High-performance high-molecular material, high-molecular coating film material and preparation method of high-performance high-molecular material

Abstract

The invention relates to the technical field of preparation and application of high-performance polymer fiber materials, in particular to a high-performance polymer material, a polymer coating film material and a preparation method thereof. The polymer polyimide fiber is prepared by taking non-rigid dianhydride and diamine as main raw materials, amino-polyethylene glycol-azide substances are added in the preparation process, a flexible polyethylene glycol chain segment and a rigid isocyanate chain segment are introduced at the same time, and then the polyimide fiber is obtained by optimizing a spinning process. The polyimide fiber has better heat resistance, mechanical property and chemical stability. Finally, the polyimide fiber is blended with polyethylene or polyvinyl chloride and the like to prepare the coating film, and the heat resistance, the chemical stability and the mechanical performance of the coating film can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation and application of high-performance polymer fiber materials, and specifically relates to a high-performance polymer material, a polymer coating film material and a preparation method thereof. Background Art

[0002] Polyimide fibers can have outstanding thermal stability. Some polyimide materials can be used for a long time in a high-temperature environment of 250-300 °C, and can even withstand a temperature above 400 °C for a short time without obvious decomposition or performance deterioration; according to the preparation method and process adjustment, some polyimide fibers also have high mechanical strength, with a tensile strength of up to 1.0-5.0 GPa and a modulus range of 50-300 GPa. In addition, through structural optimization, it can also have good chemical stability. However, there are still relatively few high-performance polyimide fibers that simultaneously have good heat resistance, mechanical properties and chemical stability, which also limits the application of polyimide fiber materials.

[0003] Existing polymer coating film materials are often made of polyethylene and polyvinyl chloride, and have problems such as insufficient thermal stability, poor chemical stability, and mechanical properties to be improved. Polyimide materials with good chemical stability, thermal stability and mechanical properties are used to prepare polymer coating film materials, which have good comprehensive properties, but the cost of using polyimide to prepare polymer coating film materials is relatively high. Blending polyimide with relatively inexpensive polyethylene or polyvinyl chloride to prepare polymer coating film materials may become a potential way to solve the above problems. However, the following problems still need to be solved: 1. The polarity difference between polyimide and PVC or PE is relatively large. Directly blending their particles to prepare a coating film may cause phase separation, affecting the performance of the prepared coating film. In addition, during the blending process, compared with particulate form, the fiber material has a larger contact area, which is beneficial to improving dispersion, but is prone to entanglement, resulting in uneven blending; 2. Existing polyimides often improve the thermal stability of polyimide by using rigid dianhydrides and diamines to prepare polyimide. However, the rigid structure makes the molecular chain have low flexibility. During the processing process, the molecular chain is difficult to rearrange and orient under the action of external force, with poor fluidity, and thus its processing performance is poor. In addition, the rigid structure restricts the movement of molecular chain segments. When subjected to external force impact, the molecular chain is difficult to disperse energy through self-adjustment, resulting in the material being prone to brittle fracture and insufficient toughness. Insufficient toughness will inevitably lead to poor mechanical properties such as impact resistance and tensile strength of the polymer coating film material prepared using it.

[0004] Therefore, providing a high-performance polyimide fiber with good processing performance, good heat resistance, good mechanical properties, good chemical stability and easy dispersion can better expand the application scenarios of polyimide materials, and is also of great significance for preparing high-performance polymer coating film materials. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a high-performance polymer material, specifically a polyimide fiber. In this application, a non-rigid dianhydride and diamine are used as the main raw materials, and during the preparation process, a flexible polyethylene glycol chain segment and a rigid isocyanate chain segment are simultaneously introduced by reacting with an amino-polyethylene glycol-azide substance. Subsequently, the polyimide fiber is obtained through spinning. This method significantly improves the heat resistance, mechanical properties, and chemical stability of the polyimide fiber. Finally, blending the polyimide fiber with polyethylene or polyvinyl chloride has good compatibility, and the prepared coating film has good processing performance, and the performance of the prepared polymer coating film material is excellent.

