Isosorbide-based polycarbonate catalyst, preparation method and application thereof

Abstract

The present invention discloses an isosorbide-based polycarbonate catalyst and its preparation method and application. The nanosheets provided by the present invention are blended with a stabilizer to form a homogeneous composite catalyst ([M 12+ 1‑x‑y M 23+ x M 3+ y (OH)2] x‑y @stabilizer), can be used for the synthesis of PIC with good selectivity and yield, and the synthesized PIC has good performance.

Description

Technical Field

[0001] The present invention belongs to the field of catalysts, and in particular relates to an isosorbide-based polycarbonate catalyst and a preparation method and application thereof. Background Art

[0002] Polycarbonate (PC) is a nearly colorless, glassy, ​​amorphous polymer with excellent optical properties, heat resistance, impact resistance, and resistance to weak acids, weak bases, and neutral oils. Due to its unique structure and excellent performance, PC has become one of the fastest-growing general-purpose engineering plastics, with widespread applications in electronics, aerospace, optical components, the automotive industry, medical devices, protective equipment, and other fields.

[0003] Polycarbonates are mainly divided into bisphenol A type and isosorbide type polycarbonate. Among them, bisphenol A type polycarbonate has certain hazards to the human body due to the chronic toxicity and estrogenic effects of its residues, and is prohibited from being used in daily products. Isosorbide-based polycarbonate (PIC), a bio-based polycarbonate, has received a lot of attention as an alternative to petroleum-based polycarbonate. PIC is produced using isosorbide (ISB), a non-toxic material extracted from glucose, as a monomer. As an important bio-based chemical raw material, ISB has the same rigid structure as bisphenol A and is green and non-toxic. It can gradually replace bisphenol A to prepare bio-based polycarbonate.

[0004] Currently, the catalysts used for melt transesterification to synthesize PIC are mainly divided into inorganic alkali metal catalysts, organic non-metallic catalysts, and ionic liquid catalysts. Organic non-metallic catalysts, such as tetraethylammonium hydroxide and tetramethylammonium hydroxide, generally decompose at high temperatures, resulting in reduced catalytic activity, long polymerization times, and severe side reactions. Ionic liquid catalysts, such as quaternary ammonium imidazoles, offer the advantages of high catalytic activity and few side reactions, but they are complex to prepare and expensive. Inorganic alkali metal catalysts, as low-cost catalysts, have also been widely studied, but they can cause side reactions such as thermal degradation, thermo-oxidative degradation, and crosslinking at high temperatures, resulting in yellowing of the final product, low molecular weight, and poor mechanical properties. Therefore, it is highly necessary to develop a PIC synthesis catalyst that is simple to prepare and exhibits high selectivity and / or high catalytic activity. Summary of the Invention

[0005] In order to improve the above technical problems, the present invention provides a nanosheet, the chemical composition of which is [M1 2+ 1-x-y M2 3+ x M3 + y (OH)2] x-y [A n-(x-y / n) ·H2O]; where

[0006] M1 2+ Divalent metal ions, such as Mg 2+ 、Zn 2+ 、Cu 2+ 、Fe 2+ 、Ni 2+ One or more of the following, preferably Mg 2+ and / or Zn 2+ ;

[0007] M2 3+ For trivalent metal ions, such as Cr 3+ 、Fe 3+ 、Al 3+ One or more of the following, preferably Al 3+ ;

[0008] M3 + for Na + , K + 、Li + 、Cs + One or more of the following, preferably Cs + ;

[0009] A n- is the anion between the nanosheet layers. n- It plays a role in balancing the charge and can be an inorganic anion or an organic anion, for example, A n- NO3 - ;

[0010] 0.33<x+y<0.80, for example, x+y=0.5;

[0011] x>y;

[0012] n>0, for example, n=1.

[0013] According to some embodiments of the invention, x=0.3, y=0.2.

[0014] According to an embodiment of the present invention, the chemical composition of the nanosheets is [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0 . 1+ [NO3 - 0.1 ·H2O]、[Mg 2+ 0.5Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O]、[Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] or [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] indicated.

