A sulfur-containing photoinitiator composition and a free radical polymerization system

Abstract

The application relates to the technical field of organic photocatalysis, and specifically puts forward a sulfur-containing photoinitiator composition and a free radical polymerization system. The sulfur-containing photoinitiator composition specifically comprises an organic photocatalyst and a sulfur-containing initiator. When used for photoinitiated free radical polymerization, the organic photocatalyst and the sulfur-containing initiator respectively act as an acceptor and a donor, a photoinduced reaction occurs under light to form a charge transfer complex, and the charge transfer complex is dissociated into free radicals to initiate free radical polymerization. The application utilizes a novel sulfur-containing photoinitiator composition, and successfully applies the sulfur-containing photoinitiator composition to the polymerization field. Since the sulfur-containing photoinitiator composition exhibits excellent insensitivity to water and oxygen, the sulfur-containing photoinitiator composition can be rapidly initiated under light in an air environment without a metal catalyst and a complicated oxygen removal operation, so that the sulfur-containing photoinitiator composition can provide a brand-new green synthesis path for the development of high-performance functional polymers, and the technical problems of existing polymerization technologies, such as environmental sensitivity, complicated steps or dependence on metal catalysts, are solved.

Description

Technical Field

[0001] This invention relates to the field of organic photocatalysis technology, and more particularly to a sulfur-containing photoinitiator composition and a free radical polymerization system. Background Technology

[0002] Polymer materials play an irreplaceable role in modern industry, biomedicine, and cutting-edge scientific research. Among them, polymers with specific topological structures (such as block copolymers, graft polymers, and polymer brushes) have become a research focus in the field of high-performance materials due to their unique phase separation behavior, self-assembly characteristics, and multifunctionality. Currently, traditional methods for preparing such complex polymer structures mainly rely on living radical polymerization (such as RAFT, ATRP, RDRP, etc.) or ionic polymerization techniques. However, these techniques have significant limitations in actual production: on the one hand, the reaction process is usually extremely sensitive to water and oxygen, requiring a harsh oxygen- and anhydrous environment; on the other hand, systems such as ATRP often involve the introduction of heavy metal catalysts (such as copper and nickel), which not only increases post-processing costs but also limits the application of the products in high-end fields such as biomedicine, electronic packaging, and food packaging due to metal residue issues.

[0003] In recent years, photoinitiated polymerization (PFRP) technology has been regarded as a green alternative for synthesizing polymer materials due to its advantages such as high efficiency, energy saving, spatial control, and mild reaction conditions. Although PFRP has made great progress, existing systems still face significant challenges in constructing complex topologies. First, most commercially available photoinitiators are extremely sensitive to oxygen, and the oxygen inhibition effect leads to long polymerization induction periods and low conversion rates, usually requiring nitrogen protection or the addition of expensive oxygen scavengers. Second, directly "grafting" or "growing" a second polymer chain onto an existing polymer backbone often requires the prior synthesis of macromolecular initiators with specific active functional groups (such as brominated or thioester groups), which involves cumbersome synthesis steps and harsh conditions.

[0004] While sulfur-containing compounds have applications in polymerization reactions, their use has been limited to thiols as chain transfer agents. Thiols, however, often suffer from drawbacks such as pungent odors, easy oxidation, and poor stability. Utilizing the more stable sulfide structure to directly initiate polymerization under light, especially through the direct induction of polymer chain growth via the adjacent carbon atoms of sulfur-containing substances, represents a highly promising direction in polymer synthesis. However, the use of sulfides for water- and oxygen-insensitive photoinitiated polymerization remains largely unexplored, indicating significant future potential. Therefore, industry and academia urgently need a simpler, more universal, and environmentally friendly polymerization method to achieve the efficient production of polymers with various morphologies. Summary of the Invention

[0005] Based on the technical problems existing in the background art, this invention proposes a sulfur-containing photoinitiator composition and a free radical polymerization system. The novel sulfur-containing photoinitiator composition has been successfully applied to the field of polymerization. Due to its excellent insensitivity to water and oxygen, it can be rapidly initiated by light in an air environment without the need for metal catalysts and complex deoxygenation operations. Therefore, it can provide a new green synthesis route for the development of high-performance functional polymers and solve the technical problems of existing polymerization technologies such as environmental sensitivity, cumbersome steps, or dependence on metal catalysts.

