CN109897375B - High-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material and preparation method thereof - Google Patents

Abstract

The invention discloses a high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material and a preparation method thereof. The toughened cyanate resin casting body has long service life and good spreadability, and is compositely molded with carbon fibers by the existing molding process, so that the flexible epoxy resin modified cyanate resin/carbon fiber composite shape memory material has the advantages of smooth surface, no obvious defect, high tensile strength, high tensile modulus, high shear strength, high bending strength and the like.

Description

A high-strength flexible epoxy resin modified cyanate resin/carbon fiber composite shape Shape memory material and preparation method thereof

technical field

The invention relates to a cyanate ester resin/carbon fiber composite shape memory material, in particular to a shape memory composite material composed of a cyanate ester resin and carbon fiber toughened together by a carboxyl-terminated liquid nitrile rubber and a flexible epoxy resin. The composite shape memory material has the advantages of excellent shape memory performance, high tensile strength, bending strength, shear strength, etc., can be applied to folding structures such as satellite lines and trusses, and belongs to the technical field of aerospace materials.

Background technique

With the continuous development and utilization of space resources, larger space devices or structures are required in the study of aerospace devices, and the huge volume of aerospace equipment increases the difficulty of transporting them from the earth's surface to the space environment. How to efficiently use the carrying space and reduce the carrying volume is the key problem that needs to be solved urgently in the space industry. The shape memory material can be folded on the ground, effectively reducing the carrying volume, and accurately unfolding to a predetermined shape after entering space. Shape memory polymer is a new type of smart material with broad application prospects. At present, the main researched shape memory polymers mainly include polyurethane, polynorbornene, styrene-butadiene copolymer and so on. The thermoplastic shape memory polymers used in the current research have defects such as poor mechanical properties, small load bearing, and low glass transition temperature. The pure shape memory polymer can only realize the shape memory function, and it is difficult to meet the requirements of the strength and stiffness of the structure. In order to solve the defects of poor mechanical properties of shape memory polymers, the research of polymer/carbon fiber composite shape memory materials is of great significance.

The polymer/carbon fiber composite shape memory material has the advantages of low density, high strength, and good shape memory performance, and is currently an attractive new material in the aerospace field. Compared with pure resin shape memory materials, polymer/carbon fiber composite shape memory materials have the advantages of higher deformation recovery output force, high stiffness, and high strength. Due to the high modulus of carbon fiber, when the cyanate ester resin/carbon fiber composite material is subjected to external force, matrix cracks are first formed on the surface of the resin, and the interface between the resin matrix and the fiber is debonded. After the resin breaks, the fiber mainly bears the load until the fiber breaks. At the same time, during the deformation process of the polymer/carbon fiber-based shape memory material, the carbon fiber undergoes forced tensile deformation, the internal stress of the material increases, and the shape recovery rate is accelerated.

SUMMARY OF THE INVENTION

Aiming at the problems that the current shape memory polymer materials have poor mechanical properties such as strength and stiffness, and the deformation recovery rate is slow, the first object of the present invention is to provide a shape memory polymer material with large deformation amount, fast recovery rate, low density, high Flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material with advantages such as mechanical properties.

Another object of the present invention is to provide a preparation method of a flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material, which is simple, low-cost, and beneficial to industrial production.

In order to achieve the above technical purpose, the present invention provides a high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material, which is composed of a carbon fiber material reinforcing phase and a modified cyanate ester resin matrix; The modified cyanate resin matrix comprises the following quality components: 2-4 parts of carboxyl-terminated liquid nitrile rubber; 2-5 parts of flexible epoxy resin; and 8-12 parts of cyanate resin.

In a preferred solution, the cyanate resin includes bisphenol E type cyanate resin and/or bisphenol A type cyanate resin. The most preferred cyanate resin is bisphenol E-type cyanate resin, which is liquid at room temperature and has a viscosity of 30-150 mpa.s/25°C, which can be purchased from Hubei Jusheng Technology Co., Ltd.

In a preferred solution, the molecular weight of the carboxyl-terminated liquid nitrile rubber is 2000-5000. The higher the molecular weight, the higher the viscosity of the material, and the less functional groups reacted under the same mass. The rubber phase particles formed by the agglomeration of the carboxyl-terminated liquid nitrile rubber in the resin matrix may be larger, which will affect the mechanical properties of the material. Compounding within the molecular weight range can obtain better overall performance.

In a preferred solution, the flexible epoxy resin includes at least one of Jef-0211, Jew-0114, and Jef-0213. The most preferred flexible epoxy resin is Jef-0211 flexible epoxy resin, which is liquid at room temperature, has a viscosity of 200-300 mpa.s/25°C, and an epoxy value of 0.35-0.40.

The carbon fiber material accounts for 40% to 60% of the total mass of the cyanate resin/carbon fiber composite shape memory material.

In a preferred solution, the carbon fiber material is T300 carbon fiber plain weave (the density of T300 carbon fiber plain weave is about 92 g/m ² ), NIMKT carbon fiber fabric or SKO carbon fiber fabric. The carbon fiber material should be as thin as possible to ensure that the resin prepreg fully penetrates between the carbon fibers.

The invention also provides a preparation method of a high-strength flexible epoxy resin modified cyanate resin/carbon fiber composite shape memory material. Pre-polymerization is carried out by heating and stirring to obtain a cast body; after the obtained cast body is coated on the surface of the carbon fiber material, vacuum heat curing is performed to obtain the obtained cast body.

In a preferred solution, the temperature of the prepolymerization reaction is 90-100° C., and the time is 1-2 hours.

In a preferred solution, the thermal curing is temperature-programmed curing: at 120-125°C, the temperature is maintained for 3-4 hours; at 150-155°C, the temperature is maintained for 1-2 hours; at 170-175°C, the temperature is maintained for 1-2 hours.

The flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material of the present invention uses the cyanate ester resin compounded and toughened by the carboxyl-terminated liquid nitrile rubber and the flexible epoxy resin as the matrix shape memory resin material, and has a relatively high performance. Long pot life and layability, good processability, and carbon fiber is used as the reinforcing phase to form a flexible epoxy resin with excellent shape memory performance, high tensile strength, flexural strength, shear strength and other advantages after compounding Modified cyanate resin/carbon fiber composite shape memory material.

The key of the present invention is to obtain a composite resin matrix with excellent shape memory performance. Cyanate ester resin in the prior art has excellent mechanical, heat-resistant and environmental-resistant properties, but the rigid structure of triazine ring formed after curing makes the system high crystallinity, brittle cured product, and poor toughness, which makes it difficult to Meet the toughness requirements of deformed structural materials. At the same time, the curing process of cyanate resin is mainly by adding a transition metal complex catalyst, so the obtained resin cast body has a short trial period and cannot meet the special requirements of some application processes. The technical scheme of the present invention adopts liquid nitrile rubber and flexible epoxy resin as composite toughening agents to improve the toughness of cyanate resin, and liquid nitrile rubber is introduced as a toughening agent with better toughening performance. The flexible structure in the chain can obviously improve the toughness of the resin system, but the compatibility of nitrile rubber and cyanate ester resin is relatively poor, and there is obvious delamination phenomenon, while the flexible epoxy resin can not only improve the toughness of the resin system, but also increase the The compatibility between the liquid nitrile rubber and the cyanate resin is improved, the viscosity of the resin system is reduced, and the processing difficulty of the resin system is reduced. Therefore, the excellent composite properties of liquid nitrile rubber, flexible epoxy resin and cyanate ester resin in the composite shape memory material are comprehensively reflected, and the obtained shape memory material has excellent shape memory properties, high strength, toughness and storage. Stability and processability.

The compounding of the cyanate ester resin of the present invention and the carbon fiber material can be compounded by conventional methods.

The cyanate resin cast body of the invention has moderate viscosity, good laying performance and long pot life, and after curing with the carbon fiber material, the cyanate resin/carbon fiber shape memory composite material has a smooth surface and no obvious defects.

The specific preparation method of the high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material of the present invention is described with carbon fiber cloth as the reinforcing phase; The cyanate ester resin is toughened and modified to prepare a resin cast body (prepolymer), and then the cast body is evenly painted on the surface of the carbon fiber cloth, followed by cutting, laying, packaging, vacuum heating and curing.

Cut the carbon fiber cloth according to the direction of [0/90°] and [+45°/-45°], and the size is about 240mm×200mm. [0/90°] 20 layers for the mechanical property test; [+45°/-45°] 10 layers for the shape memory performance test. The cyanate ester resin/carbon fiber composite material sheet is prepared by encapsulating the laid carbon fiber cloth by vacuum bag method, vacuuming and heating and curing.

The high-strength flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material of the present invention uses bisphenol E/A type cyanate ester resin as a matrix resin, and uses a carboxyl-terminated liquid nitrile rubber and a flexible epoxy resin. As a toughening agent, carbon fiber material is used as a reinforcing phase. Cyanate ester resin is toughened by carboxyl-terminated liquid nitrile rubber and flexible epoxy resin, which fully reflects the composite advantages of cyanate ester resin, carboxyl-terminated liquid nitrile rubber and flexible epoxy resin, such as high strength and toughness. and storage stability and processing performance, and then compound the toughened cyanate resin with carbon fiber, which can not only show the excellent shape memory performance of the resin matrix, but also the excellent mechanical properties of carbon fiber. The obtained cyanate ester resin/carbon fiber shape Memory composites have high tensile strength, flexural strength, shear strength and excellent shape memory properties to meet application requirements.

