阅读说明：本技术 一种高强度高韧性电磁屏蔽复合材料的制备方法 (Preparation method of high-strength high-toughness electromagnetic shielding composite material ) 是由 成惠斌 罗洁玲 黄宝铨 陈庆华 钱庆荣 肖荔人 于 2019-08-29 设计创作，主要内容包括：本发明涉及导电高分子复合材料领域,特别涉及高强度高韧性UHMWPE/PP/SCCB电磁屏蔽复合材料的制备方法。该制备方法按UHMWPE粉料、SCCB、PP粉料、复配抗氧剂、偶联剂重量份配比,先将UHMWPE、PP和SCCB粉料干燥,而后将SCCB与偶联剂在高混机中进行改性,之后将称UHMWPE、PP、复配抗氧剂和超导炭黑偶联剂改性产物一起置于高速捏合机中高速混合得到混合均匀的原料,经模压成型,脱模后获UHMWPE/PP/SCCB复合材料。采用本发明方法得到的复合材料,具有较高的导电性能,实现制品特殊功能化,如电磁屏蔽效能和抗静电应用。(The invention relates to the field of conductive polymer composite materials, in particular to a preparation method of a high-strength and high-toughness UHMWPE/PP/SCCB electromagnetic shielding composite material. The preparation method comprises the steps of proportioning UHMWPE powder, SCCB, PP powder, a compound antioxidant and a coupling agent in parts by weight, drying the UHMWPE, PP and SCCB powder, modifying the SCCB and the coupling agent in a high-speed mixer, putting the modified products of the UHMWPE, PP, the compound antioxidant and the superconducting carbon black coupling agent together in a high-speed kneader, mixing at high speed to obtain uniformly mixed raw materials, carrying out compression molding, and demoulding to obtain the UHMWPE/PP/SCCB composite material. The composite material obtained by the method has higher conductivity, and realizes special functionalization of products, such as electromagnetic shielding effectiveness and antistatic application.)

1. A preparation method of a high-strength high-toughness electromagnetic shielding composite material is characterized by comprising the following steps:

the components are proportioned as follows:

85-95 parts of UHMWPE powder, 1-15 parts of SCCB, 5-15 parts of PP powder, 0.1-0.5 part of compound antioxidant and 0.1-0.5 part of coupling agent;

2) the preparation method comprises the following steps:

A. and (3) drying: respectively drying UHMWPE, PP and SCCB powder in a drying oven for 4-6 h at 60 ℃;

B. weighing: weighing dried UHMWPE, PP and SCCB powder and a compound antioxidant according to the parts by weight;

C. modification of superconducting carbon black coupling agent: adding SCCB, a coupling agent and diluent ethanol into a high-speed mixer, keeping the rotating speed at 500-1000 rpm, and stirring at high speed for 5-30 min to obtain a superconducting carbon black coupling agent modified product;

D. blending: putting the weighed UHMWPE powder, PP powder, antioxidant and the superconducting carbon black coupling agent modified product prepared in the step C into a high-speed kneading machine, and mixing at high speed for 5-8 min to obtain a uniformly mixed raw material; the high-speed mixing is carried out at the rotating speed of 24000 rpm;

E. compression molding: and putting the fully and uniformly mixed raw materials into a mould, heating at the high temperature of 200-220 ℃ and carrying out hot pressing for 15min under the pressure condition of 17MPa, so that the mixture is fully melted and plasticized in a melting cavity of the mould, then carrying out cold pressing for 20min at the room temperature of 17MPa, fully cooling and demoulding, and obtaining the UHMWPE/PP/SCCB composite material with high strength, high toughness and high electromagnetic shielding efficiency.

2. The method for preparing the high-strength high-toughness electromagnetic shielding composite material according to claim 1, wherein the UHMWPE is powder, the particle size distribution range is 30-200 μm, the number average molecular weight is 250-650 ten thousand g/mol, and the tensile strength is more than or equal to 38 MPa.

3. The preparation method of the high-strength high-toughness electromagnetic shielding composite material according to claim 1, wherein the PP powder is prepared by the following steps: PPH-T03, melt flow rate of 3g/10min, particle size distribution range of 200-600 μm, and is provided by Michelson division of petrochemical Co.

4. The method for preparing a high-strength high-toughness electromagnetic shielding composite material according to claim 1, wherein the superconducting carbon black is prepared from the following components in percentage by weight: yiborui, model: F900A, nitrogen adsorption specific surface of 750-1100 m2/Kg, DBP absorption value of 450ml/g, particle size range of 9-17 nm, superconducting carbon black is subjected to surface modification by a coupling agent, and the preparation method comprises the following steps: mixing superconducting carbon black and a coupling agent according to a mass ratio of 15: 0.1-0.5 part by weight, adding into a high-speed blender, keeping the rotating speed at 500-1000 rpm, and stirring at high speed for 5-30 min.

5. The method for preparing a high-strength high-toughness electromagnetic shielding composite material as claimed in claims 1 and 4, wherein the coupling agent is a silane coupling agent or a titanate coupling agent.

6. The preparation method of the high-strength high-toughness electromagnetic shielding composite material according to claims 1 and 4, characterized in that the compound antioxidant is prepared by compounding antioxidant 1010 and antioxidant 168 according to a mass ratio of 2: 1.

Technical Field

The invention relates to the field of conductive polymer composite materials, in particular to a preparation method of a high-strength and high-toughness UHMWPE/PP/SCCB electromagnetic shielding composite material.

Background

With the rapid development of communication technology and electronic industry, the Electromagnetic (EM) pollution has become an inevitable problem, seriously harms people's health because of being exposed to the electromagnetic wave environment generated by the daily operation of surrounding electronic devices, and the electromagnetic waves with different energies cause different degrees of harm to human health and precision electronic instruments, so in order to meet the shielding requirements, more advanced electromagnetic shielding (EMI) materials are needed to meet the application of different fields, wherein the Conductive Polymer Composite (CPCs) as a novel electromagnetic shielding material with great application prospects draws wide attention because of the advantages of light weight, low cost, good molding processability, corrosion resistance, multiple functionalities, light weight, corrosion resistance, adjustability and the like, and in the CPCs material, the adoption of the conductive filler with high conductivity is favorable for improving the electromagnetic shielding performance of the CPCs, among them, carbon-based nano conductive fillers, such as Carbon Nanotubes (CNTs), Graphene (GNS), Carbon Nanofibers (CNF), and the like, have been widely used. However, the carbon-based nano conductive filler is easy to agglomerate in the polymer matrix due to the extremely high specific surface area, and generally higher filler content is required to obtain the required electromagnetic shielding effectiveness. With the increase of the filler content, the electromagnetic shielding performance of the material is improved, but the excessively high filler content can increase the production cost of the material, and simultaneously can reduce the processability and mechanical property of the material, thereby limiting the industrial application of the material.

The electromagnetic interference shielding effectiveness (EMI SE) of CPCs is related not only to the conductive properties, but also to the internal structure of the composite. The reflection of electromagnetic waves is determined by impedance matching, which is related to the electrical conductivity of the material. The conductive losses contribute to the absorption of the incident wave. However, excessive conductive fillers can adversely affect other important properties of the CPCs, such as material cost, processability, mechanical reliability, and the like. In addition, too high conductivity causes high electromagnetic wave reflection, resulting in serious secondary electromagnetic radiation pollution.

Chinese patent CN104558777B discloses a preparation method of a low percolation graphene/high molecular electromagnetic shielding material, which utilizes high temperature in-situ reduction graphene oxide in the material hot pressing preparation process to avoid the agglomeration of graphene oxide in the chemical reduction process. The composite material has the advantages of lower conductive percolation value, higher conductivity and electromagnetic shielding performance, simple preparation process, easy control of the process, low production cost and easy realization of mass production.

Chinese patent CN106832522A discloses an electromagnetic shielding composite material with an oriented isolation structure and a preparation method thereof, wherein the isolation structure is constructed by utilizing the selective distribution of CNT on the surface of ultra-high molecular weight polyethylene (UHMWPE) particles, and simultaneously, the high orientation of an UHMWPE matrix phase along the extrusion direction is induced by utilizing a strong flow field provided by solid phase extrusion, so that the mechanical property is greatly enhanced, and the problem of insufficient mechanical property of a conductive polymer composite material with a conventional isolation structure is solved; the preparation process of the material is simple, any high-energy ultrasonic equipment and organic solvent are not needed, and industrialization is easy to realize.

Chinese patent CN106832522A authorizes a method for preparing natural graphite/polymer electromagnetic shielding composite material, which utilizes the low-cost NG as electromagnetic functional filler, and utilizes the selective distribution of the filler on the surface of polymer particles to construct an isolation structure, thereby obtaining the composite material with high electromagnetic shielding effectiveness under the condition of low NG content. The preparation process of the material is simple, only mechanical blending and compression molding are needed, no high-energy ultrasonic equipment or organic solvent is needed, the environment is protected, the production cost is low, and mass production is easy to realize.

The superconductive carbon black (SCCB) and the UHMWPE isolated structure CPCs related in the invention can be prepared by directly carrying out high-speed mechanical mixing and compression molding, high-energy equipment for auxiliary dispersion and any organic solvent are not needed in the production process, the process is easy to master, the environment is protected, the production cost is low, and mass production is easy to realize. As the conductive filler, the carbon black has rich sources and low price, a uniform conductive coating layer can be formed on the surface of the UHMWPE through high-speed mechanical mixing, the UHMWPE has high molecular chain entanglement and can effectively prevent SCCB from diffusing to the inside in a gel state in a melting process as a polymer matrix, so that the electromagnetic shielding composite material with high conductivity and EMI SE can be successfully prepared.

At present, few patents related to the CPCs of the isolation structure for electromagnetic shielding are available, and the successful application of SCCB in the CPCs of the UHMWPE-based isolation structure to realize excellent electromagnetic shielding performance of materials is not reported. Nor is there a patent literature for the preparation of SCCB/polymer electromagnetic shielding composites by high speed mechanical mixing and press molding.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of a UHMWPE/PP/SCCB electromagnetic shielding composite material with high strength and high toughness by adopting a plastic alloy conductive filler filling modification method, thereby obtaining a new material with high performance and functionalization, improving the mechanical performance of plastic alloy application and realizing the industrial application of the electromagnetic shielding effectiveness of products.

In order to realize the purpose of the invention, the specific technical scheme is as follows:

the electromagnetic shielding composite material with high strength and high toughness comprises the following components in parts by weight:

1) the components are proportioned as follows:

85-95 parts of UHMWPE powder, 1-15 parts of superconducting carbon black (SCCB), 5-15 parts of PP powder, 0.1-0.5 part of compound antioxidant and 0.1-0.5 part of coupling agent.

The UHMWPE is powder, the particle size distribution range is 30-200 mu m, the number average molecular weight is 250-650 ten thousand g/mol, and the tensile strength is more than or equal to 38 MPa.

The PP powder adopts the following trade marks: PPH-T03, melt flow rate of 3g/10min, particle size distribution range of 200-600 μm, and product provided by the Branch of China petrochemical company Limited.

The superconducting carbon black, brand: yiborui, model: F900A, nitrogen adsorption specific surface of 750-1100 m2/Kg, DBP absorption value of 450ml/g, particle size range of 9-17 nm, superconducting carbon black is subjected to surface modification by a coupling agent, and the preparation method comprises the following steps: mixing superconducting carbon black and a coupling agent according to a mass ratio of 15: 0.1-0.5 part by weight, adding into a high-speed blender, keeping the rotating speed at 500-1000 rpm, and stirring at high speed for 5-30 min.

The coupling agent is a silane coupling agent or a titanate coupling agent.

The compound antioxidant is compounded by an antioxidant 1010 and an antioxidant 168 (the mass ratio is 2: 1).

2) The preparation method comprises the following steps:

A. and (3) drying: respectively drying UHMWPE, PP and SCCB powder in a drying oven for 4-6 h at 60 ℃;

B. weighing: weighing dried UHMWPE, PP and SCCB powder and a compound antioxidant according to the parts by weight;

C. modification of superconducting carbon black coupling agent: adding the superconducting carbon black, the coupling agent and diluent ethanol into a high-speed mixer, keeping the rotating speed at 500-1000 rpm, and stirring at high speed for 5-30 min to obtain a superconducting carbon black coupling agent modified product;

D. blending: c, placing the weighed UHMWPE powder, PP powder, antioxidant and the superconducting carbon black coupling agent modified product prepared in the step C into a high-speed kneading machine to be mixed for 5-8 min at a high speed, and realizing uniform coating of SCCB on the UHMWPE/PP surface through high-speed mechanical mixing, wherein the rotating speed of the high-speed mixing machine is 24000 rpm;

E. compression molding: and putting the fully and uniformly mixed raw materials into a mould, heating at the high temperature of 200-220 ℃ and carrying out hot pressing for 15min under the pressure condition of 17MPa, so that the mixture is fully melted and plasticized in a melting cavity of the mould, then carrying out cold pressing for 20min at the room temperature of 17MPa, fully cooling, and demoulding, thereby obtaining the UHMWPE/PP/SCCB composite material with high strength, high toughness and high electromagnetic shielding effectiveness.

After the technical scheme is adopted, the invention has the following characteristics and advantages: 1. the product has the characteristics of high strength, high toughness, better hardness and the like; 2. the product has higher conductive performance; 3. a plastic conductive modification method is adopted to obtain a high-performance and specialized new material, so that the mechanical property of the plastic alloy is improved; 4. realizing special functions of the product, such as electromagnetic shielding effectiveness and antistatic application.

Drawings

FIG. 1 shows the mechanical properties of the UHMWPE/PP/SCCB conductive composite material.

FIG. 2 shows the electromagnetic shielding effectiveness of the UHMWPE/PP/SCCB conductive composite material of the invention.

FIG. 3 is an FE-SEM topography of the UHMWPE/PP/SCCB conductive composite material of the invention.

Detailed Description

The UHMWPE adopted in the following embodiment of the invention is powder with the particle size distribution range of 30-200 mu m, the number average molecular weight of 250-650 ten thousand g/mol and the tensile strength of more than or equal to 38MPa from Shanghai Lianle chemical technology Limited company; the adopted PP powder material has the following brand: PPH-T03, melt flow rate of 3g/10min, small micro-bead powder with particle size distribution range of 200-600 mu m, and a product in the prior art; the adopted superconducting carbon black has the following brand: yiborui, model: F900A, nitrogen adsorption specific surface of 750-1100 m²(iii) powder with a DBP absorption value of 450ml/g and a particle size range of 9-17 nm.