CN117683336A

CN117683336A - Bamboo charcoal biodegradable conductive composite material and preparation method thereof

Info

Publication number: CN117683336A
Application number: CN202410139017.9A
Authority: CN
Inventors: 马建锋; 刘杏娥; 尚莉莉; 江泽慧; 马千里
Original assignee: International Center for Bamboo and Rattan
Current assignee: International Center for Bamboo and Rattan
Priority date: 2024-02-01
Filing date: 2024-02-01
Publication date: 2024-03-12
Anticipated expiration: 2044-02-01

Abstract

The invention relates to a bamboo charcoal biodegradable conductive composite material, which comprises the following raw materials in parts by mass: 8-18 parts by mass of doped bamboo charcoal material, 1-2 parts by mass of modifier, 2-4 parts by mass of compatilizer, 0.5-1 part by mass of dispersing agent, 0.5-2 parts by mass of nucleating agent, 0.2-0.4 part by mass of chain extender and 100 parts by mass of biodegradable plastic, wherein the nucleating agent is the compound of sulfonate nucleating agent and hydrazide nucleating agent. The method of the invention utilizes the cooperation of doping and graphitization to improve the conductivity of the bamboo charcoal, prepares the high-conductivity doped bamboo charcoal, then utilizes the compounding of the dispersing agent, the compatilizer and the nucleating agent to cooperatively regulate and control the morphological distribution of the bamboo charcoal in the biodegradable material matrix, induces the bamboo charcoal to be uniformly dispersed in a continuous amorphous region to form a perfect conductive path, simultaneously improves the mechanical property and the conductivity of the composite material, and realizes the comprehensive utilization of bamboo resources.

Description

Bamboo charcoal biodegradable conductive composite material and preparation method thereof

Technical Field

The invention belongs to the technical field of biomass charcoal materials, and particularly relates to a bamboo charcoal biodegradable conductive composite material and a preparation method thereof.

Background

With the consumption of petroleum resources and the aggravation of environmental pollution, the use of biodegradable plastics to gradually replace traditional petroleum-based plastics has become necessary, so the advanced development of biodegradable plastics has become the focus of research by researchers in various countries. At present, in the research of the high-conductivity biodegradable composite material, graphene, carbon nano tubes and the like are mainly adopted, the cost of the graphene and the carbon nano tubes is high, and the cost of the biodegradable material is high, so that the large-scale popularization and the use are impossible. The biomass charcoal has the advantages of wide raw material sources, low cost, reproducibility and the like, and can effectively reduce the cost of the composite material.

The bamboo plants grow fast and have strong reproductive capacity, can reach the height of the finished bamboo in three months basically, can mature in about one year, and are common renewable clean material resources. The development of new products with high technological content, strong market competitiveness and high added value becomes urgent. Taking bamboo charcoal products as an example, at present, the types of bamboo charcoal are numerous and can be roughly classified into charcoal for fuel, charcoal for water treatment, charcoal for soil improvement, charcoal for deodorization and the like according to purposes, but few reports of bamboo charcoal specially used for conductive composite materials are made. The element composition of the bamboo charcoal contains nitrogen, phosphorus, sulfur, sodium, potassium, silicon and other ions besides carbon, and the conduction of the bamboo charcoal can be divided into ion conduction and graphitization conduction, so that compared with biomass charcoal prepared from agricultural and forestry wastes such as wood, the bamboo charcoal has better conduction performance and is more suitable for preparing a conductive composite material. However, there are few reports on the preparation of high-conductivity bamboo charcoal and the literature of bamboo charcoal conductive composite materials, and in these reports, there is still a contradictory problem between conductivity and mechanical properties, and a large amount of filler is needed to improve the conductivity of the composite materials, but the mechanical properties of the composite materials cannot be considered due to the remarkable decrease of the mechanical properties caused by poor compatibility and the like, which is unfavorable for the large-scale popularization and application of the composite materials, so there is a need to develop a high-conductivity bamboo charcoal and bamboo charcoal composite material which are simple to prepare and environment-friendly in process. For example, the patent CN1216130C uses a traditional pyrolysis method to prepare conductive bamboo charcoal, which is also a common preparation method of bamboo charcoal products in the market, and the prepared bamboo charcoal has poor conductivity and poor compatibility with biodegradable materials, which can affect the mechanical properties of the conductive composite material. The patent CN 113604011A uses graphene to prepare the PBAT packaging bag, and the prepared product has no competitive advantage due to high price of the graphene, so that the product is not suitable for large-scale production and popularization and application. For the bamboo charcoal conductive composite material, the problem of contradiction between conductivity and mechanical property is the problem to be solved for improving the performance.

Therefore, the invention provides preparation and modification treatment of the bamboo charcoal to improve the conductivity and mechanical property of the composite material aiming at the preparation problem of the existing bamboo charcoal composite material.

Disclosure of Invention

In order to solve the defects of the prior art that the bamboo charcoal based conductive material has poor comprehensive performance or complex preparation method and high cost, the invention takes the bamboo charcoal rich in nitrogen, phosphorus, sulfur and other elements as the conductive filler, and activates the ion conductivity of the bamboo charcoal by adding a compound doping source from the angles of ion conductivity and graphitization conductivity of the bamboo charcoal, so as to prepare the doped bamboo charcoal with high thermal conductivity. According to the invention, the morphology distribution control auxiliary agent is added while grinding the bamboo charcoal, the special load type multifunctional modified composite bamboo charcoal powder is obtained by virtue of the extrusion force of grinding and the porous adsorption characteristic of the bamboo charcoal, the compatibility and dispersibility problems of the bamboo charcoal in a biodegradable matrix are solved by utilizing the load matrix dispersion control agent, the bamboo charcoal is more uniformly dispersed in the biodegradable matrix, the problem of difficult dispersion of the nucleating agent is solved by the load of the bamboo charcoal, meanwhile, the novel composite nucleating agent is taken as the crystalline distribution control agent, the biodegradable material is induced to form a uniformly dispersed and compact fine-grain structure, the crystal rejection effect is enhanced, the directional induction bamboo charcoal is distributed in an amorphous area with a continuous structure, a perfect three-dimensional network conductive path is constructed, the conductivity of the composite material is remarkably improved, the usage amount of the bamboo charcoal filler is reduced, and the contradiction problem of the mechanical property and conductivity of the composite material is solved.

