CN115536998B - Electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material and preparation method thereof - Google Patents
Electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material and preparation method thereof Download PDFInfo
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
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- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
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Abstract
The invention discloses an electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material and a preparation method thereof, wherein the electromagnetic shielding heat conduction PBT/PET based composite material is prepared from the following raw materials: PBT, PET, crystalline flake graphite, zinc oxide, barium ferrite, POE-g-GMA, gamma- (2, 3-epoxypropoxy) propyl trimethoxysilane and beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester. The PBT/PET-based composite material has excellent electromagnetic shielding performance and heat conducting performance, and can be widely applied to the field of electronic components needing shielding and heat conducting functions.
Description
Technical Field
The invention belongs to the field of materials, and particularly relates to an electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material and a preparation method thereof.
Background
Polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) are two important thermoplastic engineering plastics, and PBT has excellent mechanical strength, chemical corrosion resistance and thermal stability, while PET has the advantages of low cost, good rigidity and high heat distortion temperature. The PBT/PET alloy can be prepared by melt blending PBT and PET, integrates the excellent performances of the PBT and the PET, and is widely applied to the fields of electronics and electric appliances.
In recent years, with the development of the electronic and electric industry, various devices provide high efficiency and convenience for living production, and meanwhile, the problem of electromagnetic pollution is increasingly outstanding. Electromagnetic interference not only can prevent normal operation of equipment and cause information leakage, but also can cause great harm to human health. The electromagnetic shielding material realizes shielding of electromagnetic waves through absorption or reflection loss, wherein the material mainly used for absorption loss is favored, and the material converts absorbed electromagnetic wave energy into joule heat energy, so that the problem of secondary pollution is effectively avoided. Among the electromagnetic shielding materials, conductive polymer composite materials are receiving attention because of their light weight, corrosion resistance, easy processing, controllable performance and the like. Along with the updating of electronic products, the power consumption of the electronic and electric equipment is continuously increased, and the heat productivity of the equipment is also rapidly increased, so that the operating environment temperature of the equipment is higher, and the adopted materials are required to have excellent heat conduction performance in order to ensure the normal operation of the equipment and maintain the service life of the equipment.
Currently, some research is done in the prior art on electromagnetic shielding PBT or PET, for example: chinese patent CN 109135207a discloses a high-performance electromagnetic shielding PBT composite material and preparation method thereof, which is prepared from the following components in parts by weight: 80 parts of PBT (polybutylene terephthalate) and 100 parts of a thermoplastic elastomer; 10 parts of functional composite filler and 20 parts of functional composite filler; 0.1 part of antioxidant and 0.5 part of antioxidant; the functional composite filler is prepared by acidizing PPTA fiber through surface amino modification of fullerene. Chinese patent CN 112940464a discloses a high performance PBT/PET electromagnetic shielding composite material and a method for preparing the same. The coating comprises the following components in percentage by weight: 60 parts of polybutylene terephthalate, 20 parts of polyethylene terephthalate, 5 parts of compatilizer, 5 8 parts of carbon nano tube and Fe 3 O 4 5.10 parts of nanowire, 5.10 parts of stainless steel fiber, 0.6 part of surface treating agent and 0.5.0 part of antioxidant. Chinese patent CN 113621222A discloses a low-melting-point PBT electromagnetic shielding composite material and a preparation method thereof, wherein PBT base stock particles, graphene materials and a dispersing agent are added into a high-speed stirrer for stirring, a compound compatilizer, inorganic nano materials, LCP fibers, flax fibers and carbon fibers are added for continuous stirring, and then the mixture is added into double helixAnd (5) a rod extruder, and carrying out melt extrusion granulation to obtain the modified PBT material. Chinese patent CN 111925630a discloses a high-strength electromagnetic shielding and heat conducting PBT/PET nanocomposite and a preparation method thereof, the nanocomposite comprises the following components in parts by weight: 70 parts of polybutylene terephthalate, 20 parts of polyethylene terephthalate, 5 parts of toughening agent and 10 parts of graphene Fe 3 O 4 5.10 parts of composite filler, 0.05 part of filler surface treating agent and 0.5.1.4 parts of antioxidant. Chinese patent CN 103351584a discloses a heat conductive PBT composite material with shielding effect and preparation method, which is prepared from the following raw materials (by weight portion): polybutylene terephthalate (PBT), aluminum powder, a toughening agent, a coupling agent, an antioxidant, a heat stabilizer and a lubricant. Chinese patent CN 107345051A discloses a heat-conducting PBT composite material with shielding effect and a preparation method thereof, wherein the heat-conducting PBT composite material is prepared from the following raw materials in parts by weight, namely polybutylene terephthalate, aluminum powder, a toughening agent, a coupling agent, an antioxidant, a heat stabilizer and a lubricant. As can be seen from the above patent, in the prior art, electromagnetic shielding function is achieved mainly by using carbon nanofillers such as graphene or by using graphene Fe 3 O 4 The composite filler realizes electromagnetic shielding and heat conduction functions.
