CN112029247A - High-thermal-conductivity modified polylactic acid film and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of polylactic acid heat conduction materials, and discloses a high-heat-conduction modified polylactic acid film, which comprises the following formula raw materials and components: modified SiC modified GO, modified nano boron nitride, DL-lactic acid and a catalyst. According to the high-thermal-conductivity modified polylactic acid film, the silicon carbide generated by the reaction of carbon layers of nano silicon and graphene oxide has strong interface acting force with the interface of the graphene oxide to form silicon carbide modified graphene oxide, the N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane grafted graphene oxide improves the dispersibility and compatibility of the silicon carbide modified graphene oxide and the polylactic acid, the six-membered ring structure in the nano boron nitride forms pi-pi bonds with the benzene ring structure in procyanidine, the procyanidine is used for modifying the nano boron nitride, the dispersibility of the nano boron nitride in the polylactic acid is enhanced, and the uniformly dispersed silicon carbide modified graphene oxide and the modified nano boron nitride enhance the thermal conductivity of the polylactic acid film.

Description

High-thermal-conductivity modified polylactic acid film and preparation method thereof

Technical Field

The invention relates to the technical field of polylactic acid heat conduction materials, in particular to a high-heat-conduction modified polylactic acid film and a preparation method thereof.

Background

With the increasing exhaustion of fossil fuel reserves and the increasing severity of environmental pollution caused by over-burning fossil energy, the development of novel green and environment-friendly materials becomes a research hotspot, degradable polymer materials such as polylactic acid and the like are widely concerned by researchers, the polylactic acid is a polymer obtained by esterification reaction with lactic acid as a monomer, has wide raw material sources and can be regenerated, meanwhile, the pollution in the production process of the polylactic acid is low, and the polylactic acid product can be biodegraded to produce water and carbon dioxide to realize circulation in the nature, so that the polylactic acid material is an ideal green polymer material, has good thermal stability and solvent resistance, can be processed by various modes such as extrusion, injection blow molding, biaxial stretching and the like, and has excellent biodegradability and biocompatibility, the gloss and the transparency are good, and the product can be made into packaging materials, fibers, non-woven fabrics and the like, and has wide application in the fields of clothing, apparel, building materials, agriculture and forestry materials, medical treatment and health care and the like.

However, polylactic acid has a low thermal conductivity coefficient, polylactic acid material has poor thermal conductivity, which limits the application range of polylactic acid material, inorganic materials such as silicon carbide and boron nitride have very high thermal conductivity coefficient, and can be used as inorganic filler to form organic-inorganic hybrid material with polylactic acid to improve the thermal conductivity of polylactic acid material, but silicon carbide and boron nitride inorganic material have poor dispersibility and compatibility in the organic medium of polylactic acid, silicon carbide and boron nitride which are dispersed unevenly are easy to aggregate and agglomerate, which not only can not improve the thermal conductivity of polylactic acid material, but also can affect the mechanical properties such as toughness and breaking strength of polylactic acid material.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a high-thermal-conductivity modified polylactic acid film and a preparation method thereof, and solves the problem that silicon carbide and boron nitride are poor in dispersibility and compatibility in the polylactic acid film.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a high-thermal-conductivity modified polylactic acid film comprises the following formula raw materials in parts by weight: 0.5-5 parts of modified SiC modified GO, 3-8 parts of modified nano boron nitride, 85-96 parts of DL-lactic acid and 0.5-2 parts of a catalyst.

Preferably, the catalyst is stannous chloride.

Preferably, the preparation method of the modified SiC modified GO comprises the following steps:

(1) adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle according to the volume ratio of 1:2-4, adding graphite nanosheets and nano silicon powder, placing the solution in a low-temperature cooling instrument, activating for 2-4H at 0-5 ℃, heating to 20-30 ℃, adding an oxidant KMnO4, reacting for 3-6H, placing the reaction bottle in a constant-temperature water bath kettle, heating to 60-80 ℃, standing and aging for 5-10H, reducing the temperature to 30-40 ℃, adding a reducing agent H₂O₂And (3) reacting the aqueous solution for 2-4h, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide.

(2) Placing the nano silicon modified graphene oxide in an atmosphere resistance furnace, introducing argon, heating to 1280-1320 ℃ at the heating rate of 5-10 ℃/min, insulating materials for 3-6h, and grinding the materials into fine powder to prepare the silicon carbide modified graphene oxide.

(3) Adding distilled water and an ethanol solvent into a reaction bottle in a volume ratio of 1:15-25, adding silicon carbide modified graphene oxide and a silane coupling agent, placing the reaction bottle in a constant-temperature water bath, heating to 50-70 ℃, reacting for 12-18h, carrying out reduced pressure distillation on the solution to remove the solvent, washing a solid product with distilled water and ethanol, and fully drying to obtain the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO.

Preferably, the mass ratio of the graphite nanosheets to the nano silicon powder is 3-6: 1.

Preferably, the silane coupling agent is N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane, and the mass ratio of the silicon carbide modified graphene oxide to the silane coupling agent is 4-8: 1.

Preferably, the low-temperature cooling instrument comprises a cooling liquid tank, a cooling liquid tank and an inner heat preservation container fixedly connected with, an outer layer fixedly connected with vacuum heat preservation layer of the inner heat preservation container, an outer layer and an outer heat preservation layer fixedly connected with of the vacuum heat preservation layer, an outer layer fixedly connected with cooling instrument shell, a cooling instrument shell top and a heat insulation cover movably connected with each other, a reaction bottle hole and a movable rod fixedly connected with the middle of the heat insulation cover, and one end of the movable rod is movably connected with the movable clamp through a nut.

Preferably, the preparation method of the modified nano boron nitride comprises the following steps:

(1) adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 1-2h at the ultrasonic frequency of 20-30KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 8-10, placing the reaction bottle into a constant-temperature water bath kettle, heating to 60-80 ℃, stirring at a constant speed for reaction for 10-15h, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride.

Preferably, the preparation method of the high-thermal-conductivity modified polylactic acid film comprises the following steps:

(1) adding N, N-dimethylformamide solvent, 85-96 parts of DL-lactic acid, 0.5-5 parts of modified SiC modified GO, 3-8 parts of modified nano boron nitride and 0.5-2 parts of catalyst stannous chloride into a vacuum reaction kettle, heating to 190 ℃ at the pressure of 20-60Pa, reacting for 15-20h, cooling the solution to room temperature, and naturally casting to form a film in a heat-conducting film-forming mold, and fully drying to prepare the high-heat-conducting modified polylactic acid film.

(III) advantageous technical effects

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

according to the high-thermal-conductivity modified polylactic acid film, a nano silicon intercalation layer is enabled to enter a graphene oxide sheet layer and be uniformly deposited on the surface of graphene oxide through a liquid phase deposition method, carbon layers of nano silicon and the graphene oxide are enabled to have strong interfacial force between interfaces of silicon carbide and the graphene oxide generated by reaction through a high-temperature calcination method, the connection is tight and seamless, and the silicon carbide modified graphene oxide is formed. The silicon carbide modified graphene oxide is uniformly dispersed in the polylactic acid through an in-situ polymerization method.

According to the high-heat-conductivity modified polylactic acid film, the structure of nano boron nitride is a six-membered ring structure consisting of alternate boron atoms and nitrogen atoms, and can form pi-pi bonds with a benzene ring structure in procyanidine, so that procyanidine and nano boron nitride generate strong non-covalent surface effect, and the procyanidine modified nano boron nitride is obtained, and the procyanidine has abundant phenolic hydroxyl structures and can form hydrogen bonds with carboxyl, amino and imino in polylactic acid, so that the dispersibility and compatibility of nano boron nitride in polylactic acid are enhanced, the agglomeration and caking of nano boron nitride are avoided, and the uniformly dispersed silicon carbide modified graphene oxide and the modified nano boron nitride greatly enhance the heat-conducting property of the polylactic acid film.

Drawings

FIG. 1 is a schematic front view of cryogenic coolant;

FIG. 2 is a schematic top view of a reaction vial well;

fig. 3 is a schematic view of the motion of the movable clamp.

