Polyurethane material with ionic interaction and preparation method thereof

Abstract

The invention provides a polyurethane material with ionic interaction and a preparation method thereof, and relates to the technical field of polyurethane materials. The preparation method comprises the following steps: mixing polyol, diisocyanate, an organic solvent and a catalyst, and carrying out prepolymerization reaction to obtain an isocyanate-terminated polyurethane prepolymer; the isocyanate-terminated polyurethane prepolymer and a chain extender are mixed for a chain extension reaction, and a chain extension product is obtained; mixing the chain extension product with an end-capping reagent, and carrying out an end-capping reaction to obtain a polyurethane material with ionic interaction; the end-capping agent has a hydroxyl group and a positive ion group. According to the invention, ionic groups are introduced into a molecular structure, and ionic bonds are formed among polyurethane molecular chains, so that the polyurethane material with ionic interaction is obtained. The polyurethane material provided by the invention not only shows excellent mechanical properties (high strength, high toughness and high stretchability), but also has excellent heat resistance, and is expected to be applied to extreme conditions or complex environments.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane materials, and in particular to a polyurethane material with ion interaction and a preparation method thereof. Background Art

[0002] Polyurethane is a widely used polymer material. It is widely used in coatings, elastomers, adhesives, foam plastics and other fields due to its excellent mechanical properties, good chemical stability, good processing performance and strong designability. However, traditional polyurethane materials are prone to degradation or mechanical property reduction under certain conditions (such as high temperature and extreme pH environment) because they mainly rely on covalent bonds to connect molecular chains. With the development of materials science, the performance of traditional polyurethane materials can no longer meet the needs of some specific applications. Summary of the invention

[0003] In view of this, the object of the present invention is to provide a polyurethane material with ion interaction and a preparation method thereof. The polyurethane material with ion interaction prepared by the present invention has excellent mechanical properties and stability.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing a polyurethane material with ion interaction, comprising the following steps:

[0006] Mixing a polyol, a diisocyanate, an organic solvent and a catalyst for prepolymerization to obtain an isocyanate-terminated polyurethane prepolymer; the polyol includes a polyester polyol and / or a polyether polyol;

[0007] The isocyanate-terminated polyurethane prepolymer is mixed with a chain extender to carry out a chain extension reaction to obtain a chain extension product; the chain extender includes a fluorinated diamine chain extender and / or a fluorinated diol chain extender;

[0008] The chain extension product is mixed with a capping agent to carry out a capping reaction, thereby obtaining the polyurethane material with ion interaction; the capping agent has a hydroxyl group and a positive ion group.

[0009] Preferably, the weight average molecular weight of the polyol is 1000-3000.

[0010] Preferably, the diisocyanate includes one or more of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

[0011] Preferably, the prepolymerization reaction is carried out at a temperature of 60 to 90° C. for 2 to 5 hours, and the prepolymerization reaction is carried out in a nitrogen atmosphere.

[0012] Preferably, the fluorinated diamine chain extender includes one or more of 2,2-bis(trifluoromethyl)diaminobiphenyl, 4,4'-diaminooctafluorobiphenyl and 3,5-diaminotrifluorotoluene; the fluorinated diol chain extender includes one or more of tetrafluorobenzene-1,4-diol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and 2,2,3,3-tetrafluoro-1,4-butanediol.

[0013] Preferably, the temperature of the chain extension reaction is 60-100° C., the time is 1-12 h, and the chain extension reaction is carried out in a nitrogen atmosphere.

[0014] Preferably, the end-capping agent includes one or more of (2-hydroxyethyl)trimethylammonium bromide, 4-hydroxy-1,1-dimethylpiperidinium-1-ammonium bromide, 6-hydroxy-n,n,n-trimethylhexane-1-ammonium bromide, (2-hydroxybenzyl)triphenylphosphonium bromide and (5-hydroxypentyl)triphenylphosphonium bromide.

[0015] Preferably, the end-capping reaction is carried out at a temperature of 60 to 100° C. for a time of 3 to 12 hours, and the end-capping reaction is carried out in a nitrogen atmosphere.

[0016] Preferably, the molar ratio of the polyol, diisocyanate, chain extender and end-capping agent is 12:24:(2-10):(4-20).

[0017] The present invention provides a polyurethane material with ion interaction prepared by the preparation method described in the above technical solution.