The most preferred method for preparing high-strength flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material of the present invention: 30 g of carboxyl-terminated liquid nitrile rubber, 20 g of Jef-0211 flexible epoxy resin, bisphenol E Type cyanate resin 100g, heated to 100 ℃ and stirred for 2h. The obtained prepreg was evenly painted on the T300 carbon fiber plain weave fabric. The carbon fiber cloth is cut to a specified size, and then laminated, packaged, vacuumized and cured. The curing process is 120℃/4h+150℃/2h+170℃/2h.

Relative to the prior art, the beneficial effects brought by the technical solution of the present invention:

1) The flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material cyanate ester resin cast body of the present invention has a long pot life and good layability, and the prepared cyanate ester resin/carbon fiber composite material sheet has a surface Flat, no obvious defects.

2) The flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material of the present invention can adopt the existing composite material molding process, and the molding process is mature and easy to operate.

3) The flexible epoxy resin modified cyanate ester/carbon fiber composite shape memory material of the present invention has the advantages of large deformation, fast recovery rate, low density, high mechanical properties and the like.

4) The flexible epoxy resin modified cyanate ester/carbon fiber composite shape memory material of the present invention has high tensile strength, bending strength and shear strength.

5) The preparation method of the flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material of the present invention is simple and low in cost, which is beneficial to industrial production.

Description of drawings

[Fig. 1] is the infrared spectrum of the carboxyl-terminated liquid nitrile rubber and the flexible epoxy resin toughened cyanate resin system before and after curing in the embodiment of the present invention, a is before curing, b is after curing.

[Fig. 2] is a SEM picture of the cyanate resin/carbon fiber shape memory composite material in the embodiment of the present invention.

[FIG. 3] is a stress-strain curve diagram of the embodiment of the present invention and the comparative embodiment.

[Fig. 4] is the test record of the shape memory performance of the cyanate resin/carbon fiber composite material in the embodiment of the present invention, a is 0s, b is 12s, c is 20s, d is 24s, and e is the deformation state of the material at 35s.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific preferred examples of the specification, but the content of the present invention is not thereby limited.

The equipment and instruments used in the following implementations are all commercially available.

In the following examples, the shape memory material is composed of the following quality components: 2-4 parts of carboxyl-terminated liquid nitrile rubber; 2-5 parts of flexible epoxy resin; 8-12 parts of cyanate resin; 40% to 60% of the total mass of the material.

In the following implementation, the carboxyl-terminated liquid nitrile rubber is from Jingjiang Tonggao Chemical Co., Ltd., molecular weight 3000, model: FS260. Bisphenol E-type cyanate is from Hubei Jusheng Technology Co., Ltd.; Jef-0211 flexible epoxy resin is from Changshu Jiafa Chemical Co., Ltd., and its epoxy value is 0.35-0.40.

Example 1

The preparation method of the high-strength flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material is as follows: according to the above mass fractions, weigh 30 g of carboxyl-terminated liquid nitrile rubber, 30 g of Jef-0211 flexible epoxy resin, bisphenol 100 g of E-type cyanate resin was heated to 100° C. and stirred for 2 h. Then brush evenly on the T300 carbon fiber plain weave fabric of about 1 m ² , and then cut the carbon fiber plain weave fabric into the specified size according to the [0/90°] and [+45°/-45°] directions. After that, the layers were aligned and laid, with 20 layers of carbon fiber cloth cut in the [0/90°] direction, and 10 layers of carbon fiber cloth cut in the [+45°/-45°] direction. The cyanate ester resin/carbon fiber shape memory composite sheet is obtained by encapsulation by vacuum bag method, vacuum heating and curing. The curing process is 120℃/4h+150℃/2h+170℃/2h.

The carboxyl group in the carboxyl-terminated liquid nitrile rubber, the epoxy group in the Jef-0211 flexible epoxy resin, and the cyanate group in the bisphenol E-type cyanate ester resin react and cure to obtain a cyanate ester resin system. It can be seen from Figure 1 that the characteristic absorption peak of CTBN carboxyl group is at 1737 cm ^-1 , and the absorption peak of cyano group (-CN) is at 2238 cm ^-1 . In the infrared spectrum of cyanate ester, the absorption peak of epoxy group at 1735cm ^-1 and the strong absorption peak at 2270cm ^-1 and 2238cm ^-1 are cyanate group (-OCN) and cyano group (-CN), respectively. ), which gradually disappeared with the curing reaction, and new peaks appeared at 1570 cm ^-1 and 1370 cm ^-1 , corresponding to the CN and C=N structures in the triazine ring, respectively. The absorption peak of the carboxyl group at 1735cm ^-1 gradually disappeared, indicating that CTBN, Jef-0211 flexible epoxy resin reacted with bisphenol E-type cyanate resin. In addition, the infrared spectrum of the cured sample was generated at 1210cm ^-1 and The characteristic absorption peak of ester group. It can be seen from Figure 2 that the cyanate resin matrix and the carbon fibers are closely combined, and CTBN is also precipitated from the cyanate resin matrix, and is evenly distributed in the cyanate resin matrix in a sea-island structure.