[0015] According to an embodiment of the present invention, the nanosheet is a nano-scale sheet structure.

[0016] The present invention also provides a charged nanosheet, the chemical composition of which is [M1 2+ 1-x-y M2 3+ x M3 + y (OH)2] x-y , indicating that M1 2+ 、M2 3+ 、M3 + , x, y and n are all defined as above. For example, the nanosheet has a positive charge.

[0017] According to an embodiment of the present invention, the charged nanosheets are obtained by exfoliating the above nanosheets, for example, by mechanical exfoliation in isosorbide.

[0018] Preferably, the charged nanosheets are a single-layer structure.

[0019] According to an embodiment of the present invention, the specific surface area of ​​the nanosheet or the charged nanosheet is 100 to 140 m 2 .g -1 .

[0020] The present invention also provides a method for preparing the above-mentioned nanosheets, comprising: 2+ Salt containing M2 3+ Salt and containing M3 +The nanosheets are prepared by hydrothermal reaction of the salt.

[0021] According to an embodiment of the present invention, the salt may be a nitrate containing the above corresponding metals.

[0022] According to an embodiment of the present invention, the hydrothermal reaction system further contains urea.

[0023] According to an embodiment of the present invention, the preparation method comprises: 2+ Salt containing M2 3+ Salt and containing M3 + The salt is dissolved in deionized water without CO2 to obtain liquid A; urea is dissolved in deionized water without CO2 to obtain liquid B; liquid A and liquid B are mixed and subjected to hydrothermal reaction to prepare the nanosheets.

[0024] According to an embodiment of the present invention, the M1 2+ 、M2 3+ 、M3 + All have the same limitations as above.

[0025] The present invention also provides a method for preparing the charged nanosheets, which are obtained by peeling the nanosheets, for example, by mechanically peeling the nanosheets in isosorbide.

[0026] According to an embodiment of the present invention, the mass ratio of the nanosheets to isosorbide needs to ensure that the nanosheets can be fully dispersed in the isosorbide, for example, 1:(5000-50000), such as 1:10000, 1:20000.

[0027] According to an embodiment of the present invention, the stripping is performed under an inert atmosphere, for example, under nitrogen protection.

[0028] According to an embodiment of the present invention, the preparation method comprises the following steps: firstly mixing the above-mentioned nanosheets with isosorbide, and mechanically exfoliating to obtain the charged nanosheets.

[0029] According to an embodiment of the present invention, the mixing conditions include: stirring at 100-150°C.

[0030] According to an embodiment of the present invention, the time of the mechanical peeling is not less than 8 hours, for example, not less than 10 hours.

[0031] According to an embodiment of the present invention, the rotation speed of the mechanical stripping is not less than 300 rpm, preferably 350-600 rpm.

[0032] The present invention also provides the use of the nanosheets or charged nanosheets as isosorbide-based polycarbonate (PIC) catalysts.

[0033] The present invention also provides a composite catalyst comprising the charged nanosheets and a stabilizer.

[0034] According to an embodiment of the present invention, the stabilizer is selected from one or more of phosphates, phosphorous acid, phosphate esters and hindered phenols, for example, triphenyl phosphate.

[0035] According to an embodiment of the present invention, the mass ratio of the charged nanosheets to the stabilizer is 100:(0.5-2), for example, 100:1, 100:1.5, or 100:2.

[0036] The present invention also provides a method for preparing the composite catalyst, which is obtained by blending the charged nanosheets and a stabilizer. Preferably, the charged nanosheets and the stabilizer are blended in isosorbide.

[0037] The present invention also provides application of the composite catalyst in preparing PIC.