[0006] The present invention provides a sulfur-containing photoinitiator composition comprising an organic photocatalyst and a sulfur-containing initiator; When used for photo-initiated free radical polymerization, the organic photocatalyst and the sulfur-containing initiator act as acceptor and donor, respectively, and undergo a photoinduced reaction under light to form a charge-transfer complex. The charge-transfer complex dissociates into free radicals to initiate free radical polymerization.

[0007] Preferably, the organic photocatalyst is an electron-deficient compound with a conjugated structure, and the sulfur-containing initiator is a thioether containing carbon-hydrogen bonds.

[0008] Preferably, the organic photocatalyst is an aromatic imide compound, an aromatic quinone compound, or an electron-deficient polycyclic aromatic hydrocarbon compound, and its general structural formula is shown below:

[0009] R1 is independently selected from hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, any substituted or unsubstituted phenyl, any substituted or unsubstituted benzyl, halogen-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms, and aromatic imides, aromatic quinones or electron-deficient polycyclic aromatic hydrocarbons with the aforementioned substituents. R2-R5 are independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, and methoxy groups; R6, R 13 R 16 R 19 R 24 The compounds are independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, nitro, any substituted or unsubstituted phenyl, any substituted or unsubstituted benzyl, halogen-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms, as well as aromatic imides, aromatic quinones or electron-deficient polycyclic aromatic hydrocarbons with the aforementioned substituents. R7-R 12 R 14 R 15 R 17 R18 R 20 -R 23 R 25 -R 28 It is independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, and nitro groups; R 29 -R 100 It is independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, nitro, carbonyl, any substituted or unsubstituted phenyl, any substituted or unsubstituted benzyl, halogen-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms; The general structural formula of the sulfur-containing initiator is shown below: R 101 -R 103 It is independently selected from one of the substituted or unsubstituted organic groups or polymer segments.

[0010] Preferably, the organic photocatalyst is at least one of the compounds shown in the following structural formulas:

[0011] The sulfur-containing initiator is at least one of the compounds shown in the following structural formula: .

[0012] Preferably, the molar ratio of the organic photocatalyst to the sulfur-containing initiator is 1:1-100.

[0013] The present invention also proposes a free radical polymerization system comprising an alkenyl monomer and the above-mentioned sulfur-containing photoinitiator composition.

[0014] Preferably, the alkenyl monomer is an acrylate monomer with the following general structural formula:

[0015] R 104 It represents hydrogen or methyl.

[0016] R 105 It is independently selected from hydrogen, methyl, straight-chain or branched alkyl or alkyl alcohols with 1-10 carbon atoms, and hydroxyl, carboxyl, cyano, mercapto, amide, vinyl, alkoxy, alkylthio, nitro, piperazine, phenothiazine, any substituted or unsubstituted phenyl, and straight-chain or branched alkyl chains with 1-10 carbon atoms having the above substituents.

[0017] Preferably, the acrylate monomer is at least one of the compounds shown in the following structural formulas: .

[0018] In this invention, if the acrylate monomer is a liquid, the organic photocatalyst, sulfur-containing initiator, and acrylate monomer can be directly mixed in proportion; if the acrylate monomer is a solid, the organic photocatalyst, sulfur-containing initiator, and acrylate monomer can be mixed and dissolved in an organic solvent, such as dimethyl sulfoxide (DMSO), or the monomer can be heated to melt and then mixed.

[0019] Preferably, the molar ratio of the organic photocatalyst in the alkenyl monomer and sulfur-containing photoinitiator composition is 1-100000:1.

