CN108409966B - Modified bismaleimide resin suitable for resin transfer molding process and preparation method thereof - Google Patents

The invention provides a modified bismaleimide resin suitable for a resin transfer molding process and a preparation method thereof. The preparation method comprises the following steps of firstly, heating 1-allyl-2-cyanate ester benzene to 130-; and step two, adding 3-amino benzocyclobutene into the prepolymer obtained in the step one, adjusting the temperature to be 110-140 ℃, adding a bismaleimide monomer, and carrying out polymerization reaction under the condition of heat preservation to obtain the modified bismaleimide resin suitable for the resin transfer molding process.

Modified bismaleimide resin suitable for resin transfer molding process and preparation method thereof

Technical Field

The invention belongs to the technical field of composite material matrix resin materials, and relates to a modified bismaleimide resin suitable for a resin transfer molding process and a preparation method thereof.

Background

The bismaleimide molecular structure contains two maleimide rings, and due to the high unsaturated structure of the bismaleimide molecular structure, the cross-linking density is high after curing, the heat resistance is far superior to that of epoxy resin, and the bismaleimide molecular structure has the excellent characteristics of humidity resistance, heat resistance, radiation resistance, high modulus, small thermal expansion coefficient and the like. However, the unmodified bismaleimide monomer has high crystallinity and melting point, is difficult to dissolve in a conventional solvent, has large brittleness after solidification, and basically loses use value. Therefore, it is necessary to modify the resin to destroy its crystallinity, lower its melting point, improve its processability, and improve its toughness and dielectric properties.

In the aspect of composite material preparation technology, Resin Transfer Molding (RTM) forming technology is a relatively advanced liquid forming method, and is considered as one of important technologies for solving the problem of high cost of advanced composite materials. RTM is suitable for forming a product with a complex structure, has high flexibility in selecting a reinforcing material, can give full play to designability of a composite material, can reduce harm of harmful components of resin to a human body by closed-die forming, and has high surface smoothness, high fiber content and good comprehensive performance. However, RTM molding puts higher demands on the processing manufacturability of resin: the melting point of the resin is low, and is generally required to be lower than 100 ℃; the melt viscosity of the resin is low, which is generally preferably 200-500 cP, and the pot life is generally required to be more than 6 h; the resin has good wettability to the fiber; the volatile component is small.

The western countries have been leading to the development of modified bismaleimide resins, and have proposed several tens of modified bismaleimide resins, some of which are commercialized and widely used in the aerospace field. At present, bismaleimide resins produced by cyanogen and Hensmei in the United states have a great influence. The research of the bismaleimide resin in the aspect of high-performance composite materials in China starts from the eighties of the last century, and through continuous technical innovation, certain research achievements are obtained, such as the research of a group of modified bismaleimide resin varieties with excellent comprehensive performance in the composition of subjects of the aviation 625 cangzhasen, Suzhou university Liangguo (originally northwest industrial university) and the chemical institute Zhaotong of Chinese academy of sciences, the commercialization or the half-commercialization of certain varieties is realized, and the deeper application research and the application practice of the modified bismaleimide resin in the aspect of high-performance composite materials are promoted.

For modified bismaleimide resin, the resin varieties suitable for RTM molding process at home and abroad mainly comprise: 5250-4RTM from Cyanite (Narmco), 5292 from Hunsmy (XU 292 from Ciba-Geigy), QY8911-IV from aviation 625 in China, and allylphenol-aldehyde modified bismaleimide resin from chemical institute of Chinese academy, etc.

5250-4RTM comprises bismaleimide monomer (BDM) of diphenylmethane type, diallyl bisphenol A (DABPA) and BMI-1,3-tolyl, has a minimum viscosity of greater than 1000cP at 100 deg.C and an initial viscosity of about 800cP at 120 deg.C, and is still high relative to RTM processes. The glass transition temperature after curing at 227 ℃ for 4 hours was 271 ℃ and the heat resistance was impaired.

5292 it is a resin variety of DABPA-modified BDM, and the most typical method of modifying bismaleimide resin by allyl compounds is adopted. The viscosity is lower than 1000cP at 100 ℃, and the glass transition temperature Tg of the modified bismaleimide resin obtained by different DABPA/BDM ratios is 218-234 ℃ after curing for 10h at 200 ℃. DABPA/BDM prepolymerized at a lower temperature is easy to crystallize and precipitate, and the storage stability is poor. If higher temperature prepolymerization is used, this results in increased viscosity and may even result in a small amount of gel.

