CN106366402B - A kind of high thermal conductivity boron nitride enhancing polymer matrix composite preparation method - Google Patents
A kind of high thermal conductivity boron nitride enhancing polymer matrix composite preparation method Download PDFInfo
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
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Abstract
The present invention relates to a kind of preparation methods of high thermal conductivity boron nitride enhancing polymer matrix composite, after mixing stratiform hexagonal boron nitride powder and polymer powder obtain mixture, the mixture is vibrated on rotary shake table, is then carried out vacuum hotpressing and is obtained the boron nitride enhancing polymer matrix composite.The advantages of composite material prepared by the method for the present invention has high thermal conductivity, and good mechanical performance, preparation method is simple, and degree of controllability is high, and molding time is short, solidifies without long-time.
Description
Technical field
The invention belongs to engineering field of polymer composite material.Enhance in particular it relates to a kind of high thermal conductivity boron nitride and polymerize
The preparation method of object based composites.
Background technique
With electronic technology industry fast-developing, the heat that unit area distributes is more and more, and the miniaturization of equipment makes
Effective heat dissipation area is reduced increasingly, and the performance of opposite heat tube reason material proposes more strict requirements.Electronic package material is opened
Hair and pyroconductivity are as an important ring, it is desirable that material has high thermal conductivity, low-expansion coefficient, lightweight, feature at low cost.
Polymer-based composite has many advantages, such as light, inexpensive, easy to process in this regard.But due to macromolecule sheet
The thermal conductivity of body is low, causes the heat dissipation effect performance of product poor, significantly limits the use of product.It is with polyethylene (PE)
Example, it is that one kind is had excellent performance and widely used engineering plastics, have many advantages, such as it is above-mentioned light, inexpensive, easy to process, but
Its thermal conductivity is very low, generally only 0.42W/mK or so.
Existing research is reported using boron nitride powder as packing material.Using after being mixed under organic solution in air
In hot-forming technique hexagonal boron nitride/Kapton has been prepared, when boron nitride volume fraction is 60%, obtain
To heat conductivity value be up to 7W/mK.By using semar technique to obtain on etch substrate after being mixed in organic solution
Polyvinyl alcohol/boron nitride nm composite material is arrived, the thermal conductivity value finally obtained is when boron nitride volume fraction is 50%
30W/m·K.Then selection by the fiber with the degree of orientation as reinforcing agent carries out hot pressing, Ke Yiti with macromolecule matrix
The degree of orientation and intensity of high composite material.In addition also by twin-roll mixing, the method for some mechanical mixtures of screw mixes, in mould
The composite material of anti-corrosion and high strength is prepared in pressure crosslinking, but the capacity of heat transmission is not high.What these preparation methods obtained answers
All there is powders to be unevenly distributed for condensation material, high production cost, and preparation process is complicated, or can inevitably introduce variousization
Close one or more undesirable elements such as object ion.
Therefore, this field is badly in need of finding the simple and effective preparation high heat conductance boron nitride powder enhancing polymer matrix of one kind
The method of insulating heat-conductive composite material.
Summary of the invention
The purpose of the present invention is to provide a kind of interface bond strengths, and boron nitride suitable, that hot property is excellent enhances polymer
The preparation method of based composites, solution prior art is complicated, and the heat conductivity of cycle time length and acquisition is not high
The problems such as, and be intended to widen the application range of composite material, improve the heat and mechanical property of material, solve existing boron nitride/
The problems such as aligning property of boron nitride is poor in polymer composites, and polymer is uniformly dispersed poor,
The first aspect of the present invention, provides a kind of preparation method of boron nitride enhancing polymer matrix composite, including with
Lower step：
A) it under the action of double center mixing dispersion machines, mixes stratiform hexagonal boron nitride powder and polymer powder is mixed
Object is closed, so that polymer powder is adhered on boron nitride powder；
B) mixture that vibrating step a) is obtained on rotary shake table, so that sheet boron nitride powder realizes lamella
The preferential arrangement in direction；
C) mixture that vacuum hotpressing is vibrated through step b) obtains the composite material.
In another preferred example, the planar dimension of layered hexagonal boron nitride powder is 10~500 microns, with a thickness of
0.1~10 micron.
In another preferred example, the planar dimension of layered hexagonal boron nitride powder is 50~400 microns, preferably
100~300 microns.
In another preferred example, layered hexagonal boron nitride powder with a thickness of 0.5~8 μm, preferably 1~5 μm.
In another preferred example, the polymer is polyethylene, polypropylene, nylon, polyimides or polyphenylene sulfide.
In another preferred example, the polymer powder is graininess.