[0020] Preferably, the free radical polymerization system uses ultraviolet or visible light with a wavelength of 280 nm-600 nm as the light source during the polymerization reaction.

[0021] In this invention, the wavelength of the light source is related to the structure of the photocatalyst. Different types of catalysts require different excitation light sources: light conditions with wavelengths less than 280 nm have limited value for industrial production, while light conditions with wavelengths greater than 600 nm will increase the difficulty of synthesis.

[0022] Preferably, the illumination duration is 1 s-10 h.

[0023] In this invention, the irradiation time affects the molecular weight distribution of the prepared polyacrylate compound and the conversion rate of the polyacrylate monomer; the longer the irradiation time, the higher the conversion rate of the polyacrylate monomer.

[0024] In this invention, the number-average molecular weight of the polymer obtained by polymerization in the free radical polymerization system can reach more than 10,000, and the weight-average molecular weight can reach more than 50,000.

[0025] In this invention, the obtained polymer can also be purified, for example, by dissolving the polymer product in dichloromethane to obtain a mixed solution; then, the mixed solution is back-dropped into anhydrous petroleum ether, filtered repeatedly, and dried to obtain the purified polymer product.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, when the alkenyl monomer is mixed with the photocatalyst composition consisting of a photocatalyst and a sulfur-containing initiator, under light irradiation, the photocatalyst and the sulfur-containing initiator undergo photo-induced interaction to form a charge-transfer complex. The (sulfur-containing) free radicals generated by the dissociation of the charge-transfer complex can initiate the polymerization reaction of the monomer, that is, generate the target polymer. Due to the structural diversity of sulfur-containing initiators, this invention can realize the customized preparation of different topological structures of the target polymer: for example, when a small molecule sulfur-containing substance is used as an initiator, a polymer chain can be prepared; when a macromolecule containing sulfur elements in the main chain, side chain or end group is used as an initiator, since the carbon sites adjacent to its sulfur atom can all be used as initiation sites, complex topological structures such as graft polymers or block polymers can be prepared in situ.

[0027] (2) This invention utilizes a sulfur-containing initiator to directly initiate monomer polymerization from its adjacent carbon atom under light irradiation. This is not only suitable for initiating the preparation of homopolymers from small molecules, but more importantly, as long as the polymer backbone, side chains, or end groups contain sulfur, a second polymer chain can be grown in situ at its adjacent position as an initiation site, thus conveniently constructing block polymers, graft polymers, and polymer brushes, among other topological structures. Furthermore, the system of this invention exhibits excellent environmental tolerance during polymerization, being insensitive to water and oxygen. Polymerization can be efficiently initiated under light irradiation in an air environment, without the need for stringent oxygen- and anhydrous operations. Due to the simple reaction conditions, no oxygen removal is required; air is sufficient for the process, making the operation convenient and possessing potential for industrial application.

[0028] (3) The sulfur-containing photocatalyst composition proposed in this invention and its polymerization application can select appropriate parameters of light source and illumination time as needed; the illumination conditions are easy to control the reaction progress, and there is no problem of uncontrollable reaction progress caused by temperature changes in thermally initiated polymerization; at the same time, the photo-initiated polymerization reaction is rapid, faster than thermally initiated polymerization. Attached Figure Description