[0006] In the first aspect, a method for preparing a high-performance polymer material is provided, including: Step 1: Add a diamine containing a C5-C9 aliphatic hydrocarbon chain segment, an amino-polyethylene glycol-azide substance, and a non-rigid dianhydride into an organic solvent, stir and react to form a uniform polyamic acid solution; Step 2: Add a nano-level dispersion aid to the polyamic acid solution, stir evenly to obtain a spinning solution, spin the spinning solution and then imidize it to obtain a polyimide fiber; Step 3: Immerse the obtained polyimide fiber in a solution of an acid anhydride and react, and then perform heat treatment to obtain an isocyanated polyimide fiber, which is the high-performance polymer material.

[0007] In some embodiments, the amino-polyethylene glycol-azide substance in Step 1 is at least one of NH-bis(mono-polyethylene glycol-azide) and amino-bis(tri-polyethylene glycol-azide).

[0008] In some embodiments, the nano-level dispersion aid in Step 2 is at least one of nano-silica, nano-alumina, nano-titanium oxide, and nano-zinc oxide.

[0009] In some embodiments, the temperature of the reaction in Step 3 is 35 - 50 °C, and the time is 2 - 6 h.

[0010] In some embodiments, the temperature of the heat treatment in Step 3 is 200 - 300 °C, and the time is 1 - 3 h.

[0011] In the second aspect, a polyimide fiber is provided, which is prepared by the method described in the first aspect.

[0012] In the third aspect, a polymer coating film material is provided, including a main matrix, silk fibroin-modified montmorillonite, and a polyimide fiber prepared by the method described in the first aspect.

[0013] In some embodiments, the proportions of the main matrix, silk fibroin-modified montmorillonite, and the polyimide fiber in the polymer-coated film material are 62wt%-90wt%, 2wt%-7wt%, and 5wt%-32wt% respectively.

[0014] In some embodiments, the main matrix is polyethylene or polyvinyl chloride.

[0015] Fourthly, a method for preparing a polymer-coated film material is provided, including: Mix the main matrix, silk fibroin-modified montmorillonite, and the polyimide fiber prepared by the method of the first aspect at 80 - 120 °C, and then add them to a screw extruder to extrude and calender into a polymer-coated film material.

[0016] In some embodiments, the method for preparing the silk fibroin-modified montmorillonite includes: Add the calcium chloride-ethanol-water dispersion of silk fibroin to the aqueous dispersion of montmorillonite, mix well, and obtain the product after heating and stirring reaction.

[0017] More specifically, the method for preparing the silk fibroin-modified montmorillonite includes: Disperse montmorillonite in water according to the mass ratio of montmorillonite to water of 1:(10 - 20) to form a uniform suspension; at the same time, dissolve silk fibroin in a calcium chloride-ethanol-water ternary system (the volume ratio of calcium chloride, ethanol, and water is 1:2:8) until the mass concentration of silk fibroin is 2% - 5%, and then slowly add the obtained solution to the montmorillonite suspension, and stir and react at 40 °C - 60 °C for 6h - 12h to obtain the silk fibroin-modified montmorillonite.

