阅读说明：本技术 一种可逆修饰碳纤维的方法 (Method for reversibly modifying carbon fiber ) 是由 吴刚平 刘玉婷 张晓芳 于 2019-10-24 设计创作，主要内容包括：本发明涉及碳纤维表面修饰领域,具体涉及一种可逆修饰碳纤维的方法。本发明的目的是为了解决现有碳纤维表面处理方法对碳纤维表面结构破坏严重和传统表面修饰剂不能进行可逆回收的技术问题。本发明中二茂铁衍生物为开关型二茂铁衍生物,它具有良好的可逆氧化还原性质可以响应外界条件变化,可以通过氧化还原反应控制吸附与脱附的可逆转换,基于这种可逆特性,在碳纤维表面修饰、回收利用中有很好的应用前景。本发明通过在碳纤维上吸附二茂铁衍生物的方法,实现碳纤维有效修饰,同时对碳纤维表面结构几乎不会造成损坏。(The invention relates to the field of carbon fiber surface modification, in particular to a method for reversibly modifying carbon fibers. The invention aims to solve the technical problems that the surface structure of carbon fibers is seriously damaged by the existing carbon fiber surface treatment method and the traditional surface modifier cannot be reversibly recycled. The ferrocene derivative is a switch type ferrocene derivative, has good reversible redox property, can respond to the change of external conditions, can control the reversible conversion of adsorption and desorption through redox reaction, and has good application prospect in surface modification and recycling of carbon fibers based on the reversible property. According to the invention, effective modification of the carbon fiber is realized by adsorbing the ferrocene derivatives on the carbon fiber, and the surface structure of the carbon fiber is hardly damaged.)

1. A method of reversibly modifying carbon fibers, comprising: the method comprises the following steps:

step 1, pretreatment of carbon fibers: desizing the carbon fiber to obtain the desized carbon fiber;

step 2, preparing ferrocene derivative solution: adding the ferrocene derivatives into a solvent according to a ratio, and uniformly dispersing and dissolving;

step 3, surface modification of carbon fibers: and (3) adding the desized carbon fiber obtained in the step (1) into the ferrocene derivative solution prepared in the step (2), modifying the surface of the carbon fiber, separating, removing supernatant, and drying the carbon fiber modified by the ferrocene derivative, thus finishing the surface modification of the carbon fiber.

And 4, reversible desorption of the ferrocene derivatives on the surface of the carbon fiber: and (3) oxidizing the surface-modified carbon fiber in the step (3) by an oxidant or electrochemistry to realize reversible desorption of the ferrocene derivatives on the surface of the carbon fiber.

2. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the carbon fiber used in the step 1 is continuous carbon fiber or chopped carbon fiber.

3. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the concentration of the ferrocene derivative solution in the step 2 is 1.0-20 mM.

4. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the ferrocene derivatives in the ferrocene derivative solution in the step 2 refer to compounds containing ferrocene groups, including ferrocenecarboxylic acid, (ferrocenyl methyl) dodecyl dimethyl ammonium bromide, hydroxymethyl ferrocene and butyl ferrocene.

5. A method of reversibly modifying a carbon fiber according to claim 1, wherein: and the solvent in the ferrocene derivative solution in the step 2 is one or a mixture of water, alcohols, acetone and tetrahydrofuran.

6. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the volume ratio of the desized carbon fiber to the ferrocene derivative solution in the step 3 is 1mg:0.1-100 ml.

7. A method of reversibly modifying a carbon fiber according to claim 1, wherein: in the step 3, the temperature of a reaction system in the surface modification of the carbon fiber is 15-100 ℃, the carbon fiber is surface modified in a mode of oscillation, standing or combination of the oscillation and the standing, and the modification time is 1-1000 min.

8. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the separation process in the step 3 comprises centrifugation, filtration and sedimentation; separation time: 5-1500 min.

9. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the drying of the carbon fiber modified by the ferrocene derivatives in the step 3 can be normal pressure drying or vacuum oven drying, the drying temperature is 10-100 ℃, and the drying time is 1-48 h.

10. A method of reversibly modifying a carbon fiber according to claim 1, wherein: the standard electrode potential E for oxidizing the oxidant in the step 4 is in the range of 0.8-2.2V; the oxidant is any one of concentrated sulfuric acid, hypochlorous acid, oxygen, ozone, permanganic acid, bromine, iodic acid, ferric acid or silver chloride; the electrochemical oxidation is a potentiostatic method, a cyclic voltammetry method and a galvanostatic method, and the oxidation voltage range is 0.6-5V.

Technical Field

The invention relates to the field of carbon fiber surface modification, in particular to a method for reversibly modifying carbon fibers.

Background

The carbon fiber has excellent properties of high strength, high modulus, high temperature resistance, light weight and the like, and the carbon fiber composite material is widely applied to the fields of new energy, materials and the like due to the excellent properties of the carbon fiber. However, the carbon fiber without surface treatment has a smooth surface, is chemically inert, has strong hydrophobicity, and has a particularly weak bonding force with a resin matrix. Surface modification of carbon fibers is an effective method for improving chemical inertness and hydrophilicity.

The traditional surface modification methods mainly include electrochemical oxidation, plasma, gas/liquid phase oxidation, chemical grafting and the like. Manabu et al introduced special functional groups on carbon fibers by electrochemical redox methods, altered the surface structure of carbon fibers (see M.Ishifune, R.Suzuki, Y.Mima, K.Uchida, N.Yamashita, S.Kashimura.novel electrochemical surface modification method of carbon fibers and its use in the preparation of functional electrodes.) electrochemical micro Acta,2005,51:14-22. Montes-Mor-n, etc. utilize plasma treatment to improve the interfacial properties between carbon fibers and epoxy resins (see m.a.montes-Mor n, a.mart i nez-Alonso, j.m.d.tasc. yan n, m.c.paiva, c.a.bernardo, r.j.young.effects of plasma oxidation on the surface and interfacial properties of ultra-high modulus carbon fibers, comp.part a-application.sci.man. 371, 2001: 371). Jingchangliang et al compared the mechanical properties of the thermoplastic polyimide composite material and the silane coupling agent modified carbon fiber under different conditions, and the introduced silane coupling agent chemically bonded with the fiber and could not be removed (Jingchangliang, Helichrysum. mechanical properties of surface-treated carbon fiber modified polyimide composite material. plastic. 2012,41: 4-6). However, the conventional surface treatment mainly has the following problems: firstly, the surface structure of the carbon fiber is damaged, defects are introduced, and secondly, a large amount of energy consumption is needed, so that pollution is possibly caused; and thirdly, the traditional modifier is difficult to remove.

In view of the above problems, there is a need for the development of a carbon fiber surface modifier that can modify the surface of carbon fibers without damage and can be removed easily when not needed. The switch type ferrocene derivative has a ferrocene group structure, so that the switch type ferrocene derivative can respond to the change of external conditions, such as light, temperature, redox conditions and the like, can perform reversible conversion between an active state and an inactive state under the control of the external conditions, and has good application prospect.

The invention aims to provide a method for modifying the surface of carbon fiber by a physical adsorption mode based on a switch type ferrocene derivative and reversibly removing a modifier, which can effectively improve the surface inertia of the carbon fiber and has important significance for recycling and reusing the carbon fiber.

Disclosure of Invention

The invention aims to provide a method for reversibly modifying carbon fibers, and aims to solve the technical problems that the surface structure of carbon fibers is seriously damaged by the conventional carbon fiber surface treatment method and the conventional surface modifier cannot be reversibly recycled.

In order to achieve the purpose, the invention provides the following technical scheme:

a method of reversibly modifying a carbon fiber comprising the steps of:

step 1, pretreatment of carbon fibers: desizing the carbon fiber to obtain the desized carbon fiber;

step 2, preparing ferrocene derivative solution: adding the ferrocene derivatives into a solvent according to a ratio, and uniformly dispersing and dissolving;

step 3, surface modification of carbon fibers: and (3) adding the desized carbon fiber obtained in the step (1) into the ferrocene derivative solution prepared in the step (2), modifying the surface of the carbon fiber, separating, removing supernatant, and drying the carbon fiber modified by the ferrocene derivative, thus finishing the surface modification of the carbon fiber.

And 4, reversible desorption of the ferrocene derivatives on the surface of the carbon fiber: and (3) oxidizing the surface-modified carbon fiber in the step (3) by an oxidant or electrochemistry to realize reversible desorption of the ferrocene derivatives on the surface of the carbon fiber.

Further, the carbon fiber used in the step 1 is continuous carbon fiber or chopped carbon fiber. The method is suitable for surface treatment of carbon fibers with different lengths.

Still further, the desizing treatment in the step 1 is a high-temperature desizing method or a Soxhlet extraction method; the high-temperature desizing method is to desize the carbon fiber in desizing air or inert atmosphere (nitrogen and argon) at the temperature of 300-800 ℃; the Soxhlet extraction method is to carry out heating reflux desizing on the carbon fiber by acetone or DMF organic solvent, and the desizing time is 5-300 min.

Furthermore, the concentration of the ferrocene derivative solution in the step 2 is 1.0-20mM, the modification effect is poor when the concentration is too low, and the treatment cost is increased when the concentration is too high.

Further, the ferrocene derivative in the ferrocene derivative solution in step 2 refers to a compound containing a ferrocene group, including ferrocenecarboxylic acid, (ferrocenylmethyl) dodecyldimethylammonium bromide, hydroxymethyl ferrocene, and butyl ferrocene. The purpose of modifying the surface of the carbon fiber by using different functional groups is realized, so that the further application of the carbon fiber is facilitated.

Furthermore, the solvent in the ferrocene derivative solution in the step 2 is one or a mixture of several of water, alcohol, acetone and tetrahydrofuran, and the alcohol includes ethanol, n-propanol or n-butanol. The problem of poor adsorption effect caused by different ferrocene derivatives with different solubilities is avoided.

Furthermore, the volume ratio of the carbon fiber desized in the step 3 to the ferrocene derivative solution is 1mg:0.1-100 ml. Too low concentration results in poor modification effect, and too high concentration increases modification cost.

Furthermore, in the step 3, the temperature of the reaction system in the surface modification of the carbon fiber is 15-100 ℃, the carbon fiber is surface modified by adopting a mode of oscillation, standing or combination of the oscillation and the standing, and the modification time is 1-1000 min. If the temperature is too high or too low, the ferrocene derivatives have poor adsorption activity, and if the time is too short, the adsorption is insufficient, and if the time is too long, the time cost is increased.

Furthermore, the separation process in the step 3 can adopt methods including centrifugation, filtration and sedimentation; separation time: 5-1500 min. Too short a time to separate completely, too long a time increases the time cost.

Furthermore, the drying of the carbon fiber modified by the ferrocene derivative in the step 3 can be normal pressure drying or vacuum oven drying, the drying temperature is 10-100 ℃, and the drying time is 1-48 h. The drying purpose can be achieved without damaging the fiber surface.

Further, the standard electrode potential E for oxidizing the oxidant in the step 4 is in the range of 0.8-2.2V; the oxidant is any one of concentrated sulfuric acid, hypochlorous acid, oxygen, ozone, permanganic acid, bromine, iodic acid, ferric acid or silver chloride; the electrochemical oxidation is a potentiostatic method, a cyclic voltammetry method and a galvanostatic method, and the oxidation voltage range is 0.6-5V. The oxidative desorption of the ferrocene derivatives cannot be realized when the potential or electrochemical oxidation voltage of the oxidant standard electrode is too low, and the fiber structure can be damaged when the potential or electrochemical oxidation voltage of the oxidant standard electrode is too high.

Compared with the prior art, the invention has the beneficial effects that:

1. the ferrocene derivative is a switch type ferrocene derivative, has good reversible redox property, can respond to the change of external conditions, can control the reversible conversion of adsorption and desorption through redox reaction, and has good application prospect in surface modification and recycling of carbon fibers based on the reversible property.

2. According to the invention, effective modification of the carbon fiber is realized by adsorbing the ferrocene derivatives on the carbon fiber, and the surface structure of the carbon fiber is hardly damaged.

3. The reversible modification method can realize the cyclic utilization of the ferrocene derivatives, and effectively reduces the material cost.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.