[0029] Figure 1 The following is a schematic diagram of the polymerization reaction principle of the acrylate polymer compound described in Example 1 of the present invention: (a) is a schematic diagram of the polymerization principle; (b) is a schematic diagram of the donor-acceptor pair initiation mechanism; Figure 2 The following diagram illustrates the mechanism of polymerization of the acrylate polymers described in Example 1 of this invention: (a) A comparison of the fluorescence emission spectra of the donor and acceptor molecules before and after illumination in acetonitrile (donor and acceptor concentration is 10). -4 M, the test excitation wavelength is 330 nm); (b) is a comparison of the mass spectra of donor and acceptor molecular pairs before and after illumination (ESI+); (c) is the MALDI-TOF MS spectrum of the polymer compound. Figure 3 The 1H NMR spectrum of the acrylate monomer described in Example 1 of this invention in CDCl3; Figure 4 The hydrogen spectrum of the purified polymer compound described in Example 1 of this invention in CDCl3; Figure 5 This is the GPC spectrum of the purified polymer compound described in Example 1 of the present invention (THF is the mobile phase). Figure 6 The 1H NMR spectrum of the acrylate monomer described in Example 2 of this invention in CDCl3; Figure 7 The hydrogen spectrum of the purified polymer compound described in Example 2 of this invention in CDCl3; Figure 8 This is the GPC spectrum of the purified polymer compound described in Example 2 of the present invention (THF is the mobile phase). Figure 9 The hydrogen spectrum of the purified polymer compound described in Example 3 of this invention in CDCl3; Figure 10 This is the GPC spectrum of the purified polymer compound described in Example 3 of the present invention (THF is the mobile phase). Figure 11 The 1H NMR spectrum of the acrylate monomer described in Example 4 of this invention in CDCl3; Figure 12 The hydrogen spectrum of the purified polymer compound described in Example 4 of this invention in CDCl3; Figure 13 This is the GPC spectrum of the purified polymer compound described in Example 4 of the present invention (THF is the mobile phase). Figure 14 The 1H NMR spectrum of the acrylate monomer described in Example 5 of this invention in CDCl3; Figure 15 The hydrogen spectrum of the purified polymer compound described in Example 5 of this invention in CDCl3; Figure 16 This is the GPC spectrum of the purified polymer compound described in Example 5 of the present invention (THF is the mobile phase). Figure 17 The photon spectrum of the product obtained in Comparative Example 1 of this invention is shown in CDCl3. Detailed Implementation

[0030] It should be noted that the described embodiments are merely some, not all, of the embodiments disclosed herein. Other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are all within the scope of protection of this disclosure.

[0031] It should be noted that, unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning as understood by a person with ordinary skills in the art to which this disclosure pertains.

[0032] According to embodiments of this disclosure, reagents or reaction apparatus for which specific conditions are not specified can be carried out under conventional conditions or conditions recommended by the manufacturer.

[0033] According to embodiments of this disclosure, reagents or instruments without a specified manufacturer can be obtained from commercially available conventional products.

[0034] Example 1 The organic photocatalyst (scheme I3), the sulfur-containing initiator (scheme O14), and the acrylate monomer (scheme P6) were mixed in a molar ratio of 1:50:10000 and irradiated under a light source with a wavelength of 365 nm and a power of 10 W for 60 min to complete the polymerization reaction and obtain a mixture. The obtained mixture was dissolved in dichloromethane solution and then back-dropped into anhydrous petroleum ether to produce a precipitate. After filtration, washing, and drying, the purified acrylate polymer compound was obtained.

[0035] Figure 1 a illustrates the polymerization principle diagram of the acrylate polymer compound described in this embodiment, with reference to... Figure 1 As can be seen from a, the organic photocatalyst and the sulfur-containing initiator form a charge-transfer complex under light irradiation. This charge-transfer complex can dissociate to generate free radicals formed by the sulfur-containing initiator. These free radicals initiate the polymerization of acrylate monomers to obtain the target polymer.

[0036] Figure 1 b illustrates the process by which donor-acceptor pairs bind and dissociate to generate free radicals under light irradiation, as shown in reference [reference]. Figure 1 As shown in b, the initiator can initiate the reaction because a photoinduced charge transfer complex (PCTC) is formed between the donor and acceptor. Unlike the instantaneous dissociation of the traditional electron donor-acceptor complex (EDA), PCTC exhibits a degree of stability, dissociates more slowly, and is less affected by oxygen. Therefore, PCTC can be detected by both spectroscopy and mass spectrometry.

[0037] Figure 2 a shows the fluorescence spectra of donor-acceptor molecules dispersed in acetonitrile before and after light irradiation, with reference to... Figure 2 As can be seen from a, a fluorescence peak centered at 480 nm appeared in the fluorescence spectrum after illumination; the PCTC pairs formed after illumination can be measured by mass spectrometry (see reference). Figure 2 b).

