Polyurethane polymer as well as preparation method and application thereof

Abstract

The invention discloses a polyurethane polymer as well as a preparation method and application thereof, and relates to the technical field of polyurethane materials. The structural general formula of the polyurethane polymer is # imgabs0 #; wherein x and y are positive integers, x is greater than 1, and y is greater than 1; r is R1 or R2; the structural formulas of R1 and R2 are as follows: # imgabs 1 #; and # imgabs2 #. The polyurethane polymer has flexible alicyclic six-atom and aromatic benzene ring structures at the same time, the tensile strength and toughness are remarkably improved, the tensile strength reaches 90.4 MPa, the toughness is 275.5 MJ / m < 3 >, and the polyurethane polymer shows excellent mechanical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane materials, and in particular to a polyurethane polymer and a preparation method and application thereof. Background Art

[0002] As an important type of polymer material, polyurethane has attracted widespread attention due to its excellent mechanical properties, processability and biocompatibility. However, its strength and toughness often have a trade-off, which limits the development of high-performance applications. Therefore, achieving a balance between high strength and high toughness has become an important challenge in materials science. In recent years, researchers have provided effective strategies for optimizing the performance of polyurethane by introducing hydrogen bonds and π-π interactions. However, how to precisely regulate these non-covalent interactions at the molecular level to further optimize the comprehensive performance of polyurethane is still the core issue of current research. Therefore, the development of high-strength and high-toughness polyurethane materials will become an important direction for future research. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a polyurethane polymer. The polyurethane polymer has a tensile strength of 90.4 MPa and a toughness of 275.5 MJ / m 3 , showing excellent mechanical properties.

[0004] A further technical problem to be solved by the present invention is to provide a preparation method and application of the above polyurethane polymer.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A polyurethane polymer, the general structural formula of the polyurethane polymer is: ;

[0007] x and y are positive integers, and x>1, y>1; R is R 1 or R 2 ; R 1 or R 2 The structural formula is as follows: ; .

[0008] Wherein, x and y can be any positive integer greater than 1. Preferably, the values ​​of x and y are equal.

[0009] More preferably, x is 1 to 13, and y is 1 to 13. Preferably, x is 1 to 13, and y is 7 to 13.

[0010] The preparation method of the above-mentioned polyurethane polymer comprises the following steps:

[0011] The polyurethane prepolymer, the first chain extender and the organic solvent are mixed to perform a first chain extension reaction to obtain a chain extension product; the temperature of the first chain extension reaction is 60°C to 100°C, and the time is 1h to 3h; in this step, the ratio of the first chain extender to the organic solvent is 1:10 to 1:150 g / mL; more preferably, the ratio of the first chain extender to the organic solvent in this step is 1:35 to 1:135 g / mL;

[0012] The chain extension product, the second chain extender and the organic solvent are mixed to carry out a second chain extension reaction to obtain the polyurethane polymer; the temperature of the second chain extension reaction is 60°C to 100°C, and the time is 1h to 3h; in this step, the ratio of the second chain extender to the organic solvent is 1:10 to 1:150 g / mL; more preferably, in this step, the ratio of the second chain extender to the organic solvent is 1:40 to 1:130 g / mL;

[0013] Wherein, the first chain extender is a mixture of one or more of alicyclic diol chain extenders and diamine chain extenders; the second chain extender is a mixture of one or more of aromatic diol chain extenders and diamine chain extenders;

[0014] Alternatively, the first chain extender is a mixture of one or more aromatic diol chain extenders and diamine chain extenders; the second chain extender is a mixture of one or more alicyclic diol chain extenders and diamine chain extenders.

[0015] The first chain extender is one or more of cis-cyclohexane-1,4-diol, 1-methylcyclohexane-1,4-diol, 4,4'-diaminodicyclohexylmethane, 1,2-diaminocyclohexane, isophoronediamine, and 1,4-cyclohexanediamine.

[0016] The second chain extender is one or more of 4,4'-biphenol, hydroquinone dihydroxyethyl ether, 4,4'-diaminobenzanilide, 4,4'-diaminobibenzyl, 4,4'-diaminobenzophenone, benzidine, p-phenylenediamine, and 1,4-phenylenediamine.

[0017] The amount of the first chain extender and the second chain extender added determines the mechanical properties of the polyurethane polymer, and the mechanical properties can be adjusted by adjusting the amount of the first chain extender and the second chain extender added. Preferably, the total mole number of the first chain extender and the second chain extender is the same as the mole number of the polyol in the polyurethane prepolymer.