[0018] The present invention provides a method for preparing a polyurethane material with ionic interaction, comprising the following steps: mixing a polyol, a diisocyanate, an organic solvent and a catalyst for prepolymerization reaction to obtain an isocyanate-terminated polyurethane prepolymer; the polyol includes a polyester polyol and / or a polyether polyol; mixing the isocyanate-terminated polyurethane prepolymer with a chain extender for chain extension reaction to obtain a chain extension product; the chain extender includes a fluorinated diamine chain extender and / or a fluorinated diol chain extender; mixing the chain extension product with a capping agent for capping reaction to obtain the polyurethane material with ionic interaction; the capping agent has a hydroxyl group and a positive ion group. The present invention introduces ionic groups into the molecular structure of the polyurethane to form ionic bonds between the polyurethane molecular chains to obtain the polyurethane material with ionic interaction. Compared with the prior art, the present invention has the following beneficial effects:

[0019] Ionic bonds are manifested as strong interactions between positively charged cations and negatively charged anions. This attraction can significantly enhance the binding force between polymer molecular chains, thereby improving the mechanical properties of the material. Ionic bonds are dynamically reversible, and these bonds can be broken and reformed. In the present invention, the introduced ionic bonds can effectively dissipate energy through dissociation and recombination, and can enhance the interaction between molecular chains, thereby improving the mechanical properties of polyurethane materials.

[0020] The present invention constructs a polymer network structure with dynamic characteristics and ionic interaction crosslinking by incorporating a chain extender of a fluorine element with high electronegativity and a capping agent with positive ions, wherein the polymer network containing ionic bonds can integrate the advantages of a covalent polymer network and a supramolecular polymer network, which is not only conducive to building a more solid physical crosslinking network and significantly improving the mechanical properties of the material, but also can flexibly regulate the mechanical properties of supramolecular polyurethane, such as high strength, high toughness and extraordinary stretchability, as well as the film-forming property of polymer materials, excellent heat resistance, etc. Therefore, by regulating the strength and number of ionic bonds, a polymer material with specific properties can be designed.

[0021] The present invention provides a polyurethane material with ion interaction prepared by the preparation method described in the above technical scheme. The polyurethane material provided by the present invention not only exhibits excellent mechanical properties (high strength, high toughness and high stretchability), but also has excellent heat resistance, and is expected to be applied in extreme conditions or complex environments, such as in emerging fields such as flexible electronics and robots, and provides new ideas and insights for the development of the next generation of supramolecular polyurethane materials with excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The reaction route for preparing the polyurethane material with ion interaction according to Examples 1 to 3 of the present invention;

[0023] Figure 2 The reaction route for preparing the polyurethane material with ion interaction according to Examples 4 to 6 of the present invention;

[0024] Figure 3 The Fourier transform infrared spectra (FTIR) of the polyurethane materials prepared in Examples 1 to 3 and the comparative example are shown;

[0025] Figure 4 The stress-strain curves of the polyurethane materials prepared in Examples 1 to 3 and the comparative example;

[0026] Figure 5 The stress-strain curves of the polyurethane materials prepared in Examples 4 to 6;

[0027] Figure 6This is the thermal gravimetric curve of the polyurethane material prepared in Example 1. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing a polyurethane material with ion interaction, comprising the following steps:

[0029] Mixing a polyol, a diisocyanate, an organic solvent and a catalyst for prepolymerization to obtain an isocyanate-terminated polyurethane prepolymer; the polyol includes a polyester polyol and / or a polyether polyol;

[0030] The isocyanate-terminated polyurethane prepolymer is mixed with a chain extender to carry out a chain extension reaction to obtain a chain extension product; the chain extender includes a fluorinated diamine chain extender and / or a fluorinated diol chain extender;

[0031] The chain extension product is mixed with a capping agent to carry out a capping reaction, thereby obtaining the polyurethane material with ion interaction; the capping agent has a hydroxyl group and a positive ion group.

[0032] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well known in the art.

[0033] The present invention mixes a polyol, a diisocyanate, an organic solvent and a catalyst for prepolymerization to obtain an isocyanate-terminated polyurethane prepolymer. In the present invention, the polyol includes a polyester polyol and / or a polyether polyol, the polyester polyol is preferably a polyester diol, more preferably a polycarbonate diol, and the polyether polyol is preferably a polyether diol. In the present invention, the weight average molecular weight of the polyol is preferably 1000 to 3000, and can be 1000, 2000 or 3000. In the present invention, the diisocyanate preferably includes one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI) and 4,4'-dicyclohexylmethane diisocyanate (HMDI). In the present invention, the catalyst preferably includes an amine catalyst and / or an organic metal catalyst; the amine catalyst is preferably a tertiary amine catalyst, more preferably including one or more of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, triethylamine and N,N-dimethylbenzylamine; the organic metal catalyst preferably includes one or more of dibutyltin dilaurate, stannous isooctanoate, zinc isooctanoate and bismuth isooctanoate. In the present invention, the organic solvent preferably includes one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and N-methylpyrrolidone (NMP). In the present invention, the molar ratio of the polyol, diisocyanate and catalyst is preferably 4:8:0.01; the present invention has no special requirements for the amount of the organic solvent, as long as the raw materials are dissolved and the reaction proceeds smoothly.