[0038] Figure 2c shows the MALDI-TOF MS spectrum of the polymer compound formed in this embodiment, with reference to... Figure 2 As can be seen from c, the polymer generated by the reaction is indeed generated on the initiator, and the end groups are well preserved.

[0039] Figure 3 The 1H NMR spectrum of the acrylate monomer described in this embodiment in CDCl3 is shown below. Figure 3 It can be seen that the acrylate monomers shown in structure P6 exhibit characteristic peaks for each hydrogen atom in the hydrogen spectrum before the photo-initiated polymerization reaction, and these characteristic peaks are labeled as 1, 2, 3, 4, 5, 6, and 7.

[0040] Figure 4 The 1H NMR spectrum of the purified acrylate polymer compound described in this embodiment in CDCl3 is shown below. Figure 4 It can be seen that purified acrylate polymers can effectively remove unreacted monomers and other components.

[0041] Figure 5 This is the GPC spectrum of the purified acrylate polymer compound described in this embodiment (THF is the mobile phase), referring to... Figure 5 It can be seen that the number-average molecular weight Mn of the polymer is 52,600, the weight-average molecular weight Mw is 118,500, and the material dispersibility PDI is 2.25.

[0042] Example 2 The organic photocatalyst (scheme L3), the sulfur-containing initiator (scheme O1), and the acrylate monomer (scheme P2) were mixed in a molar ratio of 1:50:10000 and irradiated under a light source with a wavelength of 365 nm and a power of 10 W for 60 min to complete the polymerization reaction and obtain a mixture. The obtained mixture was dissolved in dichloromethane solution and then back-dropped into anhydrous petroleum ether to produce a precipitate. After filtration, washing, and drying, the purified acrylate polymer compound was obtained.

[0043] Figure 6 The 1H NMR spectrum of the acrylate monomer described in this embodiment in CDCl3 is shown below. Figure 6 It can be seen that the acrylate monomers represented by structure P2 show characteristic peaks for each hydrogen atom in the hydrogen spectrum before the photo-initiated polymerization reaction, and the characteristic peaks are labeled as 1, 2, 3, 4, and 5.

[0044] Figure 7 The 1H NMR spectrum of the purified acrylate polymer compound described in this embodiment in CDCl3 is shown below. Figure 7 As can be seen, the polymer peaks are clearly visible, indicating that the monomers have been removed relatively cleanly.

[0045] Figure 8This is the GPC spectrum of the purified acrylate polymer compound described in this embodiment (THF is the mobile phase), referring to... Figure 8 It can be seen that the number-average molecular weight Mn of the polymer is 38,900, the weight-average molecular weight Mw is 127,700, and the material dispersibility PDI is 3.28.

[0046] Example 3 The organic photocatalyst (Structure C7), the sulfur-containing initiator (Structure O9), and the acrylate monomer (Structure P6) were mixed in a molar ratio of 1:50:10000 and irradiated under a light source with a wavelength of 365 nm and a power of 10 W for 60 min to complete the polymerization reaction and obtain a mixture. The obtained mixture was dissolved in dichloromethane solution and then back-dropped into anhydrous petroleum ether to produce a precipitate. After filtration, washing, and drying, the purified acrylate polymer compound was obtained.

[0047] Figure 9 The 1H NMR spectrum of the purified acrylate polymer compound described in this embodiment in CDCl3 is shown below. Figure 9 As can be seen, the polymer peaks are clearly visible, indicating that the monomers have been removed relatively cleanly.

[0048] Figure 10 This is the GPC spectrum of the purified acrylate polymer compound described in this embodiment (THF is the mobile phase), referring to... Figure 10 It can be seen that the number-average molecular weight Mn of the polymer is 45300, the weight-average molecular weight Mw is 96000, and the material dispersibility PDI is 2.11.