In order to solve the problems, the invention provides the following technical scheme:

the bamboo charcoal biodegradable conductive composite material comprises the following raw materials in parts by mass: 8-18 parts by weight of doped bamboo charcoal material, 1-2 parts by weight of modifier, 2-4 parts by weight of compatilizer, 0.5-1 part by weight of dispersant, 0.5-2 parts by weight of nucleating agent, 0.2-0.4 part by weight of chain extender, 0.5-2 parts by weight of lubricant, 0.1-1 part by weight of antioxidant and 100 parts by weight of biodegradable plastic, wherein the nucleating agent is the compound of sulfonate nucleating agent and hydrazide nucleating agent; the doped bamboo charcoal material comprises the following raw materials in parts by mass: 100 parts by mass of bamboo, 5-8 parts by mass of doping source, 100-200 parts by mass of activating agent, 600-1000 parts by mass of water, 5-10 parts of inorganic acid and 300-400 parts of alcohol; the doped bamboo charcoal material is obtained by impregnating, drying, crushing, carbonizing and graphitizing a mixture of bamboo, a doping source, an activating agent and water, and then treating the mixture with inorganic acid and alcohol under the ultrasonic condition.

Further, the sulfonate nucleating agent is at least one selected from sodium dimethyl sulfophthalate, potassium dimethyl sulfophthalate, zinc dimethyl sulfophthalate, magnesium dimethyl sulfophthalate and lithium dimethyl sulfophthalate.

The hydrazide nucleating agent is selected from at least one of sebacic acid diphenyl dihydrazide, adipic acid diphenyl dihydrazide, pimelic acid diphenyl dihydrazide, dicarboxylic acid salicylic acid dihydrazide, 2-acetylhydrazone-2-phenyl-acetylhydrazine, decarbonized methylene dicarboxyl dibenzoyl dihydrazide, diphenylpropionic acid dodecanedihydrazide, dicarboxylic acid dodecanedihydrazide and isophthalic acid dihydrazide.

Furthermore, the mass ratio of the sulfonate to the hydrazide nucleating agent is 1 (1-3), the nucleating agent compounded according to the proportion has good crystalline distribution control effect, can induce the biodegradable material to form a more uniformly dispersed and compact fine crystal structure to a greater extent, enhances the crystalline repulsive effect, directionally induces the bamboo charcoal to be uniformly dispersed in an amorphous area with a continuous structure, and is more beneficial to the construction of a three-dimensional network conductive network structure.

The compatilizer is at least one selected from polylactic acid grafted maleic anhydride, polylactic acid grafted butyl acrylate, polylactic acid grafted methyl acrylate, poly (butylene adipate/terephthalate) grafted maleic anhydride, poly (butylene adipate/terephthalate) grafted butyl acrylate, poly (butylene adipate/terephthalate) grafted methyl acrylate, poly (butylene succinate) grafted maleic anhydride, poly (butylene succinate) grafted butyl acrylate, poly (butylene succinate) grafted methyl acrylate, polypropylene carbonate grafted maleic anhydride, polypropylene carbonate grafted butyl acrylate, polypropylene carbonate grafted methyl acrylate, polycaprolactone grafted maleic anhydride, polycaprolactone grafted butyl acrylate and polycaprolactone grafted methyl acrylate, and the grafting degree of the grafted polymer is 1-2%; the dispersing agent is at least one selected from stearic acid, zinc stearate, calcium stearate and polyethylene wax.

According to the invention, through compounding of the compatilizer, the dispersing agent and the nucleating agent, the dispersion of the bamboo charcoal in the biodegradable material matrix and the distribution of the bamboo charcoal in the crystalline structure are regulated and controlled cooperatively, the construction of a three-dimensional network structure is promoted to the greatest extent, the usage amount of the bamboo charcoal is reduced, and meanwhile, the contradiction problem between the conductivity and the mechanical property of the bamboo charcoal-based biodegradable conductive composite material is solved. The compatibility and the dispersibility of the bamboo charcoal and the biodegradable material matrix can be solved to a greater extent by compounding the bamboo charcoal according to the proportion, so that the bamboo charcoal is uniformly dispersed in the biodegradable material matrix. By compounding with bamboo charcoal, the problem of dispersibility of the nucleating agent is solved, the uniformly dispersed compound nucleating agent remarkably improves the nucleation efficiency of a biodegradable material matrix, forms uniform, fine and compact crystallization areas, enhances crystallization rejection effect, induces the bamboo charcoal to be mainly concentrated in continuous non-crystallization areas, and forms a three-dimensional network conductive path with an isolation structure, thereby improving the conductivity of the composite material to a greater extent.

Further, the bamboo is at least one selected from Phyllostachys Pubescens, ci Zhu, tea stalk bamboo, cornu Bubali bamboo, herba Saussureae Involueratae, arrow bamboo, hard head yellow, giant dragon bamboo, phyllostachys Pubescens, and Phyllostachys praecox; still further, the bamboo is crushed to 400-800 mesh, such as 500 mesh, 600 mesh, 700 mesh.

