound, a chain extender and a branching agent dropwise into a reactor and continue reacting at 40-100 °C for 3-12 h to obtain a polyetherester polyurethane with a long-chain branched structure.

[0045] Wherein, the epoxy compound in step (1) is any one of ethylene oxide, propylene oxide, epichlorohydrin and butylene oxide. The cyclic lactone compound is any one of glycolide, levorotatory lactide, dextrorotatory lactide, racemic lactide, valerolactone or caprolactone; the acid anhydride compound is any one of succinic anhydride, methylsuccinic anhydride or glutaric anhydride; the catalyst 1 is zinc-cobalt double metal cyanide complex (DMCC); the catalyst 2 is an organic carboxylate or oxide containing any one of metal titanium, tin, antimony and germanium; the initiator is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, polyethylene glycol 200, polyethylene glycol 400, polypropylene glycol 200 and polypropylene glycol 400.

[0046] The molar ratio of the cyclic lactone compound to the epoxy compound is 1:0.1-9; the molar ratio of the acid anhydride compound to the epoxy compound is 1:10-100; the mass ratio of the catalyst 1 to the epoxy compound is 1:100-10000. The mass ratio of the catalyst 2 to the cyclic lactone compound is 1:100-1000. The molar ratio of the initiator to the epoxy compound is 1:1-200.

[0047] The organic solvent in step (3) and the solvent used in the mixed solution in step (4) are any one of dichloromethane, chloroform and tetrahydrofuran.

[0048] The isocyanate compounds used in steps (3) and (4) are independently selected from any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate or dicyclohexylmethane-4,4'-diisocyanate; wherein the molar ratio of the isocyanate compound used in step (3) to the initiator is 1:0.9~1.2, and the molar ratio of the isocyanate compound used in step (4) to the chain extender is 1:0.9~1.2.

[0049] In step (4), the chain extender is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol or 1,4-cyclohexanedimethanol; and the branching agent is any one of propylene glycol, pentaerythritol or dipentaerythritol.

[0050] The molar ratio of the chain extender to the initiator is 1:0.1 to 9. The molar ratio of the branching agent to the chain extender is 1:1 to 100.

[0051] The technical solution of the present invention is further described below through examples.

[0052] The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art.

[0053] In the following examples, various processes and methods not described in detail are conventional methods known in the art. At the same time, due to the diverse proportions of polymer structures, not all preparation methods are described in detail, and typical examples are taken to illustrate the specific process steps of the present invention.

[0054] Example 1 A 250 mL autoclave equipped with mechanical stirring was dried at 120 °C for more than 12 h, evacuated and cooled to room temperature, and filled with nitrogen for use. Under nitrogen protection, propylene oxide (1.83 g, 31.5 mmol), L-lactide (18.2 g, 126.2 mmol), and succinic anhydride (0.158 g, 1.58 mmol) were weighed and added to the reactor at room temperature, and zinc-cobalt double metal cyanide complex (Zn-Co DMCC, 6.1 mg) with a mass ratio of 1:300 to propylene oxide, stannous octoate (18.2 mg) with a mass ratio of 1:1000 to L-lactide, and polypropylene glycol 200 (0.72 g, 3.6 mmol) were added. After the reactor was sealed, the reaction temperature was set to 80 °C and the reaction was allowed to react for 2 hours. After that, after the pressure in the reactor drops to zero, the temperature is raised to 130 °C and the reaction is continued for 6 hours to obtain polyether ester diol. After the temperature drops to 60 °C, 20 mL of tetrahydrofuran is added to the reactor. After the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.61 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 3 hours. Then, a solution of ethylene glycol / propylene glycol / hexamethylene diisocyanate / tetrahydrofuran (0.31 g / 0.046 g / 0.84 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 6 hours. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated at room temperature to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a polyether ester polyurethane material.

[0055] The GPC test results show that its number average molecular weight is 35.4 kg / mol and the molecular weight distribution is 1.68. The nuclear magnetic resonance hydrogen spectrum results show that the molar content of polyether in the polyether ester diol is 17.8%. The thermal properties test shows that the glass transition temperature of the obtained polyether ester polyurethane is 30.6 ℃ and the melting point is 124.5 ℃. The shape recovery rate of the material is 96.6%.

[0056] Example 2 A 50 mL autoclave equipped with mechanical stirring was dried at 120 °C for more than 12 h, evacuated and cooled to room temperature, and filled with nitrogen for use. Under nitrogen protection, propylene oxide (2.26 g, 39.0 mmol), å-caprolactone (17.74 g, 155.6 mmol), succinic anhydride (0.195 g, 1.95 mmol) were weighed and added to the reactor at room temperature, and zinc-cobalt double metal cyanide complex Zn-Co DMCC (7.53 mg) with a mass ratio of 1:300 to propylene oxide, stannous octoate (17.7 mg) with a mass ratio of 1:1000 to å-caprolactone, and polypropylene glycol 200 (2.0 g, 10 mmol) were added. After the reactor was sealed, the temperature was set to 80 °C and the reaction was allowed to proceed for 2 hours. After that, after the pressure in the reactor drops to zero, the temperature is raised to 130 °C and the reaction is continued for 6 hours to obtain polyether ester diol. After the temperature drops to 60 °C, 20 mL of tetrahydrofuran is added to the reactor. After the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (1.68 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 3 hours. Then, a solution of ethylene glycol / propylene glycol / hexamethylene diisocyanate / tetrahydrofuran (0.31 g / 0.046 g / 0.84 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 6 hours. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated at room temperature to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a polyether ester type polyurethane material.

[0057] The GPC test results show that its number average molecular weight is 30.2 kg / mol and the molecular weight distribution is 1.67. The H-NMR spectrum results show that the molar content of polyether in the polyether ester diol is 22.2%. The thermal properties test shows that the melting points of the obtained polyether ester copolymer are 39.4°C and 143.6°C. The shape recovery rate of the material is 95.6%.

[0058] Example 3 A 50 mL autoclave equipped with mechanical stirring was dried at 120 °C for more than 12 h, evacuated and cooled to room temperature, and filled with nitrogen for use. Under nitrogen protection, propylene oxide (1.13 g, 19.5 mmol), å-caprolactone (17.74 g, 155.6 mmol), succinic anhydride (0.195 g, 1.95 mmol) were weighed and added to the reactor at room temperature, and zinc-cobalt double metal cyanide catalyst (Zn-Co DMCC, 3.77 mg) with a mass ratio of 1:300 to propylene oxide, stannous octoate (17.7 mg) with a mass ratio of 1:1000 to å-caprolactone, and polypropylene glycol 200 (2.0 g, 10 mmol) were added. After the reactor was sealed, the temperature was set to 80 °C and the reaction was allowed to proceed for 2 hours. After that, after the pressure in the reactor drops to zero, the temperature is raised to 130 °C and the reaction is continued for 6 hours to obtain polyether ester diol. After the temperature drops to 60 °C, 20 mL of tetrahydrofuran is added to the reactor. After the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (1.68 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 3 hours. Then, a solution of ethylene glycol / propylene glycol / hexamethylene diisocyanate / tetrahydrofuran (0.31 g / 0.092 g / 0.84 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 6 hours. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated at room temperature to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a polyether ester type polyurethane material.

[0059] The GPC test results show that its number average molecular weight is 48.8 kg / mol and the molecular weight distribution is 1.78. The H-NMR spectrum results show that the molar content of polyether in the polyether ester diol is 11.3%. The thermal properties test shows that the melting point of the obtained polyether ester copolymer is 45.0 ℃. The shape recovery rate of the material is 98.1%.

[0060] Example 4 A 50 mL autoclave equipped with mechanical stirring was dried at 120 °C for more than 12 h, evacuated and cooled to room temperature, and filled with nitrogen for use. Under nitrogen protection, propylene oxide (1.13 g, 19.5 mmol), å-caprolactone (17.74 g, 155.6 mmol), succinic anhydride (0.195 g, 1.95 mmol) were weighed and added to the reactor at room temperature, and zinc-cobalt double metal cyanide catalyst (Zn-Co DMCC, 3.77 mg) with a mass ratio of 1:300 to propylene oxide, stannous octoate (17.7 mg) with a mass ratio of 1:1000 to å-caprolactone, and polypropylene glycol 200 (2.0 g, 10 mmol) were added. After the reactor was sealed, the temperature was set to 80 °C and the reaction was allowed to proceed for 2 hours. After that, after the pressure in the reactor drops to zero, the temperature is raised to 130 °C and the reaction is continued for 6 hours to obtain polyether ester diol. After the temperature drops to 60 °C, 20 mL of tetrahydrofuran is added to the reactor. After the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (1.68 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 3 hours. Then, a solution of ethylene glycol / propylene glycol / hexamethylene diisocyanate / tetrahydrofuran (0.31 g / 0.138 g / 0.84 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 6 hours. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated at room temperature to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a polyether ester polyurethane material.

[0061] The GPC test results show that its number average molecular weight is 60.1 kg / mol and the molecular weight distribution is 1.73; the nuclear magnetic resonance hydrogen spectrum results show that the molar content of polyether in the polyether ester diol is 12.3%; the thermal properties test shows that the melting point of the obtained polyether ester copolymer is 43.5℃; the shape recovery rate of the material is 94.5%.

[0062] Example 5 A 50 mL autoclave equipped with mechanical stirring was dried at 120 °C for more than 12 h, evacuated and cooled to room temperature, and filled with nitrogen for use. Under nitrogen protection, propylene oxide (1.13 g, 19.5 mmol), å-caprolactone (17.74 g, 155.6 mmol), succinic anhydride (0.195 g, 1.95 mmol) were weighed and added to the reactor at room temperature, and zinc-cobalt double metal cyanide catalyst (Zn-Co DMCC, 3.77 mg) with a mass ratio of 1:300 to propylene oxide, stannous octoate (17.7 mg) with a mass ratio of 1:1000 to å-caprolactone, and polypropylene glycol 200 (2.0 g, 10 mmol) were added. After the reactor was sealed, the temperature was set to 80 °C and the reaction was allowed to proceed for 2 hours. After that, after the pressure in the reactor drops to zero, the temperature is raised to 130 °C and the reaction is continued for 6 hours to obtain polyether ester diol. After the temperature drops to 60 °C, 20 mL of tetrahydrofuran is added to the reactor. After the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (1.68 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 3 hours. Then, a solution of ethylene glycol / propylene glycol / hexamethylene diisocyanate / tetrahydrofuran (0.31 g / 0.184 g / 0.84 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 6 hours. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated at room temperature to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a polyether ester type polyurethane material.

[0063] The GPC test results show that its number average molecular weight is 55.5 kg / mol and the molecular weight distribution is 1.77. The H-NMR spectrum results show that the molar content of polyether in the polyether ester diol is 11.7%. The thermal properties test shows that the melting point of the obtained polyether ester copolymer is 49.8°C. The shape recovery rate of the material is 95.2%.

[0064] Comparative Example A 50 mL autoclave equipped with mechanical stirring was dried at 120 °C for more than 12 h, evacuated and cooled to room temperature, and filled with nitrogen for use. Under nitrogen protection, propylene oxide (2.26 g, 39.0 mmol), å-caprolactone (17.74 g, 155.6 mmol), succinic anhydride (0.195 g, 1.95 mmol) were weighed and added to the reactor at room temperature, and zinc-cobalt double metal cyanide complex Zn-Co DMCC (7.53 mg) with a mass ratio of 1:300 to propylene oxide, stannous octoate (17.7 mg) with a mass ratio of 1:1000 to å-caprolactone, and polypropylene glycol 200 (2.0 g, 10 mmol) were added. After the reactor was sealed, the temperature was set to 80 °C and the reaction was allowed to proceed for 2 hours. After that, after the pressure in the reactor drops to zero, the temperature is raised to 130 °C and the reaction is continued for 6 hours to obtain polyether ester diol. After the temperature drops to 60 °C, 20 mL of tetrahydrofuran is added to the reactor. After the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (1.68 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 3 hours. Then, a solution of ethylene glycol / hexamethylene diisocyanate / tetrahydrofuran (0.31 g / 0.84 g / 20 mL) is added dropwise to the reactor and the reaction is kept warm for 6 hours. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated at room temperature to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried at 40 °C under vacuum for 12 hours to obtain a linear polyether ester polyurethane material.

