Bio-based high molecular weight and high transparency polycarbonate and its preparation method and application

Abstract

This application discloses a bio-based, high-molecular-weight, highly transparent polycarbonate, its preparation method, and application. The preparation method comprises: using a MXene material as a catalyst, a carbonate diester as a carbon source, and isosorbide and, optionally, other diols as raw materials, conducting an ester exchange reaction in a molten state, followed by a polycondensation reaction at elevated temperature under high vacuum conditions to obtain the target product. This application enables the preparation of a high-molecular-weight, highly transparent bio-based polycarbonate, effectively overcoming the drawbacks of existing isosorbide-based polycarbonates, such as low molecular weight and dark color.

Description

Technical Field

[0001] The present application relates to a polycarbonate, specifically to a bio-based high molecular weight and highly transparent polycarbonate and its preparation method and application, belonging to the technical field of polymer materials. Background Art

[0002] Currently, most polycarbonates (PCs) on the market are synthesized using the petroleum-based compound bisphenol A as raw material. However, bisphenol A has reproductive toxicity and estrogenic effects that affect human health, limiting its application in medical devices and food packaging.

[0003] Isosorbide is derived from biomass and is obtained from sorbitol through intramolecular secondary dehydration. It is a bio-based monomer. Isosorbide-based polycarbonate prepared from isosorbide is not only green and non-toxic, but also has superior mechanical, thermal, and optical properties. However, a drawback is the presence of an internal hydroxyl group (endo-OH) in the isosorbide molecule, which forms hydrogen bonds with adjacent THF rings, thereby reducing reactivity and resulting in a low molecular weight for the synthesized polymer. Furthermore, the isosorbide monomer is highly susceptible to thermal degradation during high-temperature polymerization, forming byproducts with degraded color, resulting in a dark product color and reduced transparency.

[0004] Therefore, synthesizing high molecular weight, highly transparent isosorbide polycarbonate remains a huge challenge. Summary of the Invention

[0005] The main purpose of this application is to provide a bio-based high molecular weight and highly transparent polycarbonate and its preparation method and application to solve the above-mentioned problems in the prior art.

[0006] To achieve the aforementioned invention objectives, the technical solutions adopted in this application include:

[0007] The first aspect of the present application provides a method for preparing a bio-based high molecular weight and highly transparent polycarbonate, comprising:

[0008] In the presence of a catalyst, at least a carbonic acid diester and isosorbide and other diols which may be added or not are subjected to a melt transesterification reaction and a polycondensation reaction in sequence to prepare the polycarbonate, wherein the polycarbonate has a molecular weight Mw of ≥60,000 and a visible light transmittance of ≥90%;

[0009] Wherein, the catalyst comprises a chemical formula M m X n T x MXene material, M is at least selected from one or a combination of two of Ti, Mo, Sc, Nb, Cr, V, X is at least selected from carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, T xAt least one selected from O, -OH, -F or -Cl.

[0010] The second aspect of the present application provides a bio-based high molecular weight and high transparency polycarbonate produced by the method for preparing the bio-based high molecular weight and high transparency polycarbonate.

[0011] The third aspect of the present application provides the use of the bio-based high molecular weight and highly transparent polycarbonate in preparing various polycarbonate products.

[0012] Compared with the prior art, this application has at least the following beneficial effects:

[0013] First, by using the aforementioned MXene material as a catalyst, it plays a highly efficient catalytic role in both the transesterification and polycondensation steps of the bio-based polycarbonate synthesis process, thereby eliminating the need to use different catalysts for the transesterification and polycondensation reactions. Furthermore, this type of MXene catalyst can rapidly catalyze the transesterification and polycondensation reactions, keeping the polycondensation time within 0.5 hours, thereby reducing the occurrence of side reactions and thermal degradation. Furthermore, the amount of MXene catalyst used is small, and has no significant effect on the thermal stability of the polymer. The bio-based polycarbonate thus prepared has a high molecular weight (M w ≥60000) and high transparency (visible light transmittance ≥90%).

[0014] Secondly, in addition to isosorbide, the synthetic raw materials of the present application may also include other cyclic diols and / or aliphatic diols, such as cyclohexanedimethanol, which have high reactivity and can quickly grow molecular chains, thereby helping to further increase the molecular weight of bio-based high molecular weight and high transparency polycarbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to explain the present application more clearly, the drawings required for use in the embodiments or description of the prior art will be briefly introduced below.

[0016] Figure 1 The bio-based polycarbonate obtained in Example 1 1 H-NMR spectrum;

[0017] Figure 2 The bio-based polycarbonate obtained in Example 6 1 H-NMR spectrum;

[0018] Figure 3 is the DSC spectrum of the bio-based polycarbonate obtained in Example 6;

[0019] Figure 4 This is a UV-visible transmittance curve of the bio-based polycarbonate obtained in Example 6. DETAILED DESCRIPTION

[0020] The existing bio-based polycarbonate synthesis process has shortcomings in many aspects, such as:

[0021] First, the existing synthesis process of isosorbide polycarbonate is difficult to prepare isosorbide polycarbonate with high molecular weight and high transparency, and often has problems such as low molecular weight, poor mechanical properties, and dark color.