[0018] The beneficial effects brought by the present invention: By using diamines containing C5 - C9 aliphatic hydrocarbon segments and non-rigid dianhydrides to prepare polyimide, the present invention breaks the regularity of the molecular chains of the prepared polyimide, making the molecular chains more likely to bend and twist, and improving the flexibility of the prepared polyimide fiber; By adding amino-polyethylene glycol-azide substances to replace a part of the diamines, the polyethylene glycol chain segments are introduced. Due to the certain spatial volume of the polyethylene glycol chain segments, the molecular chain spacing is increased, and the van der Waals force between molecules is reduced, which makes the molecular chains slide relative to each other more easily during the processing, improving the processing performance; at the same time, the polyethylene glycol chain segments have certain hydrophilicity, and the polyethylene glycol chain segments prevent excessive aggregation between polyimide molecules, making polyimide more easily dispersed; In addition, the present invention also introduces an azide active group by adding an amino-polyethylene glycol-azide substance. After the obtained polyimide fiber after spinning is soaked in an anhydride solution and heat-treated, an isocyanate rigid segment is introduced onto the polyimide fiber, significantly increasing the thermal decomposition temperature of the polyimide fiber and enhancing the resistance to chemical substances, making it suitable for harsh environments such as high temperature and high corrosion. The high-performance polyimide material contained in the polymer coating film material provided by the present invention has high heat resistance and chemical stability, and the polyimide is added in the form of fibers. Due to the reinforcing effect of the fibers, it can effectively enhance the strength and modulus of the coating film, making it not easy to break when subjected to external forces, so that the polymer coating film material simultaneously has high mechanical properties. The polymer coating film material provided by the present invention contains silk fibroin-modified montmorillonite. The lamellar structure of montmorillonite can form a barrier layer in the matrix, hindering the penetration of gas and liquid molecules, which is beneficial to improving the sealing performance of the coating film and is suitable for packaging fields with high barrier requirements such as food and chemical products. In addition, silk fibroin has good dispersibility. Adding silk fibroin-modified montmorillonite is beneficial to improving the entanglement and uneven mixing problems caused by adding polyimide fibers during mixing, and further optimizing the mechanical properties of the polymer coating film material. Specific embodiments

[0019] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] In a first aspect, a preparation method of a high-performance polymer material is provided, including: Step 1: Add a diamine containing a C5-C9 aliphatic hydrocarbon chain segment, an amino-polyethylene glycol-azide substance, and a non-rigid dianhydride to an organic solvent, stir and react to form a uniform polyamic acid solution; Step 2: Add a nano-level dispersion aid to the polyamic acid solution, stir evenly to obtain a spinning solution, spin the spinning solution and then imidize to obtain polyimide fibers; Step 3: Soak the obtained polyimide fibers in a solution of an anhydride and react, and then heat-treat to obtain isocyanated polyimide fibers, that is, the high-performance polymer material.

[0022] The above method prepares polyimide by using diamine containing C5-C9 aliphatic hydrocarbon segments and non-rigid dianhydride, breaking the regularity of the molecular chain of the prepared polyimide, making the molecular chain easier to bend and twist, and improving the flexibility of the prepared polyimide fiber; by adding amino-polyethylene glycol-azide substances to replace part of the diamine, polyethylene glycol segments are introduced. Since the polyethylene glycol segments have a certain spatial volume, the intermolecular spacing is increased and the van der Waals force between molecules is reduced, which makes the molecular chains slide relative to each other more easily during processing and improves the processing performance; at the same time, the polyethylene glycol segments have a certain hydrophilicity, and the polyethylene glycol segments prevent excessive aggregation between polyimide molecules, making the polyimide more easily dispersed; by adding amino-polyethylene glycol-azide substances, azide active groups are also introduced. After the polyimide fiber obtained after spinning is soaked in an acid anhydride solution and heat-treated, isocyanate rigid segments are introduced onto the polyimide fiber, significantly increasing the thermal decomposition temperature of the polyimide fiber and enhancing the resistance to chemical substances, making it suitable for harsh environments such as high temperature and high corrosion.

[0023] In some embodiments, the diamine containing C5-C9 aliphatic hydrocarbon segments includes but is not limited to at least one of 1,5-pentanediamine, ethylenediamine, 1,7-cycloheptanediamine, 1,8-cyclooctanediamine, 1,9-nonanediamine; by controlling the carbon chain length of the diamine containing C5-C9 aliphatic hydrocarbon segments, the chain length of the prepared polyimide is controlled, so as to make it have better flexibility; if the chain length is too long, the heat resistance is affected; if the chain length is too short, the toughness is affected.

[0024] In some embodiments, the amino-polyethylene glycol-azide substances are at least one of NH-bis(mono-polyethylene glycol-azide) and amino-bis(tri-polyethylene glycol-azide).

[0025] In some embodiments, the non-rigid dianhydride preferably selects dianhydride with C5-C9 aliphatic hydrocarbon segments; as an example, 1,5-cyclopentanedianhydride, 1,6-cyclohexanedianhydride can be listed; the presence of the non-rigid dianhydride breaks the regularity brought by the rigid structure (such as benzene ring) in the polyimide molecular chain, making the molecular chain easier to bend and twist, thereby improving the fiber flexibility; by controlling the length of the aliphatic hydrocarbon segments of the dianhydride, the content of the flexible segments can be further controlled to avoid affecting the heat resistance.

[0026] In some embodiments, the organic solvent is not limited here, as long as it has good solubility for raw materials such as diamine and dianhydride. As an example, N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP) can be listed.

[0027] In some embodiments, the nano-scale dispersion aid is nano-particles selected from at least one of nano-silica, nano-alumina, nano-titanium oxide, and nano-zinc oxide. Adding the nano-scale dispersion aid can effectively reduce the surface tension of the spinning solution and promote fiber refinement.

[0028] In some embodiments, electrospinning, wet spinning, or traditional spinning methods can be used for spinning. Among them, electrospinning can produce finer fibers, which is convenient for subsequent use. The spinning method and the size of the obtained fibers can also be selected according to actual needs.

[0029] In some embodiments, the acid anhydride used for isocyanation in step 3 can be the same as or different from the acid anhydride added in step 1, that is, it can be a rigid dianhydride and a flexible dianhydride. As examples, rigid dianhydrides are listed, such as pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and naphthalenetetracarboxylic dianhydride. As examples, flexible dianhydrides are listed, such as ethylenediaminetetraacetic dianhydride, succinic anhydride, glutaric anhydride, and dodecanedioic anhydride.

[0030] In some embodiments, the molar ratio of the acid anhydride to the amino-polyethylene glycol-azide substance added in step 3 is 1:(0.4 - 1.2), for example, 1:0.4, 1:0.6, 1:0.8, 1:1, 1:1.2.

[0031] In some embodiments, the temperature of the reaction in step 3 is 35 - 50°C, and the time is 2 - 6 h. At this temperature, the azide group reacts with the acid anhydride.

[0032] In some embodiments, the temperature of the heat treatment in step 3 is 200 - 300°C, and the time is 1 - 3 h. After treatment at this temperature, it is converted into an isocyanate chain segment after the reaction.

[0033] In a second aspect, a polyimide fiber is provided, which is prepared by the method described in the first aspect.

[0034] In a third aspect, a polymer-coated film material is provided, which includes a main matrix, silk fibroin-modified montmorillonite, and the polyimide fiber prepared by the method described in the first aspect.

[0035] The above-mentioned polymer-coated film material contains a high-performance polyimide material, which has high heat resistance and chemical stability. The polyimide is added in the form of fibers. Due to the reinforcing effect of the fibers, it can effectively enhance the strength and modulus of the coated film, making it not easy to break when subjected to external forces, so that the polymer-coated film material has high mechanical properties at the same time; it contains silk fibroin-modified montmorillonite. The lamellar structure of montmorillonite can form a barrier layer in the matrix, hindering the penetration of gas and liquid molecules, which is beneficial to improving the sealing performance of the coated film and is suitable for packaging fields with high barrier requirements such as food and chemical products; in addition, silk fibroin has good dispersibility. Adding silk fibroin-modified montmorillonite is beneficial to improving the entanglement and uneven mixing problems caused by adding polyimide fibers during mixing, and further optimizing the mechanical properties of the polymer-coated film material.

[0036] In some embodiments, the proportions of the main matrix, silk fibroin-modified montmorillonite and the polyimide fibers in the polymer-coated film material are 62wt%-90wt%, 2wt%-7wt% and 5wt%-32wt% respectively.

[0037] In some embodiments, the main matrix is polyethylene or polyvinyl chloride; the polyimide prepared by the above method has good compatibility with it, and their interaction is beneficial to obtaining a high-performance polymer-coated film material.

[0038] Fourthly, a preparation method of a polymer-coated film material is provided, including: Mix the main matrix, silk fibroin-modified montmorillonite and the polyimide fibers prepared by the method of the first aspect at 80-120°C, and then add them to a screw extruder to extrude and calender into a polymer-coated film material.

[0039] In some embodiments, the polyimide fibers can be prepared into short-cut fibers and then added. The length of the short-cut fibers can be adjusted according to the actual process and is not limited here. For example, it is 1mm, 2mm, 4mm, 5mm. It can be obtained by mechanically cutting the polyimide fibers obtained in the first aspect; in addition, the diameter of the polyimide fibers is within 20 microns, and it can be obtained by controlling the parameters and process conditions of the spinning equipment during spinning.

[0040] In some embodiments, the preparation method of the silk fibroin-modified montmorillonite includes: Add the calcium chloride-ethanol-water dispersion of silk fibroin to the aqueous dispersion of montmorillonite and mix well. After heating and stirring the reaction, it is obtained. Silk fibroin contacts the flaky montmorillonite particles by the intercalation method and coats on its surface.

[0041] More specifically, the preparation method of the silk fibroin-modified montmorillonite includes: Montmorillonite was dispersed in water at a mass ratio of montmorillonite to water of 1:(10 - 20) to form a uniform suspension; meanwhile, silk fibroin was dissolved in a ternary system of calcium chloride - ethanol - water (the volume ratio of calcium chloride, ethanol and water was 1:2:8) until the mass concentration of silk fibroin was 2% - 5%, and then the obtained solution was slowly added to the montmorillonite suspension, and stirred and reacted at 40 - 60 °C for 6 - 12 h to obtain the silk fibroin - modified montmorillonite.

[0042] Since silk fibroin itself has good flexibility and film - forming property, when silk fibroin adheres to the surface of montmorillonite and is added to the coating film, it can endow the coating film with certain flexibility. When the coating film is bent or stretched, silk fibroin can buffer the stress, reduce the generation and expansion of cracks, thereby improving the tear - resistance performance of the coating film.

[0043] The following are examples for illustration.

[0044] Example 1 I. Preparation of polymer materials: Step 1: 0.09 mol of hexamethylenediamine, 0.01 mol of NH - bis(mono - polyethylene glycol - azide) and 0.1 mol of 1,5 - cyclopentanedianhydride were added to 100 mL of DMF, and stirred at 30 °C for 4 h to form a uniform polyamic acid solution; Step 2: 1% of the mass of nano - silica was added to the polyamic acid solution, stirred evenly to obtain a spinning solution, and electrospinning was carried out on the spinning solution. The electrospinning conditions were: voltage 25 kV, ambient temperature 20 °C; ambient humidity 45%, receiving distance 16 cm; then 0.2 mol of acetic anhydride and 0.1 mol of triethylamine were added for imidization at room temperature to obtain polyimide fibers with a diameter of 4 microns; Step 3: The obtained polyimide fibers were immersed in a dimethyl sulfoxide solution containing 0.01 mol of pyromellitic dianhydride and reacted at 50 °C for 2 h, and then heated to 200 °C for 3 h to obtain isocyanated polyimide fibers, namely the high - performance polymer materials.

[0045] II. Preparation of polymer coating film materials: 75 parts of polyethylene, 20 parts of 3 - mm polyimide fibers and 5 parts of silk fibroin - modified montmorillonite were mixed evenly at 100 °C, and then added to a single - screw extruder for extrusion. The temperature of the extruder was set at 200 °C, the screw speed was controlled at 200 r / min, and then a polymer coating film material was made by the casting process.

[0046] Among them, the preparation method of the silk fibroin - modified montmorillonite is as follows: Montmorillonite was dispersed in water at a mass ratio of montmorillonite to water of 1:12 to form a uniform suspension; meanwhile, silk fibroin was dissolved in a ternary system of calcium chloride - ethanol - water with a volume ratio of 1:2:8, and the mass concentration of silk fibroin was 3%. Then the obtained solution was slowly added to the montmorillonite suspension, and the mixture was stirred and reacted at 50 °C for 10 h to obtain the silk fibroin - modified montmorillonite.

[0047] Example 2 I. Preparation of polymer material: Step 1: 0.095 mol of 1,6 - cyclohexanediamine, 0.005 mol of amino - bis(triethylene glycol - azide), and 0.09 mol of 1,6 - cyclohexanedianhydride were added to 100 mL of NMP, and the mixture was stirred at room temperature for 6 h to form a uniform polyamic acid solution; Step 2: 0.5% by mass of nano - level dispersion aid nano - alumina was added to the polyamic acid solution and stirred evenly to obtain a spinning solution. Electrospinning was carried out on the spinning solution, and the spinning conditions were: voltage 25 kV, ambient temperature 20 °C; ambient humidity 45%; receiving distance 16 cm; then 0.25 mol of acetic anhydride and 0.09 mol of triethylamine were added to obtain polyimide fibers with a diameter of 20 microns; Step 3: The obtained polyimide fibers were soaked in a dimethyl sulfoxide solution containing 0.005 mol of ethylenediaminetetraacetic dianhydride and reacted at 35 °C for 6 h, and then heated to 300 °C for 1 h to obtain isocyanated polyimide fibers, that is, the high - performance polymer material.

[0048] II. Preparation of polymer - coated membrane material: 85 parts of polyvinyl chloride, 8 parts of 5 - mm polyimide fibers, and 7 parts of silk fibroin - modified montmorillonite were mixed evenly at 80 °C, and then added to a single - screw extruder for extrusion. The temperature of the extruder was set at 160 °C, and the screw speed was controlled at 100 r / min. Then, a polymer - coated membrane material was prepared by a casting process.

[0049] Among them, the preparation method of silk fibroin - modified montmorillonite is: Montmorillonite was dispersed in water at a mass ratio of montmorillonite to water of 1:16 to form a uniform suspension; meanwhile, silk fibroin was dissolved in a ternary system of calcium chloride - ethanol - water with a volume ratio of 1:2:8, and the mass concentration of silk fibroin was 4%. Then the obtained solution was slowly added to the montmorillonite suspension, and the mixture was stirred and reacted at 60 °C for 6 h to obtain the silk fibroin - modified montmorillonite.

[0050] Example 3 I. Preparation of polymer material: Step 1: Add 0.085 mol of 1,9-cyclononanediamine, 0.015 mol of NH-bis(monoethylene glycol-azide), and 0.12 mol of 1,5-cyclopentanedianhydride into 100 mL of DMF, stir at room temperature for 4 h to form a homogeneous polyamic acid solution; Step 2: Add 2% of the mass of nano-titanium oxide into the polyamic acid solution, stir evenly to obtain a spinning solution, and perform electrospinning on the spinning solution. The spinning conditions are: voltage 25 kV, ambient temperature 20 °C; ambient humidity 45%, receiving distance 16 cm; then add 0.2 mol of acetic anhydride and 0.1 mol of triethylamine and carry out imidization at room temperature to obtain polyimide fibers with a diameter of 10 microns; Step 3: Immerse the obtained polyimide fibers in a dimethyl sulfoxide solution containing 0.009 mol of succinic anhydride and react at 50 °C for 2 h, then heat to 250 °C and treat for 2 h to obtain isocyanated polyimide fibers, that is, the high-performance polymer material.

[0051] II. Preparation of polymer-coated membrane material: Mix 70 parts of polyethylene, 26 parts of 3-mm polyimide fibers, and 4 parts of silk fibroin-modified montmorillonite at 100 °C, then add them to a single-screw extruder for extrusion. The temperature of the extruder is set at 220 °C, the screw speed is controlled at 300 r / min, and then a polymer-coated membrane material is made through a casting process.

[0052] Among them, the preparation method of silk fibroin-modified montmorillonite is as follows: Disperse montmorillonite in water according to the mass ratio of montmorillonite to water of 1:18 to form a homogeneous suspension; at the same time, dissolve silk fibroin in a ternary system of calcium chloride-ethanol-water with a volume ratio of 1:2:8, and the mass concentration of silk fibroin is 5%. Then slowly add the obtained solution to the montmorillonite suspension and stir and react at 40 °C for 12 h to obtain the silk fibroin-modified montmorillonite.