[0038] According to an embodiment of the present invention, the PIC has any one or two or more of the following parameters (1)-(6), preferably having the parameters shown in (1)-(6) at the same time:

[0039] (1) Weight average molecular weight (Mw) not less than 3.5×10 4 g / mol, for example (4.0-7.5)×10 4 g / mol, exemplified by 4.1×10 4 g / mol, 4.9×10 4 g / mol, 5.0×10 4 g / mol, 5.3×10 4 g / mol, 6.0×10 4 g / mol, 6.5×10 4 g / mol, 7.0×10 4 g / mol;

[0040] (2) a molecular weight distribution not exceeding 2.0, for example, 1.6 to 1.9, exemplified by 1.65, 1.70, 1.73, 1.80, and 185;

[0041] (3) a melt index not exceeding 25 g / min, for example, 10-22 g / min, exemplified by 13 g / min, 15 g / min, and 17 g / min;

[0042] (4) light transmittance is not less than 75%, for example, 78-90%, exemplified by 80%, 82%, or 85%;

[0043] (5) A tensile strength of not less than 35 MPa, for example, 38-60 MPa, exemplified by 40 MPa, 44 MPa, 47 MPa, 50 MPa, or 55 MPa;

[0044] (6) The elongation at break is not less than 20%, for example, 20-60%, exemplified by 22%, 25%, 30%, 32%, 35%, 40%, 50%, and 55%.

[0045] The present invention also provides a method for preparing PIC, which uses the composite catalyst.

[0046] According to an embodiment of the present invention, the method comprises the following steps: the composite catalyst, isosorbide and diphenyl carbonate are first subjected to an ester exchange reaction, and then subjected to a pre-polycondensation reaction and a polycondensation reaction to obtain the PIC.

[0047] According to an embodiment of the present invention, the mass ratio of the composite catalyst, isosorbide and diphenyl carbonate is (0.01-1):100:(130-150), preferably (0.02-0.05):100:(140-150).

[0048] According to an embodiment of the present invention, the temperature of the transesterification reaction is 180-210° C., and / or the time is 0.5-2 h; illustratively, the temperature is 200° C., and / or the time is 1 h.

[0049] According to an embodiment of the present invention, the temperature of the pre-polycondensation reaction is 215-230°C, and / or the time is 0.5-2h, and / or the environment is near vacuum or vacuum; illustratively, the temperature is 220°C, and / or the time is 1h, and the vacuum is evacuated to an absolute pressure of 5000Pa.

[0050] According to an embodiment of the present invention, the temperature of the polycondensation reaction is 235-250°C; an exemplary temperature is 240°C.

[0051] According to an embodiment of the present invention, the polycondensation reaction is stopped when the reactants are observed to have obvious pole climbing phenomenon; for example, the reaction time is 1-4 hours.

[0052] Beneficial effects

[0053] First, the present invention provides polymetallic hydroxide nanosheets and positively charged nanosheets. These nanosheets successfully break the hydrogen bonds within the isosorbide molecule and balance the reactivity of the endo-OH and exo-OH groups, making them suitable catalysts for PIC synthesis. Furthermore, the nanosheets can be prepared through a simple hydrothermal synthesis, and then exfoliated to obtain the positively charged nanosheets, resulting in a simple preparation method.

[0054] Second, the nanosheets are blended with a stabilizer to form a homogeneous composite catalyst ([M 12+ 1-x-y M 23+ x M 3+ y (OH)2] x-y @ stabilizer), can be used in the synthesis of PIC with good selectivity and yield. 2+ 1-x-y M 3+ x M + y (OH)2] x-y The PIC synthesized with a stabilizer dosage of 800 ppm of isosorbide has good performance. For example, the weight average molecular weight (Mw) can reach up to 7.5×10 4 g / mol, molecular weight distribution as low as 1.6, melt index as low as 10g / min, and its light transmittance as high as 90%, tensile strength as high as 60MPa, and elongation at break as high as 60%.

[0055] In addition, the composite catalyst is green, non-toxic, and has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] and [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0 . 1+ XRD spectrum of .