QY8911-IV adopts allyl phenolic compound modified bismaleimide monomer, the molecular weight of the prepolymer is low, the viscosity of the resin is low, the viscosity is kept below 500cP from 85 ℃ to 130 ℃, and the processing manufacturability is good. However, since the unsaturated group content of the resin system is relatively low, the heat resistance after curing is affected.

The allyl etherified phenolic aldehyde modified bismaleimide resin of the chemical institute of Chinese academy of sciences is a relatively mature variety, the modified bismaleimide resin system has excellent forming process performance, and the glass transition temperature Tg after curing is more than 350 ℃. However, the curing temperature required by the system is higher and reaches 250 ℃, and the application of the allyl etherified phenolic aldehyde is limited to a certain extent due to the instability of the allyl etherified phenolic aldehyde.

Therefore, the commercial modified bismaleimide resin suitable for RTM still has respective disadvantages in performance, it is difficult to maintain heat resistance and improve processing manufacturability, and little research work is done to improve and evaluate the dielectric properties of bismaleimide resin. Therefore, there is a need to develop a modified bismaleimide resin which has the characteristics of low dielectric constant, low dielectric loss, low melting point, low melt viscosity, high curing activity and the like, and is particularly suitable for the RTM process, while ensuring the heat resistance and high modulus of the curing system.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a modified bismaleimide resin suitable for a resin transfer molding process and a preparation method thereof.

The invention is realized by the following technical scheme:

a method for preparing modified bismaleimide resin suitable for a resin transfer molding process comprises the following steps,

heating 1-allyl-2-cyanate ester benzene to 130-160 ℃, adding a bismaleimide monomer, and carrying out heat preservation reaction to obtain a homogeneous prepolymer;

and step two, adding 3-amino benzocyclobutene into the prepolymer obtained in the step one, adjusting the temperature to be 110-140 ℃, adding a bismaleimide monomer, and carrying out heat preservation for reaction to obtain the modified bismaleimide resin suitable for the resin transfer molding process.

Preferably, in the step one, 1-allyl-2-cyanate ester radical benzene is heated to 130-160 ℃, bismaleimide monomer is slowly added within 1 hour, and the temperature is kept for reaction for 1-3 hours at the temperature, so that a homogeneous prepolymer is obtained.

Preferably, in the step one, the mass ratio of the 1-allyl-2-cyanate ester group benzene to the bismaleimide monomer is 1: (1.5-2.5).

Preferably, in the first step, the bismaleimide monomer has the following structure,

wherein R is-CH₂-、-O-、-SO₂-or-O-Ph-C (CH)₃)₂-Ph-O-。

Preferably, in the second step, the prepolymer obtained in the first step is cooled to more than 20 ℃, 3-aminobenzocyclobutene is added, the temperature is adjusted to be 110-140 ℃, the bismaleimide monomer is slowly added within 1 hour, and the temperature is kept for reaction for 1-3 hours at the temperature, so that the modified bismaleimide resin suitable for the resin transfer molding process is obtained.

Preferably, in the second step, the bismaleimide monomer has the following structure,

wherein R is-CH₂-、-O-、-SO₂-or-O-Ph-C (CH)₃)₂-Ph-O-。

Preferably, in the second step, the amount of the 3-aminobenzocyclobutene added is 50-200% of the mass of the 1-allyl-2-cyanate ester benzene added in the first step.

Preferably, in the second step, the mass ratio of the 3-aminobenzocyclobutene to the bismaleimide monomer is 1: (1.5-2.5).

