阅读说明：本技术 一种高韧性高模量聚合物及其制备方法 (High-toughness high-modulus polymer and preparation method thereof ) 是由 张帅 王城 朱方华 李娃 张龙飞 万翔宇 张�林 尹强 于 2020-08-04 设计创作，主要内容包括：本发明公开了一种高韧性高模量聚合物,属于聚合物制备领域。本发明的一种高韧性高模量聚合物,是由芳香族环氧树脂、带脂肪链的多胺交联剂和第三单体反应构筑,且聚合物含有由共价键和阳离子增强的π-π堆积形成的交联网络。通过在聚合物内形成共价键和相互作用强度呈现多分散性的阳离子增强的“面对面”π-π堆积双重交联网络,克服高模量聚合物的刚性骨架对弱的非共价相互作用的限制。动态的、强度随机变化的π-π堆积及时、连续的断裂和重组过程使聚合物网络能够及时有效地对外界刺激做出相应,同时聚合物网络中的化学交联使得聚合物结构不被破坏的作用,赋予目标刚性聚合物同时提高了拉伸强度和延伸性,实现了显著的增韧效果。(The invention discloses a high-toughness high-modulus polymer, and belongs to the field of polymer preparation. The high-toughness high-modulus polymer is formed by reacting an aromatic epoxy resin, a polyamine crosslinking agent with an aliphatic chain and a third monomer, and contains a crosslinking network formed by covalent bonds and cation-enhanced pi-pi accumulation. The limitation of weak non-covalent interactions by the rigid backbone of high modulus polymers is overcome by forming a cation-enhanced "face-to-face" pi-pi stacking double cross-linked network within the polymer that exhibits polydispersion of covalent bonds and strength of interaction. The dynamic and randomly-changed strength pi-pi accumulation is timely and continuously fractured and recombined, so that the polymer network can effectively respond to external stimulation in time, and the chemical crosslinking in the polymer network can prevent the polymer structure from being damaged, so that the target rigid polymer is endowed with the effects of improving the tensile strength and extensibility and realizing the obvious toughening effect.)

1. A high-toughness high-modulus polymer is characterized in that the polymer is formed by reacting an aromatic epoxy resin, a polyamine crosslinking agent with an aliphatic chain and a third monomer, and the polymer contains a crosslinking network formed by covalent bonds and cation-enhanced pi-pi stacking.

2. A high tenacity, high modulus polymer according to claim 1 wherein said third monomer forms "face to face" pi-pi interaction bonds with said aromatic epoxy resin that are polydisperse; chemical bonds are formed between the aromatic epoxy resin and the polyamine crosslinking agent with the aliphatic chain, and between the aromatic epoxy resin and the third monomer.

3. A high toughness and high modulus polymer according to claim 1 wherein said aromatic epoxy resin has a number of reaction sites of 2 or more; the polyamine crosslinking agent with the fatty chain is flexible chain polyamine with the number of reaction sites being more than 2; the third monomer is a chemical having two types of functions at the same time.

4. A high tenacity, high modulus polymer according to claim 3 wherein said two types of functions are respectively: can react with epoxy ring chemically and the number of reactive sites is more than or equal to 1; meanwhile, a cationic electron-deficient plane can be generated by chemical reaction with the epoxy ring.

5. A process for the preparation of a high toughness high modulus polymer according to any of claims 1 to 4 comprising the steps of:

s1, simultaneously dissolving aromatic epoxy resin, a polyamine crosslinking agent with an aliphatic chain and a third monomer in an organic solvent, and stirring for 10-20min to obtain a solution;

s2, filtering the solution obtained in the step S1 to remove micro insoluble substances, and spreading the filtrate on a flat glass plate;

s3, placing the glass plate in an oven at 50-200 ℃ for heating for 2-4h, vacuumizing until the vacuum degree of the oven is 50-550 torr, continuing to preserve heat for 4-12h, naturally cooling, and demoulding to obtain the high-toughness high-modulus polymer.