[0022] Secondly, the existing industrial melt transesterification process for synthesizing polycarbonate is mainly divided into two steps: transesterification and polycondensation. These two process steps usually require catalysts of different properties, and the transesterification catalyst often affects the polycondensation, thereby affecting the quality of the polymer.

[0023] Third, existing polycarbonates synthesized using alkali metal catalysts often require a catalyst quenching step after polycondensation or before processing to prevent residual catalyst from affecting the thermal stability of the polymer. This not only makes the synthesis process more complicated, but also affects the quality of the polymer to a certain extent.

[0024] This application primarily synthesizes high-molecular-weight, highly transparent polycarbonates by employing a non-phosgene melt transesterification and polycondensation method, adding a novel two-dimensional metal carbon / nitride (MXene) material as a transesterification and polycondensation catalyst, using a carbonate diester as a carbon source, and using isosorbide and, optionally, other diols as raw materials. The technical solution of this application is described in detail below.

[0025] Some embodiments of the present application provide a method for preparing a bio-based high molecular weight and highly transparent polycarbonate, including:

[0026] In the presence of a catalyst, at least a carbonic acid diester and one or more diols are subjected to a melt transesterification reaction and a polycondensation reaction in sequence to obtain the polycarbonate having a molecular weight Mw of ≥60,000 and a visible light transmittance of ≥90%;

[0027] Wherein, the catalyst comprises a chemical formula M m X n T x MXene material, M includes one or a combination of two of Ti, Mo, Sc, Nb, Cr, V, X includes carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, T x Including O, -OH, -F or -Cl, the diol includes isosorbide.

[0028] In some embodiments, the molecular weight M of the polycarbonate is w It can be above 130,000.

[0029] In one embodiment, the carbonic acid diester includes one or a combination of two or more of diphenyl carbonate, dimethyl carbonate, dibenzyl carbonate, diethyl carbonate, and di-tert-butyl carbonate, but is not limited thereto.

[0030] Furthermore, the carbonic acid diester may be preferably selected from dimethyl carbonate and / or diphenyl carbonate, more preferably diphenyl carbonate, which has higher reactivity.

[0031] In one embodiment, the diol further comprises cyclic diols and / or aliphatic diols other than isosorbide, preferably cyclic diols, whose cyclic structures have greater rigidity than aliphatic diols and can better maintain the heat resistance of polycarbonate.

[0032] In one embodiment, the cyclic diol is preferably 1,4-cyclohexanedimethanol. Due to its high reactivity, it can also rapidly grow the molecular chain of the polycarbonate product, further increasing the molecular weight of the bio-based polycarbonate. For example, a bio-based polycarbonate copolymerized with isosorbide and 1,4-cyclohexanedimethanol can achieve an Mw exceeding 13,000 g / mol.

[0033] For example, the diol may include, but is not limited to, a combination of one or more of the following diols:

[0034]

[0035] The MXene material described in this application, due to its presence of metallic elements such as titanium, not only has the ability to rapidly catalyze the polycondensation of polymers, but is also easier to exfoliate and surface-modify than two-dimensional materials such as graphene and boron nitride. It also possesses advantages such as abundant surface functional groups, excellent mechanical strength, and electrical and thermal conductivity, making it an ideal functional filler for residual polymers after polymerization. This application primarily utilizes MXene materials as a highly active catalyst in the synthesis of bio-based polycarbonate by incorporating them into the synthesis process.

[0036] The MXene material can be obtained from commercial sources or prepared according to methods known in the art. For example, the MAX phase material can be wet-chemically etched with an etchant to remove the metal A element therein, thereby preparing the MXene material.

[0037] Furthermore, the MAX phase material may include Ti2AlC, Ti2AlN, Ti3AlC2, Ti3SiC2, T i4 AlN3、(Ti x Nb 1-x )2AlC、(Ti x Cr 1-x )2AlC、(Ti 1 / 2V 1 / 2 )3AlC2, (Cr2 / 3Ti1 / 3)3AlC2, (Mo1 / 2Ti1 / 2)4AlC3, (Mo2 / 3Ti1 / 3)3AlC2, (Mo2 / 3Sc1 / 3)3AlC2, one or a combination of two or more, and not limited to these.

[0038] Further, the etchant may include HF solution, NH4HF2 solution, NaHF2 solution, KHF2 solution, NH4F solution, LiF-HCl mixed solution, NaF-HCl solution, NaF-H2SO4 solution, KF-H2SO4 solution, KF-HCl solution, CsF-H2SO4 solution, CsF-HCl solution, CaF2-H2SO4 solution, CaF2-HCl solution, tetrabutylammonium chloride-HCl solution, tetrabutylammonium chloride-H2SO4 solution, LiF molten salt, NaF molten salt, KF molten salt, dilute HCl, NaOH, NH4Cl and tetramethylammonium hydroxide mixture, or a combination of two or more thereof, and is not limited thereto.