[0018] The molar ratio of the first chain extender to the second chain extender is 1:1, so that a balance between strength and toughness can be achieved.

[0019] Wherein, the first chain extension reaction is carried out in a protective atmosphere; and the second chain extension reaction is carried out in a protective atmosphere.

[0020] Wherein, the polyurethane prepolymer is prepared by the following method:

[0021] The polyether or polyester polyol and the organic solvent are mixed to obtain a mixed solution; specifically, the polyester polyol is placed in a reaction container, stirred under an oil bath condition of 100-150° C. and an inert gas atmosphere, and dried after removing water; then an organic solvent is added to the reaction container as a reaction solvent, and stirred evenly to obtain a mixed solution; the ratio of the polyester polyol to the organic solvent is 1:20-1:1 g / mL; preferably, the ratio of the polyester polyol to the organic solvent is 1:1-1:3 g / mL;

[0022] The mixed solution, diisocyanate, catalyst and organic solvent are mixed for prepolymerization reaction to obtain a polyurethane prepolymer; the ratio of diisocyanate to the added organic solvent is 1:20-1:1 g / mL; the mass ratio of the diisocyanate to the catalyst is 120:1-230:1; preferably, in this step, the ratio of diisocyanate to the added organic solvent is 1:5-1:10 g / mL;

[0023] Wherein, the molar ratio of the polyether or polyester polyol to the diisocyanate is 1:2 to 1:2.4; the temperature of the prepolymerization reaction is 60° C. to 100° C., and the reaction time is 2 h to 5 h.

[0024] Wherein, the diisocyanate is one or more of toluene-2,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate; preferably, the diisocyanate is a diisocyanate with an alicyclic ring, preferably isophorone diisocyanate or 4,4'-dicyclohexylmethane diisocyanate.

[0025] The catalyst is one or more of an amine catalyst and an organic metal catalyst.

[0026] The organic solvent is preferably one or more of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran and N-methylpyrrolidone.

[0027] The average molecular weight of the polyol is 1000-3000, and the polyol is preferably one or more of polyether or polyester polyol.

[0028] The above-mentioned polyurethane polymers are used in intelligent manufacturing, aerospace and flexible electronics.

[0029] The beneficial effects of the present invention are as follows:

[0030] (1) The polyurethane polymer of the present invention has both a flexible alicyclic hexaatomic structure and an aromatic benzene ring structure, which significantly improves the tensile strength and toughness. The tensile strength reaches 90.4 MPa and the toughness is 275.5 MJ / m 3 , showing excellent mechanical properties.

[0031] (2) The polyurethane polymer of the present invention has excellent film-forming properties and heat resistance.

[0032] (3) The present invention adopts a two-step chain extension reaction, which can achieve orderly segment arrangement to form a block structure. This block structure is an ordered optimizable material with a microphase separation structure (distribution of hard segment microdomains and soft segment microdomains), thereby improving mechanical properties and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the infrared spectra of Examples 1 to 3 of the present invention and Comparative Examples 1 and 2.

[0034] Figure 2 It is the infrared spectra of Examples 4 to 6 of the present invention and Comparative Examples 3 and 4.

[0035] Figure 3 This is an atomic force microscope (AFM) image of Comparative Example 1.

[0036] Figure 4 This is an atomic force microscope (AFM) image of Comparative Example 2.

[0037] Figure 5 This is an atomic force microscope (AFM) image of Example 1.

[0038] Figure 6 This is an atomic force microscope (AFM) image of Example 2.

[0039] Figure 7 This is an atomic force microscope (AFM) image of Example 3.

[0040] Figure 8 This is an atomic force microscope (AFM) image of Comparative Example 3.

[0041] Fig. 9 This is an atomic force microscope (AFM) image of Comparative Example 4.

[0042] Fig.10 This is an atomic force microscope (AFM) image of Example 4.

[0043] Fig.11 This is an atomic force microscope (AFM) image of Example 5.

[0044] Fig.12This is an atomic force microscope (AFM) image of Example 6.

[0045] Fig.13 This is the thermogravimetric analysis curve of Example 2.

[0046] Fig.14 It is a stress-strain curve diagram of Examples 1 to 3 of the present invention and Comparative Examples 1 and 2.

[0047] Fig.15 It is a stress-strain curve diagram of Examples 4 to 6 of the present invention and Comparative Examples 3 and 4.

[0048] Fig.16 This is the hydrogen nuclear magnetic resonance spectrum of Example 2 of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Unless otherwise specified, the reagents used in the following examples are commercially available.