1. A cooling liquid tank; 2. fixing the inner heat-insulating liner; 3. a vacuum heat-insulating layer; 4. an outer insulating layer; 5. a cooling instrument housing; 6. a heat shield; 7. a reaction vial hole; 8. a movable rod; 9. a nut; 10. a movable clamp.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: a high-thermal-conductivity modified polylactic acid film comprises the following formula raw materials in parts by weight: 0.5-5 parts of modified SiC modified GO, 3-8 parts of modified nano boron nitride, 85-96 parts of DL-lactic acid and 0.5-2 parts of catalyst, wherein the catalyst is stannous chloride.

The preparation method of the modified SiC modified GO comprises the following steps:

(1) adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle at a volume ratio of 1:2-4, adding graphite nano-sheets and nano-silicon powder at a mass ratio of 3-6:1, placing the solution into a low-temperature cooling instrument, wherein the low-temperature cooling instrument comprises a cooling liquid tank, the cooling liquid tank is fixedly connected with an inner heat-insulating liner, the outer layer of the inner heat-insulating liner is fixedly connected with a vacuum heat-insulating layer, the outer layer of the vacuum heat-insulating layer is fixedly connected with an outer heat-insulating layer, the outer part of the outer heat-insulating layer is fixedly connected with a cooling instrument shell, the upper part of the cooling instrument shell is movably connected with a heat-insulating cover, the middle part of the heat-insulating cover is provided with reaction bottle holes, the reaction bottle holes are fixedly connected with movable rods, one ends of the movable rods are movably connected with movable clamps through nuts, activating the reaction bottle at 0-5, placing the reaction bottle in a constant-temperature water bath kettle, heating to 60-80 deg.C, standing and aging for 5-10H, cooling to 30-40 deg.C, and adding reducing agent H₂O₂And (3) reacting the aqueous solution for 2-4h, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide.

(2) Placing the nano silicon modified graphene oxide in an atmosphere resistance furnace, introducing argon, heating to 1280-1320 ℃ at the heating rate of 5-10 ℃/min, insulating materials for 3-6h, and grinding the materials into fine powder to prepare the silicon carbide modified graphene oxide.

(3) Adding distilled water and an ethanol solvent into a reaction bottle, wherein the volume ratio of the distilled water to the ethanol solvent is 1:15-25, adding silicon carbide modified graphene oxide and a silane coupling agent N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane according to the mass ratio of 4-8:1, placing the reaction bottle into a constant-temperature water bath kettle, heating to 50-70 ℃, reacting for 12-18h, carrying out reduced pressure distillation on the solution to remove the solvent, washing a solid product with distilled water and ethanol, and fully drying to prepare the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO.

The preparation method of the modified nano boron nitride comprises the following steps:

(1) adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 1-2h at the ultrasonic frequency of 20-30KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 8-10, placing the reaction bottle into a constant-temperature water bath kettle, heating to 60-80 ℃, stirring at a constant speed for reaction for 10-15h, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride.

The preparation method of the high-thermal-conductivity modified polylactic acid film comprises the following steps:

(1) adding N, N-dimethylformamide solvent, 85-96 parts of DL-lactic acid, 0.5-5 parts of modified SiC modified GO, 3-8 parts of modified nano boron nitride and 0.5-2 parts of catalyst stannous chloride into a vacuum reaction kettle, heating to 190 ℃ at the pressure of 20-60Pa, reacting for 15-20h, cooling the solution to room temperature, and naturally casting to form a film in a heat-conducting film-forming mold, and fully drying to prepare the high-heat-conducting modified polylactic acid film.

Example 1

(1) Preparing a nano silicon modified graphene oxide component 1: adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle at a volume ratio of 1:2, adding graphite nano-sheets and nano-silicon powder at a mass ratio of 3:1, placing the solution into a low-temperature cooling instrument, wherein the low-temperature cooling instrument comprises a cooling liquid tank, the cooling liquid tank is fixedly connected with an inner heat-insulating container, the outer layer of the inner heat-insulating container is fixedly connected with a vacuum heat-insulating layer, the outer layer of the vacuum heat-insulating layer is fixedly connected with an outer heat-insulating layer, the outer part of the outer heat-insulating layer is fixedly connected with a cooling instrument shell, the upper part of the cooling instrument shell is movably connected with a heat-insulating cover, a reaction bottle hole is arranged in the middle of the heatMovably connecting, activating at 5 deg.C for 2 hr, heating to 20 deg.C, adding oxidant KMnO₄Reacting for 3H, placing the reaction bottle in a constant-temperature water bath kettle, heating to 60 ℃, standing and aging for 5H, cooling to 30 ℃, and adding a reducing agent H₂O₂And (3) reacting the aqueous solution for 2 hours, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide component 1.