The biodegradable plastic is at least one of poly (adipic acid)/poly (butylene terephthalate) (PBAT), poly (lactic acid) (PLA), poly (caprolactone) (PCL), poly (butylene succinate) (PBS) and poly (propylene carbonate) (PPC), and the weight average molecular weight is 20-40 ten thousand.

The doping source is selected from the combination of a nitrogen source, a sulfur source, a boron source and a phosphorus source; the nitrogen source is at least one of waste polyimide powder, waste polyaniline powder and polyacrylamide; the sulfur source is thiourea; the boron source is at least one of sodium borate, ammonium borate and decaborane; the phosphorus source is at least one of phosphate and phosphite; the activating agent is at least one selected from potassium carbonate, lithium carbonate, sodium carbonate, lithium sulfate, potassium sulfate, sodium sulfate, potassium nitrate, lithium nitrate, sodium nitrate, manganese chloride, zinc chloride, lithium chloride, potassium chloride and calcium chloride; the inorganic acid is at least one of hydrochloric acid and sulfuric acid; the alcohol is at least one selected from methanol, ethanol and isopropanol.

Further, the doping source is a nitrogen source, a sulfur source, a boron source and a phosphorus source according to the mass ratio (1-3): 1: (1-2): compounding of (1-2). According to the compound doping source, the conductivity and the mechanical property of the bamboo charcoal composite material can be improved to the greatest extent.

Further, the modifier is at least one selected from oleic acid, phytic acid, monoalkoxy pyrophosphatate, (3-chloropropyl) triethoxysilane and hexadecyltrimethoxysilane.

The chain extender is at least one selected from ethylene-glycidyl methacrylate copolymer, styrene-glycidyl methacrylate copolymer, methyl methacrylate-glycidyl methacrylate copolymer, styrene-butyl methacrylate-glycidyl methacrylate copolymer, styrene-acrylonitrile-glycidyl methacrylate-methyl methacrylate copolymer. The molecular weight of the chain extender is 6000-8000.

The bamboo charcoal biodegradable conductive composite material can also comprise other auxiliary agents, such as 0.5-2 parts by mass of lubricant and 0.1-1 part by mass of antioxidant, wherein the lubricant is at least one selected from Ethylene Bis Stearamide (EBS), pentaerythritol stearate, erucamide, oleamide, liquid paraffin and glyceryl stearate; the antioxidant is at least one selected from the group consisting of antioxidant 168, antioxidant 626, antioxidant 1010, antioxidant 1076 and antioxidant 2246.

The invention also provides a preparation method of the bamboo charcoal biodegradable conductive composite material, which comprises the following steps:

(S1) dipping bamboo wood, doping sources, an activating agent and water under heating and stirring conditions, then continuously dipping under vacuum conditions, drying, crushing, heating for carbonization and graphitization, cooling, and then treating the obtained material with inorganic acid and alcohol under ultrasonic conditions, and post-treating to obtain a doped bamboo charcoal material;

(S2) mixing the doped bamboo charcoal material, the modifier, the compatilizer, the dispersing agent and the nucleating agent uniformly, mixing the obtained mixed material with the chain extender and the biodegradable plastic uniformly, optionally adding other auxiliary agents, and then extruding and granulating the materials by double screws to obtain the bamboo charcoal biodegradable conductive composite material.

Further, in the step (S1), the ultrasonic frequency is 60-100 kHz. And (3) after ultrasonic treatment, sequentially carrying out vacuum suction filtration, washing and drying to obtain the doped bamboo charcoal material. The pulverization is carried out by pulverizing to 400-800 mesh, such as 500 mesh, 600 mesh, 700 mesh.

Further, in the step (S2), the uniform mixing is ball milling, in a preferable technical scheme of the invention, the doped bamboo charcoal material is ball milled for 20-30min under the condition of 200-300rpm, then the modifier, the compatilizer and the dispersing agent are added, ball milling is continued for 1-2h, then the nucleating agent is added, and the full grinding is carried out for 1-2h. Conditions for twin screw extrusion pelletization are well known in the art, specifically blending temperatures 165-185 ℃, extrusion temperatures 155-175 ℃ and screw leaching speeds 150-200rpm. The reason for adding the nucleating agent finally is that the nucleating agent is distributed on the outer surface of the bamboo charcoal more, the nucleating effect of the compound nucleating agent can be exerted to a greater extent, and the crystallization of the biodegradable matrix material is promoted.

According to the invention, the doped bamboo charcoal with high thermal conductivity is prepared by taking the bamboo charcoal rich in nitrogen, phosphorus, sulfur and other elements as the conductive filler and activating the ion conductivity of the bamboo charcoal by adding the compound doping source from the ion conductivity and graphitization conductivity angles of the bamboo charcoal.

The method comprises the steps of grinding bamboo charcoal, adding a form distribution control auxiliary agent, obtaining special load type multifunctional modified composite bamboo charcoal powder by virtue of the grinding extrusion force and the porous adsorption characteristic of the bamboo charcoal, utilizing a load type matrix dispersion control agent to solve the problem of compatibility and dispersibility of the bamboo charcoal in a biodegradable matrix, enabling the bamboo charcoal to be more uniformly dispersed in the biodegradable matrix, solving the problem of difficult dispersion of a nucleating agent by the bamboo charcoal, simultaneously using a novel compound nucleating agent as a crystalline distribution control agent, inducing a biodegradable material to form a uniformly dispersed and compact fine crystal structure, enhancing a crystal repulsive effect, directionally inducing the bamboo charcoal to be distributed in a non-crystalline region with a continuous structure, constructing a perfect three-dimensional network conductive path, remarkably improving the conductivity of the composite material, reducing the usage amount of a bamboo charcoal filler, and solving the contradictory problem of the mechanical property and conductivity of the composite material.