[0051] The preparation method of the polyurethane polymer of the present invention is as follows:

[0052] 1. Preparation of polyurethane prepolymer (prepolymerization reaction):

[0053] First, select appropriate polyether or polyester polyol (molecular weight range: 1000-3000) and mix them, put them in a three-necked flask, and stir them in an oil bath at 100℃~150℃ with nitrogen (30min~120min) to fully remove moisture and other impurities;

[0054] After the mixed liquid temperature is cooled to 60℃~100℃, add an equivalent amount of diisocyanate (the diisocyanate can be one or more of toluene-2,4-diisocyanate (2,4-TDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI)), and measure a certain amount of organic solvent (optional solvent: N,N-dimethylformamide One or more of DMF, N,N-dimethylacetamide (DMAc), tetrahydrofuran and N-methylpyrrolidone (NMP) are added dropwise to the reaction bottle, and a small amount of catalyst is added dropwise (the optional catalysts include: amine catalysts and organic metal catalysts. Amine catalysts such as triethylamine, N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, etc.; organic metal catalysts such as dibutyltin dilaurate, stannous isooctanoate, zinc isooctanoate, etc.). The reaction is carried out in N 2 The reaction mixture was subjected to the reaction in an atmosphere for 2 h to 5 h to obtain a polyurethane prepolymer.

[0055] 2. The first chain extension reaction:

[0056] After the prepolymer is prepared, a first chain extension reaction is performed to obtain a chain extension product. The first chain extension reaction uses a mixture of one or more aromatic diol chain extenders and diamine chain extenders, or a mixture of one or more alicyclic diol chain extenders and diamine chain extenders.

[0057] Specifically, a first chain extender is added to the prepolymer. A certain amount of the same organic solvent is added to the reaction bottle. The reaction is carried out at N 2 The reaction is carried out under a nitrogen atmosphere, the reaction temperature is 60°C~100°C, the reaction time is 1h~3h, and a chain extension product is obtained.

[0058] 3. Second chain extension reaction:

[0059] A second chain extender is added to the chain extension product to carry out a second chain extension reaction. The second chain extender is a chain extender of a different type from the first chain extender. Specifically, if the first chain extender is an aromatic chain extender, the second chain extender is an alicyclic chain extender; if the first chain extender is an alicyclic chain extender, the second chain extender is an aromatic chain extender.

[0060] Specifically, the chain extension product, the second chain extender and the organic solvent are mixed to carry out a second chain extension reaction to obtain the polyurethane polymer; the temperature of the second chain extension reaction is 60° C. to 100° C., and the time is 1 h to 3 h.

[0061] 4. After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 60°C to 120°C under vacuum for 24h to 72h to remove the residual solvent to obtain a polyurethane elastomer film.

[0062] The polyurethane polymer prepared by the present invention adopts a flexible alicyclic six-atom structure to replace the rigid aromatic spacer, and two chain extenders are added step by step. Compared with adding two chain extenders at the same time, it has the following significant advantages:

[0063] (1) Ordered segment arrangement: The step-by-step reaction allows the introduction of a chain extender to react with the prepolymer to form a specific segment, which is then extended by a second chain extender to achieve a block structure. This orderliness can optimize the microphase separation of the material (such as the distribution of hard segment microdomains and soft segment microdomains), thereby improving mechanical properties (such as tensile strength, toughness) and thermal stability.

[0064] (2) Reduce the generation of by-products: Adding two chain extenders at the same time may trigger a competitive reaction, thereby producing by-products, while adding them in steps can effectively reduce the occurrence of such problems.

[0065] (3) Avoid gelation risk: Adding two chain extenders at the same time may cause local gelation. Adding them in steps can reduce the risk of process out of control.

[0066] Preferably, the first chain extender is a mixture of one or more alicyclic diol chain extenders and diamine chain extenders, and the second chain extender is a mixture of one or more aromatic diol chain extenders and diamine chain extenders.

[0067] A mixture of one or more alicyclic diol chain extenders and diamine chain extenders is used as the chain extender; (optionally, diol chain extenders: cis-cyclohexane-1,4-diol, 1-methylcyclohexane-1,4-diol; diamine chain extenders: one or more of 4,4'-diaminodicyclohexylmethane, 1,2-diaminocyclohexane, isophoronediamine, 1,4-cyclohexanediamine), and the reaction structure is shown below: ; or .

[0068] A mixture of one or more aromatic diol chain extenders and diamine chain extenders; specifically, one or more of 4,4'-biphenol, hydroquinone dihydroxyethyl ether, 4,4'-diaminobenzanilide, 4,4'-diaminobibenzyl, 4,4'-diaminobenzophenone, benzidine, p-phenylenediamine, and 1,4-phenylenediamine can be selected. If the chain extender is solid, it needs to be dissolved in an organic solvent, ultrasonically treated to completely dissolve it, and then added dropwise to the reaction bottle.

[0069] In view of the inherent contradiction between strength and toughness of traditional polyurethane materials, the present invention designs a new type of polyurethane elastomer based on a dynamic hydrogen bond network (a three-dimensional network structure formed by hydrogen bonds between or within the molecules of the carbamate (-NHCOO-) and urea (-NH-COO-NH-) groups in the structural formula) and a flexible alicyclic six-atom structure through a molecular engineering strategy. This breaks through the trade-off limitations of mechanical properties and provides an innovative solution for the development of high-performance structural materials.

[0070] The present invention has achieved significant improvements in tensile strength and toughness, with a tensile strength of 90.4 MPa and a toughness of 275.5 MJ / m 3 , showing excellent mechanical properties. To achieve this goal, a flexible alicyclic hexaatomic structure was used to replace the rigid aromatic spacer, which promoted the close packing of the molecular chains while retaining the dynamic movement ability of the chain segments, avoiding brittle fracture. At the same time, the strong dipole interaction formed by the urea group (-NH-COO-NH-) in the material effectively dissipates energy under the action of external force with the help of the breaking and recombination mechanism of dynamic hydrogen bonds, thereby enhancing strength and toughness. In addition, the polarity difference between the hard segment and the soft segment drives the formation of nanoscale micro-regions, thereby optimizing the microphase separation structure and further improving the transmission efficiency of interfacial stress.

[0071] The present invention solves the long-standing contradiction between strength and toughness of polyurethane materials by precisely regulating non-covalent interactions at the molecular scale. In addition, the polyurethane materials prepared by the present invention have adjustable mechanical properties, including high strength, high toughness, excellent stretchability, excellent film-forming properties and heat resistance. This provides a new idea for the molecular design of high-performance polymer materials and has significant industrial application potential.

[0072] Example 1

[0073] (1) First, weigh 10 mmol (20.0 g molecular weight 2000 g / mol) of polycarbonate diol (PCDL-2000) and 25 mL of N,N-dimethylformamide (DMF) and place them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0074] (2) After the mixed solution was cooled to 80°C, 20 mmol (4.45 g) of IPDI (isophorone diisocyanate, molecular weight 222.29 g / mol) and 25 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.02 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0075] (3) After the prepolymerization reaction was completed, 2.5 mmol (0.53 g) of 4,4'-diaminodicyclohexylmethane (DDM) and 62 mL of DMF solvent were weighed, the two were mixed, ultrasonicated until completely dissolved, added to a three-necked flask, and the reaction was carried out in an oil bath at a temperature of 80°C and N 2 The reaction time was 60 min with stirring.

[0076] (4) Next, 7.5 mmol (0.92 g) of solid chain extender: benzidine (BZ) and 38 mL of DMF solvent were weighed, mixed, and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at 80 °C and N 2 The reaction time was 60 min with stirring.

[0077] (5) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80° C. in a vacuum oven for 48 h to remove the residual solvent. The sample is named Example 1.

[0078] Example 2

[0079] The specific steps are the same as those of Example 1, except that the amount of the first chain extender 4,4'-diaminodicyclohexylmethane (DDM) is 5 mmol, and the amount of the second chain extender benzidine (BZ) is 5 mmol. The sample is named Example 2.

[0080] Example 3

[0081] The specific steps are the same as those of Example 1, except that the amount of the first chain extender 4,4'-diaminodicyclohexylmethane (DDM) is 7.5 mmol, and the amount of the second chain extender benzidine (BZ) is 2.5 mmol. The sample is named Example 3.

[0082] Comparative Example 1

[0083] (1) First, weigh 10 mmol (20.0 g molecular weight 2000 g / mol) of polycarbonate diol (PCDL-2000) and 25 mL of N,N-dimethylformamide (DMF) and place them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0084] (2) After the mixed solution was cooled to 80°C, 20 mmol (4.45 g) of IPDI (isophorone diisocyanate, molecular weight 222.29 g / mol) and 25 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.02 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2 The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0085] (3) After the prepolymerization reaction was completed, 10 mmol (1.84 g) of solid chain extender: benzidine (BZ) was weighed and 50 mL of DMF solvent was measured. The two were mixed and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at a temperature of 80 °C and N 2 The reaction time was 60 min with stirring.

[0086] (4) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80° C. in a vacuum oven for 48 h to remove the residual solvent. The mold is named Comparative Example 1.

[0087] Comparative Example 2

[0088] (1) First, weigh 10 mmol, 20.0 g of polycarbonate diol (PCDL-2000) with a molecular weight of 2000 g / mol and 25 mL of N,N-dimethylformamide (DMF) and place them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0089] (2) After the mixed solution was cooled to 80°C, 20 mmol, 4.45 g of IPDI (isophorone diisocyanate, molecular weight 222.29 g / mol) and 25 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.02 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2 The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0090] (3) After the prepolymerization reaction was completed, 10 mmol, 2.1 g of chain extender 4,4'-diaminodicyclohexylmethane and 50 mL of DMF solvent were weighed, the two were mixed, ultrasonically treated until completely dissolved, and added to a three-necked flask. The reaction was carried out in an oil bath at a temperature of 80°C and N 2The reaction time was 60 min with stirring.

[0091] (4) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80° C. in a vacuum oven for 48 h to remove the residual solvent. The mold is named Comparative Example 2.

[0092] Example 4

[0093] (1) First, weigh 10 mmol (20.0 g molecular weight 2000 g / mol) of polycarbonate diol (PCDL-2000) and 25 mL of N,N-dimethylformamide (DMF) and place them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0094] (2) After the mixed solution was cooled to 80°C, 20 mmol (3.48 g) of 2,4-TDI (toluene-2,4-diisocyanate, molecular weight 174.16 g / mol) and 25 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.02 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2 The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0095] (3) After the prepolymerization reaction was completed, 2.5 mmol (0.53 g) of 4,4'-diaminodicyclohexylmethane (DDM) and 62 mL of DMF solvent were weighed, the two were mixed, ultrasonicated until completely dissolved, added to a three-necked flask, and the reaction was carried out in an oil bath at a temperature of 80°C and N 2 The reaction time was 60 min with stirring.

[0096] (4) Next, 7.5 mmol (0.92 g) of solid chain extender: benzidine (BZ) and 38 mL of DMF solvent were weighed, mixed, and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at 80 °C and N 2 The reaction time was 60 min with stirring.

[0097] (5) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80° C. in a vacuum oven for 48 h to remove the residual solvent. The mold is named Example 4.

[0098] Example 5

[0099] The specific steps are the same as those of Example 4, except that the amount of the first chain extender 4,4'-diaminodicyclohexylmethane (DDM) is 5 mmol, and the amount of the second chain extender benzidine (BZ) is 5 mmol. The sample is named Example 5.

[0100] Example 6

[0101] The specific steps are the same as those of Example 4, except that the amount of the first chain extender 4,4'-diaminodicyclohexylmethane (DDM) is 7.5 mmol, and the amount of the second chain extender benzidine (BZ) is 2.5 mmol. The sample is named Example 6.

[0102] Comparative Example 3

[0103] (1) First, weigh 10 mmol (20.0 g molecular weight 2000 g / mol) of polycarbonate diol (PCDL-2000) and 25 mL of N,N-dimethylformamide (DMF) and place them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0104] (2) After the mixed solution was cooled to 80°C, 20 mmol (3.48 g) of 2,4-TDI (toluene-2,4-diisocyanate, molecular weight 174.16 g / mol) and 25 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.02 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2 The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0105] (3) After the prepolymerization reaction was completed, 10 mmol (1.84 g) of solid chain extender: benzidine (BZ) was weighed and 50 mL of DMF solvent was measured. The two were mixed and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at a temperature of 80 °C and N 2 The reaction time was 60 min with stirring.

[0106] (4) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80° C. in a vacuum oven for 48 h to remove the residual solvent. The mold is named Comparative Example 3.

[0107] Comparative Example 4

[0108] (1) First, weigh 10 mmol, 20.0 g of polycarbonate diol (PCDL-2000) with a molecular weight of 2000 g / mol and 25 mL of N,N-dimethylformamide (DMF) and place them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0109] (2) After the mixed solution was cooled to 80°C, 20 mmol (3.48 g) of 2,4-TDI (toluene-2,4-diisocyanate, molecular weight 174.16 g / mol) and 25 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.02 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2 The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0110] (3) After the prepolymerization reaction was completed, 10 mmol, 2.1 g of chain extender 4,4'-diaminodicyclohexylmethane and 50 mL of DMF solvent were weighed, the two were mixed, ultrasonically treated until completely dissolved, and added to a three-necked flask. The reaction was carried out in an oil bath at a temperature of 80°C and N 2 The reaction time was 60 min with stirring.

