阅读说明：本技术 一种精确控制磁性粒子轴向分布的磁流变弹性体及其制备方法 (Magnetorheological elastomer capable of accurately controlling axial distribution of magnetic particles and preparation method thereof ) 是由 郭训忠 王辉 陶杰 胡胜寒 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种精确控制磁性粒子轴向分布的磁流变弹性体及其制备方法,首先根据目标磁流变弹性体在某一轴向上的磁流变效应变化要求,将目标磁流变弹性体按照一定分割顺序分割为若干段磁流变效应单体,预制所述磁流变效应单体,每一段磁流变效应单体具有一个特定的磁性粒子所占质量分数；将预制得到的磁流变效应单体按顺序叠放在与所述三维模型形状一致的最终定型模具中,将组合体经加温加压成形后得到目标磁流变弹性体。本发明所制备的磁流变弹性体通过精确控制每份磁流变效应单体中的磁性粒子含量,使其所产生的磁流变效应在轴向产生梯度分布,满足作为压力成形复杂曲面金属构件介质的需求。(The invention discloses a magnetorheological elastomer for accurately controlling the axial distribution of magnetic particles and a preparation method thereof, which comprises the steps of firstly dividing a target magnetorheological elastomer into a plurality of sections of magnetorheological effect monomers according to a certain division sequence according to the change requirement of the magnetorheological effect of the target magnetorheological elastomer in a certain axial direction, prefabricating the magnetorheological effect monomers, wherein each section of the magnetorheological effect monomers has a mass fraction of a specific magnetic particle; and stacking the prefabricated magnetorheological effect monomers in a final shaping mold with the shape consistent with that of the three-dimensional model in sequence, and heating and pressurizing the combined body to form the target magnetorheological elastomer. The magneto-rheological elastomer prepared by the invention enables the magneto-rheological effect generated by the magneto-rheological elastomer to generate gradient distribution in the axial direction by accurately controlling the content of magnetic particles in each magneto-rheological effect monomer, and meets the requirement of serving as a medium for pressure forming of a complex curved surface metal component.)

1. A preparation method of a magnetorheological elastomer for accurately controlling the axial distribution of magnetic particles is characterized by comprising the following preparation steps: (1) obtaining a target magnetorheological elastomer three-dimensional model, dividing the target magnetorheological elastomer into a plurality of sections of magnetorheological effect monomers according to a certain dividing sequence according to the requirement of the magnetorheological effect change of the target magnetorheological elastomer in a certain axial direction, and prefabricating the magnetorheological effect monomers, wherein each section of the magnetorheological effect monomers has a mass fraction of a specific magnetic particle; (2) and stacking the prefabricated magnetorheological effect monomers in a final shaping mold with the same shape as the three-dimensional model in sequence to obtain a combined body which has the same shape as the target magnetorheological elastomer and meets the change requirement of the magnetorheological effect, and heating and pressurizing the combined body to obtain the target magnetorheological elastomer.

2. The method of claim 1, wherein: the specific method for prefabricating the magnetorheological effect monomer comprises the following steps: (A) weighing the magnetic particles, the substrate material and the additive according to the mass fraction of the magnetic particles corresponding to each section of the magnetorheological effect monomer; uniformly mixing a base material and an additive, and placing the obtained mixture in an oven for preheating for 3-5 min to reduce resistance on the movement of subsequently added magnetic particles in a rubber matrix, so that the magnetic particles can form an ordered structure conveniently; (B) stirring and mixing the magnetic particles and the mixture obtained in the step (A) for 10-15 min by a high-speed stirrer, so that the magnetic particles are uniformly distributed in the substrate material; (C) vacuumizing the mixture obtained in the step (B) for 30min by using a vacuum pump to remove bubbles in the mixture; (D) and placing the mixture obtained after vacuumizing in a monomer shaping mold, then placing the monomer shaping mold in a uniform magnetic field generated by two permanent magnets to enable the magnetic particles to be distributed in a structured manner, and taking out the mixture after the mixture is cured and molded to obtain the magnetorheological effect monomer.

3. The method of claim 1, wherein: the segmentation is an equal division.

4. The method of claim 2, wherein: the matrix material adopts unvulcanized natural rubber latex solution, the magnetic particles are carbonyl iron powder, and the additive comprises an initiator and a vulcanization accelerator.

