CN113667274B

CN113667274B - Tough epoxy composite material and preparation method thereof

Info

Publication number: CN113667274B
Application number: CN202110960658.7A
Authority: CN
Inventors: 沈小军; 施依呈; 党蕊琼; 马保国; 叶蓓
Original assignee: Jiaxing University
Current assignee: Jiaxing University
Priority date: 2021-08-20
Filing date: 2021-08-20
Publication date: 2023-07-07
Anticipated expiration: 2041-08-20
Also published as: CN113667274A

Abstract

The invention relates to a tough epoxy composite material and a preparation method thereof, the material comprises an epoxy matrix material and a graft PSOL- (N-TMSPRCV) of a silicon polymer uniformly dispersed in the epoxy matrix material, wherein the part of the PSOL- (N-TMSPRCV) graft relative to the epoxy matrix material is 0-3.0phr. The PSOL- (N-TMSPRCAV) grafts are obtained by grafting the composite N-TMSPRCAV in a silicone polymer PSOL. The PSOL is synthesized from silica, and the N-TMSPRCAVs is synthesized from valeryl chloride and ATPMS. The particle size of the silicon dioxide is 63-210 mu m, and the silicon dioxide is neutral. Compared with the common epoxy material, the tough epoxy composite material has excellent toughness and keeps heat resistance to a certain extent.

Description

Tough epoxy composite material and preparation method thereof

Technical Field

The invention belongs to the field of preparation of polymer matrix composite materials, and particularly relates to a tough epoxy composite material and a preparation method thereof.

Background

Epoxy resins are very important thermosetting resins, which are widely used in practical applications for coating agents, adhesives, electronic packaging and substrates for high performance composites due to their excellent mechanical properties, chemical resistance, thermal properties, electrical insulation and high bond strength. However, the epoxy resin, after curing, generates a highly crosslinked molecular structure, resulting in the cured epoxy resin exhibiting brittleness and poor crack resistance. This limits their use in products requiring high impact and breaking strength. Therefore, the modification of epoxy resins has been a hot spot of research.

The toughness of epoxy has been studied extensively. One of the most successful methods is to add a suitable rubber to the uncured epoxy resin and then control the polymerization reaction to induce phase separation. Most studies have chemically modified epoxy resins with reactive liquid rubbers, in particular carboxyl-terminated butadiene-acrylonitrile Copolymers (CTBN), hydroxyl-terminated butadiene-acrylonitrile copolymers (HTBN), amine-terminated nitrile rubbers (ATBN). While the introduction of rubber as a toughening component into the system improves toughness, it is affected by the unsaturated bonds in the rubber. The unsaturated bonds are easy to be oxidized and cracked at high temperature, so that the glass transition temperature of the rubber toughened epoxy resin system is reduced, the use of the rubber toughened epoxy resin system at high temperature is affected, and meanwhile, the strength is obviously reduced.

The organosilicon polymer is an important organic-inorganic hybrid material composed of Si-O repeating units, and has wide application. In the current synthetic route, it can be formed from silica gel (SiO ₂ ) Or water glass (sodium silicate solution) with molecular formula of [ SiO (OH) ₂ ] _n . However, PSOL has pendant reactive silanol (-SiOH) groups, which are unstable and readily react with silylating agents and the like. Thus, silanol residues using PSOL can be subjected to a simple silylation reaction with silylating agents to introduce various functional groups to achieve functionalization.

The applicant has devised a toughening agent incorporating an epoxy resin according to the desired effect. The synthesized new substance N-TMSPVaC of valeryl chloride and APTMS is grafted onto PSOL by utilizing the active silanol side group of PSOL to obtain a novel toughening agent POSL- (N-TMSPVaC); and POSL- (N-TMSPVaC) is added into epoxy resin to obtain the epoxy composite material which is tough and retains the original heat resistance to a large extent.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for preparing a tough epoxy composite material, which aims at the problems existing in the prior art.

The technical scheme of the invention is as follows:

the tough epoxy composite material provided by the invention comprises an epoxy resin matrix material and a graft PSOL- (N-TMSPRCV) of a silicon polymer uniformly dispersed in the epoxy matrix material, wherein the part of the PSOL- (N-TMSPRCV) graft relative to the epoxy matrix material is 0-3.0phr.

The PSOL- (N-TMSPRCAV) grafts are obtained by grafting the composite N-TMSPRCAV in a silicone polymer PSOL.

Wherein, the synthetic reaction formula is as follows:

the PSOL is synthesized from silica, and the N-TMSPRCAVs is synthesized from valeryl chloride and ATPMS. Wherein the particle size of the silicon dioxide is 63-210 mu m, and the silicon dioxide is neutral.

The tough epoxy composite material provided by the invention uses a graft PSOL- (N-TMSPRCV) of a silicon polymer as a reinforcement, firstly, the PSOL- (N-TMSPRCV) graft and a curing agent are mixed together, a solvent is removed, and then the mixture is subjected to blending and pouring to obtain an epoxy composite material product.

Specifically, the preparation method of the tough epoxy composite material provided by the invention comprises the following steps:

1) Adding 1.0-10.0g of silicon dioxide particles into 1.5% -1.7% sodium hydroxide aqueous solution, stirring and reacting for 1-10 hours at room temperature; then adding 0.1-5mol/L hydrochloric acid solution and tetrahydrofuran with the volume ratio of 1:1-30 and 1-50g sodium chloride respectively; then continuing to react for 10-60 minutes, standing, layering, taking clear liquid, adding anhydrous magnesium sulfate for dehydration, and finally obtaining PSOL tetrahydrofuran solution through suction filtration and distillation;

2) APTMS and Et with the molar ratio of 0.1-1:0.1-1:0.1-1.1 are added into a reaction vessel under the nitrogen environment ₃ N and DCM, and slowly dropwise adding pentanoyl chloride to react for 1-6 hours at 0-4 ℃ and then transferring to room temperature to react for 10-60 minutes. Washing the reactant with water and salt, standing to obtain a clarified liquid, adding anhydrous magnesium sulfate for dehydration, and performing suction filtration to obtain a new synthetic substance N-TMSPVaC;

3) Under the environment of vacuum nitrogen replacement, adding the N-TMSPVaC obtained in the step 2) into a reaction vessel, slowly dropwise adding the silicon polymer obtained in the step 1), and reacting for 1-6 hours at room temperature after the dropwise adding is finished to obtain a grafted silicon polymer POSL- (N-TMSPVaC) tetrahydrofuran solution;

4) And (3) adding the curing agent D230 into 0-3phr of the POSL- (N-TMSPVaC) tetrahydrofuran solution obtained in the step (3), uniformly stirring, removing tetrahydrofuran in vacuum, adding epoxy resin, stirring, removing bubbles, and pouring and molding to obtain the tough epoxy composite material.

Further, firstly synthesizing a silicon polymer PSOL and an N-TMSPVaC, then mixing the two, reacting and grafting to obtain a functionalized silicon polymer POSL- (N-TMSPVaC), and finally mixing the silicon polymer POSL- (N-TMSPVaC) with an epoxy matrix system directly to obtain the epoxy composite material product.

Compared with the prior art, the invention has the advantages that:

the crosslinked network structure of the silicon polymer can limit the movement of the epoxy polymer chain segment, thereby controlling the heat resistance of the composite material not to be greatly reduced. Meanwhile, the grafted silicon polymer achieves functionalization, and can improve the mechanical property of the epoxy composite material. Therefore, the PSOL- (N-TMSPVaC)/epoxy composite material can largely retain the original heat resistance on the basis of enhancing the impact performance and the tensile performance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is an SEM photograph of a prepared PSOL- (N-TMSPVaC)/epoxy composite; wherein (a) is the impact profile of a neat epoxy and (b) is the impact profile of an epoxy composite after the addition of 1.0phr PSOL- (N-TMSPVaC).

FIG. 2 is a graph of tensile strength (a), impact strength (b) and glass transition temperature (c) of composites of varying PSOL- (N-TMSPVaC) content.

Detailed Description

The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The present invention will be further specifically illustrated by the following examples, which are not to be construed as limiting the invention, but rather as falling within the scope of the present invention, for some non-essential modifications and adaptations of the invention that are apparent to those skilled in the art based on the foregoing disclosure.

Example 1

1) 1g of sodium hydroxide and 60ml of deionized water were prepared into a solution, 3.0g of silica particles were added to the solution, and the reaction was stirred at room temperature for 3 hours. Then, a hydrochloric acid solution and tetrahydrofuran were added in a volume ratio of 2mol/L, respectively, of 1:3, and 36g of sodium chloride was added. Then the reaction is continued for 30 minutes, the mixture is stood for layering, and the clear liquid is taken out and added with anhydrous magnesium sulfate for dehydration. Finally, obtaining the silicone polymer tetrahydrofuran solution after suction filtration and distillation.

2) APTMS, et in a molar ratio of 1:1:1.1 were added to the reaction vessel under nitrogen atmosphere ₃ N and DCM. Pentanoyl chloride was slowly added dropwise and reacted at 0℃for 2 hours, and then the reaction was carried out at room temperature for 30 minutes. Washing the reactant with water and salt, standing and taking clear liquid. Dewatering with anhydrous magnesium sulfate, and suction filtering to obtain new synthetic substance N-TMSPVaC.

3) And (3) adding the N-TMSPVaC obtained in the step (2) into a reaction vessel under the environment after vacuum nitrogen replacement, and slowly dropwise adding the silicon polymer obtained in the step (1). After completion of the dropwise addition, the reaction was carried out at room temperature for 2 hours. The grafted silicone polymer POSL- (N-TMSPVaC) tetrahydrofuran solution is obtained.

4) Curing agent D230 was added to 0.5phr of the POSL- (N-TMSPVaC) tetrahydrofuran solution obtained in step 3), and the mixture was stirred well and the tetrahydrofuran was removed in vacuo. Then adding epoxy resin, stirring to remove bubbles, and pouring and molding. And curing to obtain the epoxy composite material A.

5) And (3) carrying out mechanical testing and dynamic thermo-mechanical analysis on the epoxy composite material A obtained in the step (4), and obtaining the following results: tensile strength of 67.4MPa and impact strength of 9.9KJ/m measured by mechanical test ² The glass transition temperature was measured by DMA to be 92.3 ℃.

Example 2

4) Curing agent D230 was added to 1.0phr of the POSL- (N-TMSPVaC) tetrahydrofuran solution obtained in step 3), and the mixture was stirred well and the tetrahydrofuran was removed in vacuo. Then adding epoxy resin, stirring to remove bubbles, and pouring and molding. And curing to obtain the epoxy composite material B.

5) And (3) carrying out mechanical test and dynamic thermo-mechanical analysis on the epoxy composite material B obtained in the step (4) to obtain the following results: the tensile strength measured by the mechanical test is 65.8MPa, and the impact strength is 10.2KJ/m ² The glass transition temperature was measured by DMA to be 89.1 ℃.

Example 3

4) Curing agent D230 was added to 2.0phr of the POSL- (N-TMSPVaC) tetrahydrofuran solution obtained in step 3), and the mixture was stirred well and the tetrahydrofuran was removed in vacuo. Then adding epoxy resin, stirring to remove bubbles, and pouring and molding. And curing to obtain the epoxy composite material C.

5) And (3) carrying out mechanical testing and dynamic thermo-mechanical analysis on the epoxy composite material C obtained in the step (4), so as to obtain the following results: tensile strength of 61.6MPa and impact strength of 11.2KJ/m measured by mechanical test ² The glass transition temperature was measured by DMA to be 90.1 ℃.

Example 4

3) Under the nitrogen environment, the N-TMSPVaC obtained in the step 2) is added into a reaction vessel, and the silicon polymer obtained in the step 1) is slowly added dropwise. After completion of the dropwise addition, the reaction was carried out at room temperature for 2 hours. The grafted silicone polymer POSL- (N-TMSPVaC) tetrahydrofuran solution is obtained.

4) 3.0phr of curing agent D230 is added into the POSL- (N-TMSPVaC) tetrahydrofuran solution obtained in the step 3), and the mixture is stirred uniformly and the tetrahydrofuran is removed in vacuum. Then adding epoxy resin, stirring to remove bubbles, and pouring and molding. And curing to obtain the epoxy composite material D.

5) And (3) carrying out mechanical testing and dynamic thermo-mechanical analysis on the epoxy composite material D obtained in the step (4) to obtain the following results: tensile strength of 52.7MPa and impact strength of 11.7KJ/m measured by mechanical test ² The glass transition temperature measured by DMA was 87.8 ℃.

Comparative example

1) And adding the curing agent D230 into the epoxy resin according to the stoichiometric ratio, and curing to obtain the pure epoxy material E.

2) And (3) carrying out mechanical test and dynamic thermo-mechanical analysis on the pure epoxy material E obtained in the step 1), and obtaining the following results: the tensile strength measured by the mechanical test is 61.9MPa, the impact strength is 9.9KJ/m2, and the glass transition temperature measured by DMA is 93.3 ℃.

Wherein SEM pictures of PSOL- (N-TMSPVaC)/epoxy composites prepared by the present invention are shown in FIG. 1. Wherein, (a) shows the impact profile of pure epoxy, and (b) shows the impact profile of the epoxy composite material after addition of 1.0phr PSOL- (N-TMSPVaC).

As can be seen from FIG. 1, PSOL- (N-TMSPVaC) is uniformly mixed with epoxy resin, so that the interface compatibility is good, and the stress can be effectively transferred from the epoxy resin to PSOL- (N-TMSPVaC), thereby greatly improving the toughness of the epoxy composite material.

And as can be seen from fig. 2, as the PSOL- (N-TMSPrVaC) content increases, the tensile strength of the composite tends to increase before decrease. At a content of 0.5phr, the tensile strength of the epoxy composite is highest, which is improved by 8.9% compared with the tensile strength of the pure epoxy material. The impact strength of the epoxy composite increases linearly with increasing PSOL- (N-TMSPVaC) content. The impact strength of the epoxy composite is highest at a content of 3 phr. Compared with pure epoxy material, the epoxy material is improved by 18.2 percent. The results indicate that PSOL- (N-TMSPVaC) is a better reinforcing and toughening agent. The Tg of the pure epoxy material was 93.3 ℃. The Tg of each epoxy composite material is reduced to different degrees and is within 5 ℃. This shows that the addition of PSOL- (N-TMSPVaC) greatly maintains the thermal stability of the original epoxy material under the condition of improving the mechanical properties of the composite material.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The tough epoxy composite material is characterized by comprising an epoxy resin matrix material and PSOL- (N-TMSPVaC) grafts uniformly dispersed in the epoxy resin matrix material;

the PSOL- (N-TMSPVaC) graft is 0-3.0phr relative to the epoxy matrix material, and has a value other than 0;

the PSOL- (N-TMSPVaC) grafts are obtained by grafting the composite N-TMSPVaC in a silicone polymer PSOL;

the silicon polymer PSOL is provided with an active silanol-SiOH side group and is synthesized by silicon dioxide, and the particle size of the silicon dioxide is 63-210 mu m and neutral;

the N-TMSPVaC is synthesized from valeryl chloride and APTMS.

2. A method for preparing the tough epoxy composite material according to claim 1, wherein the preparation method specifically comprises the following steps:

1) Adding 1.0-10.0g silicon dioxide particles into 1.5-1.7% sodium hydroxide aqueous solution, and stirring at room temperature for reaction for 1-10 hours; adding 0.1-5mol/L hydrochloric acid solution and tetrahydrofuran with volume ratio of 1:1-30, and 1-50g sodium chloride respectively; then continuing to react for 10-60 minutes, standing, layering, taking clear liquid, adding anhydrous magnesium sulfate for dehydration, and finally obtaining PSOL tetrahydrofuran solution through suction filtration and distillation;

2) APTMS and Et with the molar ratio of 0.1-1:0.1-1:0.1-1.1 are added into a reaction vessel under the nitrogen environment ₃ N and DCM are slowly added dropwise with valeryl chloride to react for 1-6 hours at 0-4 ℃, then room temperature is changed to react for 10-60 minutes, the reactant is subjected to water washing and salt washing, then the reactant is stood for taking clear liquid, anhydrous magnesium sulfate is added for dehydration, and then suction filtration is carried out to obtain a new synthetic substance N-TMSPVaC;

3) Under the environment of vacuum nitrogen replacement, adding the N-TMSPVaC obtained in the step 2) into a reaction vessel, slowly dropwise adding the silicon polymer obtained in the step 1), and reacting for 1-6 hours at room temperature after the dropwise adding is completed to obtain a grafted silicon polymer PSOL- (N-TMSPVaC) tetrahydrofuran solution;

4) Adding a curing agent D230 into 0-3phr of PSOL- (N-TMSPVaC) tetrahydrofuran solution obtained in the step 3), uniformly stirring, removing tetrahydrofuran in vacuum, adding epoxy resin, stirring, removing bubbles, and pouring and molding to obtain the tough epoxy composite material.