[0111] (4) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80° C. in a vacuum oven for 48 h to remove the residual solvent. The mold is named Comparative Example 4.

[0112] Example 7

[0113] (1) First, weigh 10 mmol (20.0 g molecular weight 2000 g / mol) of polycarbonate diol (PCDL-2000) and 30 mL of N,N-dimethylformamide (DMF) and mix them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0114] (2) After the mixed solution was cooled to 80°C, 24 mmol (6.3 g) of 4,4'-dicyclohexylmethane diisocyanate (molecular weight 262.35 g / mol) and 60 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.03 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0115] (3) After the prepolymerization reaction was completed, 6 mmol (0.78 g) of 1-methylcyclohexane-1,4-diol and 62 mL of DMF solvent were weighed, mixed, and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at 80 °C and N 2 The reaction time was 120 min with stirring.

[0116] (4) Next, 8 mmol (1.82 g) of 4,4'-diaminobenzanilide and 38 mL of DMF solvent were weighed, mixed, and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at 80 °C and N 2 The reaction time was 60 min with stirring.

[0117] (5) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80°C under vacuum for 48 hours to remove the residual solvent to obtain a polyurethane polymer.

[0118] Example 8

[0119] (1) First, weigh 10 mmol (20.0 g molecular weight 2000 g / mol) of polycarbonate diol (PCDL-2000) and 60 mL of N,N-dimethylformamide (DMF) and mix them in a three-necked flask. 2 Stir under air for 60 min to fully remove water and other impurities.

[0120] (2) After the mixed solution was cooled to 80°C, 22 mmol (5.77 g) of 4,4'-dicyclohexylmethane diisocyanate and 50 mL of N,N-dimethylformamide (DMF) were weighed as an organic solvent, mixed and added to a three-necked flask, and 0.03 g of dibutyltin dilaurate (DBTDL) was added as a catalyst. The prepolymerization reaction was carried out in an oil bath at 80°C and N 2 The mixture was stirred under an aqueous atmosphere for 3 h to obtain an isocyanate-terminated polyurethane prepolymer.

[0121] (3) After the prepolymerization reaction was completed, 5 mmol (0.54 g) of p-phenylenediamine and 38 mL of DMF solvent were weighed, the two were mixed, ultrasonicated until completely dissolved, and added to a three-necked flask. The reaction was carried out in an oil bath at 80 °C and N 2 The reaction time was 60 min with stirring.

[0122] (4) Next, 4 mmol (0.46 g) of 1,4-cyclohexanediamine and 62 mL of DMF solvent were weighed, mixed, and ultrasonicated until completely dissolved. The mixture was added to a three-necked flask and the reaction was carried out in an oil bath at 80 °C and N 2 The reaction time was 60 min with stirring.

[0123] (5) After the reaction is completed, the solution is poured into a polytetrafluoroethylene mold and dried at 80°C under vacuum for 48 hours to remove the residual solvent to obtain a polyurethane polymer.

[0124] Test results and analysis:

[0125] 1. Characterization analysis:

[0126] Figure 1 and Figure 2 The Fourier transform infrared spectra (FTIR) of Examples 1 to 6 and Comparative Examples 1 to 4 are shown in FIG. As can be seen from the figure, at 3380 cm -1 The characteristic peak of NH group appeared at 1738cm -1 The peak at 1240 cm-1 is attributed to the stretching vibration of the carbonyl group (-C=O-) in the carbamate (-NHCOO-) group. -1 The characteristic peak at 2260-2280 cm -1 There is no characteristic peak of -NCO group, which proves the successful preparation of polyurethane elastomer.

[0127] In addition, the hydrogen nuclear magnetic resonance spectrum of Example 2 was also characterized. Fig.16 For Example 2, deuterated CDCI 3 The H NMR spectrum in Figure 1 shows the positions of the characteristic peaks. 7.27 ppm is the deuterated CDCI of the solvent. 3 The -CH group of benzidine (BZ) corresponds to two peak positions. The peak position of PCDL-2000 is around 4.1ppm, and the -CH, -CH of isophorone diisocyanate (IPDI) are 3.79ppm, 2.92ppm and 0.93ppm, respectively. 2 and -CH 3 The -CH and -CH 2 The positions of these peaks reflect the responses of hydrogen atoms in different parts of the molecule in the magnetic field, and the above analysis also shows that it was successfully prepared.

