Search

CN-121975320-A - Low-dielectric high-thermal-conductivity cyanate ester composite resin and preparation method thereof

CN121975320ACN 121975320 ACN121975320 ACN 121975320ACN-121975320-A

Abstract

The invention relates to the field of resin matrixes, in particular to a low-dielectric high-heat-conductivity cyanate ester composite resin and a preparation method thereof. According to the invention, the polyamide acid porous microsphere with positive charges on the surface is prepared, and nano hexagonal boron nitride is uniformly loaded on the surface of the polyamide acid hollow microsphere by utilizing an electrostatic self-assembly technology, so that the filler is uniformly dispersed in the cyanate resin, and the PAA@h-BN-PM with a core-shell structure is formed. The polyamide acid porous microsphere surface is rich in amide groups and carboxyl groups, can be subjected to synchronous imidization in the cyanate curing process, and promotes the formation of a crosslinked structure between the microspheres, so that the interface thermal resistance is effectively reduced, and a high-efficiency three-dimensional heat conduction network is constructed. Meanwhile, the addition of the polyamide acid hollow porous microspheres introduces a large amount of air into the system, so that the dielectric constant of the composite resin can be obviously reduced. The cyanate ester composite resin prepared by the invention has low dielectric constant and high heat conductivity coefficient, and is suitable for the fields of radomes, aerospace structural parts and the like.

Inventors

  • ZHONG GUANXIANG
  • Gu Wansong

Assignees

  • 电子科技大学

Dates

Publication Date
20260505
Application Date
20260317

Claims (7)

  1. 1. The preparation method of the low-dielectric high-heat-conductivity cyanate ester composite resin is characterized by comprising the following steps of: dispersing polyamic acid hollow porous microsphere powder in deionized water, adding strong cationic polyelectrolyte in a magnetic stirring state, stirring at room temperature, performing centrifugal separation after complete reaction, removing supernatant, and collecting to obtain polyamic acid hollow porous microspheres with positively charged surfaces; Step 2, dispersing nano hexagonal boron nitride h-BN in a polar organic solvent, carrying out ultrasonic treatment to ensure that the nano hexagonal boron nitride h-BN is uniformly dispersed, then adding the polyamide acid hollow porous microspheres with positively charged surfaces obtained in the step 1, carrying out centrifugal analysis after stirring, and washing and drying to obtain polyamide acid@hexagonal boron nitride microspheres PAA@h-BN-PM; step 3, weighing cyanate resin and a toughening agent with the mass ratio of 10:0.5-2, melting and mixing uniformly, adding the polyamide acid@hexagonal boron nitride microspheres obtained in the step 2, and stirring and mixing uniformly to obtain polyamide acid@hexagonal boron nitride microsphere modified cyanate resin prepolymer; And 4, adding a catalytic-toughening agent into the polyamide acid@hexagonal boron nitride microsphere modified cyanate ester resin prepolymer obtained in the step 3, heating and stirring to fully mix, pouring into a preheating mold, and carrying out vacuum degassing and then carrying out 120-220 ℃ step heating and curing to obtain the polyimide hollow microsphere@hexagonal boron nitride modified cyanate ester resin.
  2. 2. The method for preparing the low-dielectric high-heat-conductivity cyanate ester composite resin according to claim 1, wherein the strong cationic polyelectrolyte in the step 1 is one of polydiallyl dimethyl ammonium chloride PDDA and polyethyleneimine PEI.
  3. 3. The method for preparing the low-dielectric high-thermal-conductivity cyanate ester composite resin according to claim 1, wherein the polar organic solvent in the step 2 is one of isopropanol and ethanol.
  4. 4. The preparation method of the low-dielectric high-heat-conductivity cyanate ester composite resin is characterized in that the toughening agent in the step 3 is one of bisphenol A type epoxy resin E51, carboxyl-terminated nitrile rubber CTBN and epoxy-terminated nitrile rubber ETBN.
  5. 5. The method for preparing the low-dielectric high-heat-conductivity cyanate ester composite resin according to claim 1, wherein the catalytic-toughening agent in the step 4 is two or three of Diallyl Bisphenol A (DBA), cobalt acetylacetonate, dibutyl tin dilaurate DBTDL and 4-methylquinoline.
  6. 6. The method for preparing the low dielectric and high thermal conductivity cyanate ester composite resin according to claim 1, wherein the polyamic acid hollow porous microsphere powder is prepared by the following steps: Step 1, diamine is taken as a reaction monomer to be dissolved in a nonpolar solvent, dianhydride monomer is added after stirring and dissolution, and polyamide acid PAA is prepared by polycondensation reaction under a protective atmosphere and at a low temperature, and then triethylamine is added to obtain polyamide acid salt, wherein the molar ratio of organic amine to diamine monomer is 2:1, and the molar ratio of diamine to dianhydride is 1:1-1:1.5; The dianhydride monomer is one or a combination of more of pyromellitic anhydride PMDA, 3', 4' -biphenyl tetracarboxylic dianhydride BPDA and 4,4' -oxydiphthalic anhydride ODPA; The diamine monomer is one or a combination of more of 4,4 '-diaminodiphenyl ether ODA, 4' -diaminodiphenyl methane MDA and p-phenylenediamine p-PDA; The nonpolar solvent is one of N, N-dimethylacetamide DMAc and N-methylpyrrolidone NMP; Step 2, the polyamic acid salt obtained in the step 1 is dissolved in deionized water with the solid content of 1-5wt% to obtain PAA aqueous solution; step 3, adding a cationic surfactant and a liquid paraffin oil phase into the PAA aqueous solution obtained in the step 2 under stirring to form an oil-in-water emulsion and continuously stirring, wherein the volume ratio of the liquid paraffin to the PAA aqueous solution is 1:2-1:8, and the volume ratio of the cationic surfactant to the PAA aqueous solution is 1:50-1:150; the cationic surfactant is one or two of cetyl trimethyl ammonium bromide CTAB, dodecyl trimethyl ammonium bromide DTAB and dimethyl dioctadecyl ammonium chloride DODAC; and step 4, adding a mixed solution of acetic anhydride and pyridine into the solution obtained in the step 3, and washing, centrifuging and freeze-drying to obtain the polyamide acid hollow porous microsphere powder, wherein the volume ratio of acetic anhydride to pyridine is 1:1-1:3.
  7. 7. A preparation method of a low-dielectric high-heat-conductivity cyanate ester composite resin is characterized in that the cyanate ester composite resin is prepared by the method according to any one of claims 1 to 5.