In another preferred example, planar dimension≤300 micron of the polymer powder, preferably≤100 micron, more preferably
It is 1~75 micron.
In the present invention, under the action of center mixing dispersion machine rotation mixing double in step a), the mixed polymerization
Powder is evenly distributed on the six sides layered nitride boron powder surface.
In another preferred example, the volume of layered hexagonal boron nitride powder account for layered hexagonal boron nitride powder and
The 30~60% of the total volume of the mixture of polymer powder, preferably 40~60%, more preferably 50~60%.
In another preferred example, the mass ratio of layered hexagonal boron nitride powder and the polymer is 1:1~5:1.
In another preferred example, the revolving speed of double center mixing dispersion machines is 1000~2000rpm.
In another preferred example, the revolving speed in double center mixing dispersion machines be 1000~1500rpm, more preferably 1100
~1300rpm.
In another preferred example, the step a) is under the action of double center mixing dispersion machines, and the mixed time is 30~
150 seconds, preferably 30~120 seconds, more preferably 30~90 seconds, even 30~60 seconds.
In another preferred example, in the step b) vibration frequency be 40~200 revs/min, preferably 60~190 turns/
Minute, more preferably 60~180 revs/min.
In another preferred example, time of vibration is 5~100min, preferably 10~60min in the step b).
In another preferred example, the mixed powder carries out on rotary shake table.By the type games, nitridation is provided
The consistency of boron arrangement.
In another preferred example, the vacuum hotpressing is to be warming up to the mixture through step b) oscillation crosswise under vacuum
100~400 DEG C are pressurizeed, and pressure is 10~80MPa, and the dwell time is 10~60min.
In another preferred example, the warming temperature pressurizes for 100~200 DEG C.
In another preferred example, vacuum degree≤250Pa of the vacuum, preferably≤200Pa.
In another preferred example, the preparation method further includes that the composite material for obtaining vacuum hotpressing carries out cooling step
Suddenly.
The second aspect of the present invention provides a kind of boron nitride enhancing polymer matrix composite, by the stratiform aligned
Hexagonal boron nitride powder and polymer powder hot pressed sintering form, and have following one or more features：
1) density of the composite material is 1~2g/cm3；
2) composite material is 20~40W/mK along the thermal conductivity perpendicular to hot pressing direction；
3) composite material is 1.7~18mm along the thermal diffusion coefficient perpendicular to hot pressing direction2/s；
4) composite material is 1~6mm along the thermal diffusion coefficient for being parallel to hot pressing direction2/s；
5) composite material is 8~50MPa along the bending strength for being parallel to hot pressing direction；
6) mass ratio of boron nitride and polymer is 1 in the composite material:1-5:1.
In the present invention, the hot pressing direction refers to the Z-direction of composite material, the i.e. side perpendicular to powder planar arrangement
To.
In another preferred example, the composite material is along thermal conductivity >=20W/mK perpendicular to hot pressing direction, preferably
>=30W/mK, more preferably >=37W/mK.
In another preferred example, the bending strength of the composite material is 10~40MPa or 10~35MPa
The third aspect of the present invention provides the purposes of the enhancing polymer matrix composite of boron nitride described in second aspect,
As electronic package material or heat sink material.
The fourth aspect of the present invention provides a kind of product, comprising composite material described in second aspect or by second aspect
The composite material is made.
The technical method that the present invention uses is that boron nitride powder is uniform through double center mixing dispersion machines with polymer powder
After mixing, be put into the arrangement of vibration control high thermal conductivity lamella boron nitride powder on mechanical vibration generator system, then through vacuum hotpressing stove into
Row Thermocompressed sintering and forming obtains highly directional boron nitride enhancing polymer matrix composite.The boron nitride of high thermal conductivity enhances polymerization
In object based composites, the highly directional arrangement of lamella boron nitride powder is formed by rotary vibration, and polymer is in composite wood
Being uniformly distributed in material is to rotate mixing procedure by double center mixing dispersion machines to control.
Enhance polymer matrix composite thermal deformation using the boron nitride that boron nitride powder is prepared as packing material
Temperature is high, molding shrinkage is low, can be used for making solar water heater of fine heat-resisting performance, excellent thermal conductivity etc. tool
There is very big prospect.And composite material these performances can also be applied in the processing heat consumption component of microelectronics industry.
It should be understood that above-mentioned each technical characteristic of the invention and having in below (eg embodiment) within the scope of the present invention
It can be combined with each other between each technical characteristic of body description, to form a new or preferred technical solution.As space is limited, exist
This no longer tires out one by one states.