[0039] Furthermore, the temperature of the wet chemical etching may be 35° C. to 300° C., and the time of the wet chemical etching may be 6 to 200 h.

[0040] Furthermore, the surface groups of the MXene material may include, but are not limited to, one or a combination of two or more of -OH, -O, -F, and -Cl. Such MXene materials can act as catalysts to rapidly catalyze transesterification and polycondensation reactions, keeping the polycondensation time within 0.5 hours, thereby reducing side reactions and thermal degradation.

[0041] In one embodiment, the molar ratio of the carbonic acid diester to the diol is 0.9 to 10:1.

[0042] In one embodiment, the molar ratio of isosorbide to carbonic acid diester is 0.1 to 1:1, preferably 0.3 to 1:1, so as to at least make the synthesized polycarbonate product have a higher bio-based content.

[0043] In one embodiment, the catalyst is added in an amount of 1 ppm to 1000 ppm, preferably 5 to 100 ppm, and more preferably 10 to 50 ppm, of the theoretical mass of the product of the preparation method. If the catalyst is added in an amount that is too low, the catalytic activity required for the polymerization reaction will be insufficient, while if it is added in an amount that is too high, the polymer may be thermally degraded, resulting in low molecular weight, dark color, and other issues.

[0044] In one embodiment, the reaction conditions of the melt transesterification reaction include: a melting temperature of 80 to 200° C., a reaction temperature of 90 to 220° C., and a reaction time of 0.5 to 8 hours.

[0045] In one embodiment, the reaction conditions of the polycondensation reaction include: reaction temperature of 160° C. to 280° C., reaction pressure of 5 Pa to 1000 Pa, and reaction time of 0.5 h to 8 h.

[0046] In one embodiment, the preparation method specifically comprises: subjecting a polymerization reaction system comprising a uniformly mixed carbonic acid diester, isosorbide, other diols that may or may not be added, and a catalyst to sequentially perform the melt transesterification reaction and the polycondensation reaction.

[0047] Some embodiments of the present application also provide a method for preparing a bio-based high-molecular-weight, highly transparent polycarbonate, which comprises: adding a MXene material as a catalyst, using a carbonate diester as a carbon source, using isosorbide and other diols that may be optionally added as raw materials, conducting an ester exchange reaction in a molten state, and then increasing the temperature and polycondensing under high vacuum conditions to obtain a target product.

[0048] Furthermore, the preparation method may specifically include: uniformly mixing a carbonate diester with isosorbide and other diols that are optionally added or not added, and placing the mixture into a reaction vessel, exhausting the air in the reaction vessel, and filling the reaction vessel with a protective gas (such as nitrogen, Ar and other inert gases, or a mixture thereof), then raising the temperature to melt the reaction raw material mixture, adding a MXene catalyst, and conducting an ester exchange reaction under positive pressure, negative pressure or normal pressure. After the ester exchange reaction is completed, raising the temperature in the reaction vessel and lowering the pressure in the reaction vessel, preferably lowering the pressure to form a vacuum environment, to promote the polycondensation reaction, and removing small molecules in the reaction vessel during this process, to ultimately obtain bio-based polycarbonate.

[0049] The ratio of carbonate diester, isosorbide and other diols and MXene catalyst, the temperature and pressure conditions of transesterification reaction and polycondensation reaction are as described above.

[0050] Some embodiments of the present application also provide bio-based high molecular weight and high transparency polycarbonate prepared by the method for preparing the bio-based high molecular weight and high transparency polycarbonate.

[0051] Some embodiments of the present application also provide a composition for synthesizing bio-based polycarbonate, and comprising the following components:

[0052] (1) Carbonate diesters, including but not limited to one or a combination of two or more of diphenyl carbonate, dimethyl carbonate, dibenzyl carbonate, diethyl carbonate, and di-tert-butyl carbonate, preferably dimethyl carbonate and / or diphenyl carbonate, more preferably diphenyl carbonate.

[0053] (2) The first diol is isosorbide.

[0054] (3) A second diol that may be added or not added selectively includes but is not limited to a cyclic diol and / or an aliphatic diol other than isosorbide, for example, a combination of one or more of the following compounds, but not limited to:

[0055] ;

[0056]

[0057] (4) MXene material as a catalyst. Its chemical formula is M m X n T x , M is at least one selected from Ti, Mo, Sc, Nb, Cr, V or a combination of two thereof, X is at least one selected from carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, T x At least one selected from O, -OH, -F or -Cl.

[0058] Furthermore, the molar ratio of isosorbide to carbonic acid diester is 1 to 10:10, preferably 3 to 10:10.

[0059] Furthermore, the composition comprises a first diol and a second diol, and the molar ratio of the total molar amount of the diol to the carbonate diester is 0.9 to 10:1.

[0060] Furthermore, the amount of the MXene material used is 1 ppm to 1000 ppm of the theoretical yield (by mass) of the bio-based polycarbonate, preferably 25 to 100 ppm.

[0061] Some embodiments of the present application also provide a type of MXene material for use in the catalytic synthesis of bio-based polycarbonate. m X n T x MXene material, M can be selected from one or a combination of two of Ti, Mo, Sc, Nb, Cr, V, X can be selected from carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, T x It may be selected from O, -OH, -F or -Cl.

[0062] Furthermore, the MXene material has the advantages of high activity, good selectivity, and strong universality as a catalyst, and can make the molecular weight Mw of the synthesized polycarbonate ≥60,000 and the visible light transmittance ≥90%.

[0063] Some embodiments of the present application also provide the use of the bio-based high molecular weight and high transparency polycarbonate in the preparation of fire-fighting equipment, baby bottles, water cups, kitchen appliances, food packaging materials, hot-fill beverage bottles, optical base films, decorative materials or automotive accessories and other products.

[0064] Some embodiments of the present application also provide a polycarbonate processing method, which includes: inputting the bio-based high molecular weight and high transparency polycarbonate into a co-rotating twin-screw extruder for melt extrusion and granulation; wherein the operating parameters of the co-rotating twin-screw extruder include: a barrel temperature of 215°C to 250°C, and a die head temperature of 215°C to 250°C.

[0065] Some embodiments of the present application further provide a method for processing a polycarbonate film, comprising:

[0066] The bio-based high molecular weight and high transparency polycarbonate is fed into a twin-screw extruder, melt-extruded at 215° C. to 250° C., the melt delivery pump temperature is 215° C. to 250° C., and the molten fluid is cast onto a rotating cooling drum to obtain a cast sheet with a thickness of 500 μm to 5500 μm;

[0067] The cast sheet is preheated to 85-170°C and stretched longitudinally by 3-4 times, then preheated again to 85-170°C and stretched transversely by 3-4.5 times to obtain a polycarbonate film. The polycarbonate film has an ultraviolet-visible light transmittance greater than 90% and excellent mechanical properties, such as a tensile modulus of 2510±134 Pa and a breaking strength of 55±2 MPa.

[0068] There is no particular restriction on the rotation speed of the cooling drum, and it can be adjusted according to actual needs.

[0069] To more clearly understand the objectives, technical solutions, and advantages of this application, the following examples will further explain the technical solutions, their implementation processes, and principles. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of this application.

[0070] In the following examples, nuclear magnetic resonance spectra ( 1 H-NMR). Deuterated chloroform (CDCL 3) As a solvent.

[0071] In the following examples, thermal transition properties were tested using a differential scanning calorimeter (METTLER TOLEDO DSC3+) in a nitrogen atmosphere over a temperature range of 25°C to 250°C at a heating rate of 10°C / min. The test temperature program was as follows: (1) heating from 25°C to 250°C at a heating rate of 10°C / min; (2) holding at 250°C for 3 min; (3) cooling from 250°C to 25°C at a cooling rate of 10°C / min; (4) holding at 25°C for 3 min; (5) heating from 25°C to 250°C at a heating rate of 10°C / min.

[0072] In the following examples, the weight-average molecular weight (Mw) of polycarbonate was determined using a high-temperature gel chromatography (Agilent, 1260 HT Infinity II) and the sample was prepared in HPLC-grade chloroform to a concentration of 1 mg mL -1 The mobile phase was HPLC grade chloroform with a flow rate of 1 mL min -1 .

[0073] In the following examples, the transmittance was measured using an ultraviolet-visible-near-infrared spectrophotometer (Lambda 950) in a wavelength range of 200 to 800 nm, and the sample was a thin film with a thickness of approximately 200 μm.

[0074] In the following examples, unless otherwise specified, the raw materials and equipment used can be purchased from the market.

[0075] The MXene materials used in the following examples were all produced by wet chemically etching a MAX phase material with an etchant until the metal A element was removed. Specific raw material types and etching conditions are shown in Table 1. The etchant, when in liquid form, should be sufficient to completely immerse the MAX phase material.

[0076] Table 1 Preparation process conditions of MXene materials in Examples 1 to 15

[0077]

[0078] After the wet chemical etching was completed, the obtained products were characterized by X-ray diffractometer and scanning electron microscope, confirming that they were all MXene materials with the expected chemical composition.

[0079] The following will further explain the technical solution of this application, its implementation process and principles, etc. in conjunction with embodiments.

[0080] Example 1

[0081] Diphenyl carbonate and isosorbide were added into the reactor in a molar ratio of 1:1, and 20 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti3C2T x After the addition of the raw materials, the air in the reactor is removed by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. The temperature is then raised, and mechanical stirring is started after the raw materials melt at 180°C. The temperature in the reactor is then gradually raised to 220°C, and the pressure in the reactor is gradually reduced. When the amount of by-product phenol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0082] The temperature in the reactor was then further increased to 260°C, and the reactor was vacuumed within 30 minutes until the pressure in the reactor was within 1000 Pa. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (I):

[0083] ;

[0084] Here, z is an integer from 10 to 1000.

[0085] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 92%, and the glass transition temperature (T g ) is about 164℃. 1 H-NMR spectrum Figure 1 shown.

[0086] Example 2

[0087] Dimethyl carbonate and isosorbide were added to the reactor at a molar ratio of 10:1, and 1000 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti4N3T x After the feeding is completed, the air in the reactor is exhausted by vacuum, and high-purity N2 is introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 80°C. The temperature in the reactor is then gradually raised to 90°C, and the pressure in the reactor is gradually reduced. When the amount of by-product methanol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0088] Then the temperature in the reactor was further increased to 240°C, and the pressure in the reactor was evacuated to 20 Pa within 8 hours. After the polycondensation was completed, bio-based polycarbonate was obtained.

[0089] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is wThe transmittance is about 91%, and the glass transition temperature (T g ) is about 164℃.

[0090] Example 3

[0091] Diethyl carbonate and isosorbide were added to the reactor in a molar ratio of 1:1, and 20 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti2CT x After the addition of materials is completed, the air in the reactor is exhausted by vacuum, and high-purity N2 is introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 150°C. The temperature in the reactor is then gradually raised to 180°C, and the pressure in the reactor is gradually reduced. When the amount of by-product ethanol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0092] Then, the temperature in the reactor was further increased to 240°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, bio-based polycarbonate was obtained.

[0093] According to tests, the molecular weight Mw of the polycarbonate obtained in this embodiment is about 63842, the light transmittance is about 91%, and the glass transition temperature (Tg) is about 164°C.

[0094] Example 4

[0095] Dibenzyl carbonate and isosorbide were added to the reactor in a molar ratio of 1:1, and 20 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti3(C, N)2T x After the addition of the materials is completed, the air in the reactor is removed by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 150°C. The temperature in the reactor is then gradually raised to 180°C, and the pressure in the reactor is gradually reduced. When the amount of by-product benzyl alcohol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0096] Then, the temperature in the reactor was further increased to 240°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, bio-based polycarbonate was obtained.

[0097] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 91%, and the glass transition temperature (T g ) is about 164℃.

[0098] Example 5

[0099] Di-tert-butyl carbonate and isosorbide were added to the reactor in a molar ratio of 1:1, and 20 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti2NT x After the addition of materials is completed, the air in the reactor is exhausted by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 150°C. The temperature in the reactor is then gradually raised to 180°C, and the pressure in the reactor is gradually reduced. When the distillation amount of the by-product tert-butanol reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0100] Then, the temperature in the reactor was further increased to 240°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, bio-based polycarbonate was obtained.

[0101] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 90%, and the glass transition temperature (T g ) is about 164℃.

[0102] Example 6

[0103] Diphenyl carbonate, isosorbide, and 1,4-cyclohexanedimethanol were added to the reactor at a molar ratio of 0.9:0.3:0.7, and 1 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is (Mo2Ti2)C3T x After the addition of materials is completed, the air in the reactor is exhausted by vacuum pumping, and high-purity N2 is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 130°C. The temperature in the reactor is then gradually raised to 180°C, and the pressure in the reactor is gradually reduced. When the amount of by-product phenol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0104] The temperature in the reactor was then further increased to 160°C, and the pressure in the reactor was evacuated to 100 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (II):

[0105] ;

[0106] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0107] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is wThe light transmittance is about 91%, and the glass transition temperature (T g ) is about 74℃.

[0108] In this embodiment, a polycarbonate product 1 H-NMR spectrum, DSC spectrum and UV-visible transmittance curve are shown in Figure 2. Figure 2-Figure 4 shown.

[0109] Example 7

[0110] Diphenyl carbonate, isosorbide, and 1,4-cyclohexanedimethanol were added to the reactor at a molar ratio of 0.9:0.7:0.3, and 1 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is (Cr2Ti)C2T x After the addition of the materials is completed, the air in the reactor is removed by vacuum, and high-purity nitrogen is introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 130°C. The temperature in the reactor is then gradually raised to 180°C, and the pressure in the reactor is gradually reduced. When the phenol distillate reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0111] Then, the temperature in the reactor was further increased to 200°C, and the pressure in the reactor was evacuated to 100 Pa within 30 minutes. After the polycondensation was completed, bio-based polycarbonate was obtained.

[0112] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 91%, the glass transition temperature (T g ) is about 124℃.