[0128] The microstructure and surface morphology of Examples 1 to 6 and Comparative Examples 1 to 4 were systematically characterized using an atomic force microscope (AFM). The microstructure of the samples was observed by an atomic force microscope in a tapping mode, with a scanning area size of 3 μm × 3 μm. Figures 3 to 7 and Figures 8 to 12 .

[0129] Depend on Figures 3 to 7 and Figures 8 to 12 It can be seen from the results shown that the AFM phase images of the six embodiments and four comparative examples all show obvious light and dark contrast areas, clearly revealing the microphase separation characteristics of the soft and hard segments in the polyurethane system: the dark area corresponds to the amorphous phase formed by polyester diol as the soft segment, while the bright area originates from the aggregation of the hard segment part constructed by isocyanate and chain extender. This microphase separation behavior is of great significance to the mechanical properties of the material: moderate microphase separation can significantly improve the strength and toughness of the material through the synergistic effect of the hard segment physical cross-linking network and the soft segment flexible matrix. Through further comparison, it was found that the boundaries of the light and dark phase regions of Example 2 were the most distinct and the degree of phase separation was the highest, while the phase region of Comparative Example 3 was the most blurred, indicating that its degree of microphase separation was relatively weak. This result is completely consistent with the mechanical test data, which fully verifies that the microphase separation behavior of polyurethane can be effectively optimized by regulating the ratio and compatibility of soft and hard segments through molecular design, thereby giving the material excellent comprehensive mechanical properties.

[0130] Through precise molecular design, we have constructed a polyurethane elastomer with high strength, high toughness and extraordinary stretchability, breaking through the trade-off between strength and toughness of traditional polymer materials. We have conducted comparative studies on polymers with similar but slightly different structures by optimizing the structure of the hard segment to achieve the desired goal of the polyurethane elastomer. The structure of the optimized hard segment in this embodiment refers to the isocyanate and the chain extender forming the hard segment together. By changing the type of isocyanate, that is, replacing the rigid aromatic interval with a more flexible alicyclic six-atom structure, the structure of the hard segment is optimized, thereby improving the overall strength and toughness of the material.

[0131] Compared with traditional aromatic spacers, the polyurethane material prepared by the present invention adopts a more flexible alicyclic six-atom spacer structure to promote close packing between molecules and enhance the density of hydrogen bonds, thereby improving the overall strength and toughness of the material. This unique molecular construction method not only improves the stability of the polymer chain, but also provides an efficient energy dissipation mechanism when subjected to force, making the strength of the polyurethane 90.4 MPa and the toughness 275.5 MJ / m 3 .

[0132] 2. Performance Analysis

[0133] 2.1 Thermal performance

[0134] In order to effectively evaluate the thermal properties of the prepared optimal material, a thermogravimetric analysis was performed on Example 2. The test atmosphere was nitrogen, and the test temperature range was 50°C to 750°C. Fig.13 This is the thermogravimetric analysis (TGA) diagram of Example 2. Fig.13 As shown in the figure, thermogravimetric analysis shows that Example 2 exhibits higher thermal stability, and the initial thermal decomposition temperature (T d The temperature corresponding to 5% weight loss of the sample is 283.4℃, which is better than most polyurethane elastomers, showing good heat resistance, meeting the requirements of various practical applications, and is expected to be used in extreme conditions or complex environments.

[0135] 2.2 Mechanical properties

[0136] In order to effectively evaluate the mechanical properties of the prepared polyurethane materials, a tensile testing machine was used to perform stress-strain tests on the elastomer films of the six embodiments and four comparative examples. The test standard was GB / T 1040-2006, the test speed (tensile rate) was 100 mm / min, and the test environment was 25°C. The test results of tensile strength, elongation at break, and toughness (integral area of ​​the curve) were compared, and the results are shown in Table 1. Fig.14 and Fig.15 As shown, the relevant data have been summarized in Table 1.

