阅读说明：本技术 一种协同增强高温聚合物多元纳米复合材料 (Synergistic enhanced high-temperature polymer multi-element nano composite material ) 是由 张嘎 王伟 郭月霞 赵福燕 张利刚 李贵涛 于 2020-12-24 设计创作，主要内容包括：本发明涉及一种协同增强高温聚合物多元纳米复合材料,该材料是指将干燥后的质量分数为0.2~20%的纳米尺度凹凸棒石与质量分数为2~60%的微米尺度硬质颗粒同时添加到干燥后的质量分数为30~97%的高温聚合物基体中,搅拌混合或熔融共混至均匀后,经热压成型或注塑成型工艺制得。本发明高温聚合物多元复合材料成分与结构相对简单,在干摩擦条件下表现出极低的摩擦系数与磨损率；同时制备工艺简便,加工成本低、效率高,产品加工精度高。(The invention relates to a synergistically enhanced high-temperature polymer multielement nano composite material, which is prepared by adding 0.2-20% of dried nanoscale attapulgite and 2-60% of dried micron-scale hard particles into a dried high-temperature polymer matrix with the mass fraction of 30-97%, stirring, mixing or melting and blending uniformly, and then carrying out hot press molding or injection molding. The high-temperature polymer multi-element composite material has relatively simple components and structure, and shows extremely low friction coefficient and wear rate under the dry friction condition; meanwhile, the preparation process is simple and convenient, the processing cost is low, the efficiency is high, and the product processing precision is high.)

1. A synergistically enhanced high temperature polymer multicomponent nanocomposite characterized by: simultaneously adding the dried nanoscale attapulgite with the mass fraction of 0.2-20% and the dried micron-scale hard particles with the mass fraction of 2-60% into the dried high-temperature polymer matrix with the mass fraction of 30-97%, stirring, mixing or melting and blending until the mixture is uniform, and then carrying out hot press molding or injection molding to obtain the attapulgite/hard particle composite material.

2. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the rod crystal length of the nanoscale attapulgite is 0.2-800 mu m, and the diameter of the rod crystal is 5-800 nm.

3. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the micron-scale hard particles refer to one or a mixture of chopped glass fibers, chopped basalt fibers, chopped aramid fibers, chopped carbon fibers, silicon carbide fibers, whiskers, chopped metal fibers and hard ceramic particles.

4. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the high-temperature polymer is one of polyether-ether-ketone, polyimide, polyamide-imide and polyphenylene sulfide.

5. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the stirring and mixing conditions mean that the rotating speed is 25000 r/min and the time is 3 min.

6. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the conditions of melt blending refer to the conditions that the first zone heating temperature of the double-screw extruder is 370-375 ℃, the second zone heating temperature is 380-385 ℃, the third zone heating temperature is 390-395 ℃, the fourth zone heating temperature is 400-405 ℃, and the screw rotating speed is 350 rpm.

7. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the hot-press molding conditions are that the preheating temperature is set to be 400 ℃, the hot-press heat preservation temperature is 360 ℃, the pressure is 5MPa, the heat preservation time is 1h, and the room temperature cooling is carried out, wherein the cooling pressure is 15 MPa.

8. The synergistically enhanced high temperature polymer multicomponent nanocomposite according to claim 1, wherein: the conditions of the injection molding are that the temperature of an injection mold is 185 ℃, the temperature of an injection cylinder is 380 ℃, the injection back pressure is 3MPa, and the injection pressure is 170 MPa.

Technical Field

The invention relates to the field of self-lubricating material technology and application, in particular to a synergetic enhanced high-temperature polymer multielement nanocomposite.

Background

The self-lubricating material is a functional material which can provide continuous lubrication by itself without adding a lubricant during the working process. The polymer material has the characteristics of self-lubricating property, high chemical stability, shock absorption, noise reduction and the like, and is widely applied to the fields of automobiles, industrial equipment and the like. With the development of equipment technology, more and more motion mechanisms are in service under more severe working conditions, such as higher load, speed, temperature and the like, and the service life and reliability of the mechanisms are challenged. The development of a novel high-performance polymer self-lubricating material has important significance for prolonging the service life and improving the reliability of a motion mechanism.