6. The method of claim 5, wherein the molar ratio of said aromatic epoxy resin, said polyamine crosslinking agent with aliphatic chains, and said third monomer in step S1 is 20: 5-9: 2-12.

7. The method of claim 6, wherein said aromatic epoxy resin, polyamine crosslinking agent with aliphatic chains and third monomer in said step S1 are present in a molar ratio of 20: 7: 6.

8. a high toughness and high modulus polymer according to claim 5, wherein said aromatic epoxy resin is bisphenol a epoxy resin, bisphenol F epoxy resin or phenolic resin; the polyamine crosslinking agent with the aliphatic chain is one of hexamethylene diamine, 1, 4-butanediamine, 1, 5-pentamethylene diamine, 2-methylpentamethylene diamine, 1, 6-hexamethylene diamine, 1, 8-octamethylene diamine, 1, 10-decamethylene diamine, 1, 12-diaminododecane, diethylenetriamine, triethylene tetramine and tetraethylenepentamine; the third monomer is one of imidazole, 2-methylimidazole, 2-phenylimidazole and benzimidazole.

9. The process for preparing a high toughness and high modulus polymer according to claim 5, wherein said organic solvent in step S1 is one of dimethyl sulfoxide, m-xylene, N-dimethylacetamide, acetonitrile, N-dimethylformamide, 1, 4-dioxane, N-methylpyrrolidone, p-xylene and sulfolane.

10. The process for the preparation of a high tenacity, high modulus polymer according to claim 5 wherein said process is replaced by:

simultaneously putting the aromatic epoxy resin and the third monomer into a ball mill for freezing and ball milling for 1-2h, and sieving with a 400-mesh sieve to obtain fine powder; dissolving the fine powder in an organic solvent to prepare an organic fluid; adding a polyamine crosslinking agent with a fatty chain into an organic solvent to prepare a crosslinking agent solvent; pumping organic fluid and a cross-linking agent solvent into a reaction template of the micro-channel continuous flow reactor by different channels through a pump respectively, reacting for 5-10min at the temperature of 40-60 ℃ under the pressure of 0.5-1.8 MPa, separating from the micro-channel continuous flow reactor and entering a material collector, vertically spreading the material in the material collector on a glass plate, placing the glass plate in a vacuum degree of 550 dragging for 4-10h at the temperature of 80-200 ℃, and demolding to obtain the high-toughness high-modulus polymer.

Technical Field

The invention belongs to the technical field of polymer preparation, and relates to a high-toughness high-modulus polymer and a preparation method thereof.

Background

High modulus polymers are generally composed of a rigid backbone as the main polymer chain, and due to the unique aromatic structure, such polymers not only have the inherent light weight of the polymers, but also often exhibit good thermal and chemical stability, especially super-strong mechanical strength. Therefore, the composite material has great application potential in many special fields such as aerospace equipment, electrical insulation equipment, medical equipment, sports health care products, military manufacturing and the like. However, the aromatic rigid skeleton of the polymer ensures high modulus and high strength, and simultaneously causes the problem of poor ductility of the material, thereby greatly limiting the application range of the material. In addition, compared with the strength of traditional materials such as metal and inorganic materials, the mechanical strength of the polymer materials can not completely replace the traditional materials, so that the polymer materials are applied to various large projects. Therefore, further reinforcing and toughening the high modulus polymer material becomes a problem to be solved.

It is highly desirable to develop a new high modulus polymeric material that has improved strength and ductility simultaneously. Based on this, many different strategies are used to improve the mechanical properties of polymers, such as forming a high degree of chemical cross-linking between polymer backbones, and such three-dimensional chemical cross-linking networks can effectively increase the mechanical strength of polymer materials, however, such methods fail to improve the ductility of the materials. In addition, researchers have also tried to introduce different types of rigid particles into the polymer matrix in a doping manner, so that the mechanical strength of the composite material can be significantly improved, but also the material shows great brittleness.

Therefore, how to ensure better ductility of the material while improving the strength of the material is still a problem to be solved. Therefore, it is necessary to develop a high modulus polymer, a high strength and a high elongation polymer.

Disclosure of Invention

An object of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.

To achieve these objects and other advantages in accordance with the present invention, there is provided a high tenacity, high modulus polymer and a method for preparing the same, which solve the technical difficulties of the prior high modulus polymer that strength and ductility are difficult to be simultaneously improved.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a high-toughness high-modulus polymer is characterized in that the polymer is formed by reacting an aromatic epoxy resin, a polyamine crosslinking agent with an aliphatic chain and a third monomer, and the polymer contains a crosslinking network formed by covalent bonds and cation-enhanced pi-pi stacking.

Further, the third monomer can form an interactive "face-to-face" pi-pi interaction bond with the aromatic epoxy resin and exhibit polydispersity; chemical bonds are formed between the aromatic epoxy resin and the polyamine crosslinking agent with the aliphatic chain, and between the aromatic epoxy resin and the third monomer.

Further, the number of reaction sites of the aromatic epoxy resin is more than or equal to 2; the polyamine crosslinking agent with the fatty chain is flexible chain polyamine with the number of reaction sites being more than 2; the third monomer is a chemical having two types of functions at the same time.

Further, the two types of functions are respectively: can react with epoxy ring chemically and the number of reactive sites is more than or equal to 1; meanwhile, a cationic electron-deficient plane can be generated by chemical reaction with the epoxy ring.

Specifically, the number of reaction sites is the number of sites capable of participating in the reaction, known as the reaction functionality, where the number of epoxy groups is the number of aromatic epoxy resins, the number of hydrogens on the amino groups is the number of polyamine crosslinking agents with aliphatic chains, and the number of hydrogens capable of participating in the reaction is the number of third monomers.

A process for preparing a high tenacity, high modulus polymer comprising the steps of:

s1, simultaneously dissolving aromatic epoxy resin, a polyamine crosslinking agent with an aliphatic chain and a third monomer in an organic solvent, and stirring for 10-20min to obtain a solution;

s2, filtering the solution obtained in the step S1 to remove micro insoluble substances, and spreading the filtrate on a flat glass plate;

s3, placing the glass plate in an oven at 50-200 ℃ for heating for 2-4h, vacuumizing until the vacuum degree of the oven is 50-550 torr, continuing to preserve heat for 4-12h, naturally cooling, and demoulding to obtain the high-toughness high-modulus polymer.

Further, the molar ratio of the aromatic epoxy resin, the polyamine crosslinking agent with an aliphatic chain, and the third monomer in step S1 is 20: 5-9: 2-12.

Further, the molar ratio of the aromatic epoxy resin, the polyamine crosslinking agent with an aliphatic chain, and the third monomer in step S1 is 20: 7: 6.

further, the aromatic epoxy resin is bisphenol A epoxy resin, bisphenol F epoxy resin or phenolic resin; the polyamine crosslinking agent with the aliphatic chain is one of hexamethylene diamine, 1, 4-butanediamine, 1, 5-pentamethylene diamine, 2-methylpentamethylene diamine, 1, 6-hexamethylene diamine, 1, 8-octamethylene diamine, 1, 10-decamethylene diamine, 1, 12-diaminododecane, diethylenetriamine, triethylene tetramine and tetraethylenepentamine; the third monomer is one of imidazole, 2-methylimidazole, 2-phenylimidazole and benzimidazole.

Further, in the step S1, the organic solvent is one of dimethyl sulfoxide, m-xylene, N-dimethylacetamide, acetonitrile, N-dimethylformamide, 1, 4-dioxane, N-methylpyrrolidone, p-xylene, and sulfolane.

Further, simultaneously putting the aromatic epoxy resin and the third monomer into a ball mill for freezing and ball milling for 1-2h, and sieving with a 400-mesh sieve to obtain fine powder; dissolving the fine powder in an organic solvent to prepare an organic fluid; adding a polyamine crosslinking agent with a fatty chain into an organic solvent to prepare a crosslinking agent solvent; pumping organic fluid and a cross-linking agent solvent into a reaction template of the micro-channel continuous flow reactor by different channels through a pump respectively, reacting for 5-10min at the temperature of 40-60 ℃ under the pressure of 0.5-1.8 MPa, separating from the micro-channel continuous flow reactor and entering a material collector, vertically spreading the material in the material collector on a glass plate, placing the glass plate in a vacuum degree of 550 dragging for 4-10h at the temperature of 80-200 ℃, and demolding to obtain the high-toughness high-modulus polymer.

The invention at least comprises the following beneficial effects:

(1) the high-toughness high-modulus polymer overcomes the limitation of the rigid skeleton of the high-modulus polymer on weak non-covalent interaction by forming a cation-enhanced 'face-to-face' pi-pi stacking double cross-linked network in the polymer, wherein the covalent bond and the interaction strength show polydispersity. The dynamic and randomly-changed strength pi-pi accumulation is timely and continuously fractured and recombined, so that the polymer network can effectively respond to external stimulation in time, and the chemical crosslinking in the polymer network can prevent the polymer structure from being damaged, so that the target rigid polymer is endowed with the effects of improving the tensile strength and extensibility and realizing the obvious toughening effect;

(2) in the invention, when the polymer is subjected to small strain, covalent crosslinking and pi-pi accumulation work together to protect the material from being damaged, and when the polymer is subjected to larger external force, the fracture and recombination of reversible pi-pi interaction with smaller interaction force can realize energy dissipation; the strong pi-pi action and the covalent cross-linking have a combined action to protect the polymer from being damaged; when the polymer material is further stretched, the strong pi-pi action starts to generate fracture and recombination processes to transfer and eliminate internal stress, the chemical crosslinking maintains the inherent structure of the polymer, and the polymer material is further stretched without being damaged;

(3) the addition of the polymer pi-pi interaction does not affect the thermal stability of the polymer, and the polymer realizes simultaneous reinforcement and toughening and shows good thermal stability;

(4) the polymer of the invention shows good solvent resistance in common solvents because of the existence of chemical crosslinking, and has good application prospect.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 is an FT-IR spectrum of materials prepared in examples 3 and 5 and a comparative example;

FIG. 2 shows materials prepared in examples 3 and 5 and comparative example¹³C CP/MAS NMR spectra;

FIG. 3 is a thermogravimetric plot of the materials prepared in examples 3, 5 and comparative example;

FIG. 4 is a DSC curve of the materials prepared in examples 3 and 5 and comparative example;

FIG. 5 is a cyclic stress-strain curve for the material prepared in example 3 at a strain rate d/dt of 0.12mm s-1.

Detailed Description

The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

The test method of the relevant data in the embodiment of the invention is as follows:

carrying out Fourier transform infrared (FT-IR) spectrum detection on the sample by using a Nicolt 6700 Fourier transform infrared spectrometer;

sample preparation by Agilent-NMR-vnmrs 600 spectrometer¹³C solid shuttle polarized Nuclear magnetic resonance 13C (CP/MAS) NMR lightTesting a spectrum;

glass transition temperature (T) of sample using Differential Scanning Calorimetry (DSC) curve_g) And (3) testing, wherein the test conditions are as follows: under the protection of nitrogen, the temperature rising speed is 20 ℃/min;

decomposition temperature (T) of sample using thermogravimetric analysis (TGA) curve_d) And (3) testing, wherein the test conditions are as follows: under the protection of nitrogen, the temperature rising speed is 20 ℃/min;

the stress-strain curve test of the sample is carried out by using a uniaxial tension test under the conditions of a KD-5 universal tester, a sensor 1000N, a film-shaped sample with the size of 58 × 7mm, and the tension rates of the samples tested in the examples 1 to 5 are respectively 0.1 min, 0.5 min, 1 min and 2mm min^-1Room temperature;

sample testing was performed by cyclic loading test using cyclic performance with strain rate d/dt ═ 0.12mm s^-1Room temperature.