CN-122011771-A - Polymer-based heat conduction composite material based on synergistic enhancement of modified boron nitride and liquid metal and preparation method thereof

Abstract

The invention belongs to the technical field of heat conduction interface materials, and discloses a polymer-based heat conduction composite material based on synergistic enhancement of modified boron nitride and liquid metal, a preparation method and application. The polymer-based heat-conducting composite material mainly comprises an organic matrix, modified hexagonal boron nitride and liquid metal. The preparation method comprises the steps of coating polydopamine on the surface of hexagonal boron nitride and loading metal nano particles in situ, blending and grinding the polydopamine and liquid metal to construct solid-liquid hybrid filler, and finally adding the solid-liquid hybrid filler into an organic matrix for defoaming, curing and forming. According to the invention, the chip-liquid-chip heat conduction bridging network is constructed through interface chemical modification, so that the interface thermal resistance and the system compression modulus are greatly reduced, meanwhile, the liquid metal is effectively locked through the interface anchoring effect, the leakage of the liquid metal is prevented, and the method has a wide application prospect in the fields of electronic packaging and high-power device heat management.

Inventors

• WANG YUNPENG
• GAO ZHANMING
• MA HAITAO
• BAO JIAWEI

Assignees

• 大连理工大学

Dates

Publication Date

20260512

Application Date

20260407

Claims (8)

1. 1. The polymer-based heat conduction composite material based on the synergistic enhancement of modified boron nitride and liquid metal is characterized by comprising the following components in percentage by mass: 40-60 wt% of an organic matrix; 20-40 wt% of modified hexagonal boron nitride; 20-40 wt% of liquid metal.
2. 2. The polymer-based thermally conductive composite of claim 1, wherein, The modified hexagonal boron nitride is hexagonal boron nitride coated with polydopamine and in-situ grown metal nano particles on the surface, wherein the metal nano particles are metal Cu nano particles or metal Ag nano particles; The organic matrix is one or more than two of polydimethylsiloxane, room temperature vulcanized silicone rubber, epoxy resin, polyurethane and acrylic resin; the liquid metal is gallium-based alloy which is liquid at normal temperature, preferably gallium indium alloy or gallium indium tin alloy.
3. 3. The polymer-based thermally conductive composite of claim 1, wherein, The metal nano particles on the surface of the modified hexagonal boron nitride and the liquid metal are subjected to alloying reaction at a solid-liquid interface to form an intermetallic compound interface layer, the liquid metal occupies gaps among the modified hexagonal boron nitride to form a continuous network structure of a sheet-liquid-sheet, and the organic matrix wraps the continuous network structure of the sheet-liquid-sheet formed by the liquid metal and the modified hexagonal boron nitride.
4. 4. The preparation method of the polymer-based heat conduction composite material based on the synergistic enhancement of the modified boron nitride and the liquid metal is characterized by comprising the following steps: (1) Coating a layer of polydopamine on the surface of hexagonal boron nitride, namely adding hexagonal boron nitride into chemical plating solution for chemical plating, wherein the chemical plating condition is that the water bath temperature is 20-40 ℃, the rotating speed is 200-600rpm, and the time is 12-24 hours; (2) Adding the polydopamine-coated hexagonal boron nitride loaded metal nano particles into chemical plating solution according to the conditions of water bath temperature of 20-40 ℃ and rotating speed of 200-600rpm for 4-6 hours, and vacuum drying filtered powder after chemical plating to obtain modified hexagonal boron nitride; (3) Mechanically grinding and mixing the modified hexagonal boron nitride with the mass ratio of 0.5-2 with liquid metal to enable the liquid metal to carry out alloying reaction with metal nano particles on the surface of the modified hexagonal boron nitride; (4) And (3) mixing the mixture obtained in the step (3) with an organic matrix according to the mass ratio of 0.5-2, stirring at the stirring speed of 1000-3000rpm for 0.5-2h, and applying 3-10 MPa pressure to perform hot press curing for 1-4h at the temperature of 60-80 ℃ after stirring and vacuum defoaming to obtain the heat conduction interface material, and performing heating curing molding to obtain the polymer-based heat conduction composite material.
5. 5. The process according to claim 4, wherein in the step (1), The concentration of the hexagonal boron nitride in the electroless plating solution is 1-3g/L; The chemical plating solution has the formula of 2.5mM-10mM dopamine hydrochloride and 8mM-30mM tris (hydroxymethyl) aminomethane.
6. 6. The process according to claim 4, wherein in the step (2), The concentration of the hexagonal boron nitride coated with polydopamine in the electroless plating solution is 1-3g/L; The chemical plating solution comprises 5mM-20mM of soluble metal salt, 5-40mM of DMAB, 0.1M-0.2M of boric acid and 0.1M-0.2M of polyvinylpyrrolidone; The soluble metal salt is copper chloride or silver nitrate.
7. 7. The process according to claim 4, wherein in the step (3), In the step (3), an auxiliary solvent is added in the mechanical grinding and mixing process, the auxiliary solvent is absolute ethyl alcohol or n-hexane, and the auxiliary solvent is volatilized after the mechanical grinding and mixing are finished.
8. 8. The application of a polymer-based heat conduction composite material based on the synergistic enhancement of modified boron nitride and liquid metal in electronic packaging thermal interface materials.

Description

Polymer-based heat conduction composite material based on synergistic enhancement of modified boron nitride and liquid metal and preparation method thereof Technical Field The invention belongs to the technical field of heat conduction interface materials, and relates to a polymer-based heat conduction composite material based on synergistic enhancement of modified boron nitride and liquid metal and a preparation method thereof. Background With the rapid development of 5G communication, artificial intelligence operation and high-power chip technology, electronic components are evolving rapidly towards microminiaturization, high integration and high power density. This results in an exponential rise in the local heat flux density generated by the electronic device during operation. If the heat cannot be effectively dissipated in time, the service life of the electronic components is seriously shortened and the system failure is caused. Therefore, the application or the filling of the heat conduction interface material between the heat source and the heat sink to fill the air gap between the microcosmic rough interfaces and reduce the contact thermal resistance has become an indispensable key link in the heat management engineering. Currently, polymers (such as silicone rubber, polyurethane, epoxy resin, etc.) are widely used in industry as flexible substrates for thermally conductive interface materials. However, the intrinsic thermal conductivity of the polymer matrix is very low (typically between 0.1-0.3W/mK) and cannot meet the efficient heat dissipation requirements. The most common solution in the prior art is to largely fill the polymer matrix with highly thermally conductive inorganic rigid particles (e.g. hexagonal boron nitride h-BN, alumina, aluminum nitride, etc.). Hexagonal boron nitride (h-BN) is considered to be an ideal thermally conductive filler because it has both excellent thermal conductivity and excellent electrical insulation. However, in order for the composite to achieve a practical thermal conductivity, it is often necessary to add very high volume fractions of rigid filler. The high filling strategy inevitably breaks the physical balance of materials, the excessive rigid sheet layer can cause the viscosity of uncured slurry of the composite material to be greatly increased and the processing fluidity to be completely lost, the hardness and the compression modulus of the cured material to be greatly increased, the due flexibility and deformation capacity of TIMs are lost, the micro morphology of a heat dissipation interface can not be complied during actual lamination, and extremely high interface contact thermal resistance is introduced to severely limit the actual heat dissipation efficiency. In order to solve the high modulus and processing difficulties caused by the high-filling rigid filler, in recent years, the introduction of room temperature liquid metal as a synergistically enhanced soft filler has become a research hotspot in the field. The liquid metal has both extreme flexibility and deformability of liquid fluid and ultrahigh intrinsic heat conductivity of metal materials. In theory, liquid metal with fluidity is introduced into a heat-conducting framework taking rigid boron nitride as a main body, a solid-liquid hybridization bicontinuous filling network is constructed, and the liquid metal can serve as a heat-conducting liquid bridge and is perfectly filled in microscopic gaps formed by stacking rigid boron nitride sheets. The composite material can not only construct a phonon transmission channel with low thermal resistance, but also serve as a liquid lubricant to relieve friction clamping stagnation among rigid particles, so that the composite material is endowed with extremely low compression modulus and excellent interface bonding compliance. However, in the existing practical preparation and application, this "solid-liquid synergy" technique faces thermodynamic and kinetic bottlenecks that are difficult to surmount, with the following significant drawbacks: (1) Severe phase separation and extremely high interfacial thermal resistance. (2) High frequency liquid metal leakage and short circuit risk. (3) Severe corrosion to metal heat sink substrates. Therefore, the invention aims to develop a heat-conducting composite material with high heat conduction, low modulus and extremely high long-term service reliability. Disclosure of Invention Aiming at the defects of the prior art, the heat conduction composite material with high heat conduction coefficient, low compression modulus and no leakage risk of liquid metal is provided. The technical scheme of the invention is as follows: The polymer-based heat conduction composite material based on the synergistic enhancement of modified boron nitride and liquid metal comprises the following components in percentage by mass: 40-60 wt% of an organic matrix (such as PDMS); 20-40 wt% of modified hexagonal boron nitride; 20-40 wt