(2) Preparing a silicon carbide modified graphene oxide component 1: placing the nano silicon modified graphene oxide component 1 in an atmosphere resistance furnace, introducing argon, heating to 1280 ℃ at the heating rate of 5 ℃/min, insulating materials for 3 hours, grinding the materials into fine powder, and preparing to obtain the silicon carbide modified graphene oxide component 1.

(3) Preparing a modified SiC modified GO component 1: adding distilled water and an ethanol solvent into a reaction bottle, wherein the volume ratio of the distilled water to the ethanol solvent is 1:15, adding a silicon carbide modified graphene oxide component 1 and a silane coupling agent N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane according to the mass ratio of 4:1, placing the reaction bottle into a constant-temperature water bath kettle, heating to 50 ℃, reacting for 12 hours, distilling the solution under reduced pressure to remove the solvent, washing a solid product by using distilled water and ethanol, and fully drying to prepare the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO component 1.

(4) Preparing a modified nano boron nitride component 1: adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 1h at the ultrasonic frequency of 20KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 8, placing the reaction bottle into a constant-temperature water bath kettle, heating to 60 ℃, stirring uniformly for reaction for 10h, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride component 1.

(5) Preparing a high-thermal-conductivity modified polylactic acid film material 1: adding N, N-dimethylformamide solvent, 96 parts of DL-lactic acid, 0.5 part of modified SiC modified GO component 1, 3 parts of modified nano boron nitride component 1 and 0.5 part of catalyst stannous chloride into a vacuum reaction kettle, heating to 170 ℃ under the pressure of 20Pa, reacting for 15 hours, cooling the solution to room temperature, naturally casting into a film in a heat-conducting film-forming mold, and fully drying to prepare the high-heat-conducting modified polylactic acid film material 1.

Example 2

(1) Preparing a nano silicon modified graphene oxide component 2: adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle at a volume ratio of 1:2, adding graphite nano-sheets and nano-silicon powder at a mass ratio of 6:1, placing the solution into a low-temperature cooling instrument, wherein the low-temperature cooling instrument comprises a cooling liquid tank, the cooling liquid tank is fixedly connected with an inner heat preservation liner, the outer layer of the inner heat preservation liner is fixedly connected with a vacuum heat preservation layer, the outer layer of the vacuum heat preservation layer is fixedly connected with an outer heat preservation layer, the outer part of the outer heat preservation layer is fixedly connected with a cooling instrument shell, the upper part of the cooling instrument shell is movably connected with a heat insulation cover, the middle part of the heat insulation cover is provided with reaction bottle holes, the reaction bottle holes are fixedly connected with movable rods, one ends of the movable rods are movably connected with movable clamps through nuts, activating at 0 ℃ for 4 hours, heating to 20 ℃, adding an oxidant KMnO4, reacting for 3 hours, placing, reducing the temperature to 40 ℃, and then adding a reducing agent H₂O₂And (3) reacting the aqueous solution for 4 hours, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide component 2.

(2) Preparing a silicon carbide modified graphene oxide component 2: placing the nano silicon modified graphene oxide component 2 in an atmosphere resistance furnace, introducing argon, heating to 1320 ℃ at the heating rate of 10 ℃/min, preserving the heat for 3 hours, grinding the material into fine powder, and preparing to obtain the silicon carbide modified graphene oxide component 2.

(3) Preparing a modified SiC modified GO component 2: adding distilled water and an ethanol solvent into a reaction bottle, wherein the volume ratio of the distilled water to the ethanol solvent is 1:15, adding a silicon carbide modified graphene oxide component 2 and a silane coupling agent N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane according to the mass ratio of 8:1, placing the reaction bottle into a constant-temperature water bath kettle, heating to 70 ℃, reacting for 12 hours, distilling the solution under reduced pressure to remove the solvent, washing a solid product by using distilled water and ethanol, and fully drying to prepare the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO component 2.