[0034] In the present invention, the method of mixing the polyol, diisocyanate, organic solvent and catalyst is preferably:

[0035] Drying the polyol;

[0036] Diisocyanate, an organic solvent and a catalyst are added to the dried polyol.

[0037] In the present invention, during the drying treatment, an organic solvent may also be added to the polyol, and the organic solvent is preferably the same as the organic solvent used in the prepolymerization reaction. In the present invention, the temperature of the drying treatment is preferably 100-150°C, more preferably 120-130°C, the temperature of the drying treatment is preferably achieved by an oil bath, and the drying treatment is preferably carried out under a nitrogen atmosphere and stirring; the drying treatment time is preferably 120 minutes. After the drying treatment, it is preferably cooled to 60-100°C. In the present invention, the catalyst is preferably added dropwise.

[0038] In the present invention, the temperature of the prepolymerization reaction is preferably 60 to 90° C., more preferably 80° C., the time is preferably 2 to 5 hours, more preferably 3 to 4 hours, and the prepolymerization reaction is preferably carried out under nitrogen atmosphere and stirring. After the prepolymerization reaction is completed, no post-treatment is required and the next step of reaction is directly carried out.

[0039] After obtaining the isocyanate-terminated polyurethane prepolymer, the present invention mixes the isocyanate-terminated polyurethane prepolymer with a chain extender to perform a chain extension reaction to obtain a chain extension product. In the present invention, the chain extender preferably includes a fluorine-containing diamine chain extender and / or a fluorine-containing diol chain extender, and the fluorine-containing diamine chain extender preferably includes one or more of 2,2-bis(trifluoromethyl)diaminobiphenyl, 4,4'-diaminooctafluorobiphenyl and 3,5-diaminotrifluorotoluene, and the fluorine-containing diol chain extender preferably includes one or more of tetrafluorobenzene-1,4-diol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and 2,2,3,3-tetrafluoro-1,4-butanediol. The present invention adopts a fluorine-containing chain extender. The fluorine atom has high electronegativity. Since the electronegativity of the fluorine atom generates a strong electrostatic force on the positive ion, it can attract the end-capping agent with a positive ion group to form a strong fluorine-cation interaction, thereby forming an ionic bond.

[0040] The present invention preferably adds the chain extender dropwise to the isocyanate-terminated polyurethane prepolymer. In the present invention, when the chain extender is solid, it is preferably dissolved before use; the dissolution method is preferably: adding an organic solvent to the chain extender, and ultrasonically treating until the solid chain extender is completely dissolved; the organic solvent is preferably DMF, and the concentration of the chain extender solution obtained after the dissolution is preferably 0.1 g / mL.

[0041] In the present invention, the temperature of the chain extension reaction is preferably 60-100° C., more preferably 70-80° C., the time is preferably 1-12 h, more preferably 5-10 h, and the chain extension reaction is preferably carried out under nitrogen atmosphere and stirring. After the chain extension reaction, no post-treatment is required and the next step of reaction is directly carried out.

[0042] After obtaining the chain extension product, the present invention mixes the chain extension product with a capping agent for capping reaction to obtain the polyurethane material with ion interaction. In the present invention, the capping agent has a hydroxyl group and a positive ion group, preferably including one or more of (2-hydroxyethyl) trimethylammonium bromide, 4-hydroxy-1,1-dimethylpiperidinium-1-ammonium bromide, 6-hydroxy-n,n,n-trimethylhexane-1-ammonium bromide, (2-hydroxybenzyl) triphenylphosphine bromide and (5-hydroxypentyl) triphenylphosphine bromide; the capping agent is a capping agent that can form ion interaction. In the present invention, the molar ratio of the polyol, diisocyanate, chain extender and capping agent is preferably 12:24:(2-10):(4-20), more preferably 12:24:(2-6):(12-20).

[0043] In the present invention, the end-capping agent is preferably added dropwise to the chain extension product. In the present invention, when the end-capping agent is solid, it is preferably dissolved before use; the dissolution method is preferably: adding an organic solvent to the end-capping agent, and ultrasonic treatment until the solid end-capping agent is completely dissolved; the organic solvent is preferably DMF, and the concentration of the end-capping agent solution obtained after the dissolution is preferably 0.1 g / mL.

