Phenolic hydroxyl-terminated modified polysiloxane with side chain containing phenyl and sulfonate group, and preparation method of copolymerized PC

Abstract

The invention relates to the technical field of PC transparent flame-retardant toughening modification, in particular to phenolic hydroxyl-terminated modified polysiloxane with a side chain containing phenyl and sulfonate groups and a preparation method of copolymerized PC. The modified polysiloxane is prepared by the following steps: performing ring opening polymerization on phenol-containing double end sockets and cyclotetrasiloxane to obtain modified polysiloxane containing double bonds and phenyl functional groups, and grafting sulfonate through a thiol-ene click chemical reaction. Diphenyl carbonate, bisphenol A and the modified polysiloxane are used as raw materials, a polysiloxane-PC block copolymer is formed through copolymerization, efficient flame retardance and high transparency are achieved, and meanwhile extremely high low-temperature impact strength is achieved.

Description

Technical Field

[0001] This invention relates to the field of transparent flame-retardant and toughening modification technology of polysiloxane-polycarbonate, specifically to a polysiloxane with terminal phenolic hydroxyl groups containing phenyl and sulfonate groups in the side chain, and a method for preparing copolymer PC. Background Technology

[0002] Polycarbonate (PC) exhibits certain charring characteristics, with a limiting oxygen index (LOI) of approximately 23% and achieving a V-2 rating in the UL-94 test. However, its flame retardant properties still fall short of the requirements for high-end applications. Besides flame retardancy, its smoke suppression and anti-drip properties must be strictly controlled, while maintaining superior mechanical properties, especially impact resistance. High transparency is also required in some applications. Currently, flame-retardant polycarbonate is mainly achieved through blending with flame retardants such as halogen compounds, sulfonates, phosphorus compounds, siloxanes, nanomaterials, and synergistic flame retardant systems. However, these additive flame retardants have unavoidable drawbacks, such as insufficient durability, uneven distribution, damage to the inherent properties of polycarbonate, bioaccumulation, and potential toxicity, making it increasingly unable to meet industrial and environmental requirements.

[0003] Among numerous flame retardants, sulfonates (used in extremely low amounts, ranging from 0.8% to 5%, with negligible impact on transparency and toughness) and siloxanes (as green flame retardants with good smoke suppression properties) demonstrate good potential in meeting stringent requirements for low smoke, flame retardancy, impact resistance, and transparent applications. Notably, existing studies have shown that they exhibit synergistic flame retardant and anti-drip effects in polycarbonates. However, as additive flame retardants, sulfonates suffer from poor dispersibility and insufficient anti-drip properties, while siloxanes face challenges related to high loading levels and poor flowability in the matrix.

[0004] Siloxane copolycarbonate (co-PC) has seen rapid development in the industrial sector due to its high added value. SABIC has commercialized multiple grades, including EXL, HFD, CXT, and FST, each optimized for specific properties such as low-temperature impact toughness, high flowability, flame retardancy, and low smoke emission. Sanyang and LG Chem have also launched related commercial products. In China, Wanhua Chemical (STC3711, 3620, 1221), Cangzhou Dahua (continuous production line), and Gansu Yinguang Group (siloxane-copolycarbonate standard) are filling the gap in the high-end polycarbonate market. However, they still face a common challenge: thin-walled polycarbonate products struggle to meet the UL-94 V-0 standard.

[0005] A related patent, CN119978378A, has successfully synthesized a series of transparent polycarbonate-b-siloxane copolymers with inherent flame retardant properties and excellent impact resistance by incorporating Schiff base-modified polysiloxane (DMS-Schiff) and naphthalene sulfonate units into the polycarbonate (PC) chain. Compared with pure polycarbonate, these copolymers significantly improved the limiting oxygen index (LOI, up to 34.5%) and UL-94V-0 flame retardant rating at a thickness of only 1.6 mm. The introduction of the polysiloxane segment not only enhanced the flame retardant properties but also improved the impact strength. The synergistic effect between the naphthalene sulfonate and the polysiloxane segment, along with effectively controlled polysiloxane phase separation (the sulfonate unit reduces the processing viscosity of the copolymer), jointly contributed to the excellent overall performance. These achievements provide a promising path for developing high-performance copolycarbonates suitable for practical applications. However, if organosilicon and sulfonate are used as copolymer units in this scheme, the synergistic effect is weak, and the water absorption problem of sulfonate will be more prominent, and Schiff base is also prone to hydrolysis and breakage. Summary of the Invention

