Preparation method of patterned frontline polymerized flexible film and application of patterned frontline polymerized flexible film in composite material

Abstract

The invention discloses a preparation method of a patterning front-line polymerization flexible film and application of the patterning front-line polymerization flexible film in a composite material, and belongs to the technical field of front-line polymerization flexible film preparation. According to the specific scheme, the method comprises the following steps: step 1, mixing a double-bond first network monomer, a first-stage initiator, a front polymerization network monomer, a second-stage thermal initiator, a second-stage photo-acid generator and a second-stage photo-base generator to obtain a reaction precursor solution; 2, transferring the reaction precursor solution to a mold, uniformly laying the reaction precursor solution, and heating to complete first-stage curing of the flexible thin film; 3, covering the sample cured in the first stage with a photomask, and irradiating with a light source to complete release of the patterned alkaline substance; and 4, triggering frontline aggregation by using a point heat source or a light source, and advancing an aggregation wave according to a set path to complete the patterning advancing of frontline aggregation. According to the method, the two-stage curing technology is combined, and ground flexible folding and unfolding and on-orbit low-energy patterning stiffening of the composite material for the space unfolding structure are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of front polymerization flexible films, and specifically relates to a preparation method of a patternable front polymerization flexible film and its application in composite materials. Background Art

[0002] The low-energy curing process of resin-based composites based on the Frontal Polymerization (FP) technology shows breakthrough advantages. This technology triggers a self-propagating reaction through local heat sources or light initiation. Only a low-intensity energy needs to be applied in the initial stage to drive the polymerization wave to complete the material curing in a one-way self-sustaining mode, without the need for external continuous energy supply throughout the process, significantly reducing the energy consumption of on-orbit manufacturing of spacecraft (the energy consumption is reduced by more than 70% compared with traditional processes). This self-sustaining characteristic not only adapts to the intermittent power supply scenarios in deep space exploration missions, but also can precisely design the temperature at the front of the polymerization wave by regulating the chemical structure of the monomers. While achieving a strong bond at the fiber / resin interface, the overall heat exposure time is shortened to the minute level, completely eliminating the risk of fiber / resin thermal expansion mismatch caused by long-term high-temperature treatment. In addition, the unique spatio-temporal controllability of the FP technology supports on-demand curing in a vacuum environment, making it possible to modularly assemble ultra-thin deployable trusses in orbit, providing a disruptive solution for the lightweight and highly reliable deployment of the next-generation ultra-large-scale space structures.

[0003] In space deployable structures, the control of the rigid and flexible regions of resin-based composites can precisely regulate the local mechanical properties of the materials (such as modulus, flexibility, etc.), enabling highly integrated structural functions and performance optimization. The rigid region acts as a supporting framework and bears the main load after deployment; the flexible region acts as a hinge or folding node, absorbing and releasing the impact energy during the local deformation process, avoiding microcracks or interfacial debonding problems caused by stress concentration. However, based on the existing conditions of large deployment ratios and low energy supply in space folding and deploying structures, the existing curing processes of composite materials cannot achieve on-ground flexible folding and deploying and on-orbit low-energy pattern rigidification, and new solutions need to be proposed. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a preparation method of a patternable front polymerization flexible film and its application in composite materials.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A preparation method of a patternable front polymerization flexible film, comprising the following steps:

[0007] Step 1: Mix 5 - 60 parts by mass of a double - bond - containing first network monomer, 0.1 - 10 parts of a first - stage initiator, 40 - 95 parts of a front - end polymerization network monomer, 0.1 - 10 parts of a second - stage thermal initiator, 0.1 - 10 parts of a second - stage photo - acid generator, and 0.1 - 10 parts of a second - stage photo - base generator to obtain a reaction precursor solution;

[0008] Step 2: Transfer the reaction precursor solution onto a mold and spread it evenly, and heat it at 25 - 100 °C for 0.5 - 8 h to complete the first - stage curing of the flexible film;

[0009] Step 3: Cover the sample that has completed the first - stage curing with a photomask, and use a light source to irradiate to complete the release of the patterned alkaline substance;

[0010] Step 4: Use a point heat source or a light source to trigger front - end polymerization, and the polymerization wave advances along a set path to complete the patterned advancement of front - end polymerization.