The modified bismaleimide resin suitable for the resin transfer molding process is prepared by any one of the preparation methods, is in a viscose state at room temperature, is kept at 150-600 cP within 6h of viscosity at 90 ℃, and has a volatile content of less than 1.5%; the temperature corresponding to the curing peak value is lower than 225 ℃, and the glass transition temperature after curing is higher than 330 ℃; the composite material obtained by reinforcing the modified bismaleimide resin through glass cloth has the dielectric constant lower than 3.8 at 10GHz and the dielectric loss lower than 0.01.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention introduces two modifiers to modify a Bismaleimide Monomer (BMI), wherein the two modifiers are 1-allyl-2-cyanate ester benzene (ACB) and 3-Aminobenzocyclobutene (ABCB), the ACB contains an active group of allyl and cyanate ester, and the ABCB contains an amino and benzocyclobutene structure. Under the prepolymerization condition, allyl and amino can respectively generate ene addition reaction and Michael addition reaction with double bonds of bismaleimide, and the reaction activity of the cyanate ester and benzocyclobutene structures is relatively weak, so that the cyanate ester and benzocyclobutene structures can participate in the reaction at higher temperature. The prepolymerization system structure contains various reaction products such as ACB-BMI, ACB-BMI-ACB, ACB-BMI-ABCB, ABCB-BMI-ABCB and the like, presents a multi-element combination state, and more effectively breaks the regular structure of the original bismaleimide monomer compared with a single modification mode, reduces the crystallinity of the bismaleimide monomer, and further reduces the melting point. The obtained prepolymerization system has low crystallinity and low average molecular weight, so that the prepolymerization system can keep low melt viscosity and improve the solubility. These have a significant positive effect on improving the processability of the prepolymerization system, making it suitable for RTM processes. In addition, the residual cyanate ester group, benzocyclobutene structure and bismaleimide ring of the prepolymer are very stable at normal temperature, and no chemical reaction occurs, so that the prepolymer system can obtain a longer storage period. When the prepolymer system is used, the prepolymer system is cured under the action of heat, generally 160-200 ℃, and can induce chemical reactions of a prepolymerization system, including the reactions of self-polymerization of residual bismaleimide double bonds, self-polymerization of cyanate groups, self-polymerization of benzocyclobutene, copolymerization of bismaleimide double bonds and cyanate groups, and the like, and the prepolymerization system finally forms a network structure with high crosslinking density, so that the prepolymer system has excellent heat resistance and better toughness. In addition, the cyanate can generate cyclotrimerization reaction under the action of heat to generate a triazine ring structure, so that a curing system has lower dielectric constant and dielectric loss, and the dielectric property of the cyanate resin is best in thermosetting resin materials and is superior to epoxy resin, bismaleimide resin and even polyimide resin; similarly, benzocyclobutene resin has excellent electrical properties, small dielectric constant and low dielectric loss, and is continuously applied in the field of electronics and electricity. The invention introduces the cyanate group and the benzocyclobutene structure into the resin prepolymerization system, and has very positive and effective effects on further improving the dielectric property of the prepolymerization system while ensuring the excellent heat resistance of the bismaleimide. The invention adopts a one-pot two-step method during synthesis, has simple and convenient synthesis process, does not discharge three wastes and is easy for industrialization. The obtained modified bismaleimide resin is a prepolymer of a modifier and a bismaleimide monomer, does not contain an active diluent and a solvent, and has low volatile component.

The modified bismaleimide resin prepared by the invention is in a sticky state at room temperature, the viscosity is low, and the viscosity is kept between 150 and 600cP within 6 hours at 90 ℃; a volatile content of less than 1.5% measured at 150 ℃; the curing temperature is low, DSC (10 ℃/min) shows that the initial curing temperature is lower than 160 ℃, the curing peak value corresponding temperature is lower than 225 ℃, and the resin has certain strength after being kept for 1-2 h at the temperature of 200 ℃ during actual curing, and can be demoulded, which shows that the resin has excellent processing manufacturability and is suitable for RTM (resin transfer molding) process; the heat resistance is excellent, and the glass transition temperature Tg of a resin prepolymerization system is greater than 330 ℃ in a DMA test (5 ℃/min,1Hz) after the resin prepolymerization system is cured; the mechanical property is good, the bending strength of the cast body is 90MPa, and the bending modulus is 4.0 GPa. The structure of cyanate ester group and benzocyclobutene is introduced into the prepolymerization system, so that the dielectric property is obviously improved. The composite material prepared by using the modified bismaleimide resin as a matrix and adopting glass cloth for reinforcement has the dielectric constant of less than 3.8 at 10GHz and the dielectric loss of less than 0.01, and shows excellent dielectric properties.

Drawings

FIG. 1 is a DSC curing profile of the modified bismaleimide resin of the present invention, wherein the abscissa Temperature represents Temperature and the ordinate Heat Flow represents Heat Flow rate.