Disclosure of Invention
Based on the above, one of the purposes of the invention is to provide an electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material which has excellent electromagnetic shielding and heat conduction properties and can be widely applied to the field of electronic components needing shielding and heat conduction functions.
The specific technical scheme for realizing the aim of the invention comprises the following steps:
the electromagnetic shielding heat conduction PBT/PET base composite material is prepared from the following raw materials in parts by weight:
the barium ferrite is BaFe 12 O 19 Belonging to double composite dielectric materialsMaterial preparation; the POE-g-GMA is ethylene and octene copolymer grafted glycidyl methacrylate.
In some embodiments, the electromagnetic shielding heat conduction PBT/PET matrix composite material is prepared from the following raw materials in parts by weight:
in some embodiments, the electromagnetic shielding heat conduction PBT/PET matrix composite material is prepared from the following raw materials in parts by weight:
in some of these embodiments, the PBT has a number average molecular weight of 25000 to 33000g/mol; the number-average molecular weight of the PET is 21000-29000 g/mol;
In some of these embodiments, the crystalline flake graphite has a particle size of 0.5 to 1 μm; the particle size of the zinc oxide is 25-35 nm.
In some of these embodiments, the POE-g-GMA has a glycidyl methacrylate grafting of 1 to 1.4%.
In some of these embodiments, the barium ferrite is prepared as follows:
(1) FeCl in molar ratio 3 ·6H 2 O：BaCl 2 ·2H 2 O=11 to 11.6, and a certain amount of FeCl is weighed 3 ·6H 2 O and BaCl 2 ·2H 2 O is added into deionized water for dissolution, and then the mixed salt solution is transferred into a burette A for standby; in molar ratio of Na 2 CO 3 ：BaCl 2 ·2H 2 O=8 to 9 and Na 2 CO 3 : naoh=4.5 to 5.5, and Na was calculated separately 2 CO 3 Adding the mixture and NaOH in parts by weight into deionized water for dissolution, and transferring the obtained mixed alkali solution into a burette B for later use;
(2) Under the condition of continuously and continuously stirring, simultaneously dripping the buret A and the buret B into a beaker, controlling the pH value of the solution in the beaker to be 8-8.5, standing for 8-12 h after titration, respectively cleaning with ethanol and deionized water after suction filtration, drying, calcining at 700-800 ℃ for 4-6 h, and grinding to obtain the barium ferrite.
The invention further aims to provide a preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material.
The specific technical scheme for realizing the aim of the invention comprises the following steps:
a preparation method of an electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material comprises the following steps:
(1) Drying the PBT and PET at 100-115 ℃ for 2-4 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 95-105 ℃ and stirring for 0.5-1 h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.5-1 h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) in the lateral direction (such as a third zone) of the parallel double-screw extruder (total eight zones), and carrying out melt extrusion and granulation, wherein the technological parameters comprise: the temperature of the first area is 240-260 ℃, the temperature of the second area is 245-265 ℃, the temperature of the third area is 250-270 ℃, the temperature of the fourth area is 255-275 ℃, the temperature of the fifth area is 255-275 ℃, the temperature of the sixth area is 255-275 ℃, the temperature of the seventh area is 255-275 ℃, the temperature of the eighth area is 250-270 ℃, the temperature of the die head is 250-270 ℃, and the rotating speed of the screw is 350-650 rpm.
In some embodiments, the method for preparing the electromagnetic shielding heat conduction PBT/PET based composite material comprises the following steps:
(1) Drying the PBT and PET at 105-110 ℃ for 2.5-3.5 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 97-103 ℃ and stirring for 0.6-0.9 h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.6-0.9 h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) in the lateral direction (such as a third zone) of the parallel double-screw extruder (total eight zones), and carrying out melt extrusion and granulation, wherein the technological parameters comprise: the temperature of the first area is 245-255 ℃, the temperature of the second area is 250-260 ℃, the temperature of the third area is 255-265 ℃, the temperature of the fourth area is 260-270 ℃, the temperature of the fifth area is 260-270 ℃, the temperature of the sixth area is 260-270 ℃, the temperature of the seventh area is 260-270 ℃, the temperature of the eighth area is 255-265 ℃, the temperature of the die head is 255-265 ℃, and the screw rotating speed is 400-600 rpm.