[0006] To overcome the shortcomings and deficiencies of existing technologies, the present invention aims to provide a phenol-hydroxyl-terminated modified polysiloxane with phenyl and sulfonate groups in the side chain. This method involves ring-opening polymerization of a phenol-containing double-headed polysiloxane and a cyclotetrasiloxane to obtain a modified polysiloxane containing double bonds and phenyl functional groups. Then, sulfonates are grafted via a mercapto-olefin click chemistry reaction to synthesize a phenol-hydroxyl-terminated modified polysiloxane with phenyl and sulfonate groups in the side chain. By grafting sulfonates onto the organosilicon chain, the hydrophobic properties of organosilicon are fully utilized, effectively reducing the water absorption of sulfonates. The synergistic effect between sulfonates and organosilicon is optimal, while the grafted sulfonates still effectively reduce the processing viscosity of the copolymer. Furthermore, the organosilicon and polycarbonate segments are connected by Si-OC bonds, which are susceptible to hydrolysis and breakage. This method uses silicon-carbon bonds, significantly avoiding this problem. In summary, compared to patent CN119978378A, the structure synthesized by this method is more stable and is essentially unaffected by water in the environment.

[0007] Another objective of this invention is to provide a method for preparing copolymerized PC, using diphenyl carbonate, bisphenol A, and terminally phenolic hydroxyl-modified polysiloxanes with side chains containing phenyl and sulfonate groups as raw materials to copolymerize and form a polysiloxane-polycarbonate block copolymer. This method achieves high flame retardancy and high transparency while possessing extremely high low-temperature impact strength. The preparation method is simple to operate, easy to control, has high production efficiency, and low production cost, making it suitable for large-scale production.

[0008] The objective of this invention is achieved through the following technical solution: a terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in its side chain, the structural formula of which is shown below: ; In the formula, n, m, and l satisfy the following conditions: 20≤n+m+l≤100, 0.25%≤n / (n+m+l)≤0.5%, 79.5%≤m / (n+m+l)≤89.75%; 10%≤l / (n+m+l)≤20%.

[0009] Preferably, the method for preparing the terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain includes the following steps: (S1) Dissolve 2-allylphenol and platinum group catalyst in toluene solvent, then add tetramethyldisiloxane dropwise, raise the temperature to 50~70℃, react for 3~7h, then reflux for 0.5h, then remove toluene solvent and residual 2-allylphenol by atmospheric distillation, and collect the product under vacuum conditions of 0.008-0.015 torr at 225-240℃ to obtain phenol-containing double-headed products; (S2) Add the acidic catalyst, cyclotetrasiloxane and the phenol-containing double-headed compound to the reactor and stir at 50-80°C for 5-8 hours to carry out the ring-opening polymerization reaction. Then cool and filter to collect the filtrate. Remove the residual unreacted monomer at 185-195°C to obtain the modified polysiloxane containing double bonds and phenyl functional groups. (S3) Dissolve the modified polysiloxane containing double bonds and phenyl functional groups in ethanol, add mercaptosulfonate and photoinitiator, react under ultraviolet light for 1-3 hours, remove the solvent and filter to obtain the terminal phenolic hydroxyl modified polysiloxane with phenyl and sulfonate groups in the side chain.

[0010] Preferably, in step (S1), the molar ratio of 2-allylphenol to tetramethyldisiloxane is 2-3:1; the amount of platinum group catalyst added is calculated based on the platinum content, and the platinum content accounts for 0.06-0.10 ppm of the total mass of the reaction solution in step (S1); the platinum group catalyst is chloroplatinic acid H2PtCl6·6H2O or a caster catalyst.

[0011] Preferably, in step (S2), the acidic catalyst is activated clay, and the amount of acidic catalyst is 2-4% of the sum of the mass of cyclotetrasiloxane and phenol-containing double-ended head; the amount of phenol-containing double-ended head is 4% to 20% of the total mass of cyclotetrasiloxane.

[0012] Preferably, in step (S2), the cyclotetrasiloxane is octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, and tetramethyltetravinylcyclotetrasiloxane, and the amounts of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, and tetramethyltetravinylcyclotetrasiloxane account for 79.5%~89.75%, 10%~20%, and 0.25%~0.5% of the total amount of cyclotetrasiloxane, respectively.

[0013] Preferably, in step (S3), the molar ratio of the amount of mercaptosulfonate to the amount of tetramethyltetravinylcyclotetrasiloxane is 4~4.1:1; the amount of photoinitiator is 0.1%~2% of the sum of the mass of cyclotetrasiloxane, phenol-containing double-ended head and mercaptosulfonate.

[0014] Preferably, in step (S3), the mercaptosulfonate is sodium 2-mercaptoethanesulfonate and / or sodium 3-mercapto-1-propanesulfonate, and the photoinitiator is at least one of 1-hydroxycyclohexylphenyl ketone, benzophenone, 2-methylbenzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 3,4-dimethylbenzophenone, 4,4'-bis(diethylamino)benzophenone, benzoin methyl ether, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, or benzoin isobutyl ether; the wavelength used for ultraviolet lamp irradiation is 250~400nm.

[0015] Another objective of the present invention is achieved by the following technical solution: a method for preparing copolymer PC, comprising the following steps: using diphenyl carbonate, bisphenol A and the above-mentioned polysiloxane with terminal phenolic hydroxyl groups containing phenyl and sulfonate groups as raw materials, the copolymer is prepared by melt transesterification polycondensation.

[0016] Preferably, the melt transesterification polycondensation includes three stages: In the first stage of transesterification reaction, diphenyl carbonate and polysiloxane modified with phenyl and sulfonate groups on the side chain are mixed and heated to 165~185℃ until melted. Potassium hydroxide aqueous solution is added and the reaction is carried out under nitrogen flow for 0.5~2h. Then bisphenol A is added and the reaction is continued for 10~60min. The second stage of prepolymerization process involves heating to 210℃~220℃ for 30~120 min under vacuum conditions of 100~180 torr. The third stage involves constructing a high molecular weight polymer by heating to 240-250°C under a vacuum of 10-15 torr and reacting for 10-30 minutes. Then, the vacuum is increased to 1-2 torr, and the temperature is raised to 280-300°C and reacted for 25-50 minutes. The polymer is then dissolved in dichloromethane, and ethanol is used as a settling agent. After filtration and drying, the copolymer PC can be obtained.

[0017] Preferably, the amount of diphenyl carbonate is 1.05 to 1.15 times the amount of bisphenol A; the mass of the terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain is 6% to 30% of the mass of bisphenol A; and the amount of potassium hydroxide in the potassium hydroxide aqueous solution is 20 ppm to 100 ppm of the mass of bisphenol A.

[0018] The beneficial effects of this invention are as follows: (1) Imparting excellent flame retardant properties to polycarbonate (PC). By directly grafting sulfonates onto the main chain of organosilicon, sulfonates and organosilicon can produce a significant synergistic flame retardant effect. Through copolymerization with diphenyl carbonate and bisphenol A, sulfonates can achieve excellent flame retardant effects with only a very low dosage, thus endowing the material with inherent flame retardant properties. In addition, the grafting of sulfonates onto the organosilicon chain utilizes the hydrophobic characteristics of organosilicon to effectively reduce the water absorption of sulfonates, thereby making the flame retardant performance continuously stable without the need for additional additive flame retardants.

[0019] (2) By utilizing the flexible Si-O skeleton of polysiloxane, the mobility of the chain and the energy dissipation capacity are increased, thereby significantly improving the low-temperature impact resistance of the material.

[0020] (3) Improve transparency. By optimizing the structure of the copolymer and introducing side phenyl functional groups, the compatibility with PC is improved. The phase separation of polysiloxane in the polycarbonate matrix is ​​controlled, and the material properties are maintained while giving it high transparency, making it suitable for applications that require optical transparency.

[0021] (4) The application of organosilicon in polycarbonate (PC) is usually used in conjunction with sulfonate flame retardants. Ordinary methyl silicone oil is incompatible with PC. Therefore, whether it is organosilicon oil or silicone resin powder, it is usually necessary to graft phenyl or acrylic resin to improve its compatibility with PC, or directly copolymerize with PC to form a silicone-PC copolymer. The traditional specific usage methods are as follows: 1. Traditional compound addition: organosilicon and sulfonate are added separately; 2. Traditional organosilicon chemical grafting of sulfonate: for example, grafting sulfonate and acrylate monomers onto silicone resin powder simultaneously through mercapto-olefin click chemical reaction, or grafting sulfonate through mercapto-olefin click chemical reaction, followed by free radical emulsion polymerization to coat the acrylic resin with a compatible shell, or directly grafting sulfonate onto the surface of inorganic silicon through mercapto-olefin click chemical reaction. However, both traditional methods use polysiloxane-polycarbonate block copolymers as additives in PC, while this method directly synthesizes polysiloxane-polycarbonate block copolymers from raw materials. Unlike conventional silicon-PC copolymers, it eliminates the need for additional sulfonate flame retardants and anti-dripping agents. Specifically, this method grafts sulfonates onto organosilicon via a mercapto-olefin click chemistry reaction, then directly copolymerizes them with diphenyl carbonate and bisphenol A to synthesize polysiloxane-polycarbonate block copolymers. The phenyl groups in this method are used solely to enhance the compatibility of the modified polysiloxane in PC. The synthesized PC achieves highly efficient flame retardancy without the need for additional flame retardants and anti-dripping agents, while also possessing high transparency. Furthermore, the polysiloxane-polycarbonate block copolymer itself exhibits high impact resistance.

[0022] (5) If the organosilicon uses silanol groups, the copolymerization with PC will form silicon-oxygen-carbon bonds, which are extremely unstable and prone to hydrolysis. The purpose of synthesizing terminal phenolic hydroxyl groups in this scheme is to avoid this problem, and the determination of this structure is also well thought out. The modified polysiloxane synthesized in this scheme has uniqueness and purpose. Traditional silicon-PC copolymers will have incompatibility phenomena such as layer separation and phase separation to a certain extent. The purpose of introducing a small amount of phenyl groups in this scheme is to solve this problem and improve transparency. Although the flame retardant effect of phenyl is limited, its greatest role in this scheme is to improve compatibility. Attached Figure Description

[0023] Figure 1 This is a synthetic route diagram of the phenol-containing double-headed structure described in this invention; Figure 2 This is a synthetic route diagram of the modified polysiloxane containing double bonds and phenyl functional groups, and the modified polysiloxane with terminal phenolic hydroxyl groups containing phenyl and sulfonate groups in the side chain, as described in this invention. Figure 3 This is a synthetic route diagram for the copolymer PC described in this invention, wherein 25 ≤ x / y ≤ 620, that is, the mass of the organosilicon y fragment accounts for 5% to 20% of the total mass; Figure 4 This is the infrared spectrum of the phenol-containing double-ended head described in this invention; Figure 5 This is the infrared spectrum of the terminal phenolic hydroxyl modified polysiloxane with side chains containing phenyl and sulfonate groups as described in this invention. Figure 6 This is the infrared spectrum of the copolymer PC described in this invention. Detailed Implementation

[0024] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0025] A method for preparing a terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain includes the following steps: (S1) 2-Allylphenol and a platinum group catalyst were dissolved in toluene, and tetramethyldisiloxane was added dropwise. The temperature was then raised to 70°C and reacted for 3 hours, followed by reflux for 0.5 hours. The toluene solvent and residual 2-allylphenol were then removed by atmospheric distillation. The product was collected at 230°C under a vacuum of 0.01 torr to obtain a phenol-containing double-ended product, such as... Figure 1 As shown; (S2) Add the acidic catalyst, cyclotetrasiloxane and the phenol-containing double-headed compound to the reactor and stir at 70°C for 8 hours to carry out the ring-opening polymerization reaction. Then cool and filter to collect the filtrate. Remove the residual unreacted monomer at 190°C to obtain the modified polysiloxane containing double bonds and phenyl functional groups. (S3) The modified polysiloxane containing double bonds and phenyl functional groups is dissolved in ethanol, and a mercaptosulfonate and photoinitiator are added. The mixture is reacted under UV irradiation for 2 hours. The solvent is removed and the mixture is filtered to obtain a terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain, named S-APS. Figure 2 As shown.

[0026] In step (S1), the molar ratio of 2-allylphenol to tetramethyldisiloxane is 2:1; the amount of platinum group catalyst added is calculated based on the platinum content, which accounts for 0.08 ppm of the total mass of the reaction solution in step (S1); the platinum group catalyst is a caster catalyst.