Description

Low-dielectric high-thermal-conductivity cyanate ester composite resin and preparation method thereof Technical Field The invention relates to the field of resin matrixes, in particular to a low-dielectric high-heat-conductivity cyanate ester composite resin and a preparation method thereof. Background Cyanate resin is widely applied to the fields of high-frequency circuit boards, aerospace structural parts, radomes and the like due to excellent heat resistance and good dielectric properties. However, the thermal conductivity of the pure cyanate ester resin is only about 0.2W/(m·k), and it is difficult to satisfy the heat dissipation requirements of high-power electronic devices and radar systems. Adding high thermal conductivity filler into resin matrix is the most direct and effective method for improving the thermal conductivity of composite material. The hexagonal boron nitride (h-BN) has a graphite-like layered structure, has a theoretical thermal conductivity as high as 400W/(m.K), has good electrical insulation property and low dielectric property, and is an ideal filler for improving the thermal conductivity of resin. However, the h-BN has large specific surface area and high surface energy, is extremely easy to agglomerate in the resin matrix, has poor interface compatibility with the organic resin matrix, causes defects and interface thermal resistance in the composite material, and is difficult to realize the expected improvement of the heat conducting performance. If the h-BN is directly filled into a matrix, the problems of high seepage threshold, easy agglomeration, large interfacial thermal resistance caused by interfacial phonon scattering and deterioration of dielectric properties of the material are often faced. Disclosure of Invention Aiming at the problems or the defects, the method aims at solving the problem of synchronous regulation and control of the dielectric property and the heat conducting property of the cyanate at present. The invention provides a low-dielectric high-heat-conductivity cyanate ester composite resin and a preparation method thereof, wherein nano hexagonal boron nitride is uniformly loaded on the surfaces of polyamide acid hollow microspheres through an electrostatic self-assembly technology, so that the filler is uniformly dispersed in the cyanate ester resin, and a large amount of air is introduced while the hollow porous microspheres are added, so that a composite material with excellent dielectric property and heat-conductivity is obtained. A preparation method of low-dielectric high-heat-conductivity cyanate ester composite resin comprises the following steps: And step1, dispersing polyamide acid hollow microsphere powder in deionized water, adding strong cationic polyelectrolyte (polyelectrolyte completely dissociated in the current solution) under a magnetic stirring state, stirring at room temperature, performing centrifugal separation after complete reaction, removing supernatant, and collecting polyamide acid hollow porous microspheres with positively charged surfaces. Step 2, dispersing nano hexagonal boron nitride h-BN in a polar organic solvent, carrying out ultrasonic treatment to ensure that the nano hexagonal boron nitride h-BN is uniformly dispersed, then adding the polyamide acid hollow porous microsphere with positively charged surface obtained in the step 1, carrying out centrifugal analysis after stirring, and washing and drying to obtain polyamide acid@hexagonal boron nitride microsphere (PAA@h-BN-PM) And 3, weighing cyanate resin and a toughening agent with the mass ratio of 10:0.5-10:2, melting and mixing uniformly, adding the polyamide acid@hexagonal boron nitride microspheres obtained in the step 2, and stirring and mixing uniformly to obtain the polyamide acid@hexagonal boron nitride microsphere modified cyanate resin prepolymer. And step 4, adding a catalytic-toughening agent into the polyamide acid@hexagonal boron nitride microsphere modified cyanate ester resin prepolymer obtained in the step 3, and heating, stirring and fully mixing. And then pouring the mixture into a preheating mould, carrying out vacuum degassing, and carrying out step heating solidification at 120-220 ℃ to obtain the polyimide hollow microsphere@hexagonal boron nitride modified cyanate resin. Further, the strong cationic polyelectrolyte in the step 1 is one of polydiallyl dimethyl ammonium chloride (PDDA) and Polyethylenimine (PEI). Further, the polar organic solvent in the step 2 is one of isopropanol and ethanol. Further, the toughening agent in the step 3 is one of bisphenol a type epoxy resin (E51), carboxyl terminated nitrile rubber (CTBN) and epoxy terminated nitrile rubber (ETBN). Further, the catalyst-toughening agent in the step 4 is two or three of Diallyl Bisphenol A (DBA), cobalt acetylacetonate, dibutyl tin dilaurate (DBTDL) and 4-methylquinoline. Further, the polyamic acid hollow porous microsphere powder is prepared by the following steps: Step 1,