[0137] Table 1 Ultimate tensile strength, elongation at break and toughness of Examples 1 to 6 and Comparative Examples 1 to 4

[0138] Depend on Fig.14 , Fig.15 As shown in Table 1, the tensile strength (i.e., ultimate engineering stress) of Comparative Example 2 is 33.5 MPa, the elongation at break is 1132%, and the toughness is 121.2 MJ / m 3 The tensile strength (i.e., ultimate engineering stress) of Comparative Example 1 is 37.7 MPa, the elongation at break is 1114%, and the toughness is 144.2 MJ / m 3 In contrast, the tensile strength of Example 2 is as high as 90.4 MPa, which is 2.4 to 2.7 times higher than that of Comparative Example 2 and Comparative Example 1. Example 2 still maintains a high elongation at break of 972%, thereby generating 275.5 MJ / m 3 The toughness of Example 2 is 1.91 to 2.27 times higher than that of Comparative Example 2 and Comparative Example 1. Example 2 shows extremely high tensile strength, outstanding stretchability and high toughness, and its strength and toughness are significantly improved compared with Example 5. This shows that by using a more flexible alicyclic six-atom structure (IPDI) to replace the rigid aromatic spacer (TDI) to optimize the structure of the hard segment, the overall strength and toughness of the material can be effectively improved.

[0139] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0140] The parts not elaborated in detail in the description of the present invention belong to the known technology in the art. The above embodiments are provided only for the purpose of describing the present invention, and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A polyurethane polymer, characterized in that The general structural formula of the polyurethane polymer is: ； Wherein, x and y are positive integers, and x>1, y>1; R is R1 or R2; the structural formula of R1 or R2 is as follows: ； 。 2. The polyurethane polymer according to claim 1, characterized in that The x and y values ​​are equal.

3. The polyurethane polymer according to claim 1, characterized in that x is 1 to 13, y is 1 to 13.

4. A method for preparing a polyurethane polymer according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: The polyurethane prepolymer, the first chain extender and the organic solvent are mixed to perform a first chain extension reaction to obtain a chain extension product; the temperature of the first chain extension reaction is 60° C. to 100° C., and the time is 1 h to 3 h; The chain extension product, the second chain extender and the organic solvent are mixed to carry out a second chain extension reaction to obtain the polyurethane polymer; the temperature of the second chain extension reaction is 60° C. to 100° C., and the time is 1 h to 3 h; Wherein, the first chain extender is a mixture of one or more of alicyclic diol chain extenders and diamine chain extenders; the second chain extender is a mixture of one or more of aromatic diol chain extenders and diamine chain extenders; Alternatively, the first chain extender is a mixture of one or more aromatic diol chain extenders and diamine chain extenders; the second chain extender is a mixture of one or more alicyclic diol chain extenders and diamine chain extenders.

5. The method for preparing a polyurethane polymer according to claim 4, characterized in that: The alicyclic diol chain extender and the diamine chain extender are one or more of cis-cyclohexane-1,4-diol, 1-methylcyclohexane-1,4-diol, 4,4'-diaminodicyclohexylmethane, 1,2-diaminocyclohexane, isophoronediamine, and 1,4-cyclohexanediamine; The aromatic diol chain extender and the diamine chain extender are one or more of 4,4'-biphenol, hydroquinone dihydroxyethyl ether, 4,4'-diaminobenzanilide, 4,4'-diaminobibenzyl, 4,4'-diaminobenzophenone, benzidine, p-phenylenediamine, and 1,4-phenylenediamine.

6. The method for preparing a polyurethane polymer according to claim 4, characterized in that: The total mole number of the first chain extender and the second chain extender is the same as the mole number of the polyol in the polyurethane prepolymer.

7. The method for preparing a polyurethane polymer according to claim 6, characterized in that: The molar ratio of the first chain extender to the second chain extender is 1:

1.

8. The method for preparing a polyurethane polymer according to claim 4, characterized in that: The first chain extension reaction is carried out in a protective atmosphere; and the second chain extension reaction is carried out in a protective atmosphere.

9. The method for preparing a polyurethane polymer according to claim 4, characterized in that: The polyurethane prepolymer is prepared by the following method: Mixing polyether or polyester polyol and an organic solvent to obtain a mixed solution; The mixed solution, diisocyanate, catalyst and organic solvent are mixed to carry out prepolymerization reaction to obtain a polyurethane prepolymer; Wherein, the molar ratio of the polyether or polyester polyol to the diisocyanate is 1:2 to 1:2.4; the temperature of the prepolymerization reaction is 60° C. to 100° C., and the reaction time is 2 h to 5 h.

10. The method for preparing a polyurethane polymer according to claim 9, characterized in that: The diisocyanate is one or more of toluene-2,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate; The catalyst is an amine catalyst and an organic metal catalyst; The organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran and N-methylpyrrolidone.

11. Application of the polyurethane polymer according to any one of claims 1 to 3 in intelligent manufacturing, aerospace and flexible electronics.

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