Detailed description of the invention
Fig. 1 is scanning electron micrograph, and wherein a is polyethylene powder；B is stratiform hexagonal boron nitride powder.
Fig. 2 is that the scanning electron microscopy for the boron nitride enhancing composite polyethylene material that boron nitride volume fraction is 50% shines
Piece, wherein a is the scanning electron micrograph for being parallel to the section arrangement orientation in hot pressing direction；B is perpendicular to hot pressing direction
The scanning electron micrograph of section arrangement orientation.
Fig. 3 is that different volumes score boron nitride enhances composite polyethylene material thermal conductivity (Thermal to boron nitride
Conductivity, TC) influence curve.It can be seen from the figure that with the rising of boron nitride volume fraction, the composite material
Thermal conductivity also constantly rise, when volume fraction be 60% when, the direction X-Y thermal conductivity is up to 37W/mk.
Fig. 4 is the influence curve that different volumes score boron nitride enhances boron nitride composite polyethylene material anti-bending strength.
It can be seen from the figure that with the rising of volume fraction, the bending strength of the composite material constantly declines, nevertheless, working as nitrogen
When change boron volume fraction is 60%, bending strength also can reach 11.6MPa.
Fig. 5 is that boron nitride/composite polyethylene material scanning electron that boron nitride volume fraction is 50% in comparative example 2 shines
Piece, wherein a is the scanning electron photo for being parallel to the section arrangement in hot pressing direction, and b is the section arrangement perpendicular to hot pressing direction
Scanning electron photo.
Specific embodiment
The present inventor by depth studying extensively, filled out using high thermal conductivity sheet boron nitride powder as thermally conductive by discovery
Reinforcing material is filled, double center mixing dispersion machines are passed through after evenly mixing with polymer powder, through rotary vibration control high thermal conductivity piece
The arrangement of layer boron nitride powder, then carries out Thermocompressed sintering and forming through vacuum hotpressing, obtains highly directional boron nitride enhancing polymerization
Object based composites.Mechanical mixture improves powder dispersing uniformity in composite material, and it is compound that rotary oscillation crosswise improves this
The arrangement of the consistency of lamella boron nitride powder in material, vacuum hotpressing improve the relative density of composite material.In addition, of the invention
Composite material interface bond strength it is suitable, there is preferable bending strength, hot property is excellent, and thermal conductivity is good, wear-resisting, be easy to plus
Work is at complicated shape, and preparation method is simple, easy to control.On this basis, the present inventor completes the present invention.
Boron nitride powder
As used herein, the boron nitride powder that the present invention uses nitrogenizes to belong to six side of micrometer laminar (also referred to as sheet)
Boron powder.
Stratiform hexagonal boron nitride powder preferred planar is having a size of 50 microns~400 microns；Preferably 10 microns~300 is micro-
Rice.
In the present invention, the planar dimension refers to that powder tiles naturally and opens the average diameter size of rear in-plane.
Stratiform hexagonal boron nitride powder with a thickness of 0.1-10 microns, preferably 0.1-8 microns or 0.1-5 microns.
Polymer powder
Polymer powder of the invention is not particularly limited, can be with boron nitride hot pressing using preparation method of the invention
Polymer be suitable for the present invention.
For example, the polymer is polyethylene, polypropylene, nylon, polyimides, polyphenylene sulfide.Another preferred
In example, the polymer is polyethylene.The polyethylene include LDPE (low density polyethylene (LDPE) or high pressure polyethylene),
LLDPE (linear low density of polyethylene), MDPE (medium density polyethylene), HDPE (high density polyethylene (HDPE)), UHMWPE (supra polymer
Weight northylen) and various ethylene copolymers.
In the present invention, polymer powder is granulated polymer powder.In another preferred example, the grain of polymer powder
Diameter is no more than 300 microns.Preferably, the partial size of the polymer powder be no more than 100 microns, it is more preferably micro- for 1~75
Rice.
Boron nitride enhances polymer matrix composite and preparation method thereof
Boron nitride enhancing polymer matrix composite of the invention includes two kinds of component parts of boron nitride and polymer, is passed through
Composite material of the invention is made in the stratiform hexagonal boron nitride powder aligned and polymer powder hot pressed sintering.
The present invention is obtained by the way that the big partial size lamella boron nitride powder material of high thermal conductivity is added as conductive filler reinforcing material
Composite material have in terms of hot property and be significantly increased.
In another preferred example, boron nitride quality accounts for the 40%-95% of composite material gross mass, preferably 40-90%, more
Good is 50-85%.
The excellent performances such as the composite material has intensity suitable, wear-resisting, and thermal diffusivity is good.It is led in Electronic Packaging, heat dissipation etc.