[0027] In step (S2), the acidic catalyst is activated clay, and the amount of acidic catalyst is 2-4% of the sum of the mass of cyclotetrasiloxane and phenol-containing double-ended head; the amount of phenol-containing double-ended head is 4% to 20% of the total mass of cyclotetrasiloxane.

[0028] In step (S2), the cyclotetrasiloxane is octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, and tetramethyltetravinylcyclotetrasiloxane, and the amounts of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, and tetramethyltetravinylcyclotetrasiloxane account for 79.5%~89.75%, 10%~20%, and 0.25%~0.5% of the total amount of cyclotetrasiloxane, respectively.

[0029] In step (S3), the molar ratio of the amount of mercaptosulfonate to the amount of tetramethyltetravinylcyclotetrasiloxane is 4~4.1:1; the amount of photoinitiator is 0.1% of the sum of the mass of cyclotetrasiloxane, phenol-containing double-ended head and mercaptosulfonate.

[0030] In step (S3), the mercaptosulfonate is sodium 3-mercapto-1-propanesulfonate, the photoinitiator is 1-hydroxycyclohexylphenyl ketone, and the wavelength used for ultraviolet lamp irradiation is 365 nm.

[0031] Specifically, steps (S2) and (S3) prepared four groups of S-APS with different amounts of the components, as shown in Table 1 below:

[0032] Among them, the polysiloxane segment length n+m+l of S-APS 1#, S-APS 2#, and S-APS 4# is 50; the polysiloxane segment length n+m+l of S-APS 3# is 100; the tetramethyltetraphenyl in S-APS 1#, S-APS 3#, and S-APS 4# is 10% of the total molar amount of cyclotetrasiloxane monomers; the tetramethyltetraphenyl in S-APS 2# is 20% of the total molar amount of cyclotetrasiloxane monomers; the sulfonates of S-APS 1#, S-APS 2#, and S-APS 3# account for 2.3‰±0.3‰ of the total mass of polysiloxane, and the sulfonate of S-APS 4# accounts for 4.6‰±0.3‰ of the total mass of polysiloxane.

[0033] like Figure 3 As shown, a method for preparing copolymer PC includes the following steps: using diphenyl carbonate, bisphenol A, and the terminal phenolic hydroxyl-modified polysiloxane S-APS with phenyl and sulfonate groups in the side chain as described above as raw materials, it is prepared by melt transesterification polycondensation.

[0034] The molten transesterification polycondensation process includes three stages: In the first stage of transesterification reaction, diphenyl carbonate and polysiloxane modified with phenyl and sulfonate groups on the side chain were mixed, heated to 185°C until melted, potassium hydroxide aqueous solution was added, and the reaction was carried out under nitrogen flow for 1 hour. Then bisphenol A was added and the reaction was continued for 15 minutes. In the second stage of the prepolymerization process, the temperature was raised to 210°C and reacted for 50 minutes under a vacuum of 180 torr, and then the temperature was raised to 220°C and reacted for 15 minutes under a vacuum of 100 torr. In the third stage, to construct the high molecular weight, the temperature was raised to 250°C under a vacuum of 15 torr and reacted for 15 min. Then, the vacuum was increased to 2 torr and the temperature was raised to 285°C and reacted for 25 min. Then, the temperature was raised to 300°C under a vacuum of 2 torr and reacted for 10 min. The product was then dissolved in dichloromethane, and ethanol was used as a settling agent. After filtration and drying, the copolymer PC was obtained.

[0035] The amount of diphenyl carbonate is 1.05 to 1.15 times the amount of bisphenol A; the mass of the terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain is 6% to 30% of the mass of bisphenol A; the concentration of the potassium hydroxide aqueous solution is 0.002 g / ml, and the amount of potassium hydroxide in the potassium hydroxide aqueous solution is 20 ppm to 100 ppm of the mass of bisphenol A.

[0036] Specifically, the above-mentioned method for preparing copolymer PC was used to prepare multiple groups of copolymer PC with different amounts of components, as shown in Table 2 below:

[0037] Examples 1-3 used synthesized S-APS 1# as raw material, with organosilicon content of 6%, 12%, and 20%, respectively; Examples 4-6 used S-APS 2#, S-APS 3#, and S-APS 4# as raw materials, with organosilicon content of 6%, respectively.

[0038] Comparative Example 1 A polycarbonate (PC) selected from Lihua Yiweiyuan® WY-111BR.

[0039] Comparative Example 2 A polysiloxane copolymer polycarbonate, selected from Cangzhou Dahua CH9115LT, has a silicon content of 6 wt%.

[0040] Comparative Example 3 The difference from Comparative Example 2 is that a modified PC is obtained by melt blending PC-siloxane copolymer CH9115LT and flame retardant KSS, wherein the amount of flame retardant KSS added is 2wt‰.

[0041] Comparative Example 4 The difference from Comparative Example 2 is that a modified PC is obtained by melt blending PC-siloxane copolymer CH9115LT, flame retardant KSS and anti-dripping agent K-PT202, wherein the amount of flame retardant KSS added is 2wt‰ and the amount of anti-dripping agent K-PT202 added is 3wt‰.

[0042] Performance testing: The final products of Examples 1-6 and Comparative Examples 1-4 were melt-processed in a torque rheometer under the following conditions: temperature 265°C, rotation speed 60 rpm, and processing time 8 minutes. The processed materials were then placed in different molds and hot-pressed at 270°C and 18 MPa for 3 minutes to obtain standard test specimens. The specimens were then subjected to flame retardancy, impact strength, transparency, and haze tests. The test results are shown in Table 3 below.

[0043] As shown in Table 3 above, the data from both the room temperature impact test and the -30°C low temperature impact test were excellent in all the samples from the examples. The application of sulfonate flame retardants in polycarbonate (PC) exhibits the characteristic of high efficiency with minimal dosage; the better the dispersion, the lower the dosage. In the sample of Example 1, a 6% siloxane content required only a sulfonate amount on the order of 0.01% to achieve excellent flame retardant performance. The flame retardant effects of the other examples were even more outstanding; in all examples, the amount of sulfonate added was extremely small, having almost no impact on mechanical and optical properties.

[0044] As shown in Table 3 above, in Examples 1, 2, 3, and 5, higher silicone content or longer silicone segments result in better mechanical impact resistance, but reduced transparency and increased haze. In Example 4, higher phenyl content in the silicone leads to better compatibility between the silicone and PC, thereby improving transparency and reducing haze.

[0045] As shown in Table 3 above, in Comparative Example 3, when 2‰ of an additive sulfonate flame retardant is added to a silicon PC copolymer with 6% silicon content, the dripping phenomenon is still difficult to solve without the presence of a fluorinated anti-dripping agent. In contrast, the fluorinated anti-dripping agent in Comparative Example 4 has a significant impact on the transparency of the material.

[0046] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in its side chain, characterized in that: Its structural formula is shown below: ； In the formula, n, m, and l satisfy the following conditions: 20≤n+m+l≤100, 0.25%≤n / (n+m+l)≤0.5%, 79.5%≤m / (n+m+l)≤89.75%; 10%≤l / (n+m+l)≤20%.

2. The polysiloxane with terminal phenolic hydroxyl groups containing phenyl and sulfonate groups in its side chain according to claim 1, characterized in that: The method for preparing the terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain includes the following steps: (S1) Dissolve 2-allylphenol and platinum group catalyst in toluene solvent, then add tetramethyldisiloxane dropwise, raise the temperature to 50~70℃, react for 3~7h, then reflux for 0.5h, then remove toluene solvent and residual 2-allylphenol by atmospheric distillation, and collect the product under vacuum conditions of 0.008-0.015 torr at 225-240℃ to obtain phenol-containing double-headed products; (S2) Add the acidic catalyst, cyclotetrasiloxane and the phenol-containing double-headed compound to the reactor and stir at 50-80°C for 5-8 hours to carry out the ring-opening polymerization reaction. Then cool and filter to collect the filtrate. Remove the residual unreacted monomer at 185-195°C to obtain the modified polysiloxane containing double bonds and phenyl functional groups. (S3) Dissolve the modified polysiloxane containing double bonds and phenyl functional groups in ethanol, add mercaptosulfonate and photoinitiator, react under ultraviolet light for 1-3 hours, remove the solvent and filter to obtain the terminal phenolic hydroxyl modified polysiloxane with phenyl and sulfonate groups in the side chain.