[0011] The double - bond - containing first network monomer includes one or a combination of more than one of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 4 - morpholine acrylate, 2 - hydroxyethyl acrylate, 2 - hydroxyethyl methacrylate, polyurethane acrylate, 1,4 - butanediol diacrylate, 1,6 - hexanediol diacrylate, ethylene glycol phthalate diacrylate, tripropylene glycol diacrylate, and trimethylolpropane triacrylate.

[0012] The first - stage initiator includes one or a combination of more than one of benzoyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, 2,2'-azobis(2 - methylpropionamidine) dihydrochloride, cumene hydroperoxide, diisopropyl peroxydicarbonate, tert - butyl hydroperoxide, and potassium persulfate.

[0013] The front - end polymerization network monomer includes one or a combination of more than one of epoxy E51, epoxy E44, 3 - ethyl - 3 - oxetane methanol, 3,3'-[oxybis(methylene)]bis[3 - ethyl]oxetane, 3 - ethyl - 3 - [(ethylene oxide - 2 - methoxy)methyl]oxetane, 3 - ethyl - 3 - [4 - [(3 - ethyloxetane - 3 - yl)methoxy]butoxymethyl]oxetane.

[0014] The second - stage thermal initiator includes one or a combination of two of benzoin and 1,1,2,2 - tetraphenylethane.

[0015] The second-stage photoacid generator comprises one or a combination of more than one of 4-octyloxy diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsenate, di-tert-butylphenylphosphonium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluoroantimonate, and the second-stage photo-base generator comprises one or a combination of more than one of 2-nitrophenylpropoxycarbonyl-tetramethylguanidine, 1,5,7-triazabicyclodecene tetraphenylborate, WPBG-158.

[0016] Preferably, in step one, by mass, the content of each component is 60 parts of a double-bonded first network monomer, 10 parts of a first-stage initiator, 40 parts of a front polymerization network monomer, 6 parts of a second-stage thermal initiator, 6 parts of a second-stage photoacid generator, and 6 parts of a second-stage photo-base generator. The double-bonded first network monomer comprises butyl acrylate and tripropylene glycol diacrylate, and the ratio between the two is 99:1; the front polymerization network monomer is epoxy E51 and 3-ethyl-3-oxabutyl methanol, and the ratio between the two is 4:6; the first-stage initiator is azobisisobutyronitrile, the second-stage thermal initiator is benzoin; the second-stage photoacid generator is 1-butyl-3-methylimidazolium hexafluoroantimonate; the second-stage photo-base generator is 2-nitrophenylpropoxycarbonyl-tetramethylguanidine.

[0017] Preferably, in step one, by mass, the content of each component is 30 parts of a double-bonded first network monomer, 5 parts of a first-stage initiator, 70 parts of a front polymerization network monomer, 3 parts of a second-stage thermal initiator, 3 parts of a second-stage photoacid generator, and 3 parts of a second-stage photo-base generator. The double-bonded first network monomer comprises ethyl acrylate and 1,6-hexanediol diacrylate, and the ratio between the two is 9:1; the front polymerization network monomer is epoxy E51 and 3-ethyl-3-oxabutyl methanol, and the ratio between the two is 5:5; the first-stage initiator is azobisisobutyronitrile, the second-stage thermal initiator is benzoin; the second-stage photoacid generator is 1-butyl-3-methylimidazolium hexafluoroantimonate; the second-stage photo-base generator is 1,5,7-triazabicyclodecene tetraphenylborate.

[0018] Preferably, in step one, by mass, the content of each component is 40 parts of a double-bonded first network monomer, 7 parts of a first-stage initiator, 60 parts of a front polymerization network monomer, 9 parts of a second-stage thermal initiator, 9 parts of a second-stage photoacid generator, and 9 parts of a second-stage photo-base generator. The double-bonded first network monomer comprises ethyl acrylate and ethylene glycol phthalate diacrylate, and the ratio between the two is 9:1; the front polymerization network monomer is epoxy E51 and 3-ethyl-3-oxabutyl methanol, and the ratio between the two is 8:2; the first-stage initiator is diisopropyl peroxydicarbonate, the second-stage thermal initiator is 1,1,2,2-tetraphenylethane; the second-stage photoacid generator is 1-butyl-3-methylimidazolium hexafluoroantimonate; the second-stage photo-base generator is WPBG-158.

[0019] The steps for preparing the flexible composite material using the above preparation method, which are different from the preparation method of the flexible film, are as follows: In step two, lay the fiber cloth flat in the mold, then spread the reaction precursor solution evenly on the fiber cloth, and complete the first-stage curing of the flexible composite material through heat treatment. The remaining steps are the same as those of the flexible film preparation method.