[0057] Figure 2 [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ SEM image of . DETAILED DESCRIPTION

[0058] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0059] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0060] The test methods for the PIC parameters prepared in the following examples and comparative examples are as follows:

[0061] 1. Gel permeation chromatography (GPC) test conditions: column temperature 40°C, elution rate 1.0 mL / min, chromatography-grade chloroform as mobile phase, and standard polystyrene as standard;

[0062] 2. Melt flow rate tester speed: refer to GB / T 40006.7-2021, temperature 300℃, load 1.2kg, mass about 10g;

[0063] 3. Mechanical properties test: refer to GB / T 1040.2-2006;

[0064] 4. Light transmittance test: refer to GB / T 2410-2008;

[0065] 5. Color value: Referring to GB T 3143-1982 (1990), compare the color of the sample solution with the color of the standard platinum-cobalt colorimetric solution and express the result in Hazen (platinum-cobalt) color units;

[0066] 6. X-ray diffractometer test conditions: Shimadzu XRD-6000 X-ray diffractometer, Cu Ka ray, The scanning speed was 20° / min, and 2θ was 3 to 70°.

[0067] 7. Scanning electron microscopy (SEM) was performed on a Zeiss Supra 55 to observe the morphology of the samples.

[0068] Example 1

[0069] This embodiment provides a [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ The catalyst, specific preparation process, application and test results are as follows:

[0070] (1)[Mg2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ [NO3 - 0.1 Preparation of H2O:

[0071] 5mmol of Mg(NO3)2·6H2O, 3mmol of Al(NO3)3·9H2O and 2mmol of NaNO3 (all purchased from Sinopharm) were dissolved in 70ml of deionized water without CO2 and marked as liquid A. 10mmol of urea was dissolved in 70ml of deionized water without CO2 and marked as liquid B. Solutions A and B were dropped into a three-necked flask at the same time for reaction at a stirring speed of 200rpm. After the addition was complete, the mixture was stirred for 2h and then transferred to a reactor. After crystallization in an oven at 130℃ for 24h, the mixture was thoroughly washed with deionized water and ethanol and centrifuged. Finally, the mixture was dried and ground in a vacuum drying oven at 60℃ for later use.

[0072] (2)[Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ Synthesis of:

[0073] Under nitrogen protection, 300 rpm, 125 ° C, take 0.04 g of the above-prepared [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] was added to a four-necked flask containing 400 g of isosorbide (purchased from [Sinopharm Group]), stirred at 500 rpm for 12 h, and [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] were peeled off into single-layer nanosheets, and [Mg 2+ 0.5 Al 3+ 0.3 Na +0.2 (OH)2] 0 . 1+ Then, 0.005 g of triphenyl phosphate was added to the above dispersion and stirred for 2 h to obtain a composite catalyst dispersion for the synthesis of PIC.

[0074] (3) [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ For the synthesis of PIC, the details are as follows:

[0075] The composite catalyst dispersion in step (2) (according to the mass ratio of the composite catalyst to isosorbide in the polymerization reaction of 400 ppm, the same below) was mixed with isosorbide (74.31 g, purchased from Sinopharm) and diphenyl carbonate (108.72 g, purchased from Sinopharm) and subjected to transesterification reaction at 200° C. for 1 h. When the amount of phenol distilled was close to the theoretical value, the temperature was increased to 220° C., the product was evacuated to an absolute pressure of 5000 Pa, and a pre-polycondensation reaction was carried out for 1 h. Finally, the temperature was increased to 240° C. and the polycondensation reaction was carried out for 2 h. The reaction was stopped when obvious pole climbing phenomenon was observed to prepare PIC.

[0076] Figure 1 It shows that after mechanical stirring and peeling, [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] disappears, indicating that its layered structure is peeled off to [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ Nanosheets.

[0077] Figure 2 It shows that [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ The morphology is flake-like with a size of about 100 nm.

[0078] The BET test results showed that [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ The specific surface area is 130m 2 .g -1 .