FIG. 2 is a DMA graph showing a casting of a modified bismaleimide resin according to the present invention, wherein Temperature is plotted on the abscissa, Storage Modulus is plotted on the ordinate, loss Modulus is plotted on the ordinate L oss Modulus, and loss factor is plotted on the ordinate Tan Delta.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

In the practical implementation of the invention, 1-allyl-2-cyanate ester benzene and a part of bismaleimide monomer are reacted for a period of time to carry out the first-stage prepolymerization; then reducing the temperature to a certain temperature, adding 3-aminobenzocyclobutene, supplementing the other part of the bismaleimide monomer, adjusting the temperature to a proper temperature, and continuing to react for a period of time to complete the second-stage prepolymerization; prepolymerization is carried out through the one-pot two-step method, and finally cooling is carried out to obtain the modified bismaleimide resin.

The high-temperature-resistant low-dielectric modified bismaleimide resin suitable for the RTM process can be prepared by the following steps:

step one, pre-polymerization of 1-allyl-2-cyanate ester benzene and bismaleimide monomer;

heating 1-allyl-2-cyanate ester radical benzene to 130-160 ℃, slowly adding a bismaleimide monomer within 1 hour, carrying out heat preservation reaction for 1-3 hours at the temperature, and carrying out diene addition reaction on the bismaleimide monomer and the bismaleimide monomer to form a homogeneous prepolymer; the mass ratio of the 1-allyl-2-cyanate ester radical benzene to the bismaleimide monomer is 1: (1.5-2.5), preferably 1: 2;

the bismaleimide monomer has the following structure:

wherein R is-CH₂-、-O-、-SO₂-or-O-Ph-C (CH)₃)₂-Ph-O-；

Step two, pre-polymerization of the 3-aminobenzocyclobutene, the bismaleimide monomer and the prepolymer obtained in the step one;

cooling the prepolymer obtained in the step one to more than 20 ℃, adding 3-amino benzocyclobutene, readjusting the temperature to 110-140 ℃, slowly adding a bismaleimide monomer within 1 hour, and reacting for 1-3 hours at the temperature; 3-aminobenzocyclobutene and residual double bonds of the prepolymer obtained in the step one and a newly added bismaleimide monomer are subjected to Michael addition reaction to form a homogeneous transparent prepolymerization system, and the temperature is reduced to obtain the high heat-resistant low dielectric modified bismaleimide resin suitable for RTM;

wherein the adding amount of the 3-aminobenzocyclobutene is 50-200%, preferably 100%, of the mass of the 1-allyl-2-cyanate ester-based benzene added in the first step; the mass ratio of the 3-aminobenzocyclobutene to the bismaleimide monomer added in the step is 1: (1.5-2.5), preferably 1: 2;

the bismaleimide monomer in the step has the following structure, and can be the same as or different from the bismaleimide monomer in the step one:

wherein R is-CH₂-、-O-、-SO₂-or-O-Ph-C (CH)₃)₂-Ph-O-。

The invention has developed a new kind of preparation methods suitable for modified bismaleimide resin of RTM craft, introduce 1-allyl-2-cyanate group benzene, 3-amino benzocyclobutene two kinds of modifiers to modify bismaleimide monomer, they have a common characteristic that the molecular structure contains two active groups respectively, wherein active group allyl and amino can react with the double bond of bismaleimide monomer at lower temperature, and another active group cyanate group and benzocyclobutene need to raise to higher temperature can participate in the reaction; the prepolymerization system obtained after prepolymerization is in a multi-element state, breaks through the regular structure of the bismaleimide monomer, reduces the crystallinity, effectively reduces the resin melting temperature, and can effectively prevent the bismaleimide monomer from being separated out.

The obtained prepolymer has low molecular weight and low crystallinity, so that a prepolymerization system can keep a low viscosity state for a long time at a processing temperature. Actually measuring that the viscosity of the prepolymerization system is kept between 150 and 600cP within 6 hours at 90 ℃, and the method is suitable for developing an RTM forming process.

The resin prepolymerization system has low curing temperature and high curing activity, DSC shows that the curing initial temperature is lower than 170 ℃, the curing peak value corresponding temperature is lower than 225 ℃, and the resin prepolymerization system shows high reactivity. The crosslinking degree is more than 96 percent after 2 hours of curing at 200 ℃.