In some of these embodiments, the screw shape of the parallel twin screw extruder is single-flighted; the ratio L/D of the length L and the diameter D of the screw is 35-55; the screw is provided with more than 1 (containing 1) meshing block areas and more than 1 (containing 1) reverse thread areas.
In some of these embodiments, the ratio L/D of the screw length L to the diameter D is 40 to 50; and the screw is provided with 2 meshing block areas and 1 reverse thread area.
In some embodiments, in step (1) and/or step (2), the stirrer is a high-speed stirrer with a rotation speed of 500-1500 rpm.
The electromagnetic shielding heat conduction PBT/PET base composite material has the following functions of the raw materials:
according to the invention, the heat conduction performance of the PBT/PET-based composite material is improved by compounding crystalline flake graphite and zinc oxide, and the heat conduction channel is constructed by utilizing the intercalation or bridging action of the crystalline flake graphite on the zinc oxide, so that the damage of the high filling amount of a single heat conduction filler to the mechanical property of the heat conduction material is reduced. The flake graphite is of a flake structure, and the flake graphite is singly used as a heat conduction filler, and the flake graphite flakes are in certain orientation, for example, the flake graphite flakes are not easy to contact with each other; when zinc oxide is in a spherical structure and is singly used as a heat conducting filler, gaps are easy to form due to the small contact surfaces among particles. By compounding and using the crystalline flake graphite and the zinc oxide as the heat conducting filler, the crystalline flake graphite can be used for forming an intercalation and a bridging between zinc oxide particles, which is more beneficial to the framework of the heat conducting channel, thereby improving the heat conductivity coefficient of the material.
Barium ferrite (BaFe) 12 O 19 ) The double composite dielectric material has high natural resonant frequency, and the hexagonal sheet structure can realize the excellent absorption of electromagnetic wave in microwave range. The main wave absorption loss mechanism of the barium ferrite is natural resonance loss, and under the condition of no external magnetic field, the changing magnetic field of the incident electromagnetic wave can be combined with the magnetocrystalline anisotropic field H of the material A Interaction occurs and precession resonance occurs, but when the electromagnetic wave is incident, the electromagnetic field frequency f and the crystal eigenfrequency f are varied m In the same time, the ferrite crystal will absorb a large amount of electromagnetic wave energy, thereby achieving the effect of absorbing waves.
POE-g-GMA is ethylene and octene copolymer grafted glycidyl methacrylate, and the grafting rate of the glycidyl methacrylate is 1-1.4%. The epoxy group of POE-g-GMA can react with the hydroxyl end and carboxyl end of PBT and PET, so that the compatibility and interfacial adhesion of POE-g-GMA with PBT and PET base material resins are improved, and the sensitivity of the polyester material to notch strength is effectively improved.
Gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane is an epoxy functional silane. The gamma- (2, 3-glycidoxy) propyl trimethoxy silane is coated on the crystalline flake graphite, zinc oxide and barium ferrite, and the epoxy groups of the crystalline flake graphite, the zinc oxide and the barium ferrite can react with the hydroxyl end groups and carboxyl end groups of PBT and PET, so that the dispersibility and compatibility of the crystalline flake graphite, the zinc oxide and the barium ferrite in PBT and PET base material resins are effectively improved, and the heat conduction performance and the electromagnetic shielding performance of the PBT/PET base composite material are improved.
Beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester is a phenol lipoid with excellent performance, and has the advantages of no smell, better compatibility with polymer resin, high extraction resistance, high oxidation resistance, difficult coloration, less volatility, no pollution, washing resistance and the like.
Compared with the prior art, the electromagnetic shielding heat conduction PBT/PET based composite material and the preparation method thereof have the following beneficial effects:
1. according to the invention, the heat conduction performance of the PBT/PET-based composite material is improved by compounding crystalline flake graphite and zinc oxide, the electromagnetic shielding performance of the PBT/PET-based composite material is improved by using the barium ferrite serving as a double-composite dielectric material, the PBT/PET-based composite material is toughened by POE-g-GMA, and the crystalline flake graphite, zinc oxide and barium ferrite are coated by gamma- (2, 3-glycidoxy) propyl trimethoxysilane, so that the dispersibility and compatibility of the crystalline flake graphite, zinc oxide and barium ferrite in PBT and PET base material resins are improved, and the heat conduction performance and electromagnetic shielding performance of the PBT/PET-based composite material are improved.
2. The preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material has the advantages of simple process, easy control, low equipment requirement, low investment and contribution to industrial production, and all the used equipment is general polymer processing equipment.
Drawings
FIG. 1 is a flow chart of a preparation process of the electromagnetic shielding heat conducting PBT/PET based composite material.