[0044] In the present invention, the temperature of the end-capping reaction is preferably 60-100°C, more preferably 60-80°C, the time is preferably 3-12h, more preferably 5-10h, and the end-capping reaction is preferably carried out under nitrogen atmosphere and stirring. The present invention uses an end-capping agent with ionic groups to carry out end-capping and introduce ionic groups into the molecular structure of the polyurethane.

[0045] After the end-capping reaction, the present invention preferably pours the obtained reaction solution into a polytetrafluoroethylene mold for vacuum drying to obtain a polyurethane material (polyurethane elastomer) in the form of a film. In the present invention, the vacuum drying temperature is preferably 60 to 100° C., more preferably 80° C., and the time is preferably 24 to 72 hours, more preferably 48 hours; the residual solvent is removed by the vacuum drying.

[0046] The present invention provides a polyurethane material with ionic interaction prepared by the preparation method described in the above technical solution. The polyurethane material provided by the present invention has ionic groups, and ionic bonds are formed between polyurethane molecular chains through fluorine-cation interactions. The structural formula of the polyurethane material synthesized with polycarbonate diol, isophorone diisocyanate, 2,2-bis(trifluoromethyl)diaminobiphenyl (chain extender) and (2-hydroxyethyl)trimethylammonium bromide (end-capping agent) in the embodiment of the present invention is shown in Formula 1:

[0047]

[0048] Ionic polyurethane is a special polymer formed by introducing ionic groups into the main chain of polyurethane. Unlike traditional polyurethane, the molecular structure of ionic polyurethane contains not only common hydrogen bonds and covalent bonds, but also ionic bonds. The core feature of ionic polyurethane lies in the ionic groups in its molecular structure. These groups usually carry positive or negative charges and can form strong electrostatic interactions inside the material. This electrostatic interaction is different from traditional hydrogen bonds and van der Waals forces, has stronger binding force, and gives the material a series of unique properties.

[0049] In the molecular structure of the ionic bond polyurethane constructed by the present invention, oligomer polyol constitutes the soft segment of polyurethane, polyisocyanate, chain extender and end capping agent constitute the hard segment of polyurethane, the hard segment and the soft segment are connected by covalent bonds, and the molecular chains are connected by ionic bonds, with ionic interactions. The hard segment provides the strength and chemical resistance of the material, while the soft segment gives the material good elasticity and toughness. Since the ionic bonds of different contents have different dissociation time scales, the time hierarchy of energy dissipation in the material can be established by using the ionic bonds of different contents. In the present invention, by incorporating different contents of ionic receptors (fluorine-containing chain extenders) and corresponding different ligands (end capping agents with ionic groups) into the polymer network structure, it is not only conducive to building a more solid physical cross-linked network, significantly improving the mechanical properties of the material, but also can flexibly regulate the mechanical properties of the ionic polyurethane. Thus, due to the difference in the content of ionic bonds, an energy dissipation system with obvious differences can be constructed, so the polyurethane materials prepared by different embodiments of the present invention show different mechanical properties.

[0050] The polyurethane material with ionic interaction provided by the present invention exhibits excellent mechanical properties. The electrostatic interaction between ionic groups can play a role of "physical cross-linking" when the material is subjected to external force, thereby improving the tensile strength, ductility and toughness of the material. Secondly, the polyurethane material with ionic interaction also exhibits excellent thermal properties. In terms of thermal properties, ionic bonds increase the thermal deformation temperature and thermal stability of the material by limiting the movement of polymer molecular chains, so that it can still maintain good mechanical properties at higher temperatures.

[0051] The polyurethane material with ionic interaction provided by the present invention has adjustable mechanical properties, such as high strength, high toughness and extraordinary stretchability, as well as the film-forming property and excellent heat resistance of polymer materials. It is expected to be applied to emerging fields such as green materials, flexible electronics, and robotics, and provide new ideas and insights for the development of the next generation of polyurethane materials with excellent mechanical properties and stability.

[0052] In order to further illustrate the present invention, the polyurethane material with ion interaction and the preparation method thereof provided by the present invention are described in detail below in combination with examples, but they should not be construed as limiting the protection scope of the present invention.

[0053] Example 1

[0054] A polyurethane material with ion interaction, the preparation steps are as follows:

[0055] (1) First, 12 mmol, 24.0 g of polycarbonate diol (PCDL-2000) with a molecular weight of 2000 g / mol and 20 mL of DMF were weighed and placed in a three-necked flask, and stirred for drying in an oil bath at 120° C. and a N 2 atmosphere for 120 min.

[0056] (2) After the temperature of the mixed solution obtained in step (1) is cooled to 80°C, 20 mL of DMF is measured as a solvent, 24 mmol, 5.33 g of isophorone diisocyanate (IPDI, molecular weight 222.29 g / mol) is weighed and added dropwise into a three-necked flask, and 0.02 g of a catalyst dibutyltin dilaurate (DBTDL) is added dropwise, and a prepolymerization reaction is carried out under stirring at an oil bath temperature of 80°C and a N2 atmosphere for 3 hours to obtain an isocyanate-terminated polyurethane prepolymer.

[0057] (3) After the prepolymerization reaction is completed, weigh 2 mmol, 0.6 g of solid chain extender 2,2-bis(trifluoromethyl)diaminobiphenyl (BBD), and at the same time measure 6 mL of solvent DMF, keep the concentration of the mixed solution at 0.1 g / mL, dissolve the BBD solid in the solvent DMF, ultrasonically treat until completely dissolved, and add it dropwise to the reaction bottle after the reaction in step (2), stir in an oil bath at a temperature of 80°C and a N2 atmosphere to carry out a chain extension reaction, and the reaction time is 5 h.

[0058] (4) After the chain extension reaction is completed, the temperature is lowered to 60°C, and 20 mmol, 3.7 g of powdered end-capping agent (2-hydroxyethyl) trimethylammonium bromide (TLB) is weighed, and 37 mL of solvent DMF is measured at the same time. The two are mixed, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until it is completely dissolved, and the mixture is added dropwise to the reaction bottle after the reaction in step (3). The end-capping reaction is carried out by stirring in an oil bath environment at a temperature of 60°C and a N2 atmosphere. The reaction time is 5 h.

[0059] (5) After the end-capping reaction is completed, the obtained solution is poured into a polytetrafluoroethylene mold, and vacuum-dried at 80° C. for 48 hours to remove the residual solvent to obtain a polyurethane material. The sample of Example 1 is named PUFT-A.

[0060] Example 2

[0061] A polyurethane material with ion interaction, the preparation steps are as follows:

[0062] (1) The steps (1) to (2) of Example 1 are the same.

[0063] (2) After the prepolymerization reaction is completed, 6 mmol, 1.9 g of solid chain extender 2,2-bis(trifluoromethyl)diaminobiphenyl (BBD) is weighed, and 19 mL of solvent DMF is measured at the same time, and the BBD solid is dissolved in the solvent DMF, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until the mixture is completely dissolved, and the mixture is added dropwise to the reaction bottle after the prepolymerization reaction. The chain extension reaction is carried out by stirring in an oil bath at a temperature of 80°C and a N2 atmosphere. The reaction time is 5 h.

[0064] (3) After the chain extension reaction is completed, the temperature is lowered to 60°C, and 12 mmol, 2.2 g of powdered end-capping agent (2-hydroxyethyl) trimethylammonium bromide (TLB) is weighed, and 22 mL of solvent DMF is measured at the same time. The two are mixed, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until it is completely dissolved, and the mixture is added dropwise to the reaction bottle after the chain extension reaction. The end-capping reaction is carried out by stirring in an oil bath environment at a temperature of 60°C and a N2 atmosphere. The reaction time is 5 h.

[0065] (4) After the end-capping reaction is completed, the obtained solution is poured into a polytetrafluoroethylene mold, and vacuum-dried at 80° C. for 48 hours to remove the residual solvent to obtain a polyurethane material. The sample of Example 2 is named PUFT-B.

[0066] Example 3

[0067] A polyurethane material with ion interaction, the preparation steps are as follows:

[0068] (1) The steps (1) to (2) of Example 1 are the same.

[0069] (2) After the prepolymerization reaction is completed, 10 mmol, 3.2 g of solid chain extender 2,2-bis(trifluoromethyl)diaminobiphenyl (BBD) is weighed, and 32 mL of solvent DMF is measured at the same time, and the BBD solid is dissolved in the solvent DMF, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until the mixture is completely dissolved, and the mixture is added dropwise to the reaction bottle after the prepolymerization reaction. The chain extension reaction is carried out by stirring under oil bath conditions at a temperature of 80°C and a N2 atmosphere. The reaction time is 5 h.

[0070] (3) After the chain extension reaction is completed, the temperature is lowered to 60°C, and 4 mmol and 0.7 g of powdered end-capping agent (2-hydroxyethyl) trimethylammonium bromide (TLB) are weighed, and 7 mL of solvent DMF is measured at the same time. The two are mixed, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until it is completely dissolved, and the mixture is added dropwise to the reaction bottle after the chain extension reaction. The end-capping reaction is carried out by stirring in an oil bath environment at a temperature of 60°C and a N2 atmosphere. The reaction time is 5 h.