Compared with the prior art, the invention has the following technical progress:

1. the method of the invention utilizes the cooperation of doping and graphitization to improve the conductivity of the bamboo charcoal, utilizes the dispersing agent, the compatilizer and the nucleating agent to regulate and control the crystalline structure of the biodegradable matrix, induces the bamboo charcoal to be uniformly dispersed in a continuous amorphous region, promotes the construction of a conductive network, simultaneously provides the mechanical property and the conductivity of the composite material, and realizes the comprehensive utilization of bamboo resources.

2. The bamboo charcoal composite material obtained by the preparation method disclosed by the invention has high application value, the doping elements, the high specific surface and the high graphitization degree in the bamboo charcoal obviously improve the conductivity, and the morphological distribution control agent loaded on the surface and the pores of the bamboo charcoal improves the compatibility and the dispersibility of the bamboo charcoal and the biodegradable matrix material, the compounded nucleating agent reacts on the biodegradable material, the crystalline structure of the matrix material is regulated and controlled, a conductive network is easier to form, and the prepared composite material has excellent mechanical property and high conductivity and can be applied to the fields of conductive materials and the like.

3. Compared with the prior art, the method provided by the invention has the advantages that the bamboo charcoal rich in multiple elements is used for replacing other biomass charcoal and other conductive carbon materials, the conductivity of the bamboo charcoal is improved through doping and graphitizing, the multifunctional loaded modified bamboo charcoal is obtained through a grinding method, the crystalline structure of the biodegradable material and the morphological distribution of the bamboo charcoal are regulated, the contradictory problem of the conductivity and mechanical properties of the composite material is solved, the process is simple and relatively, and the whole process is safe and environment-friendly.

4. The preparation method of the bamboo charcoal biodegradable conductive composite material is simple and efficient, has high production efficiency, can be used for large-scale production, improves the utilization rate of bamboo, increases the added value of the bamboo, and improves the economic benefit of the bamboo industry.

Drawings

FIG. 1 is a polarized image of the composite material obtained in example 1;

FIG. 2 is a transmission electron microscope picture of the composite material obtained in example 1;

FIG. 3 is a polarized image of the composite material obtained in comparative example 2;

FIG. 4 is a polarized image of the composite obtained in comparative example 3.

Detailed Description

The present invention is further illustrated and described below with reference to specific examples.

In the embodiment of the invention, the parts are mass parts unless otherwise specified; the percentages are mass percentages unless otherwise specified.

Example 1

(S1) preparation of conductive bamboo charcoal

Firstly crushing Mao Zhuqie, cleaning, drying, crushing bamboo to 400 meshes, taking 100 parts by weight of bamboo powder and 5 parts by weight of doping source powder, wherein the doping source powder is composed of waste polyimide powder, thiourea, sodium borate and phosphate in a mass ratio of 1:1:1:1, simultaneously taking 100 parts by weight of potassium carbonate and 600 parts by weight of distilled water, placing into a reactor, fully stirring and soaking for 2 hours at 60 ℃, stirring at a speed of 80 revolutions/min, then further soaking for 1 hour under a vacuum condition at 60 ℃, drying the soaking material, and crushing again by a crusher. And then placing the crushed mixture into a carbonization furnace, wherein the carbonization temperature is 300 ℃, the carbonization time is 2 hours, the reaction atmosphere is nitrogen atmosphere, and the carbonization furnace is heated again after cooling to room temperature, graphitizing for 1 hour at 800 ℃, and taking out the bamboo charcoal after cooling to room temperature. Then placing the bamboo charcoal in an ultrasonic reactor, adding 5 parts by weight of hydrochloric acid and 300 parts by weight of absolute ethyl alcohol, performing ultrasonic reaction for 20min, and enabling the ultrasonic frequency to be 50 kHz to separate tar blocked in micropores of the bamboo charcoal. Finally, carrying out suction filtration treatment by using a vacuum suction filter, washing by using distilled water at 80 ℃, and drying in a baking oven at 60 ℃ to obtain the doped bamboo charcoal with high conductivity.

(S2) preparation of bamboo charcoal conductive composite material

Taking 8 parts by weight of high-conductivity doped bamboo charcoal, grinding for 20min in a ball mill at a rotating speed of 200 r/min, adding 1 part by weight of oleic acid, 2 parts by weight of poly (adipic acid)/butylene terephthalate grafted maleic anhydride and 0.5 part by weight of stearic acid after grinding, grinding again for 1h, adding 0.5 part by weight of nucleating agent which is composed of dimethyl sodium sulfophthalate and diphenyl dihydrazide sebacate in a weight ratio of 1:1, and fully grinding for 1h; then placing the mixture in a high-speed mixer, fully mixing the mixture with 0.2 weight part of ethylene-glycidyl methacrylate copolymer, 0.5 weight part of ethylene bis-stearamide and 0.1 weight part of antioxidant 168, and granulating 100 weight parts of poly (adipic acid)/butylene terephthalate with the weight average molecular weight of 20 ten thousand in a double-screw extruder, wherein the blending temperature is 165 ℃, the extrusion temperature is 155 ℃, the screw extrusion speed is 150 revolutions per minute, and then drying the composite material at 60 ℃ to finally obtain the bamboo charcoal biodegradable conductive composite material.

Through test, the area resistivity of the bamboo charcoal biodegradable conductive composite material is 3.5 multiplied by 10 ⁶ Omega/sq, tensile strength 25.8MPa, elongation at break 653%.

Fig. 1 is a polarization chart of the bamboo charcoal biodegradable conductive composite material obtained in example 1 after isothermal crystallization treatment under a polarization microscope. The compound nucleating agent can obviously improve the nucleation efficiency of the biodegradable matrix and form uniformly distributed fine crystal areas.

FIG. 2 is a transmission electron microscope image of the bamboo charcoal obtained in example 1, illustrating that the bamboo charcoal is a porous material with a microporous structure.

Example 2

(1) Preparation of conductive bamboo charcoal

Firstly, cutting the arrowhead, cleaning and drying the crushed arrowhead, crushing the arrowhead to 450 meshes, taking 100 parts by weight of bamboo powder and 6 parts by weight of doping source powder, wherein the doping source powder is composed of waste polyaniline powder, thiourea, ammonium borate and phosphate in a mass ratio of 1.5:1:1, simultaneously taking 125 parts by weight of lithium sulfate and 700 parts by weight of distilled water, placing the materials into a reactor, fully stirring and dipping the materials for 2.5 hours at 65 ℃, stirring the materials at a speed of 85 r/min, further dipping the materials for 1 hour under a vacuum condition at 62 ℃, drying the dipping materials, and crushing the materials again by a crusher. And then placing the crushed mixture into a carbonization furnace, wherein the carbonization temperature is 325 ℃, the carbonization time is 2.2 hours, the reaction atmosphere is nitrogen atmosphere, and the carbonization furnace is heated again after cooling to room temperature, graphitizing for 1.2 hours at 880 ℃, and taking out the bamboo charcoal after cooling to room temperature. Then placing the bamboo charcoal in an ultrasonic reactor, adding 6 parts by weight of hydrochloric acid and 325 parts by weight of absolute ethyl alcohol, performing ultrasonic reaction for 25min, and enabling the ultrasonic frequency to be 55KHz to separate tar blocked in micropores of the bamboo charcoal. Finally, carrying out suction filtration treatment by using a vacuum suction filter, washing by using distilled water at 80 ℃, and drying in a baking oven at 60 ℃ to obtain the doped bamboo charcoal with high conductivity.

(2) Preparation of bamboo charcoal conductive composite material

Taking 10.5 parts by weight of high-conductivity doped bamboo charcoal, grinding in a ball mill for 22min at the rotating speed of 225 r/min, adding 1.2 parts by weight of monoalkoxy pyrophosphite and 2.4 parts by weight of polylactic acid grafted methyl acrylate after grinding and 0.6 part by weight of zinc stearate, grinding again for 1.2h, adding 0.9 part by weight of nucleating agent which is composed of dimethyl zinc sulfophthalate and dicarboxylic acid salicylic acid hydrazide with the weight ratio of 1:1.5, and fully grinding for 1.2h; then placing the mixture in a high-speed mixer, fully mixing the mixture with 0.25 weight part of styrene-glycidyl methacrylate copolymer, 0.8 weight part of pentaerythritol stearate and 0.3 weight part of antioxidant 626, 80 weight parts of polylactic acid with the weight average molecular weight of 25 ten thousand and 20 weight parts of poly (adipic acid)/butylene terephthalate with the weight average molecular weight of 20 ten thousand, granulating the mixture in a double-screw extruder, setting the blending temperature to 175 ℃, setting the extrusion temperature to 160 ℃, setting the screw extrusion rotating speed to 180 revolutions per minute, and drying the composite material at 65 ℃ to finally obtain the bamboo charcoal biodegradable conductive composite material.

Through test, the area resistivity of the bamboo charcoal biodegradable conductive composite material is 1.1 multiplied by 10 ⁵ The tensile strength was 54.2MPa and the elongation at break was 24.1%. The degradable plastic in example 2 contains 80% polylactic acid, so that the tensile strength is significantly higher than that in example 1, and the elongation at break is significantly reduced, which is brought about by the characteristics of polylactic acid itself. Other embodiments are similar, in that the change in mechanical properties is mainly due to the differences in degradable plastics.

Example 3

(1) Preparation of conductive bamboo charcoal

Firstly, cutting large-eye bamboo and ox horn bamboo respectively, cleaning and drying, crushing the bamboo into 500 meshes, taking 50 parts by weight of large-eye bamboo powder, 50 parts by weight of ox horn bamboo powder and 7 parts by weight of doping source powder, wherein the doping source powder comprises polyacrylamide, thiourea, decaborane and phosphite ester according to the mass ratio of 2:1:1.5:1, simultaneously taking 150 parts by weight of lithium carbonate and 750 parts by weight of distilled water, placing the lithium carbonate and the distilled water into a reactor, fully stirring and soaking for 3 hours at 70 ℃, stirring at a speed of 90 turns/min, further soaking for 1 hour under a vacuum condition at 65 ℃, drying the soaking material, and crushing the soaking material by a crusher again. And then placing the crushed mixture into a carbonization furnace, wherein the carbonization temperature is 350 ℃, the carbonization time is 2.5 hours, the reaction atmosphere is nitrogen atmosphere, and the carbonization furnace is heated again after cooling to room temperature, graphitizing for 1.5 hours at 960 ℃, and taking out the bamboo charcoal after cooling to room temperature. Then placing the bamboo charcoal in an ultrasonic reactor, adding 7 parts by weight of hydrochloric acid and 350 parts by weight of absolute ethyl alcohol, performing ultrasonic reaction for 30min, and enabling the ultrasonic frequency to be 60KHz to separate tar blocked in micropores of the bamboo charcoal. Finally, carrying out suction filtration treatment by using a vacuum suction filter, washing by using distilled water at 80 ℃, and drying in a baking oven at 60 ℃ to obtain the doped bamboo charcoal with high conductivity.

(2) Preparation of bamboo charcoal conductive composite material

Taking 13 parts by weight of high-conductivity doped bamboo charcoal, grinding for 25min in a ball mill at the rotating speed of 250 r/min, adding 1.5 parts by weight of (3-chloropropyl) triethoxysilane, 1.52 parts by weight of poly (adipic acid)/butylene terephthalate grafted butyl acrylate, 1.52 parts by weight of polypropylene carbonate grafted maleic anhydride and 0.76 part by weight of calcium stearate after grinding for 1.5h again, adding 1.2 parts by weight of nucleating agent which consists of dimethyl magnesium sulfophthalate and decarbonized methylene dicarboxyldibenzoyl hydrazine with the weight ratio of 1:3, and fully grinding for 1.5h; then placing the mixture in a high-speed mixer, fully mixing the mixture with 0.30 weight part of styrene-acrylonitrile-glycidyl methacrylate-methyl methacrylate copolymer, 1.2 weight part of erucamide and 0.6 weight part of antioxidant 626, 80 weight parts of poly (adipic acid)/butylene terephthalate with the weight average molecular weight of 30 ten thousand and 20 weight parts of polypropylene carbonate with the weight average molecular weight of 30 ten thousand, granulating the mixture in a double-screw extruder, setting the blending temperature to 175 ℃, setting the extrusion temperature to 165 ℃, setting the screw extrusion speed to 175 revolutions per minute, and drying the composite material at 70 ℃ to finally obtain the bamboo charcoal biodegradable conductive composite material.

Through test, the area resistivity of the bamboo charcoal biodegradable conductive composite material is 5.9 multiplied by 10 ⁴ Omega/sq, tensile strength 27.9MPa, elongation at break 363%.

Example 4

(1) Preparation of conductive bamboo charcoal

Firstly, cutting hard head yellow and flower-shaped silk bamboo respectively, cleaning and drying, crushing the bamboo to 550 meshes, taking 40 parts by weight of hard head Huang Zhufen, 60 parts by weight of flower-shaped silk powder and 7.5 parts by weight of doping source powder, wherein the doping source powder comprises waste polyimide powder, thiourea, ammonium borate and phosphite ester in a mass ratio of 2.5:1:2:1, simultaneously taking 170 parts by weight of sodium nitrate and 900 parts by weight of distilled water, placing the mixture into a reactor, fully stirring and soaking the mixture for 3.5 hours at 75 ℃, stirring the mixture at a speed of 95 revolutions per minute, then further soaking the mixture for 1 hour under a vacuum condition at 67 ℃, drying the soaked material, and crushing the soaked material again by a crusher. And then placing the crushed mixture into a carbonization furnace, wherein the carbonization temperature is 375 ℃, the carbonization time is 2.7h, the reaction atmosphere is nitrogen atmosphere, and the carbonization furnace is heated again after cooling to room temperature, graphitizing for 1.7h at 1020 ℃, and taking out the bamboo charcoal after cooling to room temperature. Then placing the bamboo charcoal in an ultrasonic reactor, adding 9 parts by weight of hydrochloric acid and 380 parts by weight of absolute ethyl alcohol, performing ultrasonic reaction for 235min, and enabling the ultrasonic frequency to be 65KHz to separate tar blocked in micropores of the bamboo charcoal. Finally, carrying out suction filtration treatment by using a vacuum suction filter, washing by using distilled water at 80 ℃, and drying in a baking oven at 60 ℃ to obtain the doped bamboo charcoal with high conductivity.

(2) Preparation of bamboo charcoal conductive composite material

Taking 15.5 parts by weight of high-conductivity doped bamboo charcoal, grinding for 28min in a ball mill at a rotating speed of 280 r/min, adding 1.6 parts by weight of hexadecyltrimethoxysilane, 1.72 parts by weight of polybutylene succinate grafted maleic anhydride, 1.72 parts by weight of polycaprolactone grafted methyl acrylate, 0.43 part by weight of calcium stearate and 0.43 part by weight of polyethylene wax after grinding for 1.7h again, adding 1.6 parts by weight of nucleating agent which consists of dimethyl sulfophthalate magnesium and dodecanedihydrazide with a weight ratio of 1:2, and fully grinding for 1.7h; then placing the mixture in a high-speed mixer, fully mixing the mixture with 0.35 weight part of styrene-methyl acrylate-glycidyl methacrylate copolymer, 1.7 weight part of glyceryl stearate, 0.8 weight part of antioxidant 1076, 70 weight parts of polybutylene succinate with the weight average molecular weight of 35 ten thousand and 30 weight parts of polycaprolactone with the weight average molecular weight of 30 ten thousand, granulating the mixture in a double-screw extruder, setting the blending temperature to 180 ℃, setting the extrusion temperature to 170 ℃, setting the screw extrusion rotating speed to 190 revolutions per minute, and drying the composite material at 75 ℃ to finally obtain the bamboo charcoal biodegradable conductive composite material.

Through test, the area resistivity of the bamboo charcoal biodegradable conductive composite material is 1.3 multiplied by 10 ⁴ The tensile strength was 26.9MPa and the elongation at break was 94.5%.