[0079] The PIC prepared above was tested: The GPC test showed that the weight average molecular weight of the PIC prepared in this example was 4.1×10 4 g / mol, molecular weight distribution 1.73; melt mass flow rate 17 g / 10 min; light transmittance 80%; tensile strength 40 MPa; elongation at break 22%. PIC product yield 99.10%, transesterification rate 98.90%. PIC solution color (Hazen): 90.

[0080] Example 2

[0081] This embodiment provides a [Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ The catalyst, specific preparation process, application and test results are as follows:

[0082] (1)[Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ [NO3 - 0.1 Preparation of H2O:

[0083] 5mmol of Mg(NO3)2·6H2O, 3mmol of Al(NO3)3·9H2O and 2mmol of LiNO3 (all purchased from Sinopharm) were dissolved in 70ml of deionized water without CO2 and marked as liquid A. 10mmol of urea was dissolved in 70ml of deionized water without CO2 and marked as liquid B. Solutions A and B were dropped into a three-necked flask at the same time for reaction at a stirring speed of 200rpm. After the addition was complete, the mixture was stirred for 2h and then transferred to a reactor. After crystallization in an oven at 130℃ for 24h, the mixture was thoroughly washed with deionized water and ethanol and centrifuged. Finally, the mixture was dried and ground in a vacuum drying oven at 60℃ for later use.

[0084] (2)[Mg 2+0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ Synthesis of:

[0085] Under nitrogen protection, 300 rpm, 125 ° C, take 0.04 g of the above-prepared [Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] was added to a four-necked flask containing 400 g of isosorbide (purchased from [Sinopharm Group]), stirred at 500 rpm for 12 h, and [Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] were peeled off into single-layer nanosheets, and [Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0 . 1+ Then, 0.005 g of triphenyl phosphate was added to the above dispersion and stirred for 2 h to obtain a composite catalyst dispersion for the synthesis of PIC.

[0086] (3) [Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ For the synthesis of PIC, the details are as follows:

[0087] The composite catalyst dispersion in step (2) (based on the amount of composite catalyst relative to 450 ppm of isosorbide in the polymerization reaction) was mixed with isosorbide (74.31 g, purchased from Sinopharm) and diphenyl carbonate (108.72 g, purchased from Sinopharm) and subjected to transesterification reaction at 200° C. for 1 h. When the amount of phenol distilled was close to the theoretical value, the temperature was increased to 220° C., the product was evacuated to an absolute pressure of 5000 Pa, and a pre-polycondensation reaction was carried out for 1 h. Finally, the temperature was increased to 240° C. and the polycondensation reaction was carried out for 2 h. The reaction was stopped when obvious pole climbing phenomenon was observed, thereby preparing PIC.

[0088] The BET test results showed that [Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ The specific surface area is 124m 2 .g -1 .

[0089] The PIC prepared above was tested: The GPC test showed that the weight average molecular weight of the PIC prepared in this example was 4.9×10 4 g / mol, molecular weight distribution 1.70; melt mass flow rate 15 g / 10 min; transmittance 82%; tensile strength 44 MPa; elongation at break 32%. PIC product yield 99.14%, transesterification rate 98.96%. PIC solution color (Hazen): 130.

[0090] Example 3

[0091] This embodiment provides a [Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ The catalyst, specific preparation process, application and test results are as follows:

[0092] (1)[Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ [NO3 - 0.1 Preparation of H2O:

[0093] 5mmol of Mg(NO3)2·6H2O, 3mmol of Al(NO3)3·9H2O and 2mmol of KNO3 (all purchased from Sinopharm) were dissolved in 70ml of deionized water without CO2 and marked as liquid A. 10mmol of urea was dissolved in 70ml of deionized water without CO2 and marked as liquid B. Solutions A and B were dropped into a three-necked flask at the same time for reaction at a stirring speed of 200rpm. After the addition was complete, the mixture was stirred for 2h and then transferred to a reactor. After crystallization in an oven at 130℃ for 24h, the mixture was thoroughly washed with deionized water and ethanol and centrifuged. Finally, the mixture was dried and ground in a vacuum drying oven at 60℃ for later use.

[0094] (2)[Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ Synthesis of:

[0095] Under nitrogen protection, 300 rpm, 125 ° C, take 0.04 g of the above-prepared [Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] was added to a four-necked flask containing 400 g of isosorbide (purchased from [Sinopharm Group]), stirred at 500 rpm for 12 h, and [Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] were peeled off into single-layer nanosheets, and [Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ Then, 0.005 g of triphenyl phosphate was added to the above dispersion and stirred for 2 h to obtain a composite catalyst for the synthesis of PIC.

[0096] (3) [Mg 2+ 0.5 Al 3+ 0.3 K+ 0.2 (OH)2] 0.1+ For the synthesis of PIC, the details are as follows:

[0097] The composite catalyst dispersion in step (2) (based on the amount of the composite catalyst relative to 500 ppm of isosorbide in the polymerization reaction) was mixed with isosorbide (74.31 g, purchased from Sinopharm) and diphenyl carbonate (108.72 g, purchased from Sinopharm) and subjected to transesterification reaction at 200° C. for 1 h. When the amount of phenol distilled was close to the theoretical value, the temperature was increased to 220° C., the product was evacuated to an absolute pressure of 5000 Pa, and a pre-polycondensation reaction was carried out for 1 h. Finally, the temperature was increased to 240° C. and the polycondensation reaction was carried out for 2 h. The reaction was stopped when obvious pole climbing phenomenon was observed, thereby preparing PIC.

[0098] The BET test results showed that [Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ The specific surface area is 122m 2 .g -1 .

[0099] The PIC prepared above was tested: The GPC test showed that the weight average molecular weight of the PIC prepared in this example was 5.3×10 4 The product has a molecular weight distribution of 1.85, a melt flow rate of 13 g / 10 min, a light transmittance of 85%, a tensile strength of 47 MPa, and an elongation at break of 35%. The PIC product yield is 99.11%, the transesterification rate is 98.93%, and the PIC solution color (Hazen) is 125.

[0100] Example 4

[0101] This embodiment provides a [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ The catalyst, specific preparation process, application and test results are as follows:

[0102] (1)[Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ [NO3 -0.1 Preparation of H2O:

[0103] 5mmol of Mg(NO3)2·6H2O, 3mmol of Al(NO3)3·9H2O and 2mmol of CsNO3 (all purchased from Sinopharm) were dissolved in 70ml of deionized water without CO2 and marked as liquid A. 10mmol of urea was dissolved in 70ml of deionized water without CO2 and marked as liquid B. Solutions A and B were dropped into a three-necked flask at the same time for reaction at a stirring speed of 200rpm. After the addition was complete, the mixture was stirred for 2h and then transferred to a reactor. After crystallization in an oven at 130℃ for 24h, the mixture was thoroughly washed with deionized water and ethanol and centrifuged. Finally, the mixture was dried and ground in a vacuum drying oven at 60℃ for later use.

[0104] (2)[Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ Synthesis of:

[0105] Under nitrogen protection, 300 rpm, 125 ° C, take 0.04 g of the above-prepared [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] was added to a four-necked flask containing 400 g of isosorbide (purchased from [Sinopharm Group]), stirred at 500 rpm for 12 h, and [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ [NO3 - 0.1 ·H2O] were peeled off into single-layer nanosheets, and [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ Then, 0.005 g of triphenyl phosphate was added to the above dispersion and stirred for 2 h to obtain a composite catalyst dispersion for the synthesis of PIC.

[0106] (3) [Mg2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ For the synthesis of PIC, the details are as follows:

[0107] The composite catalyst dispersion in step (2) (based on the amount of the composite catalyst relative to 500 ppm of isosorbide in the polymerization reaction) was mixed with isosorbide (74.31 g, purchased from Sinopharm) and diphenyl carbonate (108.72 g, purchased from Sinopharm) and subjected to transesterification reaction at 200° C. for 1 h. When the amount of phenol distilled was close to the theoretical value, the temperature was increased to 220° C., the product was evacuated to an absolute pressure of 5000 Pa, and a pre-polycondensation reaction was carried out for 1 h. Finally, the temperature was increased to 240° C. and the polycondensation reaction was carried out for 2 h. The reaction was stopped when obvious pole climbing phenomenon was observed, thereby preparing PIC.

[0108] The BET test results showed that [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ The specific surface area is 133m 2 .g -1 .

[0109] The PIC prepared above was tested: The GPC test showed that the weight average molecular weight of the PIC prepared in this example was 7.5×10 4 g / mol, molecular weight distribution 1.60; melt mass flow rate 10 g / 10 min; light transmittance 90%; tensile strength 60 MPa; elongation at break 60%; PIC product yield 99.07%, transesterification rate 99.03%; PIC solution color (Hazen): 80.

[0110] Comparative Example 1

[0111] PIC was synthesized using cesium carbonate as a catalyst: cesium carbonate (purchased from Sinopharm; the amount used was 500 ppm relative to the mass of isosorbide) was mixed with isosorbide (74.31 g, purchased from Sinopharm) and diphenyl carbonate (108.72 g, purchased from Sinopharm) and subjected to an ester exchange reaction at 200°C for 1 h. When the amount of phenol distilled was close to the theoretical value, the temperature was increased to 220°C, the product was evacuated to an absolute pressure of 5000 Pa, and a pre-polycondensation reaction was carried out for 1 h. Finally, the temperature was increased to 240°C and the polycondensation reaction was carried out for 2 h. The reaction was stopped when a clear pole climbing phenomenon was observed, thereby preparing PIC.

[0112] The PIC prepared above was tested: The GPC test showed that the weight average molecular weight of the PIC prepared in this comparative example was 2.0×10 4 g / mol, molecular weight distribution 2.20; melt mass flow rate 38 g / 10 min; transmittance 60%; tensile strength 23 MPa; elongation at break 23%. PIC product yield 99.01%, transesterification rate 98.88%. PIC solution color (Hazen): 350.

[0113] Comparative Example 2

[0114] PBS was synthesized using tetraethylammonium hydroxide as a catalyst: tetraethylammonium hydroxide (25% aqueous solution, purchased from Sinopharm, mass ratio of tetraethylammonium hydroxide to isosorbide: 500 ppm) was mixed with isosorbide (74.31 g, purchased from Sinopharm) and diphenyl carbonate (108.72 g, purchased from Sinopharm) and subjected to transesterification at 200°C for 1 h. When the amount of phenol distilled approached the theoretical value, the temperature was raised to 220°C, the pressure was evacuated to 5000 Pa, and a pre-polycondensation reaction was carried out for 1 h. Finally, the temperature was raised to 240°C and the polycondensation reaction was carried out for 2 h. The reaction was stopped when a clear pole climbing phenomenon was observed, thereby preparing PIC.

[0115] The PIC prepared above was tested: The GPC test showed that the weight average molecular weight of the PIC prepared in this comparative example was 3.1×10 4 g / mol, molecular weight distribution 1.85; melt mass flow rate 30 g / 10 min; light transmittance 40%; tensile strength 26 MPa; elongation at break 20%; PIC product yield 99.10%; transesterification rate 99.01%; PIC solution color (Hazen): 300.

[0116] The parameters of the isosorbide-based polycarbonates prepared in Examples 1-4 and Comparative Examples 1-2 are summarized in Table 1.

[0117] Table 1 Parameters of isosorbide-based polycarbonates prepared in Examples 1-4 and Comparative Examples 1-2

[0118]

[0119] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A nanosheet, characterized in that: The chemical composition of the nanosheets is [M1 2+ 1-x-y M2 3+ x M 3+y (OH)2] x-y [A n- (x-y / n) ·H2O]; where M1 2+ Mg 2+ ; M2 3+ Al 3+ ; M3 + for Na + , K + 、Li + 、Cs + One or more of the following: A n- is an anion between the nanosheet layers; 0.33<x+y<0.80; x>y; n＞0。 2. The nanosheet according to claim 1, wherein The M1 2+ Mg 2+ , the M2 3+ Al 3+ , the M3 + Cs + , A n- NO3 - ;x+y=0.