[0071] (4) After the end-capping reaction is completed, the obtained solution is poured into a polytetrafluoroethylene mold and vacuum dried at 80° C. for 48 hours to remove the residual solvent to obtain a polyurethane material. The sample of Example 3 is named PUFT-C.

[0072] The reaction routes for preparing polyurethane materials with ionic interactions in Examples 1 to 3 of the present invention are as follows: Figure 1 shown.

[0073] Example 4

[0074] A polyurethane material with ion interaction, the preparation steps are as follows:

[0075] (1) The steps (1) to (2) of Example 1 are the same.

[0076] (2) After the prepolymerization reaction is completed, 2 mmol, 0.7 g of solid chain extender 4,4'-diaminooctafluorobiphenyl (DFB) is weighed, and 7 mL of solvent DMF is measured at the same time, and the DFB solid is dissolved in the solvent DMF, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until the mixture is completely dissolved, and the mixture is added dropwise to the reaction bottle after the prepolymerization reaction. The chain extension reaction is carried out by stirring under oil bath conditions at a temperature of 80°C and a N2 atmosphere. The reaction time is 5 h.

[0077] (3) After the chain extension reaction is completed, the temperature is lowered to 60°C, and 20 mmol, 3.7 g of powdered end-capping agent (2-hydroxyethyl) trimethylammonium bromide (TLB) is weighed, and 37 mL of solvent DMF is measured at the same time. The two are mixed, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until it is completely dissolved, and the mixture is added dropwise to the reaction bottle after the reaction in step (3). The end-capping reaction is carried out by stirring in an oil bath environment at a temperature of 60°C and a N2 atmosphere. The reaction time is 5 h.

[0078] (4) After the end-capping reaction is completed, the obtained solution is poured into a polytetrafluoroethylene mold, and vacuum-dried at 80° C. for 48 hours to remove the residual solvent to obtain a polyurethane material. The sample of Example 4 is named PUFT-D.

[0079] Example 5

[0080] A polyurethane material with ion interaction, the preparation steps are as follows:

[0081] (1) The steps (1) to (2) of Example 1 are the same.

[0082] (2) After the prepolymerization reaction is completed, 6 mmol, 2.0 g of solid chain extender 4,4'-diaminooctafluorobiphenyl (DFB) is weighed, and 20 mL of solvent DMF is measured at the same time, and the DFB solid is dissolved in the solvent DMF, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until the mixture is completely dissolved, and the mixture is added dropwise to the reaction bottle after the prepolymerization reaction. The chain extension reaction is carried out by stirring under oil bath conditions at a temperature of 80°C and a N2 atmosphere. The reaction time is 5 h.

[0083] (3) After the chain extension reaction is completed, the temperature is lowered to 60°C, and 12 mmol, 2.2 g of powdered end-capping agent (2-hydroxyethyl) trimethylammonium bromide (TLB) is weighed, and 22 mL of solvent DMF is measured at the same time. The two are mixed, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until it is completely dissolved, and the mixture is added dropwise to the reaction bottle after the chain extension reaction. The end-capping reaction is carried out by stirring in an oil bath environment at a temperature of 60°C and a N2 atmosphere. The reaction time is 5 h.

[0084] (4) After the end-capping reaction is completed, the obtained solution is poured into a polytetrafluoroethylene mold, and vacuum-dried at 80° C. for 48 hours to remove the residual solvent to obtain a polyurethane material. The sample of Example 5 is named PUFT-E.

[0085] Example 6

[0086] A polyurethane material with ion interaction, the preparation steps are as follows:

[0087] (1) The steps (1) to (2) of Example 1 are the same.

[0088] (2) After the prepolymerization reaction is completed, 10 mmol, 3.3 g of solid chain extender 4,4'-diaminooctafluorobiphenyl (DFB) is weighed, and 33 mL of solvent DMF is measured at the same time, and the DFB solid is dissolved in the solvent DMF, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until the mixture is completely dissolved, and the mixture is added dropwise to the reaction bottle after the prepolymerization reaction. The chain extension reaction is carried out by stirring under oil bath conditions at a temperature of 80°C and a N2 atmosphere. The reaction time is 5 h.

[0089] (3) After the chain extension reaction is completed, the temperature is lowered to 60°C, and 4 mmol and 0.7 g of powdered end-capping agent (2-hydroxyethyl) trimethylammonium bromide (TLB) are weighed, and 7 mL of solvent DMF is measured at the same time. The two are mixed, and the concentration of the mixed solution is maintained at 0.1 g / mL. Ultrasonic treatment is performed until it is completely dissolved, and the mixture is added dropwise to the reaction bottle after the chain extension reaction. The end-capping reaction is carried out by stirring in an oil bath environment at a temperature of 60°C and a N2 atmosphere. The reaction time is 5 h.

