阅读说明：本技术 热塑性环氧树脂及其应用和碳纤维用表面改性剂 (Thermoplastic epoxy resin, application thereof and surface modifier for carbon fibers ) 是由 晏义伍 朱敏杰 李常胜 于 2020-04-09 设计创作，主要内容包括：本发明公开了一种热塑性环氧树脂及其应用和碳纤维用表面改性剂,该热塑性环氧树脂包括式(I)的结构：<Image he="158" wi="700" file="DDA0002443542120000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>能够作为表面改性剂应用于碳纤维的表面处理中,经过该热塑性环氧树脂处理的碳纤维与热塑性基体树脂具有较好的界面相容性,无需退浆处理,对碳纤维的强度损失影响小,具有较好的应用前景。(The invention discloses a thermoplastic epoxy resin, application thereof and a surface modifier for carbon fibers, wherein the thermoplastic epoxy resin comprises a structure shown in a formula (I):)

1. A thermoplastic epoxy resin comprising the structure of formula (I):

wherein X is at least one selected from hydroxyl, A1, A2, A3 and A4, A1-A4 are respectively as follows:

y is selected from a sulfur atom, an oxygen atom or a carbon atom;

n1-n5 are integers, 0< n1 is less than or equal to 600, 0< n2, n3, n4 and n5 is less than or equal to 30;

W₁～W₁₄is C1-C15 alkyl.

2. The thermoplastic epoxy resin of claim 1, wherein the thermoplastic epoxy resin has a number average molecular weight of 1.0 × 10³～1.0×10⁵。

3. The thermoplastic epoxy resin according to claim 1, wherein when X is at least one of A1-A4, the molecular weight of X graft is 10% to 50% of the total number average molecular weight of the thermoplastic epoxy resin.

4. Use of the thermoplastic epoxy resin of any one of claims 1 to 3 for treating carbon fibers.

5. A surface modifier for carbon fibers, characterized by comprising the thermoplastic epoxy resin according to any one of claims 1 to 3.

6. The surface modifier for carbon fibers according to claim 5, further comprising a solvent.

7. The surface modifier for carbon fibers according to claim 6, wherein the solvent is at least one selected from the group consisting of toluene, hexane, propanol, acetone, methanol, ethylene glycol, methyl ethyl ketone, and ether.

8. The surface modifier for carbon fibers according to claim 5, further comprising an emulsifier.

9. A modified carbon fiber obtained by treating the carbon fiber according to any one of claims 5 to 8 with a surface modifier.

10. A carbon fiber thermoplastic composite material characterized by comprising a thermoplastic matrix resin and the modified carbon fiber of claim 9.

Technical Field

The invention relates to the technical field of carbon fiber modification, in particular to thermoplastic epoxy resin and application thereof, and a surface modifier for carbon fibers.

Background

Carbon fiber, a high-performance fiber, has high strength, high modulus, small thermal expansion coefficient, good chemical stability and other properties, and has recently become an important reinforcing material for resin-based composite materials. With the continuous and deep research on carbon fiber materials and the continuous and perfect processing technology, the carbon fiber with excellent mechanical property can realize the planned production and is widely applied to the fields of aerospace, national defense industry, automobile manufacturing, sports goods and the like. The base resin has the highest utilization rate at present and is thermosetting resin, but the base resin also has the defects of difficult recovery, high cost, long molding period, poor toughness and the like. Thermoplastic resins are not only easy to mold, but also exhibit greater advantages in heat resistance and mechanical strength.

Compared with thermosetting resin, the thermoplastic resin has high viscosity and poor fluidity, and the thermoplastic resin has almost no chemical reaction with the surface of the carbon fiber and mainly depends on physical diffusion and permeation. Therefore, the thermoplastic composite material system puts higher demands on the surface characteristics of the carbon fiber. Firstly, the surface of the carbon fiber is required to have a certain roughness, so that the infiltration contact area is increased; secondly, the surface of the carbon fiber is required to have a certain compatibility with the thermoplastic resin, i.e., the surface energy is close to or higher. Patent document CN105348768A has undergone surface metallization and surface heat treatment to obtain a carbon fiber thermoplastic composite material with a tensile strength of up to 180 MPa. CN109826013A provides a sizing agent containing nano-materials to improve the wettability between carbon fibers and thermoplastic resin. Although the method for modifying the surface of the carbon fiber by using the sizing agent can improve the interface compatibility of the carbon fiber and the corresponding thermoplastic resin to a certain extent, the carbon fiber needs to be subjected to desizing treatment, so that the process is complex, the cost is increased, and the mechanical property of the carbon fiber is greatly damaged.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a thermoplastic epoxy resin, application thereof and a surface modifier for carbon fibers, wherein the thermoplastic epoxy resin can improve the interface compatibility between the carbon fibers and a thermoplastic matrix resin without desizing treatment.

The technical scheme adopted by the invention is as follows:

in a first aspect of the present invention, there is provided a thermoplastic epoxy resin comprising the structure of formula (I):

wherein X is at least one selected from hydroxyl, A1, A2, A3 and A4, A1-A4 are respectively as follows:

y is selected from a sulfur atom, an oxygen atom or a carbon atom;

n1-n5 are integers, 0< n1 is less than or equal to 600, 0< n2, n3, n4 and n5 is less than or equal to 30;

W₁～W₁₄is an alkyl group of C1-C15 according to some embodiments of the present invention, the thermoplastic epoxy resin has a number average molecular weight of 1.0 × 10³～1.0×10⁵。

According to some embodiments of the present invention, when X is at least one of A1-A4, the molecular weight of the X graft is 10% to 50% of the total number average molecular weight of the thermoplastic epoxy resin. When X is hydroxyl, the structure of the formula (I) is a thermoplastic epoxy resin B which is not grafted with A1-A4, when X is selected from at least one of A1-A4, the structure of the formula (I) is a resin formed by grafting A1-A4 graft segments on the thermoplastic epoxy resin B through reaction of the A1-A4 graft segments with active hydroxyl in the thermoplastic epoxy resin B, the formed substance is generally a mixture because not every hydroxyl in the structure of the thermoplastic epoxy resin B can be grafted with A1-A4, and in some embodiments, the molecular weight of the A1-A4 graft segments accounts for 10-50% of the total number average molecular weight of the thermoplastic epoxy resin.

In a second aspect of the invention, there is provided the use of a thermoplastic epoxy resin as described above for the treatment of carbon fibres.

In a third aspect of the present invention, there is provided a surface modifier for carbon fibers, comprising the above thermoplastic epoxy resin.

The surface modifier for carbon fibers according to some embodiments of the present invention further includes a solvent. The surface modifier for carbon fibers may be a thermoplastic epoxy resin dissolved in a solvent or dispersed in water in the form of an emulsion.

According to the surface modifier for carbon fibers of some embodiments of the present invention, the solvent is selected from at least one of toluene, hexane, propanol, acetone, methanol, ethylene glycol, methyl ethyl ketone, and ether.

The surface modifier for carbon fibers according to some embodiments of the present invention further includes an emulsifier.

According to the surface modifier for carbon fibers of some embodiments of the present invention, the emulsifier is selected from at least one of alkylphenol ethoxylates, phenethylphenol ethoxylates, benzyl phenol ethoxylates, and phenethylphenol polyoxyethylene polyoxypropylene ethers.

In a fourth aspect of the present invention, there is provided a modified carbon fiber obtained by treating the carbon fiber with the surface modifier.

In a fifth aspect of the present invention, there is provided a carbon fiber thermoplastic composite material comprising a thermoplastic matrix resin and the above-described modified carbon fiber.

According to some embodiments of the invention, the thermoplastic matrix resin is at least one selected from the group consisting of polyurethane resin, polyamide resin, and polyester resin.

The embodiment of the invention has the beneficial effects that:

the embodiment of the invention provides a thermoplastic epoxy resin which can be used as a surface modifier to be applied to the surface treatment of carbon fibers, the carbon fibers treated by the thermoplastic epoxy resin have better interface compatibility with thermoplastic matrix resin, and the principle of improving the interface compatibility of the carbon fibers and the thermoplastic matrix resin is as follows: (1) the thermoplastic epoxy resin can be grafted on active sites on the surface of the carbon fiber through chemical bonds, so that the surface roughness of the carbon fiber is improved, the infiltration contact area of thermoplastic matrix resin is increased, the mechanical occlusion effect between the matrix resin and the carbon fiber is enhanced, and the infiltration property between the matrix resin and the carbon fiber is improved; (2) the thermoplastic epoxy resin is a thermoplastic material, and ether bonds and hydroxyl groups of the thermoplastic epoxy resin can form hydrogen bond interaction with matrix resin such as polyurethane resin, polyamide resin, polyester resin and the like, so that the interaction between the matrix resin and the carbon fibers is improved; (3) the graft segment in the thermoplastic epoxy resin is based on the similar compatibility principle, and can further improve the compatibility between the thermoplastic epoxy resin and polyurethane resin, polyamide resin and polyester resin. Experimental results show that in the process of preparing the thermoplastic composite material by the carbon fiber treated by the surface modifier, the surface of the carbon fiber can be fully impregnated by the thermoplastic resin, so that the composite material has good mechanical properties and good processability. The thermoplastic epoxy resin has good interface compatibility with carbon fibers, can be suitable for the surface of carbon fibers after desizing, the surface of carbon fibers coated with a conventional sizing agent and the surface of carbon fibers coated with a thermoplastic sizing agent, has wide application range, does not need desizing treatment and has small influence on the strength loss of the carbon fibers, and the thermoplastic matrix resin can fully infiltrate the surface of the carbon fibers in the process of preparing the carbon fiber thermoplastic composite material by using the carbon fibers treated by the thermoplastic epoxy resin as a surface modifier, thereby endowing the composite material with good mechanical property and better processing property.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.