5.

3. The nanosheet according to claim 1, wherein The chemical composition of the nanosheets is [Mg 2+ 0.5 Al 3+ 0.3 Na + 0.2 (OH)2] 0.1+ [NO 3-0.1 ·H2O]、[Mg 2+ 0.5 Al 3+ 0.3 Li + 0.2 (OH)2] 0.1+ [NO 3-0.1 ·H2O]、[Mg 2+ 0.5 Al 3+ 0.3 K + 0.2 (OH)2] 0.1+ [NO 3-0.1 ·H2O] or [Mg 2+ 0.5 Al 3+ 0.3 Cs + 0.2 (OH)2] 0.1+ [NO 3-0.1 ·H2O] indicates; And / or, the specific surface area of ​​the nanosheet is 100 to 140 m 2 .g -1 .

4. A charged nanosheet, characterized in that The chemical composition of the charged nanosheet is [M1 2+ 1-x-y M2 3+ x M 3+y (OH)2] x-y , indicating that M1 2+ 、M2 3+ 、M3 + , x, y and n are all as defined in any one of claims 1-3.

5. The charged nanosheet according to claim 4, characterized in that The charged nanosheets are obtained by peeling off the nanosheets according to any one of claims 1 to 3.

6. The charged nanosheet according to claim 4, characterized in that The exfoliation is performed by mixing the nanosheets with isosorbide and then mechanically exfoliating the nanosheets; The mixing conditions include: stirring at 100-150°C; The mechanical peeling time is not less than 8 hours; The rotation speed of the mechanical stripping is not less than 300 rpm.

7. The charged nanosheet according to claim 4 or 5, characterized in that The charged nanosheet is a single-layer structure; And / or, the specific surface area of ​​the charged nanosheet is 100 to 140 m 2 .g -1 .

8. Use of the nanosheet according to any one of claims 1 to 3 or the charged nanosheet according to any one of claims 4 to 7 as a catalyst for isosorbide-based polycarbonate.

9. A composite catalyst, characterized in that The composite catalyst comprises the charged nanosheets according to any one of claims 4 to 7 and a stabilizer; The stabilizer is selected from one or more of phosphates, phosphorous acid, phosphate esters and hindered phenols.

10. The composite catalyst according to claim 9, characterized in that The mass ratio of the charged nanosheets to the stabilizer is 100:(0.5-2).

11. Use of the composite catalyst according to claim 9 in the preparation of PIC.

12. The use according to claim 11, characterized in that The PIC has any one or more of the following parameters (1)-(6): (1) Weight average molecular weight (Mw) is (4.0-7.5)×10 4 g / mol; (2) Molecular weight distribution is 1.6-1.9; (3) The melt index is 10-22 g / 10 min, which is measured according to GB / T 40006.7-2021 under the conditions of a temperature of 300°C, a load of 1.2 kg, and a mass of 10 g; (4) Light transmittance is 78-90%; (5) Tensile strength is 38-60 MPa; (6) Elongation at break is 20-60%.

13. A method for preparing PIC, characterized in that: The method uses the composite catalyst according to claim 9.

14. The method according to claim 13, wherein: The method comprises the following steps: firstly subjecting the composite catalyst, isosorbide and diphenyl carbonate to an ester exchange reaction, and then subjecting them to a pre-polycondensation reaction and a polycondensation reaction to obtain the PIC; The mass ratio of the composite catalyst, isosorbide and diphenyl carbonate is (0.01-1):100:(130-150); The temperature of the transesterification reaction is 180-210°C and the time is 0.5-2h; The pre-polycondensation reaction is carried out at a temperature of 215-230° C. for 0.5-2 hours in a near vacuum or vacuum environment; The temperature of the polycondensation reaction is 235-250° C., and the reaction is stopped when the reactant is observed to climb the pole.

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