[0113] Example 8

[0114] Diphenyl carbonate, isosorbide, and 1,3-cyclohexanedimethanol were added to the reactor at a molar ratio of 0.9:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is (Mo2Ti)C2T x After the addition of the materials is completed, the air in the reactor is removed by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 140°C. The temperature in the reactor is then gradually raised to 190°C, and the pressure in the reactor is gradually reduced. When the phenol distillate reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0115] The temperature in the reactor was then further increased to 250°C, and the pressure in the reactor was evacuated to 100 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (III):

[0116] ;

[0117] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0118] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 90%, and the glass transition temperature (T g ) is about 125℃.

[0119] Example 9

[0120] Diphenyl carbonate, isosorbide and 1,2-cyclohexanedimethanol were added into the reactor at a molar ratio of 0.9:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti3C2T x After the addition of the materials is completed, the air in the reactor is removed by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 140°C. The temperature in the reactor is then gradually raised to 190°C, and the pressure in the reactor is gradually reduced. When the phenol distillate reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0121] The temperature in the reactor was then further increased to 250°C, and the pressure in the reactor was evacuated to 100 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (IV):

[0122] ;

[0123] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0124] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w =81410, light transmittance 90%, glass transition temperature (T g ) is 126℃.

[0125] Example 10

[0126] Diphenyl carbonate, isosorbide, and 1,4-cyclohexanediol were added to the reactor in a molar ratio of 1:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is two-dimensional material (Ti,V)3C2T x After the addition of the materials is completed, the air in the reactor is removed by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 140°C. The temperature in the reactor is then gradually raised to 190°C, and the pressure in the reactor is gradually reduced. When the phenol distillate reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0127] The temperature in the reactor was then further increased to 250°C, and the pressure in the reactor was evacuated to 100 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (V):

[0128] ;

[0129] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0130] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The light transmittance is about 90%, and the glass transition temperature (T g ) is about 140℃.

[0131] Example 11

[0132] Diphenyl carbonate, isosorbide, and dicyclopentanediol were added to the reactor at a molar ratio of 1:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is (Ti, Nb)2CT x After the addition of the materials is completed, the air in the reactor is exhausted by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 150°C. The temperature in the reactor is then gradually raised to 200°C, and the pressure in the reactor is gradually reduced. When the amount of phenol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0133] The temperature in the reactor was then further increased to 260°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (VI):

[0134] ;

[0135] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0136] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w =87234, light transmittance is about 90%, glass transition temperature (T g ) is about 160℃.

[0137] Example 12

[0138] Diphenyl carbonate, isosorbide, and monomethyldicyclopentanediol were added to a reactor in a molar ratio of 1:0.7:0.3, and 100 ppm of a MXene material ((Mo2Sc)C2Tx)) was added as a catalyst. After the addition of the ingredients, the air in the reactor was evacuated by vacuum, and high-purity nitrogen was introduced. This process was repeated three or more times to completely expel any remaining air. The temperature was then raised until the raw materials melted at 150°C, and mechanical stirring was initiated. The reactor temperature was then gradually raised to 200°C, and the pressure was gradually reduced. When the phenol distillate reached over 90% of the theoretical mass, the transesterification reaction was terminated and the polycondensation phase began.

[0139] The temperature in the reactor was then further increased to 260°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (VII):

[0140] ;

[0141] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0142] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The light transmittance is about 90%, and the glass transition temperature (T g ) is about 158℃.

[0143] Example 13

[0144] Diphenyl carbonate, isosorbide and dimethyldicyclopentanediol were added into the reactor in a molar ratio of 1:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti3C2T x. After the feeding is completed, the air in the reactor is vacuumed out, and high-purity N2 is introduced. Repeat three or more times to exhaust the residual air in the reactor. After the feeding is completed, the air in the reactor is vacuumed out, and high-purity N2 is introduced. Repeat three or more times to exhaust the residual air in the reactor. Subsequently, the temperature is started to rise and mechanical stirring is started after the raw materials melt at 150°C. Subsequently, the temperature in the reactor is gradually raised to 200°C, and the pressure in the reactor is gradually reduced. When the amount of phenol distilled reaches more than 90% of the theoretical mass, the ester exchange reaction is terminated and the polycondensation stage is entered.

[0145] The temperature in the reactor was then further increased to 260°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (VIII):

[0146] ;

[0147] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0148] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The light transmittance is about 90%, and the glass transition temperature (T g ) is about 155℃.

[0149] Example 14

[0150] Diphenyl carbonate, isosorbide and 2,3,5,6-tetrafluorophenylenedimethanol were added into the reactor at a molar ratio of 1:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti4C3T x After the addition of the materials is completed, the air in the reactor is removed by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 200°C. The temperature in the reactor is then gradually raised to 220°C, and the pressure in the reactor is gradually reduced. When the phenol distillate reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0151] The temperature in the reactor was then further increased to 280°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (IX):

[0152] ;

[0153] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0154] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The light transmittance is about 90%, and the glass transition temperature (T g ) is about 172℃.