[0049] Example 4 The organic photocatalyst (scheme K1), the sulfur-containing initiator (scheme O10), and the acrylate monomer (scheme P1) were mixed in a molar ratio of 1:50:10000 and irradiated under a light source with a wavelength of 365 nm and a power of 10 W for 30 min to complete the polymerization reaction and obtain a mixture. The obtained mixture was dissolved in dichloromethane solution and then back-dropped into anhydrous petroleum ether to produce a precipitate. After filtration, washing, and drying, the purified acrylate polymer compound was obtained.

[0050] Figure 11 The 1H NMR spectrum of the acrylate monomer described in this embodiment in CDCl3 is shown below. Figure 11 It can be seen that the acrylate monomers shown in structure P1 exhibit characteristic peaks for each hydrogen atom in the hydrogen spectrum before the photo-initiated polymerization reaction, and these characteristic peaks are labeled as 1, 2, and 3.

[0051] Figure 12 The 1H NMR spectrum of the purified acrylate polymer compound described in this embodiment in CDCl3 is shown below. Figure 12 As can be seen, the polymer peaks are clearly visible, indicating that the monomers have been removed relatively cleanly.

[0052] Figure 13 This is the GPC spectrum of the purified acrylate polymer compound described in this embodiment (THF is the mobile phase), referring to... Figure 13 It can be seen that the number-average molecular weight Mn of the polymer is 39300, the weight-average molecular weight Mw is 110700, and the material dispersibility PDI is 2.81.

[0053] Example 5 The organic photocatalyst (Structure N1), the sulfur-containing initiator (Structure O8), and the acrylate monomer (Structure P9) were mixed in a molar ratio of 1:50:10000 and irradiated under a light source with a wavelength of 365 nm and a power of 10 W for 30 min to complete the polymerization reaction and obtain a mixture. The obtained mixture was dissolved in dichloromethane solution and then back-dropped into anhydrous petroleum ether to produce a precipitate. After filtration, washing, and drying, the purified acrylate polymer compound was obtained.

[0054] Figure 14 The 1H NMR spectrum of the acrylate monomer described in this embodiment in CDCl3 is shown below. Figure 14 It can be seen that the acrylate monomers shown in structure P9 exhibit characteristic peaks for each hydrogen atom in the hydrogen spectrum before the photo-initiated polymerization reaction, and these characteristic peaks are labeled as 1, 2, 3, 4, and 5.

[0055] Figure 15 The 1H NMR spectrum of the purified acrylate polymer compound described in this embodiment in CDCl3 is shown below. Figure 15 As can be seen, the polymer peaks are clearly visible, indicating that the monomers have been removed relatively cleanly.

[0056] Figure 16 This is the GPC spectrum of the purified acrylate polymer compound described in this embodiment (THF is the mobile phase), referring to... Figure 16 It can be seen that the number-average molecular weight Mn of the polymer is 45,100, the weight-average molecular weight Mw is 128,700, and the material dispersibility PDI is 2.85.

[0057] Compare with Example 1 The organic photocatalyst (scheme I3), the thiol initiator (scheme Q1, with low odor), and the acrylate monomer (scheme P9) were mixed in a molar ratio of 1:50:10000 and irradiated for 30 min under a light source with a wavelength of 365 nm and a power of 10 W to complete the polymerization reaction. After that, a small amount of sample was taken and dissolved directly in CDCl3 and then tested for NMR.

[0058]

[0059] Figure 17 The 1H NMR spectrum of the product obtained in this comparative example in CDCl3 is shown below. Figure 17 As can be seen, the acrylate monomer shown in structure P9 failed to polymerize under air light irradiation with this initiator, and the 1H NMR spectrum still showed monomer peaks, which contrasts with other examples.

[0060] Compare with Example 2 The organic photocatalyst (structure I3), the thiol initiator (structure Q2), and the acrylate monomer (structure P6) were mixed in a molar ratio of 1:50:10000 and irradiated under a 365 nm wavelength, 10 W power light source for 30 min to complete the polymerization reaction. A small sample was then dissolved directly in CDCl3 and NMR was measured. The results were similar to those obtained from the previous analysis. Figure 3 The consistency indicates that it also failed to trigger aggregation.