[0020] In step three of the preparation of the flexible composite material, use a light source to irradiate both sides for 0.5 - 30 min to complete the patterned release of alkaline substances.

[0021] Preferably, the fiber cloth includes a glass fiber cloth, a quartz fiber cloth, a carbon fiber cloth, an aramid fiber cloth, or a basalt fiber cloth.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The present invention proposes a patternable front polymerization process, combined with a two-stage curing technology, which can achieve the ground flexible folding and unfolding and on-orbit low-energy patterned stiffening of the composite material for the space deployment structure. The specific implementation process is to use two independent curing resin systems to perform the first-stage curing on the ground to form a flexible intermediate state and achieve ground flexible folding and unfolding; use a patterned light source to irradiate the composite material to activate the photo-base generator (PBG) and release alkaline substances. After the space folding and unfolding device prepared by it is deployed in orbit, only a local heat source or light source needs to be applied to trigger the self-propagating reaction. Due to the acid-base neutralization effect in the area where alkaline substances are released, the polymerization front quenches, and in the area where alkaline substances are not released, the polymerization continues to advance, thereby achieving the patterned front polymerization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the flexible patternable front polymerization propulsion process of the present invention;

[0025] Figure 2 is a schematic diagram of the principle of patterned front polymerization. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1:

[0028] A preparation method of a patternable front polymerization flexible film includes the following steps:

[0029] Step 1: By mass, mix 5 parts of the first network monomer with double bonds, 0.1 part of the initiator in the first stage; 95 parts of the front polymerization network monomer, 0.5 part of the thermal initiator in the second stage, 2 parts of the photoacid generator in the second stage, and 2 parts of the photobase generator in the second stage to obtain a reaction precursor solution; the first network monomer with double bonds includes butyl acrylate and tripropylene glycol diacrylate, and the ratio of the two is 9:1; the front polymerization network monomer is epoxy E51 and 3-ethyl-3-oxetanemethanol, and the ratio of the two is 6:4; the initiator in the first stage is azobisisobutyronitrile, the thermal initiator in the second stage is benzoin; the photoacid generator in the second stage is diphenyliodonium hexafluoroantimonate; the photobase generator in the second stage is 2-nitrophenylpropoxycarbonyl-tetramethylguanidine;

[0030] Step 2: Transfer the reaction precursor solution onto a glass mold and spread it evenly, and heat it in an oven at 100 °C for 0.5 h to complete the first-stage curing of the flexible film;

[0031] Step 3: Take out the sample that has completed the first-stage curing, cover it with a photomask, and immediately irradiate it with a blue light source (10 mW / cm 2 ) for 3 min to complete the release of the patterned basic substance;

[0032] Step 4: Use a point heat source or light source to trigger front polymerization, and the polymerization wave advances along the set path to complete the patterned advancement of front polymerization. The specific process is shown in Figure 1 .

[0033] The principle of the second-stage front polymerization advancement is shown in Figure 2 . In this process, it can be triggered by a point heat / light source. If triggered by a heat source, the thermal initiator in the second stage decomposes into active free radicals, which further react with the photoacid generator in the second stage to generate superacids, triggering the monomer reaction. The generated heat in turn promotes the decomposition of the thermal initiator in the second stage, so a self-propagating advancement cycle is generated; if triggered by a light source, the photoacid generator (Photo Acid Generator, PAG) in the second stage decomposes into superacids, triggering the monomer reaction. The generated heat promotes the decomposition of the thermal initiator in the second stage, so a self-propagating advancement is generated. After pre-treating the material with a mask, the photobase generator (Photo Base Generator, PBG) in the pre-treated area decomposes to produce basic substances, which trigger an acid-base neutralization reaction with the generated superacids, destroying the reaction between the superacids and the monomers and preventing the spread of the polymerization front. Therefore, a patterned advancement effect of front polymerization is achieved.

[0034] Example 2:

[0035] A preparation method of a patterning front polymerization flexible composite material includes the following steps:

[0036] Step 1: The same as in Example 1;

[0037] Step 2: Lay the fiberglass cloth flat in a glass mold, pour the reaction precursor solution into the mold, scrape it flat with a spatula, place it in a vacuum oven to remove air bubbles, and then use the same curing conditions as in Example 1 to complete the first-stage curing of the flexible composite material, forming an intermediate state of the flexible composite material.

[0038] Step 3: In order to ensure the efficiency of the release of alkaline substances by PBG, perform double-sided irradiation using a photomask, with the irradiation conditions the same as in Example 1.

[0039] Step 4: The conditions for initiating the front polymerization are the same as in Example 1.

[0040] Example 3:

[0041] A method for preparing a patterning front polymerization flexible film includes the following steps:

[0042] Step 1: By mass, mix 50 parts of a double-bonded first network monomer, 2 parts of a first-stage initiator; 50 parts of a front polymerization network monomer, 5 parts of a second-stage thermal initiator, 5 parts of a second-stage photoacid generator, and 5 parts of a second-stage photobase generator to obtain a reaction precursor solution; the double-bonded first network monomer includes hydroxyethyl acrylate and trimethylolpropane triacrylate, with a ratio of 9:1 between the two; the front polymerization network monomer is epoxy E44 and 3-ethyl-3-[(ethylene oxide-2-methoxy)methyl]oxetane, with a ratio of 7:3 between the two; the first-stage initiator is benzoyl peroxide, the second-stage thermal initiator is 1,1,2,2-tetraphenylethane; the second-stage photoacid generator is diphenyliodonium hexafluoroantimonate; the second-stage photobase generator is 1,5,7-triazabicyclodecene tetraphenylborate;

[0043] Step 2: Transfer the reaction precursor solution onto a glass mold and spread it evenly, and heat it in an oven at 40°C for 6 h to complete the first-stage curing of the flexible film.

[0044] Step 3: Take out the sample that has completed the first-stage curing, cover it with a photomask, and immediately use a blue light source (1 mW / cm 2 ) for double-sided irradiation for 30 min to complete the release of the patterned alkaline substances.

[0045] Step 4: Use a point heat source or light source to trigger the front polymerization, and the polymerization wave advances along the set path to complete the patterned advancement of the front polymerization.

[0046] Example 4:

[0047] A method for preparing a patterning front polymerization flexible composite material includes the following steps:

[0048] Step 1: The same as in Example 3.

[0049] Step 2: Lay the carbon fiber cloth flat in the glass mold, pour the reaction precursor solution into the mold, scrape it flat with a spatula, place it in a vacuum oven to remove air bubbles, and then use the same curing conditions as in Example 3 to complete the first-stage curing of the flexible composite material, forming an intermediate state of the flexible composite material.

[0050] Step 3: To ensure the efficiency of the PBG in releasing alkaline substances, perform double-sided irradiation using a photomask, with the irradiation conditions the same as in Example 3.

[0051] Step 4: The conditions for initiating front polymerization are the same as in Example 3.

[0052] Example 5:

[0053] A method for preparing a patternable front polymerization flexible film, comprising the following steps:

[0054] Step 1: By mass, mix 20 parts of a double-bonded first network monomer, 2 parts of a first-stage initiator; 80 parts of a front polymerization network monomer, 2 parts of a second-stage thermal initiator, 2 parts of a second-stage photoacid generator, and 2 parts of a second-stage photobase generator to obtain a reaction precursor solution; the double-bonded first network monomer comprises ethyl methacrylate and trimethylolpropane triacrylate, with a ratio of 8:2 between the two; the front polymerization network monomer is epoxy E44 and 3,3'-[oxybis(methylene)]bis[3-ethyl]oxetane, with a ratio of 5:5 between the two; the first-stage initiator is benzoyl peroxide, the second-stage thermal initiator is 1,1,2,2-tetraphenylethane; the second-stage photoacid generator is diphenyliodonium hexafluoroantimonate; the second-stage photobase generator is 1,5,7-triazabicyclodecene tetraphenylborate;

[0055] Step 2: Transfer the reaction precursor solution onto the glass mold and spread it evenly, and heat it in an oven at 60°C for 2 h to complete the first-stage curing of the flexible film.

[0056] Step 3: Take out the sample that has completed the first-stage curing, cover it with a photomask, and immediately perform double-sided irradiation with a blue light source (5 mW / cm 2 ) for 5 min to complete the release of the patterned alkaline substance.

[0057] Step 4: Use a point heat source or light source to trigger front polymerization, and the polymerization wave advances along the set path to complete the patterned advancement of front polymerization.

[0058] Example 6:

[0059] A method for preparing a patternable front polymerization flexible composite material, comprising the following steps:

[0060] Step 1: The same as in Example 5;

[0061] Step 2: Lay the aramid fiber cloth flat in the glass mold, pour the reaction precursor solution into the mold, scrape it flat with a spatula, place it in a vacuum oven to remove air bubbles, and then complete the first-stage curing of the flexible composite material under the same curing conditions as in Example 5 to form an intermediate state of the flexible composite material;

[0062] Step 3: In order to ensure the efficiency of PBG in releasing alkaline substances, perform double-sided irradiation using a photomask, and the irradiation conditions are the same as in Example 5;

[0063] Step 4: The conditions for initiating the front polymerization are the same as in Example 5.

[0064] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A preparation method of a patternable frontline polymerization flexible film, characterized in that: It includes the following steps: Step 1: Mix 5 - 60 parts by mass of a double - bond - type first network monomer, 0.1 - 10 parts of a first - stage initiator, 40 - 95 parts of a front - end polymerization network monomer, 0.1 - 10 parts of a second - stage thermal initiator, 0.1 - 10 parts of a second - stage photo - acid generator, and 0.1 - 10 parts of a second - stage photo - base generator to obtain a reaction precursor solution; Step 2: Transfer the reaction precursor solution to a mold and spread it evenly, and heat it at 25 - 100 °C for 0.5 - 8 h to complete the first - stage curing of the flexible film; Step 3: Cover the sample that has completed the first - stage curing with a photomask, and use a light source to irradiate to complete the release of the patterned alkaline substance; Step 4: Use a point heat source or a light source to trigger front - end polymerization, and the polymerization wave advances along a set path to complete the patterned advancement of front - end polymerization.

2. The preparation method according to claim 1, wherein: The double - bond - type first network monomer includes one or a combination of more of methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 4 - morpholino acrylate, 2 - hydroxyethyl acrylate, 2 - hydroxyethyl methacrylate, polyurethane acrylate, 1,4 - butanediol diacrylate, 1,6 - hexanediol diacrylate, ethylene glycol phthalate diacrylate, tripropylene glycol diacrylate, and trimethylolpropane triacrylate.

3. The preparation method according to claim 1, characterized in that: The first - stage initiator includes one or a combination of more of benzoyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, 2,2'-azobis(2 - methylpropionamidine) dihydrochloride, cumene hydroperoxide, diisopropyl peroxydicarbonate, tert - butyl hydroperoxide, and potassium persulfate.

4. The preparation method according to claim 1, characterized in that: The front - end polymerization network monomer includes one or a combination of more of epoxy E51, epoxy E44, 3 - ethyl - 3 - oxetane methanol, 3,3'-[oxybis(methylene)]bis[3 - ethyl]oxetane, 3 - ethyl - 3 - [(ethylene oxide - 2 - methoxy)methyl]oxetane, and 3 - ethyl - 3 - [4 - [(3 - ethyl - oxetane - 3 - yl)methoxy]butoxymethyl]oxetane.

5. The preparation method according to claim 1, wherein: The second - stage thermal initiator includes one or a combination of two of benzoin and 1,1,2,2 - tetraphenylethane.

6. The preparation method according to claim 1, characterized in that: The second - stage photo - acid generator includes one or a combination of more of 4 - octyloxy diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroarsenate, di - tert - butylphenylphosphonium tetrafluoroborate, and 1 - butyl - 3 - methylimidazolium hexafluoroantimonate. The second - stage photo - base generator includes one or a combination of more of 2 - nitrophenylpropoxycarbonyl - tetramethylguanidine, 1,5,7 - triazabicyclo[4.4.0]dec - 5 - ene tetraphenylborate, and WPBG - 158.

7. Use of the preparation method according to any one of claims 1-6 in a composite material, characterized in that: In Step 2, lay the fiber cloth flat in the mold, then spread the reaction precursor solution evenly on the fiber cloth, and complete the first - stage curing of the flexible composite material by heat treatment. The remaining steps are the same as Steps 1, 3, and 4 in the preparation method described in any one of Claims 1 - 6.

8. The application according to claim 1, wherein: In Step 3, use a light source to irradiate both sides for 0.5 - 30 min to complete the release of the patterned alkaline substance.

9. The application according to claim 7, wherein: The fiber cloth includes fiberglass cloth, quartz fiber cloth, carbon fiber cloth, aramid fiber cloth or basalt fiber cloth.

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