阅读说明：本技术 一种本征阻燃的结构阻尼一体化树脂及其制备方法 (Intrinsic flame-retardant structural damping integrated resin and preparation method thereof ) 是由 邹华维 周勣 陈洋 衡正光 张浩若 梁梅 于 2019-11-28 设计创作，主要内容包括：本发明提供了一种本征阻燃的结构阻尼一体化树脂。相较于普通商用环氧树脂,本发明提供的本征阻燃的结构阻尼一体化树脂由于氢键与悬挂链网络的共同作用,具有明显更宽的阻尼温域,更高的热残重、玻璃化转变温度和弯曲模量,同时,其阻燃性能达到UL94V-0级别,是一种集优良的阻尼性能、热稳定性能、力学性能和阻燃性能于一体的多功能树脂,在精密机械、宇航、船舶等领域具有广阔的应用前景。(The invention provides an intrinsic flame-retardant structural damping integrated resin. Compared with common commercial epoxy resin, the intrinsic flame-retardant structural damping integrated resin provided by the invention has a remarkably wider damping temperature range, higher thermal residual weight, glass transition temperature and flexural modulus due to the combined action of hydrogen bonds and a suspension chain network, and meanwhile, the flame retardant property of the intrinsic flame-retardant structural damping integrated resin reaches the UL94V-0 level, so that the intrinsic flame-retardant structural damping integrated resin is a multifunctional resin integrating excellent damping property, thermal stability, mechanical property and flame retardant property, and has wide application prospects in the fields of precision machinery, aerospace, ships and the like.)

1. A structural damping integrated flame-retardant material is characterized in that: the structural damping integrated flame-retardant material is obtained by carrying out a curing reaction on epoxy resin and a curing agent, wherein the structure of the epoxy resin is shown as a formula A or a formula B:

m and n are independently selected from 0 to 5.

2. The structural damping integrated flame retardant material of claim 1, wherein: the structure of the epoxy resin is shown as formula 3 or formula 4:

and/or the curing agent is an aromatic amine curing agent, preferably DDM;

and/or the molar ratio of the epoxy resin to the curing agent is 1: (0.8 to 1.2), preferably 1: 1.

3. the structural damping integrated flame retardant material of claim 1 or 2, wherein: the epoxy resin is prepared by taking bisphenol compounds and epoxy chloropropane as raw materials; the structure of the bisphenol compound is shown in formula 1 or formula 2:

preferably, the raw materials for preparing the epoxy resin also comprise a catalyst, and more preferably, the catalyst is benzyltrimethylammonium chloride;

the molar ratio of the bisphenol compound to the epichlorohydrin to the catalyst is 10: (30-50): (0.5-1), preferably 10: 40: 0.5.

4. a method for preparing the structural damping integrated flame-retardant material as described in any one of claims 1 to 3, wherein: the method comprises the following steps:

(1) uniformly mixing bisphenol compounds and epoxy chloropropane, and reacting to obtain the epoxy resin of any one of claims 1 to 3; the structure of the bisphenol compound is shown in formula 1 or formula 2:

(2) and (2) uniformly mixing the epoxy resin obtained in the step (1) with a curing agent, and curing to obtain the epoxy resin.

5. The method of claim 4, wherein: in the step (1), the reaction is carried out under the action of a catalyst, preferably, the catalyst is benzyltrimethylammonium chloride;

the reaction temperature is 80-100 ℃ and the reaction time is 20-30 hours, and preferably the reaction temperature is 90 ℃ and the reaction time is 24 hours.

6. The method according to claim 4 or 5, characterized in that: in the step (2), the curing conditions are as follows: curing at 100 ℃ for 1 hour, at 135 ℃ for 3 hours and at 180 ℃ for 3 hours.

7. Bisphenol compounds represented by formula 1 or formula 2:

8. an epoxy resin of formula A or formula B:

m and n are independently selected from 0-5; preferably, m and n are both 0.

9. A process for the preparation of the bisphenols as claimed in claim 7, wherein: the method comprises the following steps:

(a) the vanillin and the p-aminophenol are subjected to condensation reaction to obtain a compound shown in a formula 1;

reacting the compound shown in the formula 1 with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a compound shown in a formula 2;

preferably, in step (a), the molar ratio of vanillin to p-aminophenol is (0.8-1.2): 1.0; the condensation reaction is carried out at the temperature of 80-100 ℃ for 2-5 hours;

in the step (b), the molar ratio of the compound shown in the formula 1 to the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1: (0.8-1.2); the reaction temperature is room temperature, and the reaction time is 10-15 hours;

more preferably, in step (a), the molar ratio of vanillin to p-aminophenol is 1.1: 1.0; the temperature of the condensation reaction is 90 ℃ and the time is 3 hours;

in the step (b), the molar ratio of the compound shown in the formula 1 to the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1: 1; the reaction temperature was room temperature and the time was 12 hours.

10. The process for producing an epoxy resin according to claim 8, wherein: the method comprises the following steps: uniformly mixing the bisphenol compound shown in the formula 1 or the bisphenol compound shown in the formula 2 with epoxy chloropropane, and reacting to obtain the bisphenol compound;

preferably, the reaction is carried out under the action of a catalyst, and the catalyst is benzyltrimethylammonium chloride;

the bisphenol compound shown in the formula 1 or the bisphenol compound shown in the formula 2, epichlorohydrin and a catalyst are in a molar ratio of 10: (30-50): (0.5-1), preferably 10: 40: 0.5;

the reaction temperature is 80-100 ℃ and the reaction time is 20-30 hours, and preferably the reaction temperature is 90 ℃ and the reaction time is 24 hours.

Technical Field

The invention belongs to the field of material design and preparation, and particularly relates to an intrinsic flame-retardant structural damping integrated resin and a preparation method thereof.

Background

Epoxy resins are widely used as resin matrices for high performance composites because of their good mechanical properties, electrical insulation properties, moisture resistance, etc. With the important application of composite materials in the high-tech fields of aerospace, national defense and the like, particularly with the recent development of aerospace equipment towards high speed, light weight, automation and multiple functions, the development trend of composite materials tends to be one-dimensional in a functionalized domain. Among the commonly used composite matrix materials, the most commonly used is epoxy resin materials, of which the commercial grade is diglycidyl ether (DGEBA), which is the product of the reaction of bisphenol a (bpa) and epichlorohydrin. As a widely used thermosetting material, while DGEBA has good mechanical properties, DGEBA is a flammable material with a Limiting Oxygen Index (LOI) of only 24.3%, which greatly limits its application in aerospace devices and some harsh environments. Meanwhile, the damping temperature range of the common epoxy resin is narrow, the effective damping temperature range (Tan delta is more than 0.3) is only 20 ℃ near the glass transition temperature (Tg), and the fatigue life and the service time of the structural member are reduced. With the development of modern precision instruments and equipment, new requirements are made on a structural damping integrated flame-retardant material which has damping shock absorption to improve the mechanical environment and flame-retardant property, and the conventional requirements cannot be met by a common composite material base material.

From the last 90 s, scholars at home and abroad put forward a plurality of existing technical schemes around the preparation of structural damping integrated composite materials, and materials with two or more Tg peaks are prepared by a method of blending rubber, plastic and resin in the early stage so as to widen the damping temperature range of the materials. Or adopts interpenetrating polymer network method to prepare damping material with forced mutual solubility and synergistic action, and also adopts molecular structure design to prepare soft material with gradient structure. More recent studies include structural designs of the materials themselves, such as porous honeycomb materials, biomimetic materials, etc. Or the damping material sensitive to the external disturbance is prepared by a method of generating reversible dissipation behavior under the condition of external disturbance through a non-covalent bond through a supramolecular network, such as hydrogen bond, ionic bond, metal coordination, pi-pi stacking, host-guest interaction and the like. These materials typically have a wide damping temperature range, but have limited environmental applicability. The methods have effective methods for widening the damping temperature range of the material and improving the damping performance of the material, and an ideal method for changing the intrinsic performance of the material during molecular structure design can be found from the methods, and meanwhile, more other characteristics can be endowed to the material.