[0155] Example 15

[0156] Diphenyl carbonate, isosorbide and polycyclic aromatic hydrocarbon diols were added to the reactor at a molar ratio of 1:0.7:0.3, and 100 ppm of MXene material was added as a catalyst. The chemical formula of the MXene material is Ti2CT x After the addition of the materials is completed, the air in the reactor is exhausted by vacuum pumping, and high-purity nitrogen is then introduced. This process is repeated three or more times to completely expel the remaining air in the reactor. Subsequently, the temperature is raised and mechanical stirring is started after the raw materials melt at 150°C. The temperature in the reactor is then gradually raised to 200°C, and the pressure in the reactor is gradually reduced. When the amount of phenol distilled reaches more than 90% of the theoretical mass, the transesterification reaction is terminated and the polycondensation stage is entered.

[0157] The temperature in the reactor was then further increased to 280°C, and the pressure in the reactor was evacuated to 20 Pa within 30 minutes. After the polycondensation was completed, a bio-based polycarbonate was obtained, the structure of which is shown in Formula (X):

[0158] ;

[0159] Here, x and y are integers of 1 to 10, and z is an integer of 10 to 1000.

[0160] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 90%, and the glass transition temperature (T g ) is about 178℃.

[0161] Comparative Example 1

[0162] The synthesis method of this comparative example is basically the same as that of Example 6, except that the type of catalyst used is changed to lithium acetylacetonate, and other conditions remain unchanged.

[0163] After testing, the molecular weight M of the polycarbonate obtained in this comparative example is w The transmittance is about 87%, and the glass transition temperature (T g ) is about 123℃.

[0164] Comparative Example 2

[0165] The synthesis method of this comparative example is basically the same as that of Example 6, except that the type of catalyst used is changed to cesium carbonate, and other conditions remain unchanged.

[0166] After testing, the molecular weight M of the polycarbonate obtained in this comparative example is w The transmittance is about 81%, and the glass transition temperature (T g ) is about 120°C. The molecular weight is low, the polymer state is hard and brittle, and it is difficult to prepare into a film.

[0167] Comparative Example 3

[0168] The synthesis method of this comparative example is basically the same as that of Example 6, except that the type of catalyst used is changed to MAX phase material, and other conditions remain unchanged.

[0169] After testing, the molecular weight M of the polycarbonate obtained in this comparative example is w The transmittance is about 86%, and the glass transition temperature (T g ) is about 121℃.

[0170] Comparative Example 4

[0171] The synthesis method of this comparative example is basically the same as that of Example 6, except that only 1,4-cyclohexanedimethanol is used as diol, and other conditions remain unchanged.

[0172] After testing, the molecular weight M of the polycarbonate obtained in this comparative example is w The light transmittance is about 90%, and the glass transition temperature (T g ) is about 26℃, and it is difficult to use in an environment above room temperature.

[0173] Comparative Example 5

[0174] The synthesis method of this embodiment is basically the same as that of Example 6, except that 1,4-cyclohexanedimethanol is replaced by the same molar amount of 1,4-butanediol, and other conditions remain unchanged.

[0175] After testing, the molecular weight M of the polycarbonate obtained in this embodiment is w The transmittance is about 90%, and the glass transition temperature (T g ) is about 93℃.

[0176] From the above examples and comparative examples, it can be concluded that MXene catalyst has a high catalytic activity compared with alkali metal catalysts, and the final polycarbonate M w ≥60000. The surface of MXene materials has multiple functional groups such as -OH, -F, -O, and -Cl, which can quickly catalyze transesterification and polycondensation reactions, keeping the high-temperature polycondensation time within 1 hour, thereby reducing side reactions and thermal degradation. The prepared polycarbonate has a low color value and a film transmittance of ≥90% at a wavelength of 700nm.

[0177] The bio-based polycarbonate prepared by the above method can be further used according to actual needs and in accordance with methods known in the art to obtain the desired polycarbonate products through a series of processing methods, including but not limited to extrusion granulation, injection molding, film forming, spinning, etc.

[0178] For example, the bio-based high molecular weight and high transparency polycarbonate prepared in the above embodiment can be input into a co-rotating twin-screw extruder for melt extrusion and granulation; wherein the operating parameters of the co-rotating twin-screw extruder include: a barrel temperature of 215°C to 250°C, and a die head temperature of 215°C to 250°C.

[0179] For example, the bio-based high molecular weight and highly transparent polycarbonate prepared in Example 1 can be input into a co-rotating twin-screw extruder for melt extrusion and granulation, and the barrel temperature is set to about 230° C. and the die head temperature is set to about 220° C. The polycarbonate particles finally obtained are colorless and transparent particles.

[0180] For example, the bio-based high-molecular-weight, highly transparent polycarbonate prepared in the above embodiment can also be prepared into a film or sheet. Specifically, the bio-based high-molecular-weight, highly transparent polycarbonate can be fed into a twin-screw extruder, melt-extruded at 215°C to 250°C, with the melt pump temperature at 215°C to 250°C, and the molten fluid cast onto a rotating cooling drum to obtain a cast sheet with a thickness of 500μm to 5500μm. The cast sheet is preheated to 85°C to 170°C, stretched longitudinally by 3 to 4 times, and then preheated again to 85°C to 170°C and stretched transversely by 3 to 4.5 times to obtain a polycarbonate film.

[0181] For example, the bio-based high molecular weight and highly transparent polycarbonate prepared in Example 1 can be fed into a twin-screw extruder and melt-extruded at approximately 230° C. The melt delivery pump temperature is set at approximately 220° C. The molten fluid is cast onto a cooling drum rotating at a low speed (about 50 rpm) to obtain a cast sheet with a thickness of approximately 2 mm. The cast sheet is then preheated to approximately 120° C. and stretched longitudinally by a factor of 3. Thereafter, it is preheated again to approximately 120° C. and stretched transversely by a factor of 4 to obtain a polycarbonate film. The polycarbonate film is a transparent film. When the film thickness is below 200 μm, the visible light transmittance is above 90%, the tensile strength is above 55 MPa, and the elastic modulus is approximately 2500 Pa.

[0182] Although the embodiments of the present application have been described in detail above, professionals in the relevant fields may make deletions and modifications to the embodiments once they become aware of the creative content and concepts therein, and such deletions and modifications shall fall within the scope of protection of the present application. Therefore, the scope of protection of the patent application shall be based on the appended claims.

[0183] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for preparing bio-based high molecular weight and highly transparent polycarbonate, characterized in that: include: In the presence of a catalyst, at least a carbonic acid diester and one or more diols are subjected to a melt transesterification reaction and a polycondensation reaction in sequence to obtain the polycarbonate, wherein the polycarbonate has a molecular weight Mw of ≥60,000 and a visible light transmittance of ≥90%; Wherein, the catalyst comprises a chemical formula M m X n T x MXene material, M includes one or a combination of two of Ti, Mo, Sc, Nb, Cr, V, X includes carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, and the surface group T x Including one or a combination of two or more of -O, -OH, -F, -Cl; The diol includes isosorbide.

2. The preparation method according to claim 1, wherein: The carbonic acid diester includes one or a combination of two or more of diphenyl carbonate, dimethyl carbonate, dibenzyl carbonate, diethyl carbonate, and di-tert-butyl carbonate.

3. The preparation method according to claim 1, wherein: The diols also include cyclic diols and / or aliphatic diols other than isosorbide.

4. The preparation method according to claim 3, wherein: The diols also include one or more combinations of the following diols: 。 5. The preparation method according to claim 1, wherein: The molar ratio of the carbonate diester to the diol is 0.9 to 10:1; and / or the molar ratio of the isosorbide to the carbonate diester is 0.1 to 1:1; and / or the amount of the catalyst added is 1 ppm to 1000 ppm of the theoretical product mass of the preparation method.

6. The preparation method according to claim 1, wherein The reaction conditions of the melt transesterification reaction include: a melt temperature of 80 to 200° C., a reaction temperature of 90 to 220° C., and a reaction time of 0.5 to 8 h; And / or, the reaction conditions of the polycondensation reaction include: reaction temperature of 160° C. to 280° C., reaction pressure of 5 Pa to 1000 Pa, and reaction time of 0.5 h to 8 h.

7. The preparation method according to any one of claims 1 to 6, characterized in that Specifically include: The polymerization reaction system comprising uniformly mixed carbonic acid diester, isosorbide, other diols optionally added or not added, and a catalyst is subjected to the melt transesterification reaction and the polycondensation reaction in sequence.

8. A bio-based high molecular weight and highly transparent polycarbonate, characterized by: The polycarbonate is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the bio-based high molecular weight and highly transparent polycarbonate according to claim 8 in the preparation of firefighting equipment, baby bottles, water cups, kitchen appliances, food packaging materials, hot-fill beverage bottles, optical base films, decorative materials, or automotive parts.

10. A polycarbonate processing method, characterized in that: include: The bio-based high molecular weight and high transparency polycarbonate described in claim 8 is input into a co-rotating twin-screw extruder for melt extrusion and granulation; wherein the operating parameters of the co-rotating twin-screw extruder include: a barrel temperature of 215°C to 250°C, and a die head temperature of 215°C to 250°C.

11. A method for processing a polycarbonate film, characterized in that: include: The bio-based high molecular weight and highly transparent polycarbonate according to claim 8 is fed into a twin-screw extruder, melt-extruded at 215° C. to 250° C., the melt delivery pump temperature is 215° C. to 250° C., and the molten fluid is cast onto a rotating cooling drum to obtain a cast sheet with a thickness of 500 μm to 5500 μm; The cast sheet is preheated to 85-170° C. and then stretched 3-4 times in the longitudinal direction. Thereafter, the cast sheet is preheated to 85-170° C. again and stretched 3-4.5 times in the transverse direction to obtain a polycarbonate film.

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