The residual active groups after prepolymerization, such as cyanate ester groups and benzocyclobutene, can start to participate in the reaction at a higher temperature, generally 160-200 ℃, can induce chemical reactions of the residual active groups, such as self-polymerization of residual bismaleimide double bonds, self-polymerization of cyanate ester groups, self-polymerization of benzocyclobutene, copolymerization of bismaleimide double bonds and benzocyclobutene, copolymerization of bismaleimide and cyanate ester groups, and the like, and has high crosslinking degree after being cured according to a standard curing system to form a network structure with high crosslinking density, thereby showing excellent heat resistance, and the glass transition temperature of a DMA test curing system is higher than 330 ℃.

The resin prepolymerization system obtained by the invention comprises the following steps: the adhesive is sticky at room temperature, the viscosity is kept between 150 and 600cP within 6h at 90 ℃, the volatile content is lower than 1.5 percent, and the adhesive can be heated and cured at the temperature of 200 ℃. The processing technology has excellent performance and meets the requirements of the RTM forming technology on resin; curing according to a curing schedule of 150 ℃/1h → 180 ℃/1h → 200 ℃/2h, and curing for 2h at 230 ℃, wherein the glass transition temperature of the curing system is more than 330 ℃, and the heat resistance is good. The glass cloth reinforced resin composite material has 40% of resin content, the dielectric constant of the composite material is lower than 3.8 at 10GHz, the dielectric loss is lower than 0.01, and the dielectric loss is far lower than the test results of epoxy and common bismaleimide resin based composite materials, and the composite material shows excellent dielectric properties. The composite material prepared by the resin has excellent mechanical property.

Specific examples are as follows.

Example 1

50g of 1-allyl-2-cyanate-ester benzene is added into a 500ml glass bottle provided with a thermometer, an addition funnel and a mechanical stirring device, the temperature is raised to 140 ℃, 100g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, the reaction is kept at 140 ℃ for 1 hour, and the system is in a homogeneous transparent state. The temperature of the system is reduced to 120 ℃, 50g of 3-aminobenzocyclobutene is added, the temperature of the system is readjusted to 120 ℃, 100g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, and the reaction is kept at 120 ℃ for 1 hour. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 2

30g of 1-allyl-2-cyanate-ester-benzene is added into a 500ml glass bottle provided with a thermometer, an addition funnel and a mechanical stirring device, the temperature is raised to 140 ℃, 75g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, the reaction is kept at 140 ℃ for 1 hour, and the system is in a homogeneous transparent state. The temperature of the system is reduced to 120 ℃, 60g of 3-aminobenzocyclobutene is added, the temperature of the system is readjusted to 120 ℃, 120g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, and the reaction is kept at 120 ℃ for 1 hour. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 3

60g of 1-allyl-2-cyanate-ester benzene is added into a 500ml glass bottle provided with a thermometer, an addition funnel and a mechanical stirring device, the temperature is raised to 140 ℃, 120g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, the reaction is kept at 140 ℃ for 1 hour, and the system is in a homogeneous transparent state. Cooling the system to 120 ℃, adding 30g of 3-aminobenzocyclobutene, readjusting the system temperature to 120 ℃, adding 45g of 4, 4' -bismaleimide diphenylmethane within 1 hour, and keeping the temperature at 120 ℃ for reaction for 1 hour. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 4

50g of 1-allyl-2-cyanate-ester-benzene is added into a 500ml glass bottle provided with a thermometer, an addition funnel and a mechanical stirring device, the temperature is raised to 130 ℃, 125g of 2, 2' -bis [4- (4-maleimide phenoxy) phenyl ] propane is added within 1 hour, the reaction is kept at 130 ℃ for 3 hours, and the system is in a homogeneous transparent state. The system was cooled to 110 ℃, 50g of 3-aminobenzocyclobutene was added, the system temperature was readjusted to 110 ℃, 125g of 2, 2' -bis [4- (4-maleimidophenoxy) phenyl ] propane was added over 1 hour, and the reaction was continued at 110 ℃ for 3 hours. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 5