Although the damping material prepared by the existing method usually has good damping performance, the mechanical performance of the material is poor at normal temperature, for example, the mechanical performance of the base material is necessarily reduced after the blending of rubber and other materials, so that the material cannot be used on structural members and mechanical and instrument shells. Or the soft material with the gradient structure is prepared by molecular structure design, due to the introduction of the soft section, the damping temperature range of the material is widened, the damping performance of the material is improved, the elastic modulus of the material is reduced, and meanwhile, the problem of complex preparation also exists. In addition, the technology for preparing the damping material or the energy dissipation material by designing the microscopic nanostructure of the material is generally complex, the process flow is tedious, and the popularization and large-area application are lacked. Meanwhile, the composite material is used as a damping material, so that the expansibility and the upper limit of performance of the material are limited. From the perspective of flame retardance, if the flame retardant property of the existing flame retardant material is poor, flame retardants such as ATH, polychlorinated biphenyl (PCBs), polybrominated diphenyl ethers (PBDEs) and the like need to be added to improve the flame retardance of the material, and the addition of the additives brings uncontrollable factors to the damping property of the material. Also these have banned various halogen based flame retardants such as brominated diphenyl ethers (PBDEs) due to the toxicity and environmental destructive nature of some of the flame retardants. In addition, the additive flame retardant has the disadvantage that the structure and mechanical properties of the base material are affected by the use of a large amount of additive flame retardant. Since some materials are subjected to severe use environments and are susceptible to high-frequency vibration in addition to being exposed to high-temperature environments, the materials are often used in structural parts and complicated formulation is performed to obtain desired properties. With the development of modern industry and the higher and higher requirements for mechanical properties, materials are developing towards functionalization and integration.

In the fields of precision machinery, aerospace, ships and the like, the problems of mechanical vibration and noise are increasingly prominent. Firstly, the vibrations and noise of the machine affect not only the comfort of the passengers and operators but also the stable operation of the machine and in some cases even the mechanical damage, and in some cases even the safety of the body. The research on damping and noise reduction in modern machinery and machines is always a great key development direction in the field of modern materials, and meanwhile, in order to have a special field of material application, the intrinsic flame retardance of the materials is also very important. However, it is difficult to prepare the structural damping integrated flame retardant material, and in order to obtain the performance in two directions at the same time, the element capable of exerting the flame retardant effect needs to be used to design the microstructure of the material so as to enhance the damping performance of the material. From the application and theoretical requirements, the method is one of the works which needs to be completed at present for changing the material structure to enhance the material versatility, and the preparation of the structural damping integrated resin with the intrinsic flame retardant property has important significance for the application of mechanical structure parts in some extreme environments.

Disclosure of Invention

The invention aims to provide an intrinsic flame-retardant structural damping integrated resin and a preparation method thereof.

The invention provides a structural damping integrated flame-retardant material, which is obtained by carrying out a curing reaction on epoxy resin and a curing agent, wherein the structure of the epoxy resin is shown as a formula A or a formula B:

m and n are independently selected from 0 to 5.

Further, the structure of the epoxy resin is shown as formula 3 or formula 4:

and/or the curing agent is an aromatic amine curing agent, preferably DDM;

and/or the molar ratio of the epoxy resin to the curing agent is 1: (0.8 to 1.2), preferably 1: 1.

further, the epoxy resin is prepared by taking bisphenol compounds and epoxy chloropropane as raw materials; the structure of the bisphenol compound is shown in formula 1 or formula 2:

preferably, the raw materials for preparing the epoxy resin also comprise a catalyst, and more preferably, the catalyst is benzyltrimethylammonium chloride;

the molar ratio of the bisphenol compound to the epichlorohydrin to the catalyst is 10: (30-50): (0.5-1), preferably 10: 40: 0.5.

the invention also provides a method for preparing the damping integrated flame-retardant material with the structure, which comprises the following steps:

(1) uniformly mixing bisphenol compounds and epoxy chloropropane, and reacting to obtain the epoxy resin; the structure of the bisphenol compound is shown in formula 1 or formula 2:

(2) and (2) uniformly mixing the epoxy resin obtained in the step (1) with a curing agent, and curing to obtain the epoxy resin.

Further, in the step (1), the reaction is carried out under the action of a catalyst, preferably, the catalyst is benzyltrimethylammonium chloride;

the reaction temperature is 80-100 ℃ and the reaction time is 20-30 hours, and preferably the reaction temperature is 90 ℃ and the reaction time is 24 hours.

Further, in the step (2), the curing conditions are as follows: curing at 100 ℃ for 1 hour, at 135 ℃ for 3 hours and at 180 ℃ for 3 hours.

The invention also provides bisphenol compounds represented by formula 1 or formula 2:

the invention also provides an epoxy resin shown in the formula A or the formula B:

m and n are independently selected from 0-5; preferably, m and n are both 0.

The invention also provides a preparation method of the bisphenol compound, which comprises the following steps:

(a) the vanillin and the p-aminophenol are subjected to condensation reaction to obtain a compound shown in a formula 1;

reacting the compound shown in the formula 1 with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a compound shown in a formula 2;

preferably, in step (a), the molar ratio of vanillin to p-aminophenol is (0.8-1.2): 1.0; the condensation reaction is carried out at the temperature of 80-100 ℃ for 2-5 hours;

in the step (b), the molar ratio of the compound shown in the formula 1 to the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1: (0.8-1.2); the reaction temperature is room temperature, and the reaction time is 10-15 hours;

more preferably, in step (a), the molar ratio of vanillin to p-aminophenol is 1.1: 1.0; the temperature of the condensation reaction is 90 ℃ and the time is 3 hours;

in the step (b), the molar ratio of the compound shown in the formula 1 to the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1: 1; the reaction temperature was room temperature and the time was 12 hours.

The invention also provides a preparation method of the epoxy resin, which comprises the following steps: uniformly mixing the bisphenol compound shown in the formula 1 or the bisphenol compound shown in the formula 2 with epoxy chloropropane, and reacting to obtain the bisphenol compound;

preferably, the reaction is carried out under the action of a catalyst, and the catalyst is benzyltrimethylammonium chloride;

the bisphenol compound shown in the formula 1 or the bisphenol compound shown in the formula 2, epichlorohydrin and a catalyst are in a molar ratio of 10: (30-50): (0.5-1), preferably 10: 40: 0.5;

the reaction temperature is 80-100 ℃ and the reaction time is 20-30 hours, and preferably the reaction temperature is 90 ℃ and the reaction time is 24 hours.

As described above, the present invention provides an inherently flame retardant structural damping integrated resin, and a method for preparing the same. Firstly, synthesizing a Schiff base type bisphenol intermediate containing carbon-nitrogen double bonds by vanillin and p-aminophenol, and then carrying out phosphorus-hydrogen addition reaction on the intermediate and DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) to prepare a second bisphenol intermediate. And finally, reacting the two bisphenol intermediates with epichlorohydrin by using a phase transfer catalyst method, and curing to obtain two novel intrinsic flame-retardant structural damping integrated resins.

Experimental results show that the two intrinsic flame-retardant structural damping integrated resins obtained by the invention have intrinsic flame-retardant characteristics, compared with common commercial epoxy resins, due to the combined action of hydrogen bonds and a suspension chain network in the materials, the intrinsic flame-retardant structural damping integrated resins have obviously wider damping temperature range, higher heat residual weight, glass transition temperature and flexural modulus, and meanwhile, the flame-retardant performance of the intrinsic flame-retardant structural damping integrated resins reaches the UL94V-0 level, so that the intrinsic flame-retardant structural damping integrated resins are multifunctional resins integrating excellent damping performance, thermal stability, mechanical performance and flame-retardant performance, and have wide application prospects in the fields of precision machinery, space navigation, ships and the like.

Obviously, many modifications, substitutions, and variations are possible in light of the above teachings of the invention, without departing from the basic technical spirit of the invention, as defined by the following claims.

The present invention will be described in further detail with reference to the following examples. This should not be understood as limiting the scope of the above-described subject matter of the present invention to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention.

Drawings

Figure 1. synthesis steps for VSscb and VDP.

FIG. 2 Synthesis procedure of VSE and VDE.

FIG. 3 is a graph of the dynamic mechanical properties (a) and loss modulus tan delta (b) of VSE-DDM, VDE-DDM and E51-DMM as a function of temperature.

FIG. 4 thin film temperature swing infrared analysis of VSE-DDM, VDE-DDM and E51-DMM.

FIG. 5 positron annihilation spectra of VSE-DDM, VDE-DDM, and E51-DMM.

FIG. 6 TG and DTG curves for VSE-DDM, VDE-DDM and E51-DMM.

FIG. 7 limiting oxygen index of VSE-DDM, VDE-DDM and E51-DMM.

Fig. 8 SEM of front surface of carbon layer after LOI test: (a) is E51-DMM, (b) is VSE-DDM, and (c) is VDE-DDM.

FIG. 9 shows SEM images of the rear surfaces of carbon layers after LOI test, wherein (a) is VSE-DDM and (b) is VDE-DDM.

FIG. 10 shows SEM images of the surfaces of the carbon layers under the LOI test, wherein (a) is VSE-DDM and (b) is VDE-DDM.

Figure 11 EDS energy spectrum.

Detailed Description

The raw materials and equipment used in the invention are known products and are obtained by purchasing commercial products.