[0053] Example 4 I. Preparation of polymer material: Step 1: Add 0.09 mol of hexamethylenediamine, 0.01 mol of NH-bis(monoethylene glycol-azide), and 0.12 mol of 1,6-cyclohexanedianhydride into 100 mL of DMF, stir at room temperature for 5 h to form a homogeneous polyamic acid solution; Step 2: Add 1.5% of the mass of nano-zinc oxide to the polyamic acid solution, stir evenly to obtain a spinning solution, and perform electrospinning on the spinning solution. The electrospinning conditions are as follows: voltage 25 kV, ambient temperature 20 °C; ambient humidity 45%, receiving distance 16 cm; then add 0.2 mol of acetic anhydride and 0.1 mol of triethylamine for imidization at room temperature to obtain polyimide fibers with a diameter of 5 microns. Step 3: Immerse the obtained polyimide fibers in a dimethyl sulfoxide solution containing 0.012 mol of 1,6-cyclohexanedicarboxylic anhydride and react at 40 °C for 3 h, then heat to 300 °C and treat for 2 h to obtain isocyanated polyimide fibers, namely the high-performance polymer material.

[0054] II. Preparation of the polymer-coated film material: Mix 64 parts of polyethylene, 30 parts of 3-mm polyimide fibers, and 6 parts of silk fibroin-modified montmorillonite at 100 °C, then add them to a single-screw extruder for extrusion. The temperature of the extruder is set at 200 °C, and the screw speed is controlled at 200 r / min, and then a polymer-coated film material is made through a casting process.

[0055] Among them, the preparation method of the silk fibroin-modified montmorillonite is as follows: Disperse montmorillonite in water according to the mass ratio of montmorillonite to water of 1:14 to form a uniform suspension; at the same time, dissolve silk fibroin in a ternary system of calcium chloride-ethanol-water with a volume ratio of 1:2:8, and the mass concentration of silk fibroin is 2%, then slowly add the obtained solution to the montmorillonite suspension and stir and react at 60 °C for 6 h to obtain the silk fibroin-modified montmorillonite.

[0056] Comparative Example 1 I. Preparation of the polymer material: Replace NH-bis(monoethylene glycol-azide) in Example 1 with polyethylene glycol diamine, and other features are the same as in Example 1.

[0057] II. Preparation of the polymer-coated film material: The preparation process of the coated film is the same as that in Example 1.

[0058] Comparative Example 2 I. Preparation of the polymer material: Replace 1,5-cyclopentanedicarboxylic anhydride in Example 1 with pyromellitic dianhydride, and other features are the same as in Example 1.

[0059] II. Preparation of the polymer-coated film material: The preparation process of the coated film is the same as that in Example 1.

[0060] Comparative Example 3 I. Preparation of polymer materials: The preparation process of the polymer material in this comparative example is the same as that in Example 1.

[0061] II. Preparation of polymer-coated film materials: Cut the above polymer material into polyimide powder, replace the polyimide fiber in Example 1 with this polyimide powder, and other features are the same as those in Example 1.

[0062] Comparative Example 4 Preparation of polymer-coated film materials: Mix 75 parts of polyethylene, 20 parts of 3-mm polyimide fiber, 4 parts of silk fibroin-modified montmorillonite, and 1 part of silk fibroin at 100 °C, then add them to a screw extruder for extrusion. The temperature of the extruder is set at 200 °C, the screw speed is controlled at 200 r / min, and then a polymer-coated film material is made through a casting process.

[0063] Comparative Example 5 Preparation of polymer-coated film materials: Mix 95 parts of polyethylene and 5 parts of silk fibroin-modified montmorillonite at 100 °C, then add them to a single-screw extruder for extrusion. The temperature of the extruder is set at 200 °C, the screw speed is controlled at 200 r / min, and then a polymer-coated film material is made through a casting process.

[0064] Among them, the preparation method of silk fibroin-modified montmorillonite is as follows: Disperse montmorillonite in water according to the mass ratio of montmorillonite to water of 1:12 to form a uniform suspension; at the same time, dissolve silk fibroin in a calcium chloride-ethanol-water ternary system with a volume ratio of 1:2:8, and the mass concentration of silk fibroin is 3%. Then slowly add the obtained solution to the montmorillonite suspension and stir and react at 50 °C for 10 h to obtain the silk fibroin-modified montmorillonite.

[0065] Testing: Take the polymer-coated film materials of the examples and comparative examples to detect properties such as tensile strength, elongation at break, flexural strength, compressive strength, and heat distortion temperature. The test results are shown in Table 1.

[0066] Among them, the antibacterial property test refers to the standard method of ASTM E2180-07. Add 40 μL of Escherichia coli ATCC25922 bacterial solution or Staphylococcus aureus ATCC6538 with a concentration of 108 CFU / mL to a 2-cm × 2-cm coated film, cover the surface with a sterile glass slide, and culture all samples in a petri dish (35 mm) at 37 °C for 1 h. Then rinse the glass slide and the film surface with 3.6 ml of PBS, and then perform a series of dilutions, and finally perform viable bacteria colony counting and culture at 37 °C for 24 h.

[0067] The tensile strength and elongation at break were determined with reference to the standard GB / T 1040. For the flexural strength, a universal material testing machine was used. The coated film was placed on a bending test device, and a bending load was applied until the specimen reached the specified deformation or failure. The load and deformation data during the test were recorded, and the flexural strength was calculated. The heat distortion temperature was tested with reference to the standard GB / T 1634.2.

[0068] Table 1 From the above test results, it can be seen that the coated films of Examples 1 to 4 have good properties such as tensile strength, elongation, compressive strength, and heat distortion temperature, and are suitable for the requirements of various application scenarios. On the other hand, it was confirmed that the coated films of Comparative Examples 1 to 5 did not meet the market requirements in terms of heat resistance, mechanical properties, or chemical stability.

[0069] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0070] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preparing a high-performance polymer material, characterized in that: include: Step 1, adding a diamine containing a C5-C9 aliphatic hydrocarbon chain segment, an amino-polyethylene glycol-azide substance and a non-rigid dianhydride into an organic solvent, stirring to react, and forming a uniform polyamic acid solution; Step 2, adding a nano-scale dispersing aid to the polyamic acid solution, stirring evenly to obtain a spinning solution, spinning the spinning solution and then imidizing it to obtain a polyimide fiber; Step 3: soaking the obtained polyimide fiber in an acid anhydride solution for reaction, and then heating it to obtain isocyanate-treated polyimide fiber, namely the high-performance polymer material.

2. The method for preparing a high-performance polymer material according to claim 1, characterized in that: The amino-polyethylene glycol-azide substance in step 1 is at least one of NH-bis(monopolyethylene glycol-azide), amino-bis(tripolyethylene glycol-azide) and azide polyethylene glycol amine.

3. The method for preparing a high-performance polymer material according to claim 1, characterized in that: The nano-scale dispersing aid in step 2 is at least one of nano-silicon oxide, nano-aluminum oxide, nano-titanium oxide and nano-zinc oxide.

4. The method for preparing a high-performance polymer material according to claim 1, characterized in that: The temperature of the heating treatment in step 3 is 200° C.-300° C., and the time is 1 h-3 h.

5. The method for preparing a high-performance polymer material according to claim 1, characterized in that: The reaction temperature in step 3 is 35°C-50°C, and the reaction time is 2h-6h.

6. A polymer coating material, characterized in that: The invention comprises a main matrix, montmorillonite modified with silk fibroin and polyimide fiber prepared by the method according to any one of claims 1 to 5.

7. The polymer coating material according to claim 6, characterized in that: The main matrix, silk fibroin modified montmorillonite and polyimide fiber in the polymer coating film material account for 62wt%-90wt%, 2wt%-7wt% and 5wt%-32wt% respectively.

8. The polymer coating material according to claim 6, characterized in that: The main matrix is ​​polyethylene or polyvinyl chloride.

9. A method for preparing a polymer coating material, characterized in that: include: The main matrix, silk fibroin modified montmorillonite and the polyimide fiber prepared by the method according to any one of claims 1 to 5 are mixed at 80-120° C., and then added into a screw extruder for extrusion and calendering into a polymer coating film material.

10. The method for preparing a polymer coating material according to claim 9, characterized in that: The preparation method of the silk fibroin modified montmorillonite comprises: The calcium chloride-ethanol-water dispersion of silk fibroin is added into the aqueous dispersion of montmorillonite, mixed evenly, and heated and stirred for reaction to obtain the silk fibroin dispersion.

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