50g of 1-allyl-2-cyanate-ylbenzene were added to a 500ml glass bottle equipped with a thermometer, an addition funnel and a mechanical stirring device, the temperature was raised to 135 ℃ and 100g of 4, 4' -bismaleimide diphenyl ether was added within 1 hour, and the reaction was continued at 135 ℃ for 2 hours, at which time the system was in a homogeneous transparent state. The system is cooled to 115 ℃, 50g of 3-aminobenzocyclobutene is added, the system temperature is readjusted to 115 ℃, 100g of 4, 4' -bismaleimide diphenyl ether is added within 1 hour, and the reaction is kept at 115 ℃ for 2 hours. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 6

50g of 1-allyl-2-cyanate-ester benzene is added into a 500ml glass bottle provided with a thermometer, an addition funnel and a mechanical stirring device, the temperature is raised to 140 ℃, 100g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, the reaction is kept at 140 ℃ for 1 hour, and the system is in a homogeneous transparent state. The system is cooled to 115 ℃, 50g of 3-aminobenzocyclobutene is added, the system temperature is readjusted to 115 ℃, 100g of 4, 4' -bismaleimide diphenyl ether is added within 1 hour, and the reaction is kept at 115 ℃ for 2 hours. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 7

50g of 1-allyl-2-cyanate-ylbenzene were added to a 500ml glass bottle equipped with a thermometer, an addition funnel and a mechanical stirring device, the temperature was raised to 160 ℃ and 100g of 4, 4' -bismaleimide diphenyl sulfone were added within 1 hour, and the reaction was continued at 160 ℃ for 1 hour, at which time the system was homogeneous and transparent. The system is cooled to 140 ℃, 50g of 3-aminobenzocyclobutene is added, the system temperature is readjusted to 140 ℃, 100g of 4, 4' -bismaleimide diphenylmethane is added within 1 hour, and the reaction is kept at 140 ℃ for 1 hour. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

Example 8

30g of 1-allyl-2-cyanate-ylbenzene were added to a 500ml glass bottle equipped with a thermometer, an addition funnel and a mechanical stirring device, the temperature was raised to 150 ℃ and 45g of 4, 4' -bismaleimide diphenyl sulfone were added within 1 hour, and the reaction was continued at 150 ℃ for 3 hours, at which time the system was homogeneous and transparent. The system is cooled to 130 ℃, 60g of 3-aminobenzocyclobutene is added, the system temperature is readjusted to 130 ℃, 90g of 4, 4' -bismaleimide diphenyl sulfone is added within 1 hour, and the reaction is kept at 130 ℃ for 1 hour. And cooling to obtain the reddish brown homogeneous transparent modified bismaleimide resin.

The modified bismaleimide resin prepared in example 1 was used to test the following properties.

The viscosity of the modified bismaleimide resin is 250cP at 90 ℃ by a rotational viscometer test, and the viscosity rises to 480cP after 6 h.

The modified bismaleimide resin was kept in an oven at 150 ℃ for 1 hour, and the volatile content was measured to be 1.22%.

The curing activity of the obtained resin is characterized by a differential scanning calorimeter, the temperature range is RT-350 ℃, and the temperature rise rate is 10 ℃/min. As can be seen from FIG. 1, the modified bismaleimide resin showed a high curing reactivity with a curing initiation temperature of only 152 ℃ and a peak-to-peak temperature of 223 ℃.

Curing by adopting a schedule of 150 ℃/1h → 180 ℃/1h → 200 ℃/2h → 230 ℃/2h to obtain a brown-black compact resin casting body after curing. And testing the glass transition temperature of the curing system by using a dynamic thermal mechanical analyzer, wherein the temperature rise rate is 5 ℃/min. As is clear from FIG. 2, the storage modulus started to significantly decrease at 330 ℃ or higher, and the glass transition temperature corresponding to the peak loss tangent tan was 382 ℃. The test result shows that the material has excellent heat resistance and can be extended to the application field requiring the heat resistance grade to be higher than 300 ℃.

The resin is used as a matrix, electronic grade glass cloth (specification 7628) is used as a reinforcing material, and an RTM process is adopted to prepare the composite material plate, wherein the resin content is about 40%. And (3) performing a dielectric property test at 10GHz, and measuring that the dielectric constant of the composite plate is 3.7 and the dielectric loss tangent value is 0.008. Is far superior to the similar composite materials taking epoxy and common bismaleimide resin as matrixes.