[0065] The GPC test results show that its number average molecular weight is 30.7 kg / mol and the molecular weight distribution is 1.65. The H-NMR spectrum results show that the molar content of polyether in the polyether ester diol is 8.5%. The thermal properties test shows that the melting point of the obtained polyether ester copolymer is 53.5°C. The shape recovery rate of the material is 81.7%.

[0066] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing a polyetherester polyurethane having shape memory properties, characterized in that: The following steps are involved: (1) adding an epoxy compound, a cyclic lactone compound, an acid anhydride compound, a catalyst 1, a catalyst 2 and an initiator into a reactor for a primary reaction; (2) After the pressure in the reactor drops to 0, the temperature is raised to carry out a secondary reaction to obtain a polyether ester diol; (3) adding an isocyanate compound dissolved in an organic solvent dropwise into a reactor to carry out three reactions; (4) A mixed solution containing an isocyanate compound, a chain extender and a branching agent is added dropwise into a reactor to carry out four reactions to obtain a polyetherester polyurethane with a long-chain branched structure.

2. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The epoxy compound in step (1) is any one of ethylene oxide, propylene oxide, epichlorohydrin and butylene oxide; The cyclic lactone compound is any one of glycolide, L-lactide, D-lactide, racemic lactide, valerolactone or caprolactone; The acid anhydride compound is any one of succinic anhydride, methylsuccinic anhydride or glutaric anhydride; The catalyst 1 is a zinc-cobalt double metal cyanide complex; The catalyst 2 is an organic carboxylate or oxide containing any one of metal titanium, tin, antimony and germanium; The initiator is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, polyethylene glycol 200, polyethylene glycol 400, polypropylene glycol 200, and polypropylene glycol 400.

3. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The molar ratio of the cyclic lactone compound to the epoxy compound used in step (1) is 1:0.1-9; the molar ratio of the acid anhydride compound to the epoxy compound is 1:10-100; the mass ratio of the catalyst 1 to the epoxy compound is 1:100-10000; the mass ratio of the catalyst 2 to the cyclic lactone compound is 1:100-1000; and the molar ratio of the initiator to the epoxy compound is 1:1-200.

4. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The temperature of the primary reaction in step (1) is 60-120°C and the time is 0.5-3 h.

5. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The temperature of the secondary reaction in step (2) is 70-150°C and the time is 2-6 h.

6. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The organic solvent in step (3) is any one of dichloromethane, chloroform and tetrahydrofuran.

7. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The temperature of the three reactions in step (3) is 40-100°C and the time is 3-12 h.

8. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The isocyanate compounds used in steps (3) and (4) are independently selected from any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate or dicyclohexylmethane-4,4'-diisocyanate; wherein the molar ratio of the isocyanate compound used in step (3) to the initiator is 1:0.9~1.2, and the molar ratio of the isocyanate compound used in step (4) to the chain extender is 1:0.9~1.

2.

9. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The chain extender in step (4) is any one of ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, diethylene glycol or 1,4-cyclohexanedimethanol, and the molar ratio of the amount thereof to the initiator in step (1) is 1:0.1-9; the branching agent is any one of propylene glycol, pentaerythritol or dipentaerythritol, and the molar ratio of the amount thereof to the chain extender is 1:1-100.

10. The method for preparing polyetherester polyurethane according to claim 1, characterized in that: The temperature of the four reactions in step (4) is 40-100°C and the time is 3-12 h.

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