Example 5

(1) Preparation of conductive bamboo charcoal

Firstly, respectively cutting giant dragon bamboo, arrow bamboo and tea stalk bamboo, cleaning and drying, crushing the bamboo into 600 meshes, taking 40 parts by weight of giant dragon bamboo powder, 30 parts by weight of arrow bamboo powder, 30 parts by weight of tea stalk bamboo powder and 8 parts by weight of doping source powder, wherein the doping source powder comprises polyacrylamide, waste polyaniline powder, thiourea, sodium borate, decaborane and phosphate in a mass ratio of 1.5:1:1:1:1, simultaneously taking 100 parts by weight of manganese chloride, 100 parts by weight of potassium carbonate and 1000 parts by weight of distilled water, placing the materials into a reactor, fully stirring and impregnating for 4 hours at 80 ℃, stirring the materials at a speed of 100 revolutions/min, further impregnating the materials for 1 hour at a vacuum condition at 70 ℃, drying the impregnating materials, and crushing the impregnating materials by a crusher. And then placing the crushed mixture into a carbonization furnace, wherein the carbonization temperature is 400 ℃, the carbonization time is 3 hours, the reaction atmosphere is nitrogen atmosphere, and the carbonization furnace is heated again after cooling to the room temperature, graphitizing for 2 hours at 1100 ℃, and taking out the bamboo charcoal after cooling to the room temperature. Then placing the bamboo charcoal in an ultrasonic reactor, adding 10 parts by weight of hydrochloric acid and 400 parts by weight of absolute ethyl alcohol, performing ultrasonic reaction for 40min, and enabling the ultrasonic frequency to be 70KHz to separate tar blocked in micropores of the bamboo charcoal. Finally, carrying out suction filtration treatment by using a vacuum suction filter, washing by using distilled water at 80 ℃, and drying in a baking oven at 60 ℃ to obtain the doped bamboo charcoal with high conductivity.

(2) Preparation of bamboo charcoal conductive composite material

Taking 18 parts by weight of high-conductivity doped bamboo charcoal, grinding for 30min in a ball mill at a rotating speed of 300 r/min, adding 2 parts by weight of monoalkoxy pyrophosphite, 2 parts by weight of polylactic acid grafted maleic anhydride, 2 parts by weight of poly adipic acid/butylene terephthalate grafted maleic anhydride, 0.5 part by weight of zinc stearate and 0.5 part by weight of polyethylene wax after grinding for 2h again, adding 2 parts by weight of nucleating agent, wherein the nucleating agent consists of dimethyl magnesium sulfophthalate and dodecanedihydrazide diphenylpropionate in a mass ratio of 1:1, and fully grinding for 2h; then placing the mixture in a high-speed mixer, fully mixing the mixture with 0.4 part by weight of 2, 3-glycidyl methacrylate, 2 parts by weight of ethylene bis stearamide, 1 part by weight of antioxidant 2246, 60 parts by weight of poly (adipic acid)/butylene terephthalate with weight average molecular weight of 40 ten thousand, 20 parts by weight of polylactic acid with weight average molecular weight of 30 ten thousand and 20 parts by weight of polycaprolactone with weight average molecular weight of 35 ten thousand, granulating the mixture in a double-screw extruder, setting the blending temperature to 185 ℃, setting the extrusion temperature to 175 ℃ and the screw extrusion speed to 200 revolutions per minute, and drying the composite material at 80 ℃ to finally obtain the bamboo charcoal biodegradable conductive composite material.

Through test, the area resistivity of the bamboo charcoal biodegradable conductive composite material is 8.7X10 ³ Omega/sq., tensile strength of 31.5MPa and elongation at break of 81.1%.

It can be seen from examples 1-5 that, along with the improvement of the proportion of the highly conductive doped bamboo charcoal in the material and the regulation and control of the matrix crystal morphology of the biodegradable material by compounding nucleation and the like, the bamboo charcoal is induced to be more uniformly distributed in a continuous amorphous region, so that the formed conductive network structure is more and more perfect, and the area resistivity is lower and lower.

Comparative example 1

The preparation of conductive bamboo charcoal and the preparation of the bamboo charcoal composite material were the same as in example 1, except that 5 parts by weight of doping source powder was not added.

Through test, the area resistivity of the bamboo charcoal biodegradable conductive composite material is 1.0 multiplied by 10 ⁷ Omega/sq., tensile strength of 25.3MPa and elongation at break of 637%.

Comparative example 2

The preparation of conductive bamboo charcoal and the preparation of the bamboo charcoal composite material are the same as in example 1, except that the nucleating agent is diphenyl dihydrazide sebacate, i.e. dimethyl sodium sulfophthalate is not added.

Through testing, bamboo charcoal is producedThe area resistivity of the biodegradable conductive composite material is 9.8x10 ⁶ Omega/sq, tensile strength of 23.7MPa and elongation at break of 619%.

Comparative example 3

The preparation of conductive bamboo charcoal and the preparation of the bamboo charcoal composite material are the same as in example 1, except that the nucleating agent is dimethyl sodium sulfophthalate, i.e. diphenyl dihydrazide sebacate is not added.

The area resistivity of the biodegradable conductive composite material is 8.8X10 ⁶ Omega/sq., tensile strength of 24.1MPa and elongation at break of 589%.

Fig. 3 and 4 are polarization diagrams of isothermal crystallization treatments under a polarization microscope of the composite materials obtained in comparative example 2 and comparative example 3, respectively, and it can be seen that the grain size is significantly increased and the ratio of the crystallization area is significantly decreased as compared with fig. 1 of example 1, indicating that the effect of using a single nucleating agent is deteriorated. Therefore, the compounded nucleating agent can more effectively promote the nucleation and crystal morphology distribution of the biodegradable matrix, improve the crystallinity, promote the bamboo charcoal to be more intensively distributed in a uniform amorphous area, form a more perfect conductive path with an isolation structure, and further reduce the area resistivity of the composite material.

Claims

1. The bamboo charcoal biodegradable conductive composite material is characterized by comprising the following raw materials in parts by mass: 8-18 parts by weight of doped bamboo charcoal material, 1-2 parts by weight of modifier, 2-4 parts by weight of compatilizer, 0.5-1 part by weight of dispersant, 0.5-2 parts by weight of nucleating agent, 0.2-0.4 part by weight of chain extender, 0.5-2 parts by weight of lubricant, 0.1-1 part by weight of antioxidant and 100 parts by weight of biodegradable plastic, wherein the nucleating agent is the compound of sulfonate nucleating agent and hydrazide nucleating agent; the doped bamboo charcoal material comprises the following raw materials in parts by mass: 100 parts by mass of bamboo, 5-8 parts by mass of doping source, 100-200 parts by mass of activating agent, 600-1000 parts by mass of water, 5-10 parts of inorganic acid and 300-400 parts of alcohol; the doped bamboo charcoal material is obtained by impregnating, drying, crushing, carbonizing and graphitizing a mixture of bamboo, a doping source, an activating agent and water, and then treating the mixture with inorganic acid and alcohol under the ultrasonic condition.

2. The bamboo charcoal biodegradable conductive composite material according to claim 1, wherein the sulfonate nucleating agent is at least one selected from the group consisting of sodium dimethyl sulfophthalate, potassium dimethyl sulfophthalate, zinc dimethyl sulfophthalate, magnesium dimethyl sulfophthalate, and lithium dimethyl sulfophthalate.

3. The bamboo charcoal biodegradable conductive composite material according to claim 1, wherein the hydrazide nucleating agent is at least one selected from the group consisting of sebacic acid diphenyl dihydrazide, adipic acid diphenyl dihydrazide, pimelic acid diphenyl dihydrazide, dicarboxylic acid salicylic acid dihydrazide, 2-acetylhydrazone-2-phenyl-acetylhydrazine, decarbonized methylene dicarboxyl dibenzoyl dihydrazide, diphenylpropionic acid dodecanedihydrazide, dicarboxylic acid dodecanedihydrazide, isophthalic acid dihydrazide.

4. The bamboo charcoal biodegradable conductive composite material according to claim 1, wherein the mass ratio of sulfonate to hydrazide nucleating agent is 1 (1-3).

5. The bamboo charcoal biodegradable conductive composite according to claim 1, wherein the compatibilizer is selected from at least one of polylactic acid grafted maleic anhydride, polylactic acid grafted butyl acrylate, polylactic acid grafted methyl acrylate, poly (butylene adipate/terephthalate) grafted maleic anhydride, poly (butylene adipate/terephthalate) grafted butyl acrylate, poly (butylene adipate/terephthalate) grafted methyl acrylate, poly (butylene succinate) grafted maleic anhydride, poly (butylene succinate) grafted butyl acrylate, poly (butylene succinate) grafted methyl acrylate, polypropylene carbonate grafted maleic anhydride, polypropylene carbonate grafted butyl acrylate, polypropylene carbonate grafted methyl acrylate, polycaprolactone grafted maleic anhydride, polycaprolactone grafted butyl acrylate, and polycaprolactone grafted methyl acrylate, and the degree of grafting of the grafted polymer is 1-2%; the dispersing agent is at least one selected from stearic acid, zinc stearate, calcium stearate and polyethylene wax.

6. The bamboo charcoal biodegradable conductive composite material according to claim 1, wherein the bamboo is at least one selected from the group consisting of moso bamboo, arrowhead bamboo, tea-stalk bamboo, ox horn bamboo, macyoto bamboo, arrow bamboo, hard head yellow, megalobrama, large-eye bamboo, and flower-hanging silk bamboo; the bamboo is crushed to 400-800 meshes; the biodegradable plastic is at least one of poly (adipic acid)/poly (butylene terephthalate) (PBAT), poly (lactic acid) (PLA), poly (caprolactone) (PCL), poly (butylene succinate) (PBS) and poly (propylene carbonate) (PPC), and the weight average molecular weight is 20-40 ten thousand.

7. The bamboo charcoal biodegradable conductive composite material according to claim 1, wherein the doping source is selected from the group consisting of a nitrogen source, a sulfur source, a boron source, and a phosphorus source; the nitrogen source is at least one of waste polyimide powder, waste polyaniline powder and polyacrylamide; the sulfur source is thiourea; the boron source is at least one of sodium borate, ammonium borate and decaborane; the phosphorus source is at least one of phosphate and phosphite; the activating agent is at least one selected from potassium carbonate, lithium carbonate, sodium carbonate, lithium sulfate, potassium sulfate, sodium sulfate, potassium nitrate, lithium nitrate, sodium nitrate, manganese chloride, zinc chloride, lithium chloride, potassium chloride and calcium chloride; the inorganic acid is at least one of hydrochloric acid and sulfuric acid; the alcohol is at least one selected from methanol, ethanol and isopropanol.

8. The bamboo charcoal biodegradable conductive composite material according to claim 1, wherein the doping source is a nitrogen source, a sulfur source, a boron source and a phosphorus source according to the mass ratio (1-3): 1: (1-2): compounding of (1-2).

9. The bamboo charcoal biodegradable conductive composite according to claim 1, wherein the modifier is at least one selected from oleic acid, phytic acid, monoalkoxy pyrophosphate, (3-chloropropyl) triethoxysilane, hexadecyltrimethoxysilane; the chain extender is at least one selected from ethylene-glycidyl methacrylate copolymer, styrene-glycidyl methacrylate copolymer, methyl methacrylate-glycidyl methacrylate copolymer, styrene-butyl methacrylate-glycidyl methacrylate copolymer, styrene-acrylonitrile-glycidyl methacrylate-methyl methacrylate copolymer; the molecular weight of the chain extender is 6000-8000.

10. The method for preparing the bamboo charcoal biodegradable conductive composite material according to any one of claims 1 to 9, comprising the steps of: