阅读说明：本技术 一种单向热固性芳纶纤维复合材料及制备方法 (Unidirectional thermosetting aramid fiber composite material and preparation method thereof ) 是由 冯平法 查慧婷 徐捷 冯峰 张彤 于 2020-11-13 设计创作，主要内容包括：本发明提供一种单向热固性芳纶纤维复合材料及制备方法,制备方法包括：S1.将单向芳纶纤维预浸料按照设定的尺寸裁剪为单层预浸料,并将裁剪后的单层预浸料按照设定的方向进行单个方向的铺层以形成预浸料叠层；S2.将预浸料叠层进行预热并压实预浸料叠层；S3.将预热压实后的预浸料叠层放置于模具中加热并保压；S4.将步骤S3获得的产品进行冷却并形成热固性芳纶纤维复合材料。利用本方法可以制备出纯单向的热固性芳纶纤维复合材料,且制备方法工艺方便简单,可操作性强,适用于小批量和对材料单向性能有特殊要求的试件生产。(The invention provides a unidirectional thermosetting aramid fiber composite material and a preparation method thereof, wherein the preparation method comprises the following steps: s1, cutting unidirectional aramid fiber prepreg into single-layer prepreg according to a set size, and layering the cut single-layer prepreg in a single direction according to a set direction to form prepreg lamination; s2, preheating and compacting the prepreg lamination; s3, placing the preheated and compacted prepreg laminate in a mould to be heated and pressure-maintained; and S4, cooling the product obtained in the step S3 and forming the thermosetting aramid fiber composite material. The method can be used for preparing the pure unidirectional thermosetting aramid fiber composite material, has convenient and simple process and strong operability, and is suitable for the production of small-batch test pieces with special requirements on the unidirectional performance of the material.)

1. A preparation method of a unidirectional thermosetting aramid fiber composite material is characterized by comprising the following steps:

s1, cutting unidirectional aramid fiber prepreg into single-layer prepreg according to a set size, and layering the cut single-layer prepreg in a single direction according to a set direction to form prepreg lamination;

s2, preheating and compacting the prepreg lamination;

s3, placing the preheated and compacted prepreg laminate in a mould to be heated and pressure-maintained;

and S4, cooling the product obtained in the step S3 and forming the thermosetting aramid fiber composite material.

2. The method of claim 1, wherein the reinforcing phase of the unidirectional aramid fiber prepreg comprises one or more of para-aramid fiber 1414, kevlar, and ar 2; the matrix phase comprises one or more of E51 epoxy resin and E31 epoxy resin.

3. The method of claim 1, wherein the direction set in step S1 includes: one of 0 °, 45 °, 90 °, 135 °.

4. The method of claim 1, wherein the preheating in step S2 is performed by a hot air blower and a molding press.

5. The method of claim 4, wherein the preheating temperature is from 65 ℃ to 75 ℃.

6. The method according to claim 1, wherein the mold is made of a material that is less deformed during heating and pressure holding, and the mold is a steel mold.

7. The method of claim 6, wherein the steel mold comprises SKD61 hot-work die steel or SKD5 high-temperature die steel.

8. The production method according to claim 1, wherein a temperature rise rate during the heating in the step S3 is 2 ℃/min to 3 ℃/min; the heat preservation temperature is 125-134 ℃, and the heat preservation time is 30 min.

9. The method of claim 1, wherein the cooling rate of the cooling process in the step S4 is 5 ℃/min to 7 ℃/min.

10. A unidirectional thermosetting aramid fiber composite material characterized by being produced by the production method of the unidirectional thermosetting aramid fiber composite material as recited in any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of aramid fiber composite materials, in particular to a unidirectional thermosetting aramid fiber composite material and a preparation method thereof.