[0061]

[0062] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A sulfur-containing photoinitiator composition, characterized in that, Including organic photocatalysts and sulfur-containing initiators; When used for photo-initiated free radical polymerization, the organic photocatalyst and the sulfur-containing initiator act as acceptor and donor, respectively, and undergo a photoinduced reaction under light to form a charge-transfer complex. The charge-transfer complex dissociates into free radicals to initiate free radical polymerization.

2. The sulfur-containing photoinitiator composition according to claim 1, characterized in that, The organic photocatalyst is an electron-deficient compound with a conjugated structure, and the sulfur-containing initiator is a thioether containing carbon-hydrogen bonds.

3. The sulfur-containing photoinitiator composition according to claim 2, characterized in that, The organic photocatalyst is an aromatic imide compound, an aromatic quinone compound, or an electron-deficient polycyclic aromatic hydrocarbon compound, and its general structural formula is shown below: R1 is independently selected from hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, any substituted or unsubstituted phenyl, any substituted or unsubstituted benzyl, halogen-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms, and aromatic imides, aromatic quinones or electron-deficient polycyclic aromatic hydrocarbons with the aforementioned substituents. R2-R5 are independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, and methoxy groups; R6, R 13 R 16 R 19 R 24 The compounds are independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, nitro, any substituted or unsubstituted phenyl, any substituted or unsubstituted benzyl, halogen-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms, as well as aromatic imides, aromatic quinones or electron-deficient polycyclic aromatic hydrocarbons with the aforementioned substituents. R7-R 12 R 14 R 15 R 17 R 18 R 20 -R 23 R 25 -R 28 It is independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, and nitro groups; R 29 -R 100 It is independently selected from one of hydrogen, halogen, amino, hydroxyl, carboxyl, cyano, mercapto, amide, methoxy, nitro, carbonyl, any substituted or unsubstituted phenyl, any substituted or unsubstituted benzyl, halogen-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms; The general structural formula of the sulfur-containing initiator is shown below: R 101 -R 103 It is independently selected from one of the substituted or unsubstituted organic groups or polymer segments.

4. The sulfur-containing photoinitiator composition according to claim 3, characterized in that, The organic photocatalyst is at least one of the compounds shown in the following structural formula: The sulfur-containing initiator is at least one of the compounds shown in the following structural formula: 。 5. The sulfur-containing photoinitiator composition according to any one of claims 1-4, characterized in that, The molar ratio of the organic photocatalyst to the sulfur-containing initiator is 1:1-1000.

6. A free radical polymerization system, characterized in that, Includes alkenyl monomers and the sulfur-containing photoinitiator composition according to any one of claims 1-5.

7. The free radical polymerization system according to claim 6, characterized in that, The alkenyl monomer is an acrylate monomer, and its general structural formula is shown below: R 104 Represents hydrogen or methyl; R 105 It is independently selected from hydrogen, methyl, straight-chain or branched alkyl or alkyl alcohols with 1-10 carbon atoms, and hydroxyl, carboxyl, cyano, mercapto, amide, vinyl, alkoxy, alkylthio, nitro, piperazine, phenothiazine, any substituted or unsubstituted phenyl, and straight-chain or branched alkyl chains with 1-10 carbon atoms having the above substituents.

8. The free radical polymerization system according to claim 7, characterized in that, The acrylate monomer is at least one of the compounds shown in the following structural formula: 。 9. The free radical polymerization system according to any one of claims 6-8, characterized in that, The molar ratio of the organic photocatalyst in the composition of the alkenyl monomer and the sulfur-containing photoinitiator is 1-100000:

1.

10. The free radical polymerization system according to any one of claims 6-8, characterized in that, The free radical polymerization system uses ultraviolet or visible light with a wavelength of 280 nm-600 nm as the light source during the polymerization reaction.

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