Domain has a wide range of applications.
The preparation method of composite material of the invention, includes the following steps：
A) under the action of double center mixing dispersion machines, stratiform hexagonal boron nitride powder and polymer powder are mixed, so that
The polymer powder uniform adhesion obtains mixture on the boron nitride powder surface；
B) mixture that vibrating step a) is obtained on rotary shake table, so that sheet boron nitride powder realizes lamella
The preferential arrangement in direction；
C) mixture of the vacuum hotpressing through step b) oscillation crosswise obtains the composite material.
In another preferred example, the polymer is polyethylene, polypropylene, nylon, polyimides, polyphenylene sulfide.
In another preferred example, described be blended under the action of double center mixing dispersion machines carries out.Mixing rate is 1000
~2000 revs/min, incorporation time is 30~120s.In another preferred example, mixing rate is 1200 revs/min, when mixing
Between be 30~60s.
In another preferred example, the mixed powder carries out on rotary shake table, provides lamella boron nitride powder row
The consistency of column.The rotary speed of the oscillation crosswise, also referred to as vibration frequency are 40~200 revs/min.Preferably 60~190
Rev/min, more preferably 60~180 revs/min.In another preferred example, the time of vibration of the oscillation crosswise is 5~100 points
Clock, preferably 5~80 or 10~60 minutes.
In another preferred example, the vacuum hotpressing is to be warming up to the mixture through step b) oscillation crosswise under vacuum
100~400 DEG C are pressurizeed, and pressure is 10~80MPa (preferably 10~50MPa, more preferably 10~30MPa), dwell time
For 10~60min (preferably 20~60min, more preferably 20~30min).In another preferred example, the vacuum degree of the vacuum
≤200Pa。
In another preferred example, it is described prepare boron nitride/composite polyethylene material warming temperature be 100~200 DEG C (compared with
Good is 130~180 degrees Celsius, more preferably 140~160 degrees Celsius).
In another preferred example, it is described prepare boron nitride/PP composite material warming temperature be 100~200 DEG C (compared with
Good is 150~180 degrees Celsius, more preferably 160~180 degrees Celsius).
In another preferred example, the boron nitride/nylon composite materials warming temperature for preparing is 200~300 DEG C (preferable
It is 250~280 degrees Celsius, more preferably 255~270 degrees Celsius).
In another preferred example, the boron nitride/composite polyimide material warming temperature for preparing is 300~400 DEG C
(preferably 350~380 degrees Celsius, more preferably 350~370 degrees Celsius).
In another preferred example, the boron nitride/polyphenyl thioether composite material warming temperature for preparing is 200~300 DEG C
(preferably 250~300 degrees Celsius, more preferably 290~300 degrees Celsius).
In another preferred example, preparation method of the invention includes the following steps：
(a) weighing mass ratio is 1:1~5:1 boron nitride and polyethylene powder, boron nitride powder and polyethylene powder exist
It is uniform that mixed at high speed is carried out in double center mixing dispersion machines, so that polyethylene powder uniform adhesion is on boron nitride micro-powder surface
Improve polyethylene distributing homogeneity in the composite；
Preferably, it is calculated by the mixture total volume, the volume of layered hexagonal boron nitride powder accounts for layered six
The 30~60% of the total volume of the mixture of square boron nitride powder and polymer powder, preferably 40~60%, more preferably 50~
60%.
(b) mixture is put into mold, is subsequently placed on rotary shake table and carries out powder vibration arrangement, improves nitridation
Boron micron sheet direction arrangement consistency；The time range of vibration is between 10~60min；
The rotary speed and time of vibration of vibration depending on powder and its filling volume, preferably vibration rotary speed be 40~
200 (revs/min), time of vibration are 10~60min；
(c) mold is put into vacuum hotpressing furnace apparatus, sample is warming up to 100~200 by the hot pressing under vacuum atmosphere
It when temperature range, pressurizes, then keeps the temperature 10~60min, demould sampling after being finally cooled to room temperature, obtain boron nitride enhancing
Composite polyethylene material.
Preferably, the true temp is 130~180 DEG C, preferably 140~160 DEG C；
The dwell time of the vacuum hotpressing is 10~60min；Preferably 20~30min；
The pressure of the vacuum hotpressing is 10~50MPa；Preferably 10~30MPa.
Sheet hexagonal boron nitride has its special structure, has high thermal conductivity in boron nitride lamella direction (X-Y plane),
There are certain partial size difference, polymer powder such as polyethylene powders between lamella boron nitride and polymer powder such as polyethylene powder
Body also has certain viscosity, is coated on small particle polymer powder such as polyethylene powder greatly by physics mode high speed mixing
The surface of particle splat boron nitride, so that improving polymer powder such as polyethylene powder enhances polymer matrix composite wood in boron nitride
Even distribution in material；By control mixing velocity and time, i.e. guarantee mixing uniformity, and guarantee that boron nitride powder will not
Because too fast revolving speed ruptures.
The present invention uses sheet boron nitride powder as particle filled composite by using the method for vacuum hot pressing formation, and poly-
It is compound to close powder such as polyethylene powder progress, on the one hand due to the sliding of hexagonal boron nitride piece interlayer in hot pressing and the temperature
The melting deformation of polymer powder such as polyethylene powder makes the mechanical snap of interface cohesion between boron nitride and polymer under spending
It acts on more obvious；On the other hand due to the big partial size of lamella boron nitride powder, be conducive to the preferentially fixed of sheet boron nitride powder
To arrangement, therefore primary concern is that the partial size ruler of boron nitride in the preparation process of boron nitride enhancing polymer matrix composite
The very little preferential arrangement problem with boron nitride powder.The high-termal conductivity for making full use of boron nitride lamella direction (X-Y plane), so that piece
Layer boron nitride powder obtains oriented preferentially in composite material preparation process.Preparation high thermal conductivity boron nitride is increased in this way
Strength polymer composite material is just particularly important.For the present inventor by extensively and profoundly studying, discovery passes through rotary vibration
Arrangement can effectively improve the oriented alignment of sheet boron nitride.
In addition, being conducive to sufficiently connect between hexagonal boron nitride and polymer powder such as polyethylene powder under vacuum conditions
Touching reduces the inside and forms stomata, advantageously forms the high boron nitride enhancing polymer matrix composite of relative density.
Boron nitride powder enhances polymer such as composite polyethylene material thermal change as the boron nitride that packing material is prepared
Shape temperature is high, molding shrinkage is low, can be used for making the excellent heat conducting pipe of fine heat-resisting performance, resistance to chemical corrosion, thermally conductive
Solar water heater haveing excellent performance etc. has very big prospect.And composite material these performances can also be applied to
In the processing heat consumption component of microelectronics industry.
The preparation method of composite material of the present invention improves powder using double center mixing dispersion machine mechanical equipment mixed powders
Uniformity between body；The consistency arrangement of boron nitride powder is improved using the use of rotary shake table；Under vacuum condition
It is hot-forming, improve the relative density of composite material.Boron nitride enhance polymer such as composite polyethylene material, along perpendicular to
Hot pressing direction (i.e. the direction X-Y of sample) highest thermal coefficient (total heat-transfer capability) reaches 37W/mK, with certain intensity and
It is easily processed into complicated shape, and solves that high molecular polythene material thermal conductivity is low, and molding cycle is long, needs prolonged curing ask
Topic.
The feature that the features described above or embodiment that the present invention mentions are mentioned can be in any combination.Disclosed in this case specification
All features can be used in combination with any composition form, each feature disclosed in specification, can it is any provide it is identical, equal
Deng or similar purpose alternative characteristics replace.Therefore except there is special instruction, revealed feature is only impartial or similar features
General example.
Present invention will be further explained below with reference to specific examples.It should be understood that these embodiments are merely to illustrate the present invention
Rather than it limits the scope of the invention.In the following examples, the experimental methods for specific conditions are not specified, usually according to conventional strip
Part or according to the normal condition proposed by manufacturer.Unless otherwise defined, all professional and scientific terms as used herein and sheet
Meaning known to the skilled person of field is identical.In addition, any method similar to or equal to what is recorded and material all may be used
Applied in the method for the present invention.The preferred methods and materials described herein are for illustrative purposes only.
Universal method
(1) thermal conductivity
It tests by GB/T 14452-93 standard.
(2) bending strength and bending modulus
It tests by GB/T 14452-93 standard.
Specimen types are specimen size (mm)：(50 ± 2) (length) × (10 ± 0.2) × (10 ± 0.2)
The preparation of 1 boron nitride of embodiment enhancing polymer matrix composite 1
A：It is matched by following volumes and measures following components：
Boron nitride powder 40vol%
Polyethylene powder 60vol%
B：It is put into after the powder is mixed in double center mixing dispersion machines and stirs 30s, revolution is controlled in 1200rpm.
Obtained mixture is put into accurate compacting tool set, after uniformly vibrating 30min on rotary shake table, oscillation crosswise turns
Speed is 162rpm.