(4) Preparing a modified nano boron nitride component 2: adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 1h at the ultrasonic frequency of 20KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 10, placing the reaction bottle into a constant-temperature water bath kettle, heating to 80 ℃, stirring uniformly for reaction for 10h, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride component 2.

(5) Preparing a high-thermal-conductivity modified polylactic acid film material 2: adding N, N-dimethylformamide solvent, 94 parts of DL-lactic acid, 1.5 parts of modified SiC modified GO component 2, 3.7 parts of modified nano boron nitride component 2 and 0.8 part of catalyst stannous chloride into a vacuum reaction kettle, heating to 170 ℃ under the pressure of 60Pa, reacting for 20 hours, cooling the solution to room temperature, naturally casting into a film in a heat-conducting film-forming die, and fully drying to prepare the high-heat-conducting modified polylactic acid film material 2.

Example 3

(1) Preparing a nano silicon modified graphene oxide component 3: adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle at a volume ratio of 1:3, adding graphite nano-sheets and nano-silicon powder at a mass ratio of 4.5:1, placing the solution into a low-temperature cooling instrument, wherein the low-temperature cooling instrument comprises a cooling liquid tank, the cooling liquid tank is fixedly connected with an inner heat-insulating liner, the outer layer of the inner heat-insulating liner is fixedly connected with a vacuum heat-insulating layer, the outer layer of the vacuum heat-insulating layer is fixedly connected with an outer heat-insulating layer, the outer part of the outer heat-insulating layer is fixedly connected with a cooling instrument shell, the upper part of the cooling instrument shell is movably connected with a heat-insulating cover, a reaction bottle hole is arranged in the middle of the heat-insulating cover, the reaction bottle hole is fixedly connected with a movable rod, one end of the movable rod is movably connected with a movable clamp through aPlacing the reaction bottle in a constant-temperature water bath kettle, heating to 70 ℃, standing and aging for 8 hours, reducing the temperature to 35 ℃, and adding a reducing agent H₂O₂And (3) reacting the aqueous solution for 3 hours, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide component 3.

(2) Preparing a silicon carbide modified graphene oxide component 3: placing the nano silicon modified graphene oxide component 3 in an atmosphere resistance furnace, introducing argon, heating to 130020 ℃ at the heating rate of 8 ℃/min, preserving the heat for 4 hours, grinding the material into fine powder, and preparing to obtain the silicon carbide modified graphene oxide component 3.

(3) Preparing a modified SiC modified GO component 3: adding distilled water and an ethanol solvent into a reaction bottle, wherein the volume ratio of the distilled water to the ethanol solvent is 1:20, adding a silicon carbide modified graphene oxide component 3 and a silane coupling agent N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane according to the mass ratio of 7:1, placing the reaction bottle into a constant-temperature water bath kettle, heating to 60 ℃, reacting for 15 hours, distilling the solution under reduced pressure to remove the solvent, washing a solid product by using distilled water and ethanol, and fully drying to prepare the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO component 3.

(4) Preparing a modified nano boron nitride component 3: adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic disperser, performing ultrasonic dispersion treatment for 1.5h at the ultrasonic frequency of 25KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH of the solution to 9, placing the reaction bottle into a constant-temperature water bath kettle, heating to 70 ℃, stirring uniformly for reaction for 12h, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride component 3.

(5) Preparing a high-thermal-conductivity modified polylactic acid film material 3: adding N, N-dimethylformamide solvent, 91 parts of DL-lactic acid, 3 parts of modified SiC modified GO component 3, 5 parts of modified nano boron nitride component 3 and 1 part of catalyst stannous chloride into a vacuum reaction kettle, heating to 180 ℃ under the pressure of 40Pa, reacting for 18h, cooling the solution to room temperature, carrying out natural flow casting in a heat-conducting film-forming mold to form a film, and fully drying to prepare the high-heat-conducting modified polylactic acid film material 3.

Example 4

(1) Preparing a nano silicon modified graphene oxide component 4: adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle at a volume ratio of 1:4, adding graphite nano-sheets and nano-silicon powder at a mass ratio of 3:1, placing the solution into a low-temperature cooling instrument, wherein the low-temperature cooling instrument comprises a cooling liquid tank, the cooling liquid tank is fixedly connected with an inner heat preservation liner, the outer layer of the inner heat preservation liner is fixedly connected with a vacuum heat preservation layer, the outer layer of the vacuum heat preservation layer is fixedly connected with an outer heat preservation layer, the outer part of the outer heat preservation layer is fixedly connected with a cooling instrument shell, the upper part of the cooling instrument shell is movably connected with a heat insulation cover, the middle part of the heat insulation cover is provided with reaction bottle holes, the reaction bottle holes are fixedly connected with movable rods, one ends of the movable rods are movably connected with movable clamps through nuts, activating at the temperature of 2 ℃ for 2 hours, heating to the temperature of 30 ℃, adding an oxidant KMnO4, cooling to 30 deg.C, adding reducing agent H₂O₂And (3) reacting the aqueous solution for 4 hours, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide component 4.

(2) Preparing a silicon carbide modified graphene oxide component 4: placing the nano-silicon modified graphene oxide component 4 in an atmosphere resistance furnace, introducing argon, heating to 1280 ℃ at the heating rate of 5 ℃/min, insulating materials for 6 hours, grinding the materials into fine powder, and preparing the silicon carbide modified graphene oxide component 4.

(3) Preparing a modified SiC modified GO component 4: adding distilled water and an ethanol solvent into a reaction bottle, wherein the volume ratio of the distilled water to the ethanol solvent is 1:15, adding a silicon carbide modified graphene oxide component 4 and a silane coupling agent N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane according to the mass ratio of 8:1, placing the reaction bottle into a constant-temperature water bath kettle, heating to 50 ℃, reacting for 12 hours, distilling the solution under reduced pressure to remove the solvent, washing a solid product by using distilled water and ethanol, and fully drying to prepare the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO component 4.

(4) Preparing a modified nano boron nitride component 4: adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 2 hours at the ultrasonic frequency of 30KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 8, placing the reaction bottle into a constant-temperature water bath kettle, heating to 60 ℃, stirring uniformly for reaction for 15 hours, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride component 4.

(5) Preparing a high-thermal-conductivity modified polylactic acid film material 4: adding N, N-dimethylformamide solvent, 87 parts of DL-lactic acid, 4.5 parts of modified SiC modified GO component 4, 7 parts of modified nano boron nitride component 4 and 1.5 parts of catalyst stannous chloride into a vacuum reaction kettle, heating to 170 ℃ under the pressure of 60Pa, reacting for 20 hours, cooling the solution to room temperature, naturally casting into a film in a heat-conducting film-forming mold, and fully drying to prepare the high-heat-conducting modified polylactic acid film material 4.

Example 5

(1) Preparing a nano silicon modified graphene oxide component 5: adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle at a volume ratio of 1:4, adding graphite nano-sheets and nano-silicon powder at a mass ratio of 6:1, placing the solution into a low-temperature cooling instrument, wherein the low-temperature cooling instrument comprises a cooling liquid tank, the cooling liquid tank is fixedly connected with an inner heat-insulating liner, the outer layer of the inner heat-insulating liner is fixedly connected with a vacuum heat-insulating layer, the outer layer of the vacuum heat-insulating layer is fixedly connected with an outer heat-insulating layer, the outer part of the outer heat-insulating layer is fixedly connected with a cooling instrument shell, the upper part of the cooling instrument shell is movably connected with a heat-insulating cover, the middle part of the heat-insulating cover is provided with reaction bottle holes, the reaction bottle holes are fixedly connected with movable rods, one ends of the movable rods are movably₄Reacting for 6h, placing the reaction bottle in a constant-temperature water bath kettle, heating to 80 ℃, standing and aging for 10h, reducing the temperature to 40 ℃, and thenAddition of reducing agent H₂O₂And (3) reacting the aqueous solution for 4 hours, filtering the solution to remove the solvent, washing the solid product with a dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare the nano silicon modified graphene oxide component 5.