Detailed Description
In order that the invention may be understood more fully, the invention will be described with reference to the accompanying drawings. This invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The reaction mechanism of the electromagnetic shielding heat conduction PBT/PET base composite material is as follows (the preparation process flow chart is shown in figure 1):
wherein R1 is POE-g-GMA, or gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane cladding crystalline flake graphite, zinc oxide and barium ferrite; r2 is PBT, or PET.
Reaction mechanism
From the reaction formula, the epoxy groups of POE-g-GMA and gamma- (2, 3-glycidoxy) propyl trimethoxy silane coated crystalline flake graphite, zinc oxide and barium ferrite can react with hydroxyl and carboxyl end groups of PBT and PET, so that the compatibility and interfacial adhesion of POE-g-GMA and PBT and PET base material resins are improved, the sensitivity of a polyester material to notch strength is effectively improved, the dispersibility and compatibility of crystalline flake graphite, zinc oxide and barium ferrite in the PBT and PET base material resins are effectively improved, and the heat conducting property and electromagnetic shielding property of the PBT/PET base composite material are improved.
The raw materials used in the examples and comparative examples of the present invention are as follows:
PBT has a number average molecular weight of 29000g/mol and is available from Taiwan vinca petrochemical Co., ltd.
PET has a number average molecular weight of 25000g/mol and is available from Huarun composite Co., ltd.
Flake graphite, 0.8 μm in particle size, was purchased from Ningbo sea-eotaxis chemical Co.
Zinc oxide, 30nm in particle size, was purchased from the new materials limited of xuan city crystal rayleigh.
FeCl 3 ·6H 2 O, purchased from Chengdu Kelong chemical reagent plant.
BaCl 2 ·2H 2 O, available fromChengdu Kelong chemical reagent factory.
Na 2 CO 3 Purchased from national pharmaceutical group chemical reagent limited.
NaOH, available from national pharmaceutical chemicals limited.
Ethanol, available from national pharmaceutical group chemical company, inc.
Deionized water, available from national pharmaceutical groups chemical company, inc.
POE-g-GMA, glycidyl methacrylate grafting 1.2%, available from Shenyang Kotong plastics Co., ltd.
Gamma- (2, 3-glycidoxy) propyltrimethoxysilane, available from Qingdao Hengda New Material technology Co.
Beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionate n-stearyl alcohol was purchased from Hubei Xin Rundex chemical Co.
The barium ferrite used in the following examples and comparative examples was prepared by the following steps:
(1) FeCl in molar ratio 3 ·6H 2 O：BaCl 2 ·2H 2 O=11.3, 305.3g of FeCl are weighed out 3 ·6H 2 O and 24.4g of BaCl 2 ·2H 2 Adding O into 1000mL of deionized water for dissolution, and transferring the mixed salt solution into a burette A for later use; in molar ratio of Na 2 CO 3 ：BaCl 2 ·2H 2 O=8.5 and Na 2 CO 3 : naoh=5, 90.1g of Na, respectively 2 CO 3 And 6.8g of NaOH are added into 500mL of deionized water for dissolution, and then the obtained mixed alkali solution is transferred into a burette B for standby;
(2) Under the condition of continuously and continuously stirring, simultaneously dripping the buret A and the buret B into a beaker, controlling the pH value of the solution in the beaker to be 8.2, standing for 10 hours after titration, respectively cleaning with ethanol and deionized water after suction filtration, drying, calcining for 5 hours at 750 ℃, and grinding to obtain the barium ferrite.
The present invention will be described in detail with reference to specific examples.
Example 1 electromagnetic shielding heat conduction PBT/PET base composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 4 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 95 ℃ and stirring for 1h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 1h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 240 ℃, the temperature of the second area is 245 ℃, the temperature of the third area is 250 ℃, the temperature of the fourth area is 255 ℃, the temperature of the fifth area is 255 ℃, the temperature of the sixth area is 255 ℃, the temperature of the seventh area is 255 ℃, the temperature of the eighth area is 250 ℃, the temperature of the die head is 250 ℃, and the rotating speed of the screw is 350rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 35; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 500 revolutions per minute.
Example 2 electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at 115 ℃ for 2 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 105 ℃, stirring for 0.5h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.5h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the first zone temperature was 260 ℃, the second zone temperature was 265 ℃, the third zone temperature was 270 ℃, the fourth zone temperature was 275 ℃, the fifth zone temperature was 275 ℃, the sixth zone temperature was 275 ℃, the seventh zone temperature was 275 ℃, the eighth zone temperature was 270 ℃, the die temperature was 270 ℃, and the screw speed was 650rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 55; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1500 rpm.
Example 3 electromagnetic shielding heat conduction PBT/PET base composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at 105 ℃ for 3.5 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 97 ℃ and stirring for 0.9h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.9h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 245 ℃, the temperature of the second area is 250 ℃, the temperature of the third area is 255 ℃, the temperature of the fourth area is 260 ℃, the temperature of the fifth area is 260 ℃, the temperature of the sixth area is 260 ℃, the temperature of the seventh area is 260 ℃, the temperature of the eighth area is 255 ℃, the temperature of the die head is 255 ℃, and the rotating speed of the screw is 400rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 40; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 500 revolutions per minute.
Example 4 electromagnetic shielding heat conduction PBT/PET base composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Example 5 electromagnetic shielding and Heat conducting PBT/PET base composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at the temperature of 110 ℃ for 2.5 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 103 ℃ and stirring for 0.6h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.6h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the first zone temperature was 255 ℃, the second zone temperature was 260 ℃, the third zone temperature was 265 ℃, the fourth zone temperature was 270 ℃, the fifth zone temperature was 270 ℃, the sixth zone temperature was 270 ℃, the seventh zone temperature was 270 ℃, the eighth zone temperature was 265 ℃, the die temperature was 265 ℃, and the screw speed was 600rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 50; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1500 rpm.
Example 6 electromagnetic shielding and Heat conducting PBT/PET base composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Example 7 electromagnetic shielding and Heat conducting PBT/PET base composite material and preparation method thereof
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
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the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Comparative example 1
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material of the comparative example is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the barium ferrite into a stirrer, heating to 100 ℃ and stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Comparative example 2
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material of the comparative example is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite and zinc oxide into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Comparative example 3
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material of the comparative example is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and the PET at the temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT and the cooled PET and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Comparative example 4
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material of the comparative example is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 100 ℃, stirring for 1.5h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Comparative example 5
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite and the barium ferrite into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
Comparative example 6
The electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material is prepared from the following raw materials in parts by weight:
the preparation method of the electromagnetic shielding heat conduction PBT/PET base composite material comprises the following steps:
(1) Drying the PBT and PET at a temperature of 100 ℃ for 3 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the zinc oxide and the barium ferrite into a stirrer, heating to 100 ℃, stirring for 0.75h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane, stirring for 0.75h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, adding the mixed mixture obtained in the step (2) into the lateral direction (third zone) of the parallel double-screw extruder (total eight zones) for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 250 ℃, the temperature of the second area is 255 ℃, the temperature of the third area is 260 ℃, the temperature of the fourth area is 265 ℃, the temperature of the fifth area is 265 ℃, the temperature of the sixth area is 265 ℃, the temperature of the seventh area is 265 ℃, the temperature of the eighth area is 260 ℃, the temperature of the die head is 260 ℃, and the rotating speed of the screw is 500rpm.
The screw shape of the parallel double-screw extruder is single-thread; the ratio L/D of the length L and the diameter D of the screw is 45; the screw is provided with 2 meshing block areas and 1 reverse thread area; in the step (1) and the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 1000 rpm.
The following is a list of the raw material compositions of examples 1-7 and comparative examples 1-6.
Table 1 list of raw material compositions of examples 1 to 7 and comparative examples 1 to 6
Examples 1 to 7 were electromagnetic shielding heat conductive PBT/PET based composites prepared by adjusting the addition amounts of PBT, PET, crystalline flake graphite, zinc oxide, barium ferrite, POE-g-GMA, gamma- (2, 3-glycidoxy) propyltrimethoxysilane, beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionate, comparative example 1 was an electromagnetic shielding heat conductive PBT/PET based composite prepared without crystalline flake graphite, zinc oxide, comparative example 2 was an electromagnetic shielding heat conductive PBT/PET based composite prepared without barium ferrite, comparative example 3 was an electromagnetic shielding heat conductive PBT/PET based composite prepared without POE-g-GMA, comparative example 4 was an electromagnetic shielding heat conductive PBT/PET based composite prepared without gamma- (2, 3-glycidoxy) propyltrimethoxysilane, comparative example 5 was crystalline flake graphite with all heat conductive fillers, and comparative example 6 was zinc oxide with all heat conductive fillers.
The electromagnetic shielding heat conduction PBT/PET base composite material prepared in the examples and the comparative examples is subjected to the following performance tests:
tensile strength: the stretching rate was 50mm/min according to GB/T1040-2006 standard.
Notched impact strength: tested according to GB/T1843-2008 standard.
Electromagnetic shielding performance: cutting a sheet made of an electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material into a sample with the size of 23X 10X 0.5mm, and testing the electromagnetic shielding performance of the material by using a vector network analyzer (model AGILENT N5244A PNA-X), wherein the testing method is a waveguide method, and the testing wave band is 8-12 GHz of an X wave band; the larger the test value, the better the electromagnetic shielding performance.
Thermal conductivity: cutting a sheet made of an electromagnetic shielding heat conduction PBT/PET (polybutylene terephthalate/polyethylene terephthalate) based composite material into a sample with the size of 20 x 0.5mm, and testing the heat conduction performance of the material by using a heat conduction tester (model NETZSCH LFA 457); the larger the test value, the better the thermal conductivity.
The results of the performance test are shown in Table 2.
TABLE 2 Properties of electromagnetic shielding Heat conducting PBT/PET base composite Material of examples 1-7 and comparative examples 1-6
As can be seen from table 2:
as the amount of PET added increases, the tensile strength and notched impact strength of the PBT/PET based composite decreases. This is because PET is a difficult-to-crystallize polymer, and an increase in the content thereof causes a gradual decrease in the crystallization rate of the composite material, and the crystallinity after cooling also decreases, so that the tensile strength of the system decreases. Meanwhile, the PET soft chain segment has shorter fatty chain and poorer chain segment flexibility than PBT, so the notch impact strength of the system is reduced.
With the addition of barium ferriteThe amount is reduced, and the maximum electromagnetic shielding performance of the PBT/PET composite material is reduced. This is because barium ferrite (BaFe 12 O 19 ) The double composite dielectric material has high natural resonant frequency, and the hexagonal sheet structure can realize the excellent absorption of electromagnetic wave in microwave range. The main wave absorption loss mechanism of the barium ferrite is natural resonance loss, and under the condition of no external magnetic field, the changing magnetic field of the incident electromagnetic wave can be combined with the magnetocrystalline anisotropic field H of the material A Interaction occurs and precession resonance occurs, but when the electromagnetic wave is incident, the electromagnetic field frequency f and the crystal eigenfrequency f are varied m In the same time, the ferrite crystal will absorb a large amount of electromagnetic wave energy, thereby achieving the effect of absorbing waves.
As the addition amount of the crystalline flake graphite and the zinc oxide is reduced, the heat conduction performance of the PBT/PET-based composite material is reduced. The invention adopts flake graphite and zinc oxide to improve the heat conduction performance of the PBT/PET-based composite material, and utilizes the layered structure of the flake graphite to build a heat conduction channel by the intercalation or bridging action of the zinc oxide, thereby reducing the damage of the high filling amount of single heat conduction filler to the mechanical property of the heat conduction material. The flake graphite is of a flake structure, and the flake graphite is singly used as a heat conduction filler, and the flake graphite flakes are in certain orientation, for example, the flake graphite flakes are not easy to contact with each other; when zinc oxide is in a spherical structure and is singly used as a heat conducting filler, gaps are easy to form due to the small contact surfaces among particles. By compounding and using the crystalline flake graphite and the zinc oxide as the heat conducting filler, the crystalline flake graphite can be used for forming an intercalation and a bridging between zinc oxide particles, which is more beneficial to the framework of the heat conducting channel, thereby improving the heat conductivity coefficient of the material.
In summary, the electromagnetic shielding heat conduction PBT/PET-based composite material with excellent electromagnetic shielding performance and heat conduction performance and price advantage can be obtained by adjusting the addition amount of PBT, PET, crystalline flake graphite, zinc oxide, barium ferrite, POE-g-GMA, gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane and beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester under the synergistic cooperation of the auxiliary agents.
Compared with the embodiment 4, in the comparative example 1, the electromagnetic shielding heat conduction PBT/PET base composite material is prepared without adding crystalline flake graphite and zinc oxide, and the crystalline flake graphite and the zinc oxide can be used as heat conduction fillers to form an intercalation and a bridging between zinc oxide particles by using the crystalline flake graphite, so that the framework of a heat conduction channel is more beneficial to improving the heat conduction coefficient of the material, and therefore, the heat conduction performance of the comparative example 1 is inferior to that of the embodiment 4.
In comparison with example 4, comparative example 2 was an electromagnetic shielding heat conductive PBT/PET based composite material prepared without adding barium ferrite, since barium ferrite (BaFe 12 O 19 ) Is a double dielectric material with higher natural resonance frequency, and the hexagonal sheet structure can realize good absorption of electromagnetic waves in the microwave range, so that the maximum value of the electromagnetic shielding performance of the comparative example 2 is inferior to that of the embodiment 4.
Compared with the example 4, the comparative example 3 is the electromagnetic shielding heat conduction PBT/PET base composite material prepared without POE-g-GMA, and the grafting rate of the glycidyl methacrylate is 1-1.4% because the POE-g-GMA is the glycidyl methacrylate grafted by the ethylene and octene copolymer. The epoxy group of POE-g-GMA can react with the hydroxyl end and carboxyl end of PBT and PET, so that the compatibility and interfacial adhesion of POE-g-GMA with PBT and PET base material resins are improved, and the sensitivity of the polyester material to notch strength is effectively improved. Thus, the notched impact strength of comparative example 3 was inferior to that of example 4.