Background

Aramid fiber reinforced composites (AFRP) have numerous excellent physical and mechanical properties: high hardness, high heat resistance, high chemical stability, high specific strength, high specific modulus and the like. In recent years, the material is widely accepted due to excellent mechanical properties, especially in the aspects of light weight and high bulletproof property, so that the material has wide application prospects in the armor protection fields of aerospace, special vehicles, naval vessels, tanks and the like. However, these advantages become a difficult problem for the machining field. Due to the limitations of the state of the art and production costs, the following problems often arise in the machining of AFRP: (1) burr and edge breakage, (2) tearing and layering, (3) subsurface damage, (4) burning, (5) debonding of a fiber substrate, and (6) processing problems such as substrate breakage and fiber instability. These problems seriously affect the processing quality and efficiency, greatly increase the production cost, and further limit the application range of the material. In the prior art, the material preparation method is mainly used for materials with a woven structure, a multidirectional layering structure or a multi-material laminating structure, but composite materials with a pure unidirectional layering structure are few. The two methods not only consume expensive manpower and material resources and have high production cost, but also are only suitable for small-batch production of large-scale parts (both aiming at large-scale production of military and civil enterprises), are not suitable for large-batch production of medium and small enterprises and manufacture of special parts. On the other hand, in the scientific research field, for example, when the mechanical processing problem of the material is researched, the research of the aramid fiber composite material with woven and multidirectional layers is very difficult due to the complexity and multifactorial properties of the structure, and quantitative mechanism research and analysis cannot be carried out.

Disclosure of Invention

In order to solve the problems, the invention provides a unidirectional thermosetting aramid fiber composite material and a preparation method thereof; the aramid fiber composite material is single in fiber direction, convenient and simple in preparation process, strong in operability, suitable for production of test pieces with special requirements on material one-way performance in small batches, and low in production cost.

The invention provides a preparation method of a unidirectional thermosetting aramid fiber composite material, which comprises the following steps: s1, cutting unidirectional aramid fiber prepreg into single-layer prepreg according to a set size, and layering the cut single-layer prepreg in a single direction according to a set direction to form prepreg lamination; s2, preheating and compacting the prepreg lamination; s3, placing the preheated and compacted prepreg laminate in a mould to be heated and pressure-maintained; and S4, cooling the product obtained in the step S3 and forming the thermosetting aramid fiber composite material.

In some embodiments, the reinforcing phase of the unidirectional aramid fiber prepreg comprises one or more of para-aramid fiber 1414, kevlar, ar 2; the matrix phase comprises one or more of E51 epoxy resin and E31 epoxy resin.

In some embodiments, the directions set in step S1 include: one of 0 °, 45 °, 90 °, 135 °.

In some embodiments, the preheating in step S2 is performed by a hot air blower and a molding press, and the preheating temperature is 65 ℃ to 75 ℃.

In some embodiments, the material of the mold is a steel mold, which can satisfy the requirement of small deformation during heating and pressure maintaining. The steel mould comprises SKD61 hot work die steel or SKD5 high temperature die steel.

In some embodiments, the temperature increase rate during the heating in the step S3 is 2 ℃/min to 3 ℃/min; the heat preservation temperature is 125-134 ℃, and the heat preservation time is 30 min.

In some embodiments, the cooling rate of the cooling process in the step S4 is 5 ℃/min-7 ℃/min.

The invention also provides a unidirectional thermosetting aramid fiber composite material which is prepared by the preparation method of the unidirectional thermosetting aramid fiber composite material.

The invention has the beneficial effects that: the preparation method provided by the invention is convenient and simple in process and strong in operability, is suitable for the production of small-batch test pieces with special requirements on the unidirectional performance of the material, and can be used for preparing test pieces (unidirectional thermosetting aramid fiber composite material) with the same fiber angle according to actual requirements. In addition, for the unidirectional aramid fiber laminated plate parts with smaller size and less stacking quantity, the preparation method can replace the autoclave forming process with higher cost and longer time to a certain extent.

Drawings

Fig. 1 is a schematic structural diagram of a preparation mold in an embodiment of the present invention.

FIG. 2 shows the ply direction of a unidirectional aramid fiber prepreg in an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a unidirectional thermosetting aramid fiber composite material in an embodiment of the present invention.

Fig. 4 is an application example of the unidirectional thermosetting aramid fiber composite material in the embodiment of the present invention.

Detailed Description

The present invention is described in further detail below with reference to specific embodiments and with reference to the attached drawings, it should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

Designing a special mold according to actual needs, wherein the mold for preparing the unidirectional aramid fiber composite material shown in fig. 1 comprises a female mold 101 and a male mold 102 which are matched with each other, and the material of the mold needs to meet the requirement that the deformation is small enough in the subsequent high-temperature and low-temperature states, so that the precision of the prepared unidirectional thermosetting aramid fiber composite material is ensured; the mold in the embodiment is made of steel, and can be made of P20 steel, SKD61 hot-working die steel, SKD5 high-temperature die steel and the like, and the service life of the steel mold can reach more than 10000 times.

The preparation method of the unidirectional thermosetting aramid fiber composite material by utilizing the special die comprises the following steps:

s1, cutting unidirectional aramid fiber prepreg into single-layer prepreg according to a set size, and performing single-direction laying on the cut single-layer prepreg according to a set direction to form prepreg lamination.

The unidirectional aramid fiber prepreg adopts any one of the unidirectional aramid fiber prepregs in the prior art. The unidirectional aramid fiber prepreg comprises a reinforcing phase and a matrix phase, wherein the reinforcing phase can be any one or more of para-aramid fiber 1414, Kevlar and aramid fiber 2; the matrix phase can be one or more of epoxy E51 and epoxy E31.

And cutting the unidirectional aramid fiber prepreg according to the size of a special die to obtain the single-layer prepreg. Such as: and the length, width and height of the die are 105mm x 6mm, and the unidirectional aramid fiber prepreg is cut into a specification of 100mm x 100 mm. The thickness of the unidirectional aramid fiber prepreg is different according to the selected material types, and the unidirectional aramid fiber prepreg with a single-layer thickness range of about 0.1-0.15mm is generally preferred, and the unidirectional aramid fiber prepreg with a thickness of about 0.1mm is preferred. If the reinforcing phase is para-aramid fiber 1414 and the basic phase is epoxy resin E51, the single-layer thickness of the reinforcing phase is 0.12-0.15 mm, and the gram weight is 100g/m²The fiber content volume fraction is about 60-70%.

And after cutting, laying according to a certain single direction, wherein the laying direction of each single-layer prepreg is consistent so as to ensure that the finally molded product has unidirectionality. As shown in fig. 2, the ply direction may be one of directions such as 0 °, 45 °, 90 °, 135 °, or may be other single directions.

S2, preheating the prepreg lamination and compacting the prepreg lamination.

The one-way aramid fiber prepreg spread with the layers is preheated after being coated with a release paper film, and can be preheated by means of an air heater, a molding press and the like. The pre-heating temperature is preferably set at 65 ℃ to 70 ℃, at which temperature the epoxy resin in the prepreg softens, further compacting the prepreg layup and venting some of the air.

And S3, placing the preheated and compacted prepreg laminate in a mould for heating and maintaining pressure.

After the prepreg lamination is compacted, the mould is heated at a certain heating rate and then is insulated. In this embodiment, the mold is first heated to 80 ℃, then the heating temperature gradient is increased to 125-134 ℃ at a rate of 2-3 ℃/min, and the pressure is set to 1Mpa during the temperature increase process. And after the temperature rise is finished, preserving the heat of the glass fiber for 30 min. The temperature rising and heat preservation process is to carry out thermosetting on the aramid fiber composite material.

And S4, cooling the product obtained in the step S3 and forming the thermosetting aramid fiber composite material.

And after heating and heat preservation, cooling the product at a certain cooling rate. In the embodiment, the temperature is reduced to 60 ℃ at the speed of 5-7 ℃/min, the mold is opened, and the material is taken out, so that the unidirectional thermosetting aramid fiber composite material can be obtained, and the finally formed composite material structure is shown in fig. 3.

The preparation method provided by the invention is convenient and simple in process and strong in operability, is suitable for the production of small-batch test pieces with special requirements on the unidirectional performance of the material, and can be used for preparing test pieces (unidirectional thermosetting aramid fiber composite material) with the same fiber angle according to actual requirements. The test piece can be used for researching the influence of different processing parameters on the processing quality under the same fiber angle, or the influence of the same processing parameters and different processing modes on the surface quality and the processing efficiency under the same fiber angle. The researches can improve the production efficiency and the processing quality, provide important guiding significance for actual production, provide theoretical guarantee for the application prospect of the aramid fiber, and can be used for processing special parts with high requirements on unidirectional strength and applied to the fields of aerospace, military industry and the like. In addition, for the unidirectional aramid fiber laminated plate parts with smaller size and less stacking quantity, the method can replace the autoclave forming process with higher cost and longer time to a certain extent.

As shown in fig. 4, an orthogonal cutting experiment was performed using the unidirectional aramid fiber composite material prepared as above, and the unidirectional aramid fiber composite material 401 was fixed on a force measuring gauge 403 by a jig (vise) 402, cut by a cutter 404, and then output a cutting force generated during the cutting process. On the platform, the influence of different cutting speeds, cutting thicknesses, cutting depths and cutter geometric relations on different fiber laying directions can be researched.

The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention.