阅读说明：本技术 原位合成的pekk/cf复合材料的密度纯化法 (Density purification method of in-situ synthesized PEKK/CF composite material ) 是由 杨雪勤 马忠实 宣正伟 张亚东 于 2020-07-31 设计创作，主要内容包括：本发明通过材料密度间的差异,通过筛选溶剂和溶液,将原位合成的聚醚酮酮(PEKK)/碳纤维(CF)复合粉末与合成过程中未被PEKK包裹的CF粉末和未包裹CF的PEKK粉末进行分离,达到对原材料纯化的目的,提高PEKK/CF复合材料的纯度,该方法科学合理,简单可行,操作性强,也为其它粉末复合材料的纯化提供了借鉴。(According to the invention, through the difference between the densities of the materials, the polyether ketone (PEKK)/Carbon Fiber (CF) composite powder synthesized in situ is separated from the CF powder which is not coated by the PEKK and the PEKK powder which is not coated by the CF in the synthesis process by screening the solvent and the solution, so that the purpose of purifying the raw materials is achieved, and the purity of the PEKK/CF composite material is improved.)

1. The density purification method of the polyether ketone (PEKK)/Carbon Fiber (CF) composite material synthesized in situ is characterized in that: the PEKK/CF composite powder synthesized in situ is screened and purified through density difference among materials.

2. The in situ synthesized PEKK/CF composite according to claim 1, characterized in that: the composite material is added during the synthesis of PEKK for compounding, and the final form is powder, including non-PEKK coated CF, PEKK/CF coated by PEKK, and PEKK without CF coating.

3. Density purification process according to claim 1, characterized in that: the PEKK/CF composite material, the PEKK material and the CF material are separated by using the density difference and using solvents or solutions with different densities.

4. The solvent or solution according to claim 3, characterized in that: PEKK is not soluble and chemically reactive with PEKK nor with CF.

5. The solvent or solution according to claim 3, characterized in that: the solvent or solution density is between that of PEKK and CF.

6. The solvent or solution according to claims 3-5, characterized in that: organic solvents such as: methylene chloride, chloroform, carbon tetrachloride, and the like; or one or more of a plurality of inorganic salt solutions with relatively high solubility, such as: sodium silicate, zinc chloride, ammonium nitrate, etc.; or diluted medium strong acid such as phosphoric acid; but also ionic liquids.

7. The in situ synthesized PEKK/CF composite powder of claim 1 is purified by screening through density difference between materials, comprising the following two main steps: wherein step (a) and step (b) are not in sequence.

8. Selecting a solution or solvent having a density greater than PEKK and less than PEKK/CF in order to separate the PEKK from the composite powder by the following steps: putting the composite powder into a solution or a solvent, adding magnetons, fully and uniformly stirring, carrying out ultrasonic treatment, and then standing.

9. When the solution is kept stand, the layering phenomenon can occur due to the density difference, at the moment, the powder on the upper layer is PEKK, the powder on the upper layer is taken out, and the rest solution is stirred and kept stand for many times until no powder exists on the upper layer of the solution.

10. The lower powder and the solution or solvent are then filtered off with suction and washed several times.

11. Selecting a solution or solvent having a density greater than PEKK/CF and less than PEKK in order to separate CF from PEKK/CF by: putting the composite powder into a solution or a solvent, adding magnetons, fully and uniformly stirring, carrying out ultrasonic treatment, and then standing.

12. When the powder is kept still, the layering phenomenon can occur due to the density difference, and the powder at the lower layer is CF.

13. And taking out the powder and the solution or the solution on the upper layer, continuously adding the solution or the solvent, stirring for many times, and standing until no powder precipitates on the lower layer.

14. The remaining portion of the powder and the solution or solvent is then suction filtered and washed several times.

15. And after the treatment of the two steps, drying the composite powder to obtain the purified composite powder.

Technical Field

The invention relates to the technical field of composite materials, in particular to a method for purifying a composite material through the difference between impurities and the density of the composite material.

Background

The Carbon Fiber (CF) thermoplastic composite material based on polyether ketone (PEKK) has high temperature resistance, excellent mechanical properties, flame retardance, low fuming property, corrosion resistance, hydrolysis resistance, radiation resistance, surface decoration, repairability and other excellent properties, and is widely concerned in the fields of aerospace, automobile field, wind power blades, pressure containers, building market, rail traffic, customized structure, 3D printing and the like.

The interfacial bonding properties between PEKK and CF can be improved by the PEKK/CF composite synthesized in situ, but the powder synthesized in situ inevitably contains uncoated CF and uncoated PEKK, which are impurities for PEKK/CF, affecting the properties of the composite subsequently prepared. In order to remove the impurities, selecting a solvent or a solution with the density between CF and PEKK/CF through the density difference among PEKK, CF and PEKK/CF, and separating the CF and the PEKK/CF; and then selecting a solvent with the density between PEKK/CF and PEKK or dissolving the solvent or the solvent, and separating the solvent and the PEKK/CF, thereby achieving the purpose of purifying the PEKK/CF composite material. In addition, the method can also be used for screening PEKK/CF composite powder with a specific density range, such as 60 wt% PEKK and 40 wt% CF composite powder and the like. The method is simple to operate, has strong feasibility, has important significance for purifying the PEKK/CF composite material, and has reference significance for purifying other powder composite materials.

Disclosure of Invention

The invention aims to solve the technical problem of providing a simple and feasible density screening method for removing PEKK powder and CF powder mixed in an in-situ synthesized PEKK/CF composite material.

The technical solution of the invention is as follows:

the solvent or solution for purifying the PEKK/CF composite material according to the present invention may be an organic solvent, such as: methylene chloride, chloroform, carbon tetrachloride, and the like; or one or more of a plurality of inorganic salt solutions with relatively high solubility, such as: zinc chloride, sodium silicate, ammonium nitrate, etc.; or diluted medium strong acid such as phosphoric acid; but also ionic liquids.

Preferably one or more inorganic salt solutions having greater solubility, such as: zinc chloride, ammonium nitrate, sodium silicate, and the like.

The PEKK/CF composite powder and the solvent or the solution are prepared from the following components in percentage by mass: less than or equal to 1:9, and the amount of the specific solution or solvent is sufficient to allow the composite powder to be layered in the solution or solvent. Preferably: 1:18.

Putting the composite powder into a solvent or a solution, adding magnetons, stirring at 100-1000 r/min, preferably 500 r/min, performing ultrasonic treatment for 5-60 min, preferably 20min, standing, and waiting for layering.

The process flow of the invention comprises the following two steps: the steps are not divided into a front order and a back order.

(1) Separating the PEKK from the composite powder: the solution or solvent, preferably an inorganic salt solution, is selected to have a density greater than PEKK and less than PEKK/CF. The specific operation is as follows: putting the composite powder into a solution or a solvent, adding magnetons, fully and uniformly stirring, assisting with ultrasonic treatment, and standing for layering. And after layering occurs, taking out the powder on the upper layer, and adding the solution or the solvent for multiple times to stir and stand the rest solution until no powder exists on the upper layer of the solution. The lower powder and the solution or solvent are then filtered off with suction and washed several times.

(2) Separating the CF from the composite powder: the solution or solvent, preferably an inorganic salt solution, is selected to have a density greater than PEKK/CF and less than PEKK. The specific operation is as follows: putting the composite powder into a solution or a solvent, adding magnetons, fully and uniformly stirring, assisting with ultrasonic treatment, and standing for layering. After delamination occurred, the powder of the lower layer was CF at this time. And taking out the powder and the solution or the solvent on the upper layer, continuously adding the solution or the solvent, stirring for many times, and standing until no powder precipitates on the lower layer. The remaining portion of the powder and the solution or solvent is then suction filtered and washed several times.

(3) And after the treatment of the two steps, drying the composite powder to obtain the purified composite powder.

The reagents and starting materials used in the present invention are commercially available.

The invention has the beneficial effects that: the method is scientific, reasonable, simple and easy to implement. The PEKK/CF composite material with PEKK content in a certain range can be screened out, and preparation is provided for the next application. And also provides reference for the purification of other similar powder composite materials.

Drawings

FIG. 1 is an electron micrograph of the raw material PEKK/CF in example 1.

FIG. 2 is an electron micrograph of CF impurities in example 1.

FIG. 3 is an electron micrograph of the PEKK impurity of example 1.

FIG. 4 is an electron micrograph of the PEKK/CF composite obtained after purification in example 1.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following specific examples.