In comparison with example 4, comparative example 4 is an electromagnetic shielding and heat conducting PBT/PET based composite material prepared without adding gamma- (2, 3-glycidoxy) propyltrimethoxysilane. Since gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane is epoxy functional silane, the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coats crystalline flake graphite, zinc oxide and barium ferrite, and epoxy groups of the gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane can react with hydroxyl and carboxyl end groups of PBT and PET, so that the dispersibility and compatibility of the crystalline flake graphite, zinc oxide and barium ferrite in PBT and PET base material resins are effectively improved, and the heat conducting performance and electromagnetic shielding performance of the PBT/PET base composite material are improved. Thus, the tensile strength, notched impact strength, electromagnetic shielding property maximum value, and heat conductive property of comparative example 4 were inferior to those of example 4.
In comparison with example 4, comparative example 5 is that the heat conductive filler is all crystalline flake graphite, and comparative example 6 is that the heat conductive filler is all zinc oxide. Because the flake graphite is of a flake structure, the flake graphite is singly used as the heat conduction filler, and because the flake graphite flakes are in certain orientation in contact, the contact between layers is difficult; when zinc oxide is in a spherical structure and is singly used as a heat conducting filler, gaps are easy to form due to the small contact surfaces among particles. By compounding and using the crystalline flake graphite and the zinc oxide as the heat conducting filler, the crystalline flake graphite can be used for forming an intercalation and a bridging between zinc oxide particles, which is more beneficial to the framework of the heat conducting channel, thereby improving the heat conductivity coefficient of the material. Thus, the thermal conductivity of comparative example 5 and comparative example 6 were both inferior to that of example 4.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (9)
1. The electromagnetic shielding heat conduction PBT/PET base composite material is characterized by being prepared from the following raw materials in parts by weight:
60-90 parts of PBT,
10-40 parts of PET (polyethylene terephthalate),
12-18 parts of flake graphite,
3-6 parts of zinc oxide,
13-21 parts of barium ferrite and the like,
3 to 7 parts of POE-g-GMA,
0.8 to 2.6 portions of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane,
0.15 to 0.35 portion of beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester;
the barium ferrite is BaFe 12 O 19 Belongs to double-composite dielectric materials; the POE-g-GMA is ethylene and octene copolymer grafted glycidyl methacrylate; the grain diameter of the crystalline flake graphite is 0.5-1 mu m; the particle size of the zinc oxide is 25-35 nm;
the preparation method of the barium ferrite comprises the following steps:
(1) FeCl in molar ratio 3 ·6H 2 O：BaCl 2 ·2H 2 O=11 to 11.6, and a certain amount of FeCl is weighed 3 ·6H 2 O and BaCl 2 ·2H 2 O is added into deionized water for dissolution, and then the mixed salt solution is transferred into a burette A for standby; in molar ratio of Na 2 CO 3 ：BaCl 2 ·2H 2 O=8 to 9 and Na 2 CO 3 : naoh=4.5 to 5.5, and Na was calculated separately 2 CO 3 Adding the mixture and NaOH in parts by weight into deionized water for dissolution, and transferring the obtained mixed alkali solution into a burette B for later use;
(2) Under the condition of continuously and continuously stirring, simultaneously dripping the buret A and the buret B into a beaker, controlling the pH value of the solution in the beaker to be 8-8.5, standing for 8-12 h after titration, respectively cleaning with ethanol and deionized water after suction filtration, drying, calcining at 700-800 ℃ for 4-6 hours, and grinding to obtain the barium ferrite.
2. The electromagnetic shielding heat conduction PBT/PET matrix composite material according to claim 1, which is characterized by being prepared from the following raw materials in parts by weight:
65-85 parts of PBT (polybutylene terephthalate),
15-35 parts of PET (polyethylene terephthalate),
13-17 parts of flake graphite,
3.5 to 5.5 portions of zinc oxide,
14-20 parts of barium ferrite,
4-6 parts of POE-g-GMA,
1 to 2.4 portions of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane,
0.2 to 0.3 portion of beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester.
3. The electromagnetic shielding heat conduction PBT/PET based composite material according to claim 2, which is characterized by being prepared from the following raw materials in parts by weight:
70-80 parts of PBT,
20-30 parts of PET (polyethylene terephthalate),
14-16 parts of flake graphite,
4-5 parts of zinc oxide,
16-18 parts of barium ferrite and the like,
4.5 to 5.5 parts of POE-g-GMA,
1.4 to 2 parts of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane,
0.22 to 0.28 portion of beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester.
4. The electromagnetic shielding and heat conducting PBT/PET-based composite material according to claim 1, wherein the PBT has a number-to-molecular mass of 25000-33000 g/mol; the number average molecular weight of the PET is 21000-29000 g/mol.
5. The electromagnetic shielding heat conducting PBT/PET based composite material according to claim 1, wherein the grafting ratio of glycidyl methacrylate of POE-g-GMA is 1-1.4%.
6. A method of preparing an electromagnetic shielding and heat conducting PBT/PET based composite material according to any one of claims 1 to 5, comprising the steps of:
(1) Drying the PBT and PET at 100-115 ℃ for 2-4 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 95-105 ℃ and stirring for 0.5-1 h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.5-1 h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, and adding the mixed mixture obtained in the step (2) in the lateral direction of the parallel double-screw extruder for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 240-260 ℃, the temperature of the second area is 245-265 ℃, the temperature of the third area is 250-270 ℃, the temperature of the fourth area is 255-275 ℃, the temperature of the fifth area is 255-275 ℃, the temperature of the sixth area is 255-275 ℃, the temperature of the seventh area is 255-275 ℃, the temperature of the eighth area is 250-270 ℃, the temperature of the die head is 250-270 ℃, and the rotating speed of the screw is 350-650 rpm.
7. The method of preparing the electromagnetic shielding and heat conducting PBT/PET based composite material according to claim 6, comprising the steps of:
(1) Drying the PBT and PET at 105-110 ℃ for 2.5-3.5 hours, cooling, and adding the cooled PBT, PET, POE-g-GMA and the beta- (4-hydroxyphenyl-3, 5-di-tert-butyl) propionic acid n-stearyl alcohol ester into a stirrer for mixing;
(2) Adding the crystalline flake graphite, zinc oxide and barium ferrite into a stirrer, heating to 97-103 ℃ and stirring for 0.6-0.9 h, adding gamma- (2, 3-glycidoxy) propyl trimethoxy silane and stirring for 0.6-0.9 h, and cooling to room temperature;
(3) Adding the mixed mixture obtained in the step (1) into a parallel double-screw extruder through a feeder, and adding the mixed mixture obtained in the step (2) in the lateral direction of the parallel double-screw extruder for melt extrusion, and granulating, wherein the technological parameters comprise: the temperature of the first area is 245-255 ℃, the temperature of the second area is 250-260 ℃, the temperature of the third area is 255-265 ℃, the temperature of the fourth area is 260-270 ℃, the temperature of the fifth area is 260-270 ℃, the temperature of the sixth area is 260-270 ℃, the temperature of the seventh area is 260-270 ℃, the temperature of the eighth area is 255-265 ℃, the temperature of the die head is 255-265 ℃, and the screw rotating speed is 400-600 rpm.
8. The method of any one of claims 6 to 7, wherein the parallel twin-screw extruder has a screw shape of a single-thread; and/or the ratio L/D of the screw length L and the diameter D of the parallel double screw extruder is 35-55; and/or more than 1 meshing block area and more than 1 reverse thread area are arranged on the screw of the parallel double-screw extruder; in the step (1) and/or the step (2), the stirrer is a high-speed stirrer, and the rotating speed is 500-1500 rpm.
9. The process according to claim 8, wherein the ratio L/D of the screw length L to the diameter D of the parallel twin-screw extruder is 40 to 50; and/or, the screw of the parallel double-screw extruder is provided with 2 meshing block areas and 1 reverse thread area.
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| CN105273689A (en) * | 2014-07-18 | 2016-01-27 | 广东工业大学 | Novel multi-element structure composite conductive filling material |
| CN111925630A (en) * | 2020-07-21 | 2020-11-13 | 浙江大学 | High-strength electromagnetic shielding and heat conducting PBT/PET nano composite material and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105273689A (en) * | 2014-07-18 | 2016-01-27 | 广东工业大学 | Novel multi-element structure composite conductive filling material |
| CN111925630A (en) * | 2020-07-21 | 2020-11-13 | 浙江大学 | High-strength electromagnetic shielding and heat conducting PBT/PET nano composite material and preparation method thereof |
Non-Patent Citations (2)
| Title |
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| Three-dimensional (3D) reduced graphene oxide (RGO)/zinc oxide (ZnO)/barium ferrite nanocomposites for electromagnetic absorption;Xing Sun;《 Journal of Materials Science: Materials in Electronics》;第28卷(第17期);12900-12908 * |
| 棒状氧化锌/氧化石墨烯复合材料的制备及其吸附放射性铀性能研究;王化宁;《广东化工》;第46卷(第8期);7-9 * |
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