3. The terminal phenolic hydroxyl-modified polysiloxane with side chains containing phenyl and sulfonate groups according to claim 2, characterized in that: In step (S1), the molar ratio of 2-allylphenol to tetramethyldisiloxane is 2-3:1; the amount of platinum group catalyst added is calculated based on the platinum content, and the platinum content accounts for 0.06-0.10 ppm of the total mass of the reaction solution in step (S1); the platinum group catalyst is chloroplatinic acid H2PtCl6·6H2O or a cassiterite catalyst.

4. The terminal phenolic hydroxyl-modified polysiloxane with side chains containing phenyl and sulfonate groups according to claim 2, characterized in that: In step (S2), the acidic catalyst is activated clay, and the amount of acidic catalyst is 2-4% of the sum of the mass of cyclotetrasiloxane and phenol-containing double-ended head; the amount of phenol-containing double-ended head is 4% to 20% of the total mass of cyclotetrasiloxane.

5. The terminal phenolic hydroxyl-modified polysiloxane with side chains containing phenyl and sulfonate groups according to claim 2, characterized in that: In step (S2), the cyclotetrasiloxane is octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, and tetramethyltetravinylcyclotetrasiloxane, and the amounts of octamethylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane, and tetramethyltetravinylcyclotetrasiloxane account for 79.5%~89.75%, 10%~20%, and 0.25%~0.5% of the total amount of cyclotetrasiloxane, respectively.

6. The terminal phenolic hydroxyl-modified polysiloxane with side chains containing phenyl and sulfonate groups according to claim 5, characterized in that: In step (S3), the molar ratio of the amount of mercaptosulfonate to the amount of tetramethyltetravinylcyclotetrasiloxane is 4~4.1:1; the amount of photoinitiator is 0.1%~2% of the sum of the mass of cyclotetrasiloxane, phenol-containing double-ended head and mercaptosulfonate.

7. A terminal phenolic hydroxyl-modified polysiloxane with side chains containing phenyl and sulfonate groups according to claim 2, characterized in that: In step (S3), the mercaptosulfonate is sodium 2-mercaptoethanesulfonate and / or sodium 3-mercapto-1-propanesulfonate, and the photoinitiator is at least one of 1-hydroxycyclohexylphenyl ketone, benzophenone, 2-methylbenzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 3,4-dimethylbenzophenone, 4,4'-bis(diethylamino)benzophenone, benzoin methyl ether, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, or benzoin isobutyl ether; the wavelength used for ultraviolet lamp irradiation is 250~400nm.

8. A method for preparing copolymerized PC, characterized in that, The process includes the following steps: using diphenyl carbonate, bisphenol A, and terminal phenolic hydroxyl-modified polysiloxanes with side chains containing phenyl and sulfonate groups as described in any one of claims 1-7 as raw materials, the process is prepared by melt transesterification polycondensation.

9. The method for preparing copolymerized PC according to claim 8, characterized in that, The molten transesterification polycondensation process includes three stages: In the first stage of transesterification reaction, diphenyl carbonate and polysiloxane modified with phenyl and sulfonate groups on the side chain are mixed and heated to 165~185℃ until melted. Potassium hydroxide aqueous solution is added and the reaction is carried out under nitrogen flow for 0.5~2h. Then bisphenol A is added and the reaction is continued for 10~60min. The second stage of prepolymerization process involves heating to 210℃~220℃ and reacting for 30~120 minutes under vacuum conditions of 100~180 torr. The third stage involves constructing a high molecular weight polymer by heating to 240-250°C under a vacuum of 10-15 torr and reacting for 10-30 minutes. Then, the vacuum is increased to 1-2 torr, and the temperature is raised to 280-300°C and reacted for 25-50 minutes. The polymer is then dissolved in dichloromethane, and ethanol is used as a settling agent. After filtration and drying, the copolymer PC can be obtained.

10. The method for preparing copolymerized PC according to claim 9, characterized in that: The amount of diphenyl carbonate is 1.05 to 1.15 times the amount of bisphenol A; the mass of the terminal phenolic hydroxyl-modified polysiloxane with phenyl and sulfonate groups in the side chain is 6% to 30% of the mass of bisphenol A; the amount of potassium hydroxide in the potassium hydroxide aqueous solution is 20 ppm to 100 ppm of the mass of bisphenol A.

Images