(2) Preparing a silicon carbide modified graphene oxide component 5: placing the nano silicon modified graphene oxide component 5 in an atmosphere resistance furnace, introducing argon, heating to 1320 ℃ at the heating rate of 10 ℃/min, preserving the heat for 6 hours, grinding the material into fine powder, and preparing to obtain the silicon carbide modified graphene oxide component 5.

(3) Preparing a modified SiC modified GO component 5: adding distilled water and an ethanol solvent into a reaction bottle, wherein the volume ratio of the distilled water to the ethanol solvent is 1:25, adding a silicon carbide modified graphene oxide component 5 and a silane coupling agent N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane according to the mass ratio of 8:1, placing the reaction bottle into a constant-temperature water bath kettle, heating to 70 ℃, reacting for 18 hours, distilling the solution under reduced pressure to remove the solvent, washing a solid product by using distilled water and ethanol, and fully drying to prepare the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO component 5.

(4) Preparing a modified nano boron nitride component 5: adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 2 hours at the ultrasonic frequency of 30KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 10, placing the reaction bottle into a constant-temperature water bath kettle, heating to 80 ℃, stirring uniformly for reaction for 15 hours, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride component 5.

(5) Preparing a high-thermal-conductivity modified polylactic acid film material 5: adding N, N-dimethylformamide solvent, 85 parts of DL-lactic acid, 5 parts of modified SiC modified GO component 5, 8 parts of modified nano boron nitride component 5 and 2 parts of catalyst stannous chloride into a vacuum reaction kettle, heating to 190 ℃ under the pressure of 60Pa, reacting for 20 hours, cooling the solution to room temperature, carrying out natural flow casting in a heat-conducting film-forming mold to form a film, and fully drying to prepare the high-heat-conducting modified polylactic acid film material 5.

The BDR-003A material thermal conductivity coefficient tester is used for testing the thermal conductivity of the high-thermal-conductivity modified polylactic acid film material 1-5, and the test standard is GB/T29284-2012.

In summary, according to the modified polylactic acid film with high thermal conductivity, the nano-silicon intercalation layer is made to enter the lamellar layer of the graphene oxide through a liquid phase deposition method and uniformly deposited on the surface of the graphene oxide, the carbon layers of the nano-silicon and the graphene oxide are made to have strong interfacial force between the interfaces of the silicon carbide and the graphene oxide generated by the reaction through a high-temperature calcination method, the connection is tight and seamless, and the silicon carbide modified graphene oxide is formed And the silicon carbide modified graphene oxide is uniformly dispersed in the polylactic acid by an in-situ polymerization method.

The nanometer boron nitride has a structure of a six-membered ring consisting of alternate boron atoms and nitrogen atoms, can form pi-pi bonds with a benzene ring structure in procyanidine, and enables procyanidine and the nanometer boron nitride to generate strong non-covalent surface effect, so that the procyanidine modified nanometer boron nitride is obtained, the procyanidine has abundant phenolic hydroxyl structures, and can form hydrogen bonds with carboxyl groups, amino groups and imino groups in polylactic acid, thereby enhancing the dispersibility and compatibility of the nanometer boron nitride in the polylactic acid, avoiding the agglomeration and caking of the nanometer boron nitride, and the uniformly dispersed silicon carbide modified graphene oxide and the modified nanometer boron nitride greatly enhance the heat-conducting property of the polylactic acid film.

Claims (8)

1. The high-thermal-conductivity modified polylactic acid film comprises the following formula raw materials and components in parts by weight, and is characterized in that: 0.5-5 parts of modified SiC modified GO, 3-8 parts of modified nano boron nitride, 85-96 parts of DL-lactic acid and 0.5-2 parts of a catalyst.

2. The modified polylactic acid film with high thermal conductivity according to claim 1, wherein: the catalyst is stannous chloride.

3. The modified polylactic acid film with high thermal conductivity according to claim 1, wherein: the preparation method of the modified SiC modified GO comprises the following steps:

(1) adding concentrated nitric acid and concentrated sulfuric acid into a reaction bottle according to the volume ratio of 1:2-4, adding graphite nanosheets and nano silicon powder, placing the solution in a low-temperature cooling instrument, activating for 2-4H at 0-5 ℃, heating to 20-30 ℃, adding an oxidant KMnO4, reacting for 3-6H, placing the reaction bottle in a constant-temperature water bath kettle, heating to 60-80 ℃, standing and aging for 5-10H, reducing the temperature to 30-40 ℃, adding a reducing agent H₂O₂Reacting the aqueous solution for 2-4h, filtering the solution to remove the solvent, washing the solid product with dilute sodium hydroxide solution and distilled water until the solid product is neutral, and fully drying to prepare nano silicon modified graphene oxide;

(2) placing the nano silicon modified graphene oxide in an atmosphere resistance furnace, introducing argon, heating to 1280-1320 ℃ at the heating rate of 5-10 ℃/min, insulating materials for 3-6h, grinding the materials into fine powder, and preparing to obtain the silicon carbide modified graphene oxide;

(3) adding distilled water and an ethanol solvent into a reaction bottle in a volume ratio of 1:15-25, adding silicon carbide modified graphene oxide and a silane coupling agent, placing the reaction bottle in a constant-temperature water bath, heating to 50-70 ℃, reacting for 12-18h, carrying out reduced pressure distillation on the solution to remove the solvent, washing a solid product with distilled water and ethanol, and fully drying to obtain the modified silicon carbide modified graphene oxide, namely the modified SiC modified GO.

4. The modified polylactic acid film with high thermal conductivity according to claim 3, wherein: the mass ratio of the graphite nanosheets to the nano silicon powder is 3-6: 1.

5. The modified polylactic acid film with high thermal conductivity according to claim 3, wherein: the silane coupling agent is N- (beta-aminoethyl) -gamma-aminopropyltrimethoxysilane, and the mass ratio of the silicon carbide modified graphene oxide to the silane coupling agent is 4-8: 1.

6. The modified polylactic acid film with high thermal conductivity according to claim 3, wherein: the low-temperature cooling instrument comprises a cooling liquid tank, a cooling liquid tank and an inner heat preservation container, wherein an outer layer of the inner heat preservation container is fixedly connected with a vacuum heat preservation layer, an outer layer of the vacuum heat preservation layer is fixedly connected with an outer heat preservation layer, an outer layer of the outer heat preservation layer is fixedly connected with a cooling instrument shell, the upper portion of the cooling instrument shell is movably connected with a heat insulation cover, and the middle of the heat insulation cover is provided with a reaction bottle hole, the reaction bottle hole is fixedly connected with a movable rod, and one end of the movable rod is movably connected with.

7. The modified polylactic acid film with high thermal conductivity according to claim 1, wherein: the preparation method of the modified nano boron nitride comprises the following steps:

(1) adding a proper amount of distilled water solvent, nano boron nitride and procyanidine into a reaction bottle, placing the reaction bottle into an ultrasonic dispersion instrument, performing ultrasonic dispersion treatment for 1-2h at the ultrasonic frequency of 20-30KHz, adding tris (hydroxymethyl) aminomethane, stirring uniformly, adding hydrochloric acid to adjust the pH value of the solution to 8-10, placing the reaction bottle into a constant-temperature water bath kettle, heating to 60-80 ℃, stirring at a constant speed for reaction for 10-15h, performing vacuum drying on the solution to remove the solvent, washing the solid product by using distilled water and ethanol, and fully drying to prepare the procyanidine grafted modified nano boron nitride.

8. The modified polylactic acid film with high thermal conductivity according to claim 1, wherein: the preparation method of the high-thermal-conductivity modified polylactic acid film comprises the following steps:

(1) adding N, N-dimethylformamide solvent, 85-96 parts of DL-lactic acid, 0.5-5 parts of modified SiC modified GO, 3-8 parts of modified nano boron nitride and 0.5-2 parts of catalyst stannous chloride into a vacuum reaction kettle, heating to 190 ℃ at the pressure of 20-60Pa, reacting for 15-20h, cooling the solution to room temperature, and naturally casting to form a film in a heat-conducting film-forming mold, and fully drying to prepare the high-heat-conducting modified polylactic acid film.

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