C：It after sample in step B is assembled with mold, is put into vacuum hotpressing stove, is evacuated to vacuum degree extremely
200Pa carries out hot pressing hereinafter, heating rate is that 8 DEG C/min is warming up to 150 DEG C, pressure size 20MPa, pressure maintaining 20min, so
After cool to room temperature with the furnace.
The sample that high-temperature process is crossed takes out demoulding and obtains boron nitride enhancing polymer matrix composite after being cooled to room temperature.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 26.32W/m.K.Bending strength is 26.12MPa.It is close
Degree is 1.475g/cm3, vertical direction thermal diffusion coefficient is 12.220mm2/ s, parallel direction thermal diffusion coefficient are 2.386mm2/s。
In the present embodiment, the polyethylene powder is UHMWPE ultra-high molecular weight polyethylene, and grain diameter size exists
50~75 microns, boron nitride powder is six side's powder of sheet, and powder planar dimension size is 10-500 microns, and thickness is in 0.1-
10 microns.Polyethylene powder and the scanning electron micrograph of sheet hexagonal boron nitride powder are as shown in Figure 1.
The preparation of 2 boron nitride of embodiment enhancing polymer matrix composite 2
With embodiment 1, difference is：Boron nitride powder volume fraction is 30vol.%.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 8.78W/m.K, bending strength 32MPa.
Density is 1.345g/cm3, vertical direction thermal diffusion coefficient is 4.049mm2/ s, parallel direction thermal diffusion coefficient are
1.707mm2/s。
The preparation of 3 boron nitride of embodiment enhancing polymer matrix composite 3
With embodiment 1, difference is：Boron nitride powder volume fraction is 50vol.%.
Fig. 2 is boron nitride/composite polyethylene material scanning electron photo, it can be seen that polyethylene is uniformly dispersed, big partial size
Boron nitride powder be easier to carry out bridging connection between each other in the composite, keep preferred orientation in X-Y and Z-direction.
After rotary shake table, boron nitride is effectively preferentially arranged, and specifically, refers to that most of sheet boron nitride powder totally becomes
Want to tile in towards the direction X-Y, is interconnected to form heat transfer path between lamella.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 31.25W/m.K, bending strength 18MPa.
Density is 1.603g/cm3, vertical direction thermal diffusion coefficient is 14.605mm2/ s, parallel direction thermal diffusion coefficient are
5.97mm2/s。
The preparation of 4 boron nitride of embodiment enhancing polymer matrix composite 4
With embodiment 1, difference is：Boron nitride powder volume fraction is 60vol.%.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 37.31W/m.K, bending strength 12MPa.
Density is 1.732g/cm3, vertical direction thermal diffusion coefficient is 17.548mm2/ s, parallel direction thermal diffusion coefficient are
5.126mm2/s。
Fig. 3 and Fig. 4 different volumes score boron nitride enhances composite polyethylene material thermal conductivity (Thermal to boron nitride
Conductivity, TC) and anti-bending strength influence curve.It can be seen from the figure that with the rising of boron nitride volume fraction,
The thermal conductivity of the composite material also constantly rises, and when volume fraction is 60%, the direction X-Y thermal conductivity is up to 37W/mk.This
Outside with the rising of volume fraction, the bending strength of the composite material constantly declines, nevertheless, when boron nitride volume fraction is
When 60%, bending strength also can reach 11.6MPa.
The preparation of 5 boron nitride of embodiment enhancing polymer matrix composite
A：It is matched by following volumes and measures following components：
Boron nitride powder 60vol%
Nylon -66 powder 40vol%
B：It is put into after the powder is mixed in double center mixing dispersion machines and stirs 30s, revolution is controlled in 1300rpm.
Obtained mixture is put into accurate compacting tool set, after uniformly vibrating 30min on rotary shake table, oscillation crosswise turns
Speed is 170rpm.
C：It after sample in step B is assembled with mold, is put into vacuum hotpressing stove, is evacuated to vacuum degree extremely
200Pa carries out hot pressing hereinafter, heating rate is that 8 DEG C/min is warming up to 268 DEG C, pressure size 20MPa, pressure maintaining 20min, so
After cool to room temperature with the furnace.
The sample that high-temperature process is crossed takes out demoulding and obtains boron nitride enhancing polymer matrix composite after being cooled to room temperature.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 25.4536W/m.K.Bending strength is 21.3MPa.It is close
Degree is 1.969g/cm3, vertical direction thermal diffusion coefficient is 11.633mm2/ s, parallel direction thermal diffusion coefficient are 2.292mm2/s。
In the present embodiment, the polymer powder be nylon -66 powder, grain diameter size at 50~75 microns,
Boron nitride powder is six side's powder of sheet, and powder planar dimension size is 10-500 microns, and thickness is at 0.1-10 microns.
The preparation of 6 boron nitride of embodiment enhancing polymer matrix composite
A：It is matched by following volumes and measures following components：
Boron nitride powder 60vol%
Polyimides powder 40vol%
B：It is put into after the powder is mixed in double center mixing dispersion machines and stirs 30s, revolution is controlled in 1300rpm.
Obtained mixture is put into accurate compacting tool set, after uniformly vibrating 30min on rotary shake table, oscillation crosswise turns
Speed is 170rpm.
C：It after sample in step B is assembled with mold, is put into vacuum hotpressing stove, is evacuated to vacuum degree extremely
200Pa carries out hot pressing hereinafter, heating rate is that 8 DEG C/min is warming up to 360 DEG C, pressure size 20MPa, pressure maintaining 20min, so
After cool to room temperature with the furnace.
The sample that high-temperature process is crossed takes out demoulding and obtains boron nitride enhancing polymer matrix composite after being cooled to room temperature.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 22.745W/m.K.Bending strength is 20.2MPa.It is close
Degree is 1.977g/cm3, vertical direction thermal diffusion coefficient is 11.932mm2/ s, parallel direction thermal diffusion coefficient are 2.386mm2/s。
In the present embodiment, the polymer powder be polyimides powder, grain diameter size at 50~75 microns,
Boron nitride powder is six side's powder of sheet, and powder planar dimension size is 10-500 microns, and thickness is at 0.1-10 microns.
The preparation of 7 boron nitride of embodiment enhancing polymer matrix composite
A：It is matched by following volumes and measures following components：
Boron nitride powder 60vol%
Polyphenylene sulfide powder 40vol%
B：It is put into after the powder is mixed in double center mixing dispersion machines and stirs 30s, revolution is controlled in 1250rpm.
Obtained mixture is put into accurate compacting tool set, after uniformly vibrating 30min on rotary shake table, oscillation crosswise turns
Speed is 165rpm.
C：It after sample in step B is assembled with mold, is put into vacuum hotpressing stove, is evacuated to vacuum degree extremely
200Pa carries out hot pressing hereinafter, heating rate is that 8 DEG C/min is warming up to 295 DEG C, pressure size 20MPa, pressure maintaining 20min, so
After cool to room temperature with the furnace.
The sample that high-temperature process is crossed takes out demoulding and obtains boron nitride enhancing polymer matrix composite after being cooled to room temperature.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 12.16W/m.K.Bending strength is 26.12MPa.It is close
Degree is 1.993g/cm3, vertical direction thermal diffusion coefficient is 8.311mm2/ s, parallel direction thermal diffusion coefficient are 2.386mm2/s。
In the present embodiment, the polymer powder be polyphenylene sulfide powder, grain diameter size at 50~75 microns,
Boron nitride powder is six side's powder of sheet, and powder planar dimension size is 10-500 microns, and thickness is at 0.1-10 microns.
The preparation of 8 boron nitride of embodiment enhancing polymer matrix composite
A：It is matched by following volumes and measures following components：
Boron nitride powder 60vol%
Polypropylene powder 40vol%
B：It is put into after the powder is mixed in double center mixing dispersion machines and stirs 30s, revolution is controlled in 1300rpm.
Obtained mixture is put into accurate compacting tool set, after uniformly vibrating 35min on rotary shake table, oscillation crosswise turns
Speed is 164rpm.
C：It after sample in step B is assembled with mold, is put into vacuum hotpressing stove, is evacuated to vacuum degree extremely
200Pa carries out hot pressing hereinafter, heating rate is that 9 DEG C/min is warming up to 165 DEG C, pressure size 20MPa, pressure maintaining 20min, so
After cool to room temperature with the furnace.
The sample that high-temperature process is crossed takes out demoulding and obtains boron nitride enhancing polymer matrix composite after being cooled to room temperature.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 22.32W/m.K.Bending strength is 22.3MPa.Density
For 2.0542g/cm3, vertical direction thermal diffusion coefficient is 12.341mm2/ s, parallel direction thermal diffusion coefficient are 2.253mm2/s。
In the present embodiment, the polymer powder is polypropylene powder, and grain diameter size is at 50~75 microns, nitrogen
Change boron powder is six side's powder of sheet, and powder planar dimension size is 10-500 microns, and thickness is at 0.1-10 microns.
The preparation of the pure composite polyethylene material of comparative example 1
Substantially with embodiment 1, difference is step：Polyethylene powder volume fraction is 100vol.%.
The thermal conductivity (be subject to highest in terms of) for measuring sample is 0.42W/m.K, bending strength 14MPa.
The preparation of 2 boron nitride of comparative example enhancing polymer matrix composite
A：It is matched by following volumes and measures following components：
Boron nitride powder 50vol.%
Polyethylene powder 50vol.%
B：It is put into after the powder is mixed in double center mixing dispersion machines and stirs 30s, revolution is controlled in 1200rpm.
Obtained mixture is put into accurate compacting tool set, on a vibration table uniformly after vibration 30min, the rotary speed of oscillation crosswise is
160rpm。
C：It after sample in step B is assembled with mold, is put into vacuum hotpressing stove, is evacuated to vacuum degree extremely
200Pa carries out hot pressing hereinafter, heating rate is that 8 DEG C/min is warming up to 152 DEG C, pressure size 20MPa, pressure maintaining 20min, so
After cool to room temperature with the furnace.The sample that high-temperature process is crossed takes out demoulding and obtains boron nitride enhancing polymer matrix complex.Measurement
The thermal conductivity (be subject to highest in terms of) of sample is 9.399W/m.K, bending strength 8.53MPa.
In this example, the polyvinyl resin is UHMWPE ultra-high molecular weight polyethylene, grain diameter size 150~
200 microns, which is the powder of sheet, and powder size is at 10-50 microns, and thickness is at 0.1-10 microns.
Fig. 5 is boron nitride/composite polyethylene material scanning electron photo.As can be seen that small particle boron nitride powder with
It preferably can preferentially arrange after polyethylene mixing, but there are the arrangement of a part of hexagonal boron nitride powder is inconsistent.
As can be seen that boron nitride obtained in the present invention enhances polymer matrix composite wood from embodiment 1-8 and comparative example
Material has good mechanical performance and processing performance, also has good hot property, when the volume ratio of boron nitride and polyethylene is
1:When 1, various performances are relatively more comprehensive.
All references mentioned in the present invention is incorporated herein by reference, independent just as each document
It is incorporated as with reference to such.In addition, it should also be understood that, after reading the above teachings of the present invention, those skilled in the art can
To make various changes or modifications to the present invention, such equivalent forms equally fall within model defined by the application the appended claims
It encloses.
Claims (10)
1. a kind of preparation method of boron nitride enhancing polymer matrix composite, which is characterized in that the preparation method include with
Lower step：
A) it under the action of double center mixing dispersion machines, mixes stratiform hexagonal boron nitride powder and polymer powder is mixed
Object, the revolving speed of double center mixing dispersion machines are 1000~2000rpm, and the mixed time is 30~150 seconds；
B) mixture that vibrating step a) is obtained on rotary shake table, vibration frequency are 40~200 revs/min, when vibration
Between be 5~100min；
C) mixture that vacuum hotpressing is vibrated through step b) obtains the composite material, wherein the vacuum hotpressing is vacuum
Under, the mixture vibrated through step b) is warming up to 100~400 DEG C and is pressurizeed, pressure is 10~80MPa, and the dwell time is
10~60min.
2. preparation method as described in claim 1, which is characterized in that layered hexagonal boron nitride powder tiles naturally open after
The average diameter of in-plane is 10~500 microns, with a thickness of 0.1~10 micron.
3. preparation method as described in claim 1, which is characterized in that the polymer is polyethylene, polypropylene, nylon, gathers
Acid imide or polyphenylene sulfide.
4. preparation method as described in claim 1, which is characterized in that the polymer powder tiles naturally opens rear in-plane
Average diameter≤300 micron.
5. preparation method as described in claim 1, which is characterized in that the volume of layered hexagonal boron nitride powder accounts for described
The 30~60% of the total volume of the mixture of stratiform hexagonal boron nitride powder and polymer powder.
6. preparation method as described in claim 1, which is characterized in that layered hexagonal boron nitride powder and the polymer
Mass ratio be 1:1~5:1.
7. preparation method as described in claim 1, which is characterized in that the revolving speed of double center mixing dispersion machines is 1100-
1300rpm。
8. preparation method as described in claim 1, which is characterized in that the time mixed in the step a) is 30-120 seconds.
9. preparation method as described in claim 1, which is characterized in that vibration frequency is 60-190 revs/min in the step b)
Clock；And/or
Time of vibration is 10-60min in the step b).
10. preparation method as described in claim 1, which is characterized in that the vacuum hotpressing will be shaken through step b) under vacuum
Dynamic mixture is warming up to 100~200 DEG C and pressurizes, and pressure is 10~80MPa, and the dwell time is 10~60min, described true
Empty vacuum degree≤250Pa.
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