[0090] (4) After the end-capping reaction was completed, the obtained solution was poured into a polytetrafluoroethylene mold and vacuum dried at 80° C. for 48 h to remove the residual solvent and obtain a polyurethane material. The sample of Example 6 was named PUFT-F.

[0091] The reaction routes for preparing polyurethane materials with ion interaction in Examples 4 to 6 of the present invention are as follows: Figure 2 shown.

[0092] Comparative Example

[0093] (1) The steps (1) to (2) of Example 1 are the same.

[0094] (2) After the prepolymerization reaction is completed, 12 mmol, 3.8 g of solid chain extender 2,2-bis(trifluoromethyl)diaminobiphenyl (BBD) is weighed, and 38 mL of solvent DMF is measured at the same time, and the concentration of the mixed solution is maintained at 0.1 g / mL. The BBD solid is dissolved in the solvent DMF, and ultrasonic treatment is performed until it is completely dissolved. The mixture is added dropwise to the reaction bottle after the prepolymerization reaction, and the chain extension reaction is carried out by stirring under oil bath conditions at a temperature of 80°C and a N2 atmosphere. The reaction time is 5 h.

[0095] (3) After the chain extension reaction is completed, the obtained solution is poured into a polytetrafluoroethylene mold, and vacuum-dried at 80° C. for 48 hours to remove the residual solvent and obtain a polyurethane material. The comparative sample is named PUF.

[0096] (I) Structural characterization

[0097] Figure 3 The following are Fourier transform infrared spectra (FTIR) of the polyurethane materials prepared in Examples 1 to 3 and the comparative example. Figure 3 The results show that 1738cm -1 Stretching vibration peak attributable to the carbonyl (-C=O-) group in the carbamate (-NHCOO-) group, 1240 cm -1 The characteristic peak at 3360 cm is the stretching vibration peak of the -CO- part in the carbamate (-NHCOO-) group, while the peak at 3360 cm -1 The characteristic peak at 2260 to 2280 cm -1 There is no vibration peak corresponding to -NCO, indicating the complete reaction of diisocyanate and the successful preparation of polyurethane material.

[0098] (II) Mechanical properties test

[0099] In order to effectively evaluate the mechanical properties of the prepared polyurethane material, stress-strain curve tests were performed on all samples of Examples 1 to 6 and the comparative example. The test standard was GB / T 1040-2006, the test speed was 10 mm / min, and the test environment was 25°C. The test results are shown in Figure 4 and Figure 5 , the results are summarized in Table 1.

[0100] Table 1 Summary of mechanical properties of polyurethane material samples obtained in Examples 1 to 6 and Comparative Examples

[0101] Example Ultimate tensile strength (MPa) Elongation at break (%) <![CDATA[Toughness (MJ / m 3 )]]> Comparative Example 34.2 1444 97.62 Example 1 50.4 1251 141.8 Example 2 46.4 1304 132.2 Example 3 32.1 1749 124.7 Example 4 55.8 1154 138.9 Example 5 66.6 1309 185.9 Example 6 53.6 1382 151.7

[0102] Depend on Figures 4-5As shown in the results of Table 1, compared with the comparative example, the toughness of all embodiments has been improved. The difference is that the maximum tensile strength of embodiments 1, 2, 4, 5, and 6 is much higher than that of the comparative example, but the elongation at break is lower than that of the comparative example, while the elongation at break of embodiment 3 is much higher than that of the comparative example, but the maximum tensile strength is slightly lower than that of the comparative example. Therefore, through reasonable molecular design, the materials of the embodiments all show extraordinary mechanical properties, namely high mechanical strength, high tensile properties and high toughness. By changing the ratio of the fluorinated chain extender and the end-capping agent that can form ionic interactions, significantly different mechanical properties are obtained. It is worth noting that in this way, materials that can meet different application requirements can be obtained, that is, PUFT-A and PUFT-E can be used in situations where higher mechanical strength is required, and PUFT-C can be used in situations where higher tensile properties are required.

[0103] The polyurethane material prepared by the preparation method of the present invention is rich in a large number of ionic bonds, which provides an opportunity for the excellent toughness of the polyurethane material. Specifically, Examples 1 to 6 all exhibit mechanical properties comparable to those of traditional polyurethanes, which is mainly due to the ionic interactions in the polyurethane network structure. The presence of these ionic interactions will form a reversible cross-linked network in its structure. In addition, ionic bonds have strong non-covalent bond interactions and play a vital role in enhancing the energy dissipation of bond breakage, thereby toughening the material. Relative to the relatively weak π-π stacking interactions and hydrogen bonds, ionic interactions exhibit higher interaction strength. The presence of ionic groups in the polymer matrix leads to the formation of clusters, thereby enhancing physical cross-linking by dispersing in the soft polyester network domain.

[0104] The present invention constructs a polymer network with ionic interactions, which can effectively integrate ionic interactions and entangled conformations at one node. Compared with the comparative example, in terms of properties, the polyurethane material PUFT prepared in the embodiment can combine the advantages of physical cross-linking network and supramolecular interaction. The electrostatic interaction between ionic groups can play the role of "physical cross-linking" when the material is subjected to external force, thereby improving the tensile strength, ductility and toughness of the material. At the same time, the ionic groups in the molecular structure of ionic bond polyurethane can form strong electrostatic interactions inside the material. This electrostatic interaction is different from traditional hydrogen bonds and van der Waals forces, has stronger binding force, and gives the material a series of unique properties. Therefore, it exhibits higher ductility and more obvious energy dissipation than the physical cross-linking network, which is due to the dynamic effect of ionic interactions. And with the introduction of ionic bonds, PUFT has obvious improvements in various properties.

[0105] The above results indicate that ionic interaction can effectively integrate dynamic performance and good stability, and is an emerging and promising new functional polymer material.

[0106] (III) Thermal stability test

[0107] The thermal stability of the polyurethane material prepared in Example 1 was tested in a nitrogen atmosphere and a temperature range from room temperature to 600°C.

[0108] Figure 6 This is the thermal gravimetric curve of the polyurethane material prepared in Example 1.

[0109] Depend on Figure 6 It can be seen that the thermal weight loss temperature (T d The temperature corresponding to 5% weight loss of the sample is about 255°C, which is better than most polyurethane elastomers and shows good stability. The samples of Examples 2 to 6 all show excellent heat resistance.

[0110] The results of the thermogravimetric analysis experiment fully demonstrate that the ion interaction polyurethane elastomer prepared by the present invention not only exhibits high strength, high toughness and high stretchability, but also has excellent heat resistance, and is expected to be applied in extreme conditions or complex environments.

[0111] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a polyurethane material having ionic interaction, characterized in that: The following steps are involved: Mixing a polyol, a diisocyanate, an organic solvent and a catalyst for prepolymerization to obtain an isocyanate-terminated polyurethane prepolymer; the polyol includes a polyester polyol and / or a polyether polyol; The isocyanate-terminated polyurethane prepolymer is mixed with a chain extender to carry out a chain extension reaction to obtain a chain extension product; the chain extender includes a fluorinated diamine chain extender and / or a fluorinated diol chain extender; The chain extension product is mixed with a capping agent to carry out a capping reaction, thereby obtaining the polyurethane material with ion interaction; the capping agent has a hydroxyl group and a positive ion group.

2. The preparation method according to claim 1, characterized in that: The weight average molecular weight of the polyol is 1000-3000.

3. The preparation method according to claim 1, characterized in that: The diisocyanate includes one or more of hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The prepolymerization reaction is carried out at a temperature of 60 to 90° C. for 2 to 5 hours in a nitrogen atmosphere.

5. The preparation method according to claim 1, characterized in that: The fluorine-containing diamine chain extender includes one or more of 2,2-bis(trifluoromethyl)diaminobiphenyl, 4,4'-diaminooctafluorobiphenyl and 3,5-diaminotrifluorotoluene; the fluorine-containing diol chain extender includes one or more of tetrafluorobenzene-1,4-diol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol and 2,2,3,3-tetrafluoro-1,4-butanediol.

6. The preparation method according to claim 1 or 5, characterized in that: The temperature of the chain extension reaction is 60-100° C., the time is 1-12 hours, and the chain extension reaction is carried out in a nitrogen atmosphere.

7. The preparation method according to claim 1, characterized in that: The end-capping agent includes one or more of (2-hydroxyethyl)trimethylammonium bromide, 4-hydroxy-1,1-dimethylpiperidinium-1-ammonium bromide, 6-hydroxy-n,n,n-trimethylhexane-1-ammonium bromide, (2-hydroxybenzyl)triphenylphosphonium bromide and (5-hydroxypentyl)triphenylphosphonium bromide.

8. The preparation method according to claim 1 or 7, characterized in that: The end-capping reaction is carried out at a temperature of 60 to 100° C. for a time of 3 to 12 hours in a nitrogen atmosphere.

9. The preparation method according to claim 1, 2, 3, 5 or 7, characterized in that: The molar ratio of the polyol, diisocyanate, chain extender and end-capping agent is 12:24:(2-10):(4-20).

10. The polyurethane material with ion interaction prepared by the preparation method according to any one of claims 1 to 9.

Images