The carbon fiber cloth content of the cyanate ester resin/carbon fiber shape memory composite material prepared by the present invention is about 50% to 56%. The glass transition temperature of the material is 150°C, and the material has good mechanical properties and excellent shape memory properties. The tensile strength is about 579MPa, the Young's modulus is about 36.7GPa, the flexural strength is 711MPa, the flexural modulus is 44.7GPa, the interlaminar shear strength is 44MPa, the shape fixation rate is about 97%, and the shape recovery rate is about 98%. Elongation at break The rate was 2.06%. It can be seen from Figure 4 that it takes about 35s to complete one shape memory recovery of the prepared cyanate resin/carbon fiber shape memory composite.

Comparative Example

The preparation method of the high-strength flexible epoxy resin-modified cyanate ester resin/carbon fiber composite shape memory material is as follows: according to the above mass fractions, weigh 30 g of carboxyl-terminated liquid nitrile rubber and 100 g of bisphenol E-type cyanate ester, and heat to After 100 °C, the reaction was stirred for 2 h. Then brush evenly on the T300 carbon fiber plain weave fabric of about 1 m ² , and then cut the carbon fiber plain weave fabric into the specified size according to the [0/90°] and [+45°/-45°] directions. After that, the layers were aligned and laid, with 20 layers of carbon fiber cloth cut in the [0/90°] direction, and 10 layers of carbon fiber cloth cut in the [+45°/-45°] direction. The cyanate ester resin/carbon fiber shape memory composite sheet is obtained by encapsulation by vacuum bag method, vacuum heating and curing. The curing process is 120℃/4h+150℃/2h+170℃/2h.

The carbon fiber cloth content of the cyanate ester resin/carbon fiber shape memory composite material prepared by the present invention is about 40% to 60%. The glass transition temperature of the material is 180 °C, and the material has good mechanical properties and excellent shape memory properties. The tensile strength is about 541MPa, the Young's modulus is about 34.2GPa, the flexural strength is 601MPa, the flexural modulus is 40.1GPa, the interlaminar shear strength is 48MPa, the shape fixation rate is about 97%, the shape recovery rate is about 98%, and the elongation at break is about 97%. The length is 2.35%.

Claims (8)

1. A high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material is characterized in that: is compounded by a carbon fiber material reinforcing phase and a modified cyanate ester resin matrix;

the modified cyanate resin matrix comprises the following components in parts by mass:

2-4 parts of carboxyl-terminated liquid nitrile rubber;

2-5 parts of flexible epoxy resin;

8-12 parts of cyanate ester resin; the flexible epoxy resin comprises at least one of Jef-0211, Jew-0114 and Jef-0213.

2. The high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material as claimed in claim 1, wherein: the cyanate ester resin comprises bisphenol E type cyanate ester resin and/or bisphenol A type cyanate ester resin.

3. The high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material as claimed in claim 1, wherein: the molecular weight of the carboxyl-terminated liquid nitrile rubber is 2000-5000.

4. The high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material as claimed in claim 1, wherein: the carbon fiber material accounts for 40-60% of the total mass of the cyanate resin/carbon fiber composite shape memory material.

5. The high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material as claimed in claim 4, wherein: the carbon fiber material is T300 carbon fiber plain woven fabric, NIMKT carbon fiber fabric or SKO carbon fiber fabric.

6. The preparation method of the high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material as claimed in any one of claims 1 to 5, wherein the preparation method comprises the following steps: heating and stirring cyanate ester resin, carboxyl-terminated liquid nitrile rubber and flexible epoxy resin for prepolymerization reaction to obtain a casting body; and (3) coating the obtained casting body on the surface of the carbon fiber material, and then carrying out vacuum thermosetting to obtain the carbon fiber material.

7. The preparation method of the high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material according to claim 6, wherein the preparation method comprises the following steps: the temperature of the prepolymerization reaction is 90-100 ℃, and the time is 1-2 hours.

8. The preparation method of the high-strength flexible epoxy resin modified cyanate ester resin/carbon fiber composite shape memory material according to claim 6, wherein the preparation method comprises the following steps: the thermal curing is temperature programmed curing: preserving the heat for 3-4 h at 120-125 ℃; preserving the heat for 1-2 h at 150-155 ℃; keeping the temperature for 1-2 h at 170-175 ℃.

Images