Research shows that in the friction process, if a transfer film with high bearing capacity and easy shearing property is formed on the interface of the polymer self-lubricating material and the metal matching pair, the friction and the abrasion of the friction pair can be obviously reduced, and the service life of the material is prolonged [ polymer material science and engineering, 2020, 36, 165-containing material 172 ]. However, pure polymeric materials tend to have poor wear and self-lubricating properties. The conventional way to improve the tribological properties of polymer materials is to add solid lubricants (such as graphite, molybdenum disulfide, polytetrafluoroethylene, etc.) and reinforcing fillers (such as hard particles and fibers, etc.) [ Wear, 2010, 268, 893-899]

Attapulgite is a crystalline hydrated magnesium aluminum silicate mineral, has a layer chain structure, and is a common adsorbing material. Previous studies show that the mechanical properties of the material can be improved by adding the nano-scale attapulgite into a polymer matrix [ Composite Interfaces, 2019, 27, 73-85; Composite Part A: Applied Science and Manufacturing, 2009, 40, 1785-1791 ]. The wear resistance of the matrix material can be improved to a certain extent by adding attapulgite into the polypropylene matrix [ Macromolecular Materials and Engineering, 2005, 195-201 ]. So far, there are few systematic reports on the tribological properties of attapulgite-filled polymer materials.

Disclosure of Invention

The invention aims to solve the technical problem of providing a synergistic enhanced high-temperature polymer multielement nano composite material with good friction performance.

In order to solve the above problems, the present invention provides a synergistically enhanced high temperature polymer multicomponent nanocomposite, which is characterized in that: simultaneously adding the dried nanoscale attapulgite with the mass fraction of 0.2-20% and the dried micron-scale hard particles with the mass fraction of 2-60% into the dried high-temperature polymer matrix with the mass fraction of 30-97%, stirring, mixing or melting and blending until the mixture is uniform, and then carrying out hot press molding or injection molding to obtain the attapulgite/hard particle composite material.

The rod crystal length of the nanoscale attapulgite is 0.2-800 mu m, and the diameter of the rod crystal is 5-800 nm.

The micron-scale hard particles refer to one or a mixture of chopped glass fibers, chopped basalt fibers, chopped aramid fibers, chopped carbon fibers, silicon carbide fibers, whiskers, chopped metal fibers and hard ceramic particles.

The high-temperature polymer is one of polyether-ether-ketone, polyimide, polyamide-imide and polyphenylene sulfide.

The stirring and mixing conditions mean that the rotating speed is 25000 r/min and the time is 3 min.

The conditions of melt blending refer to the conditions that the first zone heating temperature of the double-screw extruder is 370-375 ℃, the second zone heating temperature is 380-385 ℃, the third zone heating temperature is 390-395 ℃, the fourth zone heating temperature is 400-405 ℃, and the screw rotating speed is 350 rpm.

The hot-press molding conditions are that the preheating temperature is set to be 400 ℃, the hot-press heat preservation temperature is 360 ℃, the pressure is 5MPa, the heat preservation time is 1h, and the room temperature cooling is carried out, wherein the cooling pressure is 15 MPa.

The conditions of the injection molding are that the temperature of an injection mold is 185 ℃, the temperature of an injection cylinder is 380 ℃, the injection back pressure is 3MPa, and the injection pressure is 170 MPa.

Compared with the prior art, the invention has the following advantages:

1. according to the invention, the nano-attapulgite and the micron-scale hard particles are simultaneously added and uniformly dispersed into the high-temperature polymer matrix, and the high flash temperature and stress of the micron-scale hard particles on the friction interface are utilized to promote the friction sintering of the nano-attapulgite released on the friction interface into the transfer film with high bearing and easy shearing characteristics, so that the direct scraping of a friction pair is avoided.

2. The nanometer attapulgite and the micron hard particles in the invention show obvious synergistic antifriction and antiwear effects. The hard particles have a high elastic modulus, and bear a major load at the frictional interface, so that the stress and flash temperature of the actual contact area on the sliding interface are high. In the friction running-in stage, the attapulgite released at the interface can be mixed with residual polymer particles (part of which is thermally decomposed) under high stress and flash temperature conditions, compacted and finally friction-sintered to form a film. In the friction stabilization stage, the generation of the high-performance transfer film obviously inhibits the direct contact of a friction pair, and the friction and the abrasion of materials are greatly reduced.

3. The multi-element composite material of the invention shows extremely low friction coefficient and wear rate under dry friction condition. The direct comparison test result shows that compared with the pure high-temperature polymer matrix material, the wear resistance of the multielement composite material synergistically enhanced by the nano attapulgite and the micron hard particles can be improved by 50 times. In addition, compared with the composite material filled with the nano attapulgite or the micron hard particles respectively, the wear-resisting property of the multi-element composite material reinforced by the synergy of the nano attapulgite and the micron hard particles is greatly improved, and the friction coefficient is greatly reduced.

4. The multi-element self-lubricating nano composite material is used as a moving part (a sliding bearing, a joint sliding bearing, a sliding block, a thrust washer, a sealing ring and the like), can greatly improve the reliability and the service life of a moving mechanism, reduces the friction energy consumption, and has remarkable significance in energy conservation and emission reduction. Meanwhile, the high-temperature polymer multi-element composite material can be used for a long time under the severe working condition of more than 200 ℃, has excellent self-lubricating performance, and can reduce or avoid the maintenance of a movement mechanism.

5. The high-temperature polymer multi-element composite material disclosed by the invention is relatively simple in components and structure, does not need to add other additives, is simple and convenient in preparation process, is suitable for hot pressing or injection molding, is convenient for batch production, and is strong in operability, low in processing cost, high in efficiency and high in product processing precision.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

FIG. 1 is a graph showing the friction coefficient curves of the composite materials of example 1 of the present invention and comparative examples 1, 2 and 3.

FIG. 2 is a graph showing the characteristic wear rates of the composites of example 1 and comparative examples 1, 2 and 3 of the present invention.

Detailed Description

Example 1 a synergistically enhanced high temperature polymer multicomponent nanocomposite material comprising the following components: 87% of polyether-ether-ketone, 3% of nanoscale attapulgite (rod crystal length of 0.5 mu m and diameter of 70 nm) and 10% of short-cut carbon fiber.

Simultaneously adding the nano-scale attapulgite and the short carbon fibers into a polyether-ether-ketone matrix, and mechanically mixing for 3 min at the rotating speed of 25000 r/min to uniformly disperse the attapulgite and the short carbon fibers; setting the preheating temperature of a vulcanizing machine to be 400 ℃, adding uniformly dispersed polymer powder, carrying out hot-pressing heat preservation at 360 ℃, carrying out heat preservation for 1h under the pressure of 5MPa, cooling at room temperature under the cooling pressure of 15MPa, and carrying out hot-pressing molding to obtain the block material.

Example 2 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 69% of polyether-ether-ketone, 30% of short carbon fiber and 1% of nano-scale attapulgite (rod crystal length is 0.8 mu m, and diameter is 20 nm).

Firstly, adding the nano-scale attapulgite and the short carbon fiber into the polyether-ether-ketone powder for mechanical mixing. And then putting the powder which is uniformly mixed mechanically into a double-screw extruder for melting, mixing and extruding. The melt-extruded pellets were injection molded by an injection molding machine. The first zone heating temperature of the double-screw extruder is 370-375 ℃, the second zone heating temperature is 380-385 ℃, the third zone heating temperature is 390-395 ℃, the fourth zone heating temperature is 400-405 ℃, and the screw rotating speed is 350 rpm; the temperature of an injection mould of the injection machine is 185 ℃, the temperature of an injection tube is 380 ℃, the injection back pressure is 3MPa, and the injection pressure is 170 MPa.

Example 3 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 45% of polyether-ether-ketone, 50% of short carbon fiber and 5% of nano-scale attapulgite. The specification of the nano-scale attapulgite is the same as that of example 1.

The powder material of each component is mechanically stirred and mixed and then is hot-pressed to form a block material, and the processing parameters are the same as those of the embodiment 1.

Example 4 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 90% of polyether-ether-ketone powder, 2% of short carbon fiber and 8% of nano-scale attapulgite. The specification of the nano-scale attapulgite is the same as that of example 1.

The powder material of each component is mechanically stirred and mixed and then is hot-pressed to form a block material, and the processing parameters are the same as those of the embodiment 1.

Example 5 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 85% of polyether-ether-ketone powder, 10% of short carbon fiber and 5% of nano-scale attapulgite. The specification of the nano-scale attapulgite is the same as that of example 1.

The powder material of each component is mechanically stirred and mixed, and then is subjected to thermal injection molding to prepare a block material, and the processing parameters are the same as those of the example 2.

Example 6 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 30% of polyether-ether-ketone powder, 60% of short carbon fiber and 10% of nano-scale attapulgite. The specification of the nano-scale attapulgite is the same as that of example 1.

The powder material of each component is mechanically stirred and mixed and then is hot-pressed to form a block material, and the processing parameters are the same as those of the embodiment 1.

Example 7 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 97% of polyether-ether-ketone powder, 2.8% of short carbon fiber and 0.2% of nano-scale attapulgite. The specification of the nano-scale attapulgite is the same as that of example 1.

The powder material of each component is mechanically stirred and mixed and then is hot-pressed to form a block material, and the processing parameters are the same as those of the embodiment 1.

Example 8 a synergistically enhanced high temperature polymer multicomponent nanocomposite, comprising the following components: 70% of polyether-ether-ketone powder, 10% of short carbon fiber and 20% of nano-scale attapulgite. The specification of the nano-scale attapulgite is the same as that of example 1.

The powder material of each component is mechanically stirred and mixed, and then is subjected to thermal injection molding to prepare a block material, and the processing parameters are the same as those of the example 2.

In the above examples 1 to 8, the rod crystal length of the nano-scale attapulgite was 0.2 to 800 μm and the diameter was 5 to 800 nm. The content of each component is in percentage by mass and the unit is kg.

The micron-scale hard particles refer to one or a mixture of chopped glass fibers, chopped basalt fibers, chopped aramid fibers, chopped carbon fibers, silicon carbide fibers, whiskers, chopped metal fibers and hard ceramic particles.

The high-temperature polymer is one of polyether-ether-ketone, polyimide, polyamide-imide and polyphenylene sulfide.

Comparative example 1

Pure polyetheretherketone material: the 100 percent of polyether-ether-ketone powder material is subjected to hot-press molding to prepare a block material, and the hot-press processing parameters are the same as those in example 1.

Comparative example 2

The micron hard particle reinforced polyether-ether-ketone composite material comprises the following components in percentage by weight: 90% of polyether-ether-ketone and 10% of micron hard particles. The hard particles were of the same size as in example 1. The polyetheretherketone powder and the hard particle powder are mechanically stirred and mixed and then hot-pressed to form a block material, and the processing parameters are the same as those in example 1.

Comparative example 3

The nanometer attapulgite reinforced polyether-ether-ketone composite material comprises the following components in percentage by weight: 97% of polyether-ether-ketone and 3% of nano attapulgite. The polyetheretherketone powder and the nano attapulgite powder are mechanically stirred and mixed and then hot-pressed to form a block material, and the processing parameters are the same as those in example 1.

Comparative example 4

The nanometer attapulgite reinforced polyether-ether-ketone composite material comprises the following components in percentage by weight: 90% of polyether-ether-ketone and 10% of nano attapulgite. The polyetheretherketone powder and the nano attapulgite powder are mechanically stirred and mixed and then hot-pressed to form a block material, and the processing parameters are the same as those in example 1.

The materials described in examples 1 to 5 and comparative examples 1 to 4 were formed into a plate and processed into a thickness of 4X 12mm³Sample block ofAnd (3) inspecting the frictional wear performance of various materials by using a pin-disc friction tester, and repeating the test for at least 3 times.

The tribology test conditions were: the mating metal is GCr15 bearing steel, and the initial surface roughness R_a=0.25 μm, inner diameter of the steel ring 25mm, outer diameter 42 mm. The test load is 3MPa, the sliding speed is 1m/s, the friction and wear test time is 3h, and the friction is dry (no lubricating medium).

The friction coefficient of the material is measured in real time by a torque sensor and automatically recorded. The wear rate of the material was calculated by the following formula and the results are shown in table 1:

in the formula: Δ m is the loss (g) of the material before and after the experiment, ρ is the density (g/cm) of the material³) F is the pressure exerted on the polymer and L is the total sliding distance (m) during the friction test.

TABLE 1 measurement and calculation results of average friction coefficient and wear rate of materials prepared in examples and comparative examples