5. The method of claim 2, wherein: the specific method of the step (2) is as follows: and (2) placing the magnetorheological effect monomers prepared in the step (1) into a final shaping mold according to the sequence that the mass fractions of the magnetic particles are increased or decreased progressively or increased progressively and then decreased progressively, pressurizing at two ends of the final shaping mold, and putting the whole shaping mold into an oven for heating to bond contact surfaces of the magnetorheological effect monomers and finally curing and forming to obtain the target magnetorheological elastomer.

6. The method of claim 2, wherein: the circular truncated cone magnetorheological elastomer is prepared in the step (1), the magnetorheological elastomer to be prepared is divided into 8 equal parts along the axial direction of the vertical bottom surface of the circular truncated cone, the content of the added magnetic particles in each part is 10%, 20%, 30%, 40%, 50%, 60%, 70% and 80%, the content of the corresponding rubber matrix is 80%, 70%, 60%, 50%, 40%, 30%, 20% and 10%, and the content of the additive is 10%.

7. The method of claim 2, wherein: preparing the drum magnetorheological elastomer in the step (1), dividing the magnetorheological elastomer to be prepared into 7 equal parts in the axial direction according to the shape of the drum-shaped component to be formed, wherein the content of the added magnetic particles in each part is 20%, 40%, 60%, 80%, 60%, 40% and 20%, the content of the corresponding rubber matrix is 70%, 50%, 30%, 10%, 30%, 50% and 70%, and the content of the additive is 10%.

8. The method of claim 2, wherein: preparing the cylindrical magnetorheological elastomer in the step (1), dividing the magnetorheological elastomer to be prepared into 7 equal parts in the length direction, wherein the content of the added magnetic particles in each part is 80%, 60%, 40%, 20%, 40%, 60% and 80%, the content of the corresponding rubber matrix is 10%, 30%, 50%, 70%, 50%, 30% and 10%, and the content of the additive is 10%.

9. The method of claim 2, wherein: the monomer shaping mould and the final shaping mould are made of high-pressure polyethylene.

10. The magnetorheological elastomer with the accurately controlled axial distribution of the magnetic particles obtained by the preparation method according to any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of intelligent materials, and particularly relates to a magnetorheological elastomer for accurately controlling the axial distribution of magnetic particles and a preparation method thereof.

Background

The magnetorheological elastomer is a novel magnetorheological intelligent material, is formed by solidifying natural rubber or artificial rubber, micron-level ferromagnetic particles and additives under the action of a magnetic field, and has the advantages of stable magnetic particles, difficult sedimentation, high response speed, low preparation cost and the like compared with magnetorheological fluid. The magnetorheological elastomers can be divided into isotropic magnetorheological elastomers and anisotropic magnetorheological elastomers according to whether the performances in different directions are the same. The mechanical property of the anisotropic magnetorheological elastomer can be controlled by the content and distribution condition of magnetic particles contained in the anisotropic magnetorheological elastomer, the intensity and the direction of an external magnetic field, so that the anisotropic magnetorheological elastomer is wider than the isotropic magnetorheological elastomer in engineering application and is more difficult in a preparation method. In order to realize that the magneto-rheological effects generated in different directions in the magneto-rheological elastomer are different or are in gradient distribution under the action of a certain uniform magnetic field, the problem becomes one of the problems to be solved urgently in the preparation process of the magneto-rheological elastomer.

Disclosure of Invention

The invention provides a magnetorheological elastomer for accurately controlling the axial distribution of magnetic particles and a preparation method thereof aiming at the defects of the prior art.

A preparation method of a magnetorheological elastomer for accurately controlling the axial distribution of magnetic particles comprises the following preparation steps: (1) obtaining a target magnetorheological elastomer three-dimensional model, dividing the target magnetorheological elastomer into a plurality of sections of magnetorheological effect monomers according to a certain dividing sequence according to the requirement of the magnetorheological effect change of the target magnetorheological elastomer in a certain axial direction, and prefabricating the magnetorheological effect monomers, wherein each section of the magnetorheological effect monomers has a mass fraction of a specific magnetic particle; (2) and stacking the prefabricated magnetorheological effect monomers in a shaping mold with the same shape as the three-dimensional model in sequence to obtain a combined body which has the same shape as the target magnetorheological elastomer and meets the change requirement of the magnetorheological effect, and heating and pressurizing the combined body to obtain the target magnetorheological elastomer.

The preparation method comprises the following specific steps of prefabricating the magnetorheological effect monomer: (A) weighing the magnetic particles, the substrate material and the additive according to the mass fraction of the magnetic particles corresponding to each section of the magnetorheological effect monomer; uniformly mixing a base material and an additive, and placing the obtained mixture in an oven for preheating for 3-5 min to reduce resistance on the movement of subsequently added magnetic particles in a rubber matrix, so that the magnetic particles can form an ordered structure conveniently; (B) stirring and mixing the magnetic particles and the mixture obtained in the step (A) for 10-15 min by a high-speed stirrer, so that the magnetic particles are uniformly distributed in the substrate material; (C) vacuumizing the mixture obtained in the step (B) for 30min by using a vacuum pump to remove bubbles in the mixture; (D) and placing the mixture obtained after vacuumizing in a monomer shaping mold, then placing the monomer shaping mold in a uniform magnetic field generated by two permanent magnets to enable the magnetic particles to be distributed in a structured manner, and taking out the mixture after the mixture is cured and molded to obtain the magnetorheological effect monomer.

According to the preparation method, the segmentation is divided into equal parts.

In the preparation method, the matrix material adopts unvulcanized natural rubber latex solution, the magnetic particles are carbonyl iron powder, and the additives comprise an initiator and a vulcanization accelerator.

The preparation method comprises the following specific steps of (2): and (2) placing the magnetorheological effect monomers prepared in the step (1) into a final shaping mold according to the sequence that the mass fractions of the magnetic particles are increased or decreased progressively or increased progressively and then decreased progressively, pressurizing at two ends of the final shaping mold, and putting the whole shaping mold into an oven for heating to bond contact surfaces of the magnetorheological effect monomers and finally curing and forming to obtain the target magnetorheological elastomer.

The preparation method comprises the step (1) of preparing the circular truncated cone magnetorheological elastomer, wherein the magnetorheological elastomer to be prepared is divided into 8 equal parts along the axial direction of the vertical bottom surface of the circular truncated cone, the content of the added magnetic particles in each part is respectively 10%, 20%, 30%, 40%, 50%, 60%, 70% and 80%, the content of the corresponding rubber matrix is respectively 80%, 70%, 60%, 50%, 40%, 30%, 20% and 10%, and the content of the additive is 10%.

According to the preparation method, the drum-shaped magnetorheological elastomer is prepared in the step (1), the magnetorheological elastomer to be prepared is axially divided into 7 equal parts according to the shape of the drum-shaped member to be formed, the content of the added magnetic particles in each part is respectively 20%, 40%, 60%, 80%, 60%, 40% and 20%, the content of the corresponding rubber matrix is respectively 70%, 50%, 30%, 10%, 30%, 50% and 70%, and the content of the additive is 10%.

The preparation method comprises the step (1) of preparing the cylindrical magnetorheological elastomer, wherein the magnetorheological elastomer to be prepared is divided into 7 equal parts in the length direction, the content of the added magnetic particles in each part is 80%, 60%, 40%, 20%, 40%, 60% and 80%, the content of the corresponding rubber matrix is 10%, 30%, 50%, 70%, 50%, 30% and 10%, and the content of the additive is 10%.

In the preparation method, the monomer shaping mold and the final shaping mold are made of high-pressure polyethylene.

The magnetorheological elastomer capable of accurately controlling the axial distribution of the magnetic particles is prepared by the preparation method.

The invention has the following beneficial effects: according to the invention, carbonyl iron powder and an additive are mixed into a natural rubber latex solution to prepare a magnetorheological effect monomer, and then a plurality of magnetorheological effect monomers are bonded and cured into a target magnetorheological elastomer in a pressurizing and heating manner. The formula of the invention is reasonable in design, raw materials are easy to purchase, and the process route is easy to implement. The preparation method of the magnetorheological elastomer reduces the motion resistance of the magnetic particles in the rubber matrix, enables the distribution and the content of the magnetic particles in the rubber matrix to be accurately controlled, improves the distribution of the magnetic particles in the thickness direction of the cylindrical magnetorheological elastomer, improves the magnetorheological effect of the magnetorheological elastomer, and is suitable for preparing the magnetorheological elastomer with anisotropy and certain requirements on mechanical and physical properties.

Drawings

FIG. 1 is a schematic view of a magnetorheological elastomer for preparing a pressure forming medium for a circular truncated cone member according to the present invention;

FIG. 2 is a schematic view of a magnetorheological elastomer for making a pressure forming medium for a drum shaped member in accordance with the present invention;

FIG. 3 is a schematic representation of a magnetorheological elastomer for making a cylindrical member pressure forming medium according to the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples.