Bio-based high-molecular-weight high-transparency polycarbonate as well as preparation method and application thereof

Abstract

The invention discloses bio-based high-molecular-weight high-transparency polycarbonate as well as a preparation method and application thereof. The preparation method comprises the following steps: taking an MXene material as a catalyst, taking diester carbonate as a carbon source, taking isosorbide and other dihydric alcohols which can be selectively added or not added as raw materials, carrying out transesterification in a molten state, then raising the temperature, and carrying out condensation polymerization under a high vacuum condition, so as to obtain a target product. According to the preparation method, the bio-based polycarbonate with high molecular weight and high transparency can be prepared, and the defects that isosorbide polycarbonate prepared in the prior art is low in molecular weight, dark in color and the like are effectively overcome.

Description

Technical Field

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

[0002] At present, most of the polycarbonates (PCs) on the market are synthesized from the petroleum-based compound bisphenol A. However, bisphenol A has reproductive toxicity and estrogenic effects, which affect human health and limit its applications in medical devices and food packaging.

[0003] Isosorbide is derived from biomass and is obtained by intramolecular secondary dehydration of sorbitol, belonging to a bio-based monomer. The isosorbide-based polycarbonate prepared from isosorbide is not only green and non-toxic, but also has more excellent mechanical properties, thermal properties and optical properties. However, the problem is that there is an endo-hydroxy group (endo-OH) in the isosorbide molecule, which will form hydrogen bonds with the adjacent THF ring, thereby reducing the reaction activity and resulting in a low molecular weight of the synthesized polymer. Moreover, the isosorbide monomer is extremely prone to thermal degradation during high-temperature polymerization, forming by-products with deteriorated color, resulting in a dark color and a decrease in transparency of the product.

[0004] Therefore, synthesizing a high molecular weight and high transparency isosorbide-based polycarbonate is still a huge problem. Summary of the Invention

[0005] The main purpose of the present application is to provide a bio-based high molecular weight and high transparency polycarbonate, its preparation method and application, so as to solve the above problems of the prior art.

[0006] To achieve the foregoing invention purpose, the technical solutions adopted in the present application include: In a first aspect of the present application, a preparation method of a bio-based high molecular weight and high transparency polycarbonate is provided, which includes: In the presence of a catalyst, at least a carbonic acid diester, isosorbide and an optional other diol are successively subjected to a melt transesterification reaction and a polycondensation reaction to obtain the polycarbonate, wherein the molecular weight Mw of the polycarbonate is ≥60000, and the visible light transmittance is ≥90%; Wherein, the catalyst includes an MXene material with the chemical formula M m X n T x where M is at least selected from one or a combination of two of Ti, Mo, Sc, Nb, Cr, and 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, and T x is at least selected from O, -OH, -F or -Cl.

[0007] The second aspect of the present application provides a 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.

[0008] The third aspect of the present application provides the use of the bio-based high molecular weight and high transparency polycarbonate in the preparation of various polycarbonate products.

[0009] Compared with the prior art, the present application has at least the following beneficial effects: Firstly, by using the aforementioned MXene material as a catalyst, it plays an efficient catalytic role in both the transesterification and polycondensation steps of the bio-based polycarbonate synthesis process. Therefore, it is not necessary to use different catalysts in the transesterification and polycondensation reactions. And this type of MXene catalyst can rapidly catalyze the transesterification and polycondensation reactions, controlling the polycondensation time within 0.5 h, thereby reducing the occurrence of side reactions and thermal degradation. At the same time, the amount of MXene catalyst used is small, and it has no obvious impact on the thermal stability of the polymer. The bio-based polycarbonate prepared thereby has advantages such as high molecular weight (M w ≥60000) and high transparency (visible light transmittance ≥90%).

[0010] Secondly, in addition to using isosorbide, the synthesis raw materials of the present application may also include other cyclic diols and / or aliphatic diols, etc., such as cyclohexanedimethanol, which has high reactivity and can rapidly grow the molecular chain, thus being conducive to further increasing the molecular weight of the bio-based high molecular weight and high transparency polycarbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to illustrate the present application more clearly, the drawings required for use in the following examples or the description of the prior art will be briefly introduced.

[0012] Figure 1 is the 1 H-NMR spectrum of the bio-based polycarbonate obtained in Example 1; Figure 2 is the 1 H-NMR spectrum of the bio-based polycarbonate obtained in Example 6; Figure 3 is the DSC spectrum of the bio-based polycarbonate obtained in Example 6; Figure 4 is the ultraviolet-visible transmittance curve of the bio-based polycarbonate obtained in Example 6. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] For the existing bio-based polycarbonate synthesis process, it has deficiencies in many aspects. For example: First, the existing synthesis process of isosorbide-based polycarbonate is difficult to prepare isosorbide-based polycarbonate with high molecular weight and high transparency, and there are often problems such as low molecular weight, poor mechanical properties, and dark color.

[0014] Second, the existing industrial melt transesterification process for synthesizing polycarbonate mainly consists of two steps: transesterification and polycondensation. These two process steps usually require catalysts with different properties, and the transesterification catalyst often affects the polycondensation, thereby affecting the quality of the polymer.

[0015] Third, for the existing polycarbonate synthesized using alkali metal catalysts, in order to avoid the influence of residual catalysts on the thermal stability of the polymer after the polycondensation or before processing, a catalyst quenching step often needs to be added. This not only makes the synthesis process more complicated but also affects the quality of the polymer to a certain extent.

[0016] This application mainly synthesizes high molecular weight and high transparency polycarbonate by using the non-phosgene melt transesterification polycondensation method, adding a new two-dimensional metal carbon / nitride (MXene) material as the transesterification and polycondensation catalyst, and using carbonic acid diester as the carbon source, with isosorbide and other diols that are selectively added or not added as raw materials. The technical solutions of this application are specifically described as follows.

[0017] A method for preparing a bio-based high molecular weight and high transparency polycarbonate provided by some embodiments of this application includes: Under the condition of the presence of a catalyst, at least carrying out a melt transesterification reaction and a polycondensation reaction of carbonic acid diester and one or more diols in sequence to obtain the polycarbonate with a molecular weight Mw≥60000 and a visible light transmittance≥90%; Wherein, the catalyst includes an MXene material with the chemical formula M m X n T x M includes one or a combination of two of Ti, Mo, Sc, Nb, Cr, and V, X includes carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, and T x includes O, -OH, -F, or -Cl, and the diol includes isosorbide.

[0018] In some embodiments, the molecular weight M of the polycarbonate w can be above 130000.

[0019] 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, and is not limited thereto.

[0020] Further, the carbonic diester may preferably be selected from dimethyl carbonate and / or diphenyl carbonate, more preferably diphenyl carbonate, which has higher reactivity.

[0021] In one embodiment, the diol further includes a cyclic diol and / or an aliphatic diol other than isosorbide, preferably a cyclic diol, and its cyclic structure has greater rigidity than that of aliphatic diols, and can better maintain the heat resistance of the polycarbonate.

[0022] In one embodiment, the cyclic diol is preferably 1,4-cyclohexanedimethanol. Because of its high reactivity, it can also rapidly grow the molecular chain of the polycarbonate product, thereby further increasing the molecular weight of the bio-based polycarbonate. Exemplarily, the bio-based polycarbonate copolymerized and modified with isosorbide and 1,4-cyclohexanedimethanol can have an Mw of more than 13,000 g / mol.

[0023] Exemplarily, the diol may include, but is not limited to, one or a combination of more than one of the following diols:

[0024] In the present application, the MXene material contains metal elements such as titanium, and not only has the effect of rapidly catalyzing the polycondensation of polymers, but also compared with two-dimensional materials such as graphene and boron nitride, the MXene material is easier to exfoliate and surface modify, and has advantages such as rich surface functional groups, excellent mechanical strength, and conductive and thermal conductive functional properties. Therefore, it can be used as an ideal functional filler remaining after polymer polymerization. In the present application, the MXene material is mainly added during the synthesis process of the bio-based polycarbonate, and it is used as a highly active catalyst to participate in the synthesis reaction of the polycarbonate.

[0025] The MXene material can be obtained from market channels or prepared according to known methods in the art. For example, an etching agent can be used to perform wet chemical etching on the MAX phase material to remove the metal A element therein, thereby preparing the MXene material.

[0026] Further, 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 / 2 V 1 / 2)One or a combination of two or more of 3AlC2, (Cr2 / 3Ti1 / 3)3AlC2, (Mo1 / 2Ti1 / 2)4AlC3, (Mo2 / 3Ti1 / 3)3AlC2, (Mo2 / 3Sc1 / 3)3AlC2, and is not limited thereto.

[0027] Further, the etchant may include one or a combination of two or more of 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 salt-HCl solution, tetrabutylammonium chloride salt-H2SO4 solution, LiF molten salt, NaF molten salt, KF molten salt, dilute HCl, NaOH, NH4Cl, and a mixture of tetramethylammonium hydroxide, and is not limited thereto.

[0028] Further, 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.

[0029] Further, 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 rapidly catalyze transesterification and polycondensation reactions as catalysts, controlling the polycondensation time within 0.5 h, thereby reducing the occurrence of side reactions and thermal degradation.

[0030] In one embodiment, the molar ratio of the carbonic acid diester to the diol is 0.9 to 10:1.

[0031] In one embodiment, the molar ratio of isosorbide to the 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 high bio-based content.

[0032] In one embodiment, the addition amount of the catalyst is 1 ppm to 1000 ppm, preferably 5 to 100 ppm, more preferably 10 to 50 ppm of the theoretical product mass of the preparation method. If the addition amount of the catalyst is too small, the catalytic activity required for the polymerization reaction will be lacking, and if it is too much, it is easy to cause problems such as thermal degradation of the polymer, low molecular weight of the product, and dark color.

[0033] 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 h.

[0034] In one embodiment, the reaction conditions of the polycondensation reaction include: a reaction temperature of 160°C to 280°C, a reaction pressure of 5 Pa to 1000 Pa, and a reaction time of 0.5 h to 8 h.

[0035] In one embodiment, the preparation method specifically includes: subjecting a polymerization reaction system containing uniformly mixed carbonic acid diester, isosorbide, other optional diols that may or may not be added, and a catalyst to the melt transesterification reaction and the polycondensation reaction in sequence.

[0036] Some embodiments of the present application also provide a preparation method of a bio-based high molecular weight and high transparency polycarbonate, which includes: adding MXene material as a catalyst, using carbonic acid diester as a carbon source, using isosorbide and other optional diols that may or may not be added as raw materials, performing a transesterification reaction in a molten state, and then raising the temperature to perform polycondensation under high vacuum conditions to obtain a target product.

[0037] Further, the preparation method may specifically include: uniformly mixing carbonic acid diester with isosorbide and other optional diols that may or may not be added and placing them in a reaction vessel, exhausting the air in the reaction vessel, and filling the reaction vessel with a protective gas (such as an inert gas such as nitrogen, Ar, etc. or a mixed gas thereof), then raising the temperature to make the reaction raw material mixture in a molten state, adding an MXene catalyst, and performing a transesterification reaction under positive pressure, negative pressure, or normal pressure. After the transesterification reaction is completed, raise the temperature in the reaction vessel and reduce the pressure in the reaction vessel, preferably reducing the pressure to form a vacuum environment to promote the polycondensation reaction, and removing small molecule substances in the reaction vessel during this process, and finally obtaining a bio-based polycarbonate.

[0038] Among them, the dosage ratios of carbonic acid diester, isosorbide, other diols, and the MXene catalyst, and the temperature and pressure conditions of the transesterification reaction and the polycondensation reaction are as described above.

[0039] Some embodiments of the present application also provide a bio-based high molecular weight and high transparency polycarbonate prepared by the preparation method of the bio-based high molecular weight and high transparency polycarbonate.

[0040] Some embodiments of the present application also provide a composition, which is used for synthesizing a bio-based polycarbonate and includes the following components: (1) Carbonic acid diester, including but not limited to one or a combination of two or more of diphenyl carbonate, dimethyl carbonate, dibenzyl carbonate, diethyl carbonate, di-tert-butyl carbonate, preferably selected from dimethyl carbonate and / or diphenyl carbonate, and more preferably diphenyl carbonate.

[0041] (2) The first diol, which is selected as isosorbide.

[0042] (3) A second diol that can be selectively added or not added, including but not limited to cyclic diols and / or aliphatic diols other than isosorbide. For example, it can be selected from one or a combination of more than one of the following compounds: ;

[0043] (4) An MXene material as a catalyst. Its chemical formula is M m X n T x , where M is selected from at least one or a combination of two of Ti, Mo, Sc, Nb, Cr, and V, X is selected from at least carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, and T x is selected from at least O, -OH, -F, or -Cl.

[0044] Further, the molar ratio of isosorbide to the carbonate diester is 1 to 10:10, preferably 3 to 10:10.

[0045] Further, the composition contains 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.

[0046] Further, the dosage of the MXene material is 1 ppm to 1000 ppm, preferably 25 to 100 ppm, based on the theoretical yield (by mass) of the bio-based polycarbonate.

[0047] Some embodiments of the present application also provide a use of a class of MXene materials in the catalytic synthesis of bio-based polycarbonates. The chemical formula is M m X n T x of the MXene material, where M can be selected from one or a combination of two of Ti, Mo, Sc, Nb, Cr, and 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, and T x can be selected from O, -OH, -F, or -Cl.

[0048] Further, the MXene material as a catalyst has the advantages of high activity, good selectivity, and strong universality, and can make the molecular weight Mw of the synthesized polycarbonate ≥60000 and the visible light transmittance ≥90%.

[0049] Some embodiments of the present application also provide a use of the bio-based high molecular weight and high transparency polycarbonate in the preparation of products such as fire-fighting equipment, baby bottles, water cups, kitchen electrical products, food packaging materials, hot-filled beverage bottles, optical base films, decorative materials, or automotive parts.

[0050] Some embodiments of the present application also provide a polycarbonate processing method, which includes: feeding the bio-based high molecular weight and high transparency polycarbonate into a co-rotating twin-screw extruder for melt extrusion and pelletizing; wherein, the operating parameters of the co-rotating twin-screw extruder include: the barrel temperature is 215°C to 250°C, and the die head temperature is 215°C to 250°C.

[0051] Some embodiments of the present application also provide a processing method of a polycarbonate film, which includes: Feeding the bio-based high molecular weight and high transparency polycarbonate into a twin-screw extruder, melt extruding at 215°C to 250°C, the melt transfer pump temperature is 215 to 250°C, and making the molten fluid flow-cast onto a rotating cooling drum to obtain a cast sheet with a thickness of 500 μm to 5500 μm; Preheating the cast sheet to 85~170°C and then longitudinally stretching it by 3 to 4 times, and then preheating it again to 85~170°C and transversely stretching it by 3 to 4.5 times to obtain a polycarbonate film. The ultraviolet-visible light transmittance of the polycarbonate film is greater than 90%, and it also has good mechanical properties, etc. For example, its tensile modulus can reach 2510 ± 134 Pa, and the breaking strength can reach 55 ± 2 Mpa.

[0052] There is no particular limitation on the rotation speed of the cooling drum, and it can be adjusted according to actual needs.

[0053] To more clearly understand the purpose, technical solution and advantages of the present application, the following will further explain and illustrate the technical solution, its implementation process and principle, etc. in combination with embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present application more thorough and comprehensive.

[0054] In the following embodiments, a nuclear magnetic resonance spectrometer (Bruker, 600 MHz AVANCE NEO 600) was used to measure the nuclear magnetic resonance hydrogen spectrum ( 1 1H-NMR). Deuterated chloroform (CDCl 3) 3) was used as the solvent.

[0055] In the following examples, a differential scanning calorimeter (METTLER TOLEDO DSC3+) was used to test the thermal transition properties. The N2 atmosphere, the temperature range was 25°C - 250°C, and the heating rate was 10°C / min. The test temperature program was as follows: (1) Heat from 25°C to 250°C at a heating rate of 10°C / min; (2) Hold at 250°C for 3 min; (3) Cool from 250°C to 25°C at a cooling rate of 10°C / min; (4) Hold at 25°C for 3 min; (5) Heat from 25°C to 250°C at a heating rate of 10°C / min.

[0056] In the following examples, a high-temperature gel permeation chromatograph (Agilent, 1260 HT Infinity II) was used to determine the weight-average molecular weight (Mw) of polycarbonate. The sample was prepared with HPLC-grade chloroform at a concentration of 1 mg·mL -1 . The mobile phase was HPLC-grade chloroform, and the flow rate was 1 mL·min -1 .

[0057] In the following examples, a UV-Vis-NIR spectrophotometer (Lambda 950) was used to measure the transmittance. The wavelength range was 200 - 800 nm, and the sample was a film with a thickness of about 200 μm.

[0058] In the following examples, unless otherwise specified, the raw materials and equipment used could be purchased from the market.

[0059] In the following examples, the MXene materials used were all prepared by wet chemical etching of MAX phase materials with an etchant until the metal A element therein was removed. The specific raw material types and etching conditions are shown in Table 1 below, where the etchant should be at least sufficient to completely immerse the MAX phase materials when in liquid form.

[0060] Table 1 Preparation process conditions of MXene materials in Examples 1 - 15

[0061] After the above wet chemical etching was completed, the obtained products were characterized by an X-ray diffractometer and a scanning electron microscope, and it was confirmed that they were all MXene materials with the expected chemical composition.

[0062] In the following, the technical solutions, implementation processes, principles, etc. of the present application will be further explained and illustrated in combination with examples.

[0063] Example 1 Diphenyl carbonate and isosorbide were added to a reaction kettle in a molar ratio of 1:1, and 20 ppm of MXene material was added as a catalyst. The chemical formula of this MXene material was Ti3C2Tx After the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2, repeating three times or more to exhaust the residual air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 180 °C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 220 °C, and gradually reduce the pressure in the reaction kettle. When the distillation amount of the by-product phenol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0064] Subsequently, further increase the temperature in the reaction kettle to 260 °C, and evacuate to a pressure within 1000 Pa in the reaction kettle within 30 min. After the polycondensation is completed, a bio-based polycarbonate is obtained, and the structure is as shown in formula (I): ; wherein, z is an integer from 10 to 1000.

[0065] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 66555, the light transmittance is about 92%, and the glass transition temperature (T g ) is about 164 °C. The 1 1H-NMR spectrum of this bio-based polycarbonate is as Figure 1 shown.

[0066] Example 2 Add dimethyl carbonate and isosorbide to the reaction kettle according to a molar ratio of 10:1, and add 1000 ppm of MXene material as a catalyst. The chemical formula of this MXene material is Ti4N3T x . After the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2, repeating three times or more to exhaust the residual air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 80 °C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 90 °C, and gradually reduce the pressure in the reaction kettle. When the distillation amount of the by-product methanol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0067] Subsequently, further increase the temperature in the reaction kettle to 240 °C, and evacuate to a pressure of 20 Pa in the reaction kettle within 8 h. After the polycondensation is completed, a bio-based polycarbonate is obtained.

[0068] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 62532, the light transmittance is about 91%, and the glass transition temperature (T g ) is about 164 °C.

[0069] Example 3 Add diethyl carbonate and isosorbide to the reaction kettle in a molar ratio of 1:1, and add 20 ppm of MXene material as a catalyst. The chemical formula of this MXene material is Ti2CT x After the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2. Repeat this process three times or more to exhaust the residual air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 150 °C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 180 °C, and gradually reduce the pressure in the reaction kettle. When the distillation amount of the by-product ethanol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0070] Subsequently, further increase the temperature in the reaction kettle to 240 °C, evacuate to a pressure of 20 Pa in the reaction kettle within 30 min. After the polycondensation is completed, a bio-based polycarbonate is obtained.

[0071] After testing, the molecular weight Mw of the polycarbonate obtained in this example is about 63,842, the light transmittance is about 91%, and the glass transition temperature (Tg) is about 164 °C.

[0072] Example 4 Add dibenzyl carbonate and isosorbide to the reaction kettle in a molar ratio of 1:1, and add 20 ppm of MXene material as a catalyst. The chemical formula of this MXene material is Ti3(C, N)2T x After the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2. Repeat this process three times or more to exhaust the residual air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 150 °C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 180 °C, and gradually reduce the pressure in the reaction kettle. When the distillation amount of the by-product benzyl alcohol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0073] Subsequently, further increase the temperature in the reaction kettle to 240 °C, evacuate to a pressure of 20 Pa in the reaction kettle within 30 min. After the polycondensation is completed, a bio-based polycarbonate is obtained.

[0074] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 65,079, the light transmittance is about 91%, and the glass transition temperature (T g ) is about 164 °C.

[0075] Example 5 Add di-tert-butyl carbonate and isosorbide to the reaction kettle in a molar ratio of 1:1, and add 20 ppm of MXene material as a catalyst. The chemical formula of this MXene material is Ti2NT xAfter the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2. Repeat this process three times or more to exhaust the remaining air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 150 °C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 180 °C, and gradually reduce the pressure in the reaction kettle. When the distillation amount of the by-product tert-butanol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0076] Subsequently, further increase the temperature in the reaction kettle to 240 °C, and evacuate to a pressure of 20 Pa in the reaction kettle within 30 min. After the polycondensation is completed, a bio-based polycarbonate is obtained.

[0077] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 65,873, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 164 °C.

[0078] Example 6 Add diphenyl carbonate, isosorbide, and 1,4-cyclohexanedimethanol to the reaction kettle according to a molar ratio of 0.9:0.3:0.7, and add 1 ppm of MXene material as a catalyst. The chemical formula of this MXene material is (Mo2Ti2)C3T x After the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2. Repeat this process three times or more to exhaust the remaining air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 130 °C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 180 °C, and gradually reduce the pressure in the reaction kettle. When the distillation amount of the by-product phenol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0079] Subsequently, further increase the temperature in the reaction kettle to 160 °C, and evacuate to a pressure of 100 Pa in the reaction kettle within 30 min. After the polycondensation is completed, a bio-based polycarbonate is obtained, and the structure is as shown in formula (II): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0080] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 130,701, the light transmittance is about 91%, and the glass transition temperature (T g ) is about 74 °C.

[0081] In this example, the 1 1H-NMR spectrum, DSC spectrum, and ultraviolet-visible transmittance curve of a polycarbonate product are respectively as Figures 2 - 4 shown.

[0082] Example 7 Diphenyl carbonate, isosorbide and 1,4-cyclohexanedimethanol were added to the reaction kettle in 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 feeding, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to exhaust the residual air in the reaction kettle. Subsequently, the temperature was raised. After the raw materials melted at 130 °C, mechanical stirring was started. Subsequently, the temperature in the reaction kettle was gradually raised to 180 °C, and the pressure in the reaction kettle was gradually reduced. When the distillation amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was terminated and the polycondensation stage was entered.

[0083] Subsequently, the temperature in the reaction kettle was further raised to 200 °C, and the pressure in the reaction kettle was evacuated to 100 Pa within 30 min. After polycondensation, a bio-based polycarbonate was obtained.

[0084] After testing, the molecular weight M of the polycarbonate obtained in this example w was approximately 91,691, the light transmittance was approximately 91%, and the glass transition temperature (T g ) was approximately 124 °C.

[0085] Example 8 Diphenyl carbonate, isosorbide and 1,3-cyclohexanedimethanol were added to the reaction kettle in 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 feeding, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to exhaust the residual air in the reaction kettle. Subsequently, the temperature was raised. After the raw materials melted at 140 °C, mechanical stirring was started. Subsequently, the temperature in the reaction kettle was gradually raised to 190 °C, and the pressure in the reaction kettle was gradually reduced. When the distillation amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was terminated and the polycondensation stage was entered.

[0086] Subsequently, the temperature in the reaction kettle was further raised to 250 °C, and the pressure in the reaction kettle was evacuated to 100 Pa within 30 min. After polycondensation, a bio-based polycarbonate was obtained, and the structure is as shown in formula (III): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0087] After testing, the molecular weight M of the polycarbonate obtained in this example wis approximately 88742, the light transmittance is approximately 90%, and the glass transition temperature (T g is approximately 125 °C.

[0088] Example 9 Diphenyl carbonate, isosorbide, and 1,2-cyclohexanedimethanol were added to the reaction kettle in 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 this MXene material is Ti3C2T x . After feeding, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to completely remove the residual air in the reaction kettle. Subsequently, the temperature was raised. After the raw materials melted at 140 °C, mechanical stirring was started. Subsequently, the temperature in the reaction kettle was gradually raised to 190 °C, and the pressure in the reaction kettle was gradually reduced. When the distillate amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was ended and the polycondensation stage was entered.

[0089] Subsequently, the temperature in the reaction kettle was further raised to 250 °C, and the pressure in the reaction kettle was evacuated to 100 Pa within 30 min. After polycondensation, a bio-based polycarbonate was obtained, and its structure is as shown in formula (IV): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0090] After testing, the molecular weight M w of the polycarbonate obtained in this example is 81410, the light transmittance is 90%, and the glass transition temperature (T g ) is 126 °C.

[0091] Example 10 Diphenyl carbonate, isosorbide, and 1,4-cyclohexanediol were added to the reaction kettle 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 this MXene material is two-dimensional material (Ti, V)3C2T x . After feeding, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to completely remove the residual air in the reaction kettle. Subsequently, the temperature was raised. After the raw materials melted at 140 °C, mechanical stirring was started. Subsequently, the temperature in the reaction kettle was gradually raised to 190 °C, and the pressure in the reaction kettle was gradually reduced. When the distillate amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was ended and the polycondensation stage was entered.

[0092] Subsequently, the temperature in the reaction kettle was further raised to 250 °C, and the pressure in the reaction kettle was evacuated to 100 Pa within 30 min. After polycondensation, a bio-based polycarbonate was obtained, and its structure is as shown in formula (V): ; Among them, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0093] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 99867, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 140 °C.

[0094] Example 11 Diphenyl carbonate, isosorbide and dicyclopentyl glycol were added to the reaction kettle 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 this MXene material is (Ti,Nb)2CT x . After the feeding was completed, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to exhaust the residual air in the reaction kettle. Subsequently, the temperature was raised. After the raw materials melted at 150 °C, mechanical stirring was started. Subsequently, the temperature in the reaction kettle was gradually raised to 200 °C, and the pressure in the reaction kettle was gradually reduced. When the distillation amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was terminated and transferred to the polycondensation stage.

[0095] Subsequently, the temperature in the reaction kettle was further raised to 260 °C, and the pressure in the reaction kettle was evacuated to 20 Pa within 30 min. After the polycondensation was completed, a bio-based polycarbonate was obtained, and the structure was as shown in formula (VI): ; Among them, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0096] After testing, the molecular weight M of the polycarbonate obtained in this example w = 87234, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 160 °C.

[0097] Example 12 Diphenyl carbonate, isosorbide and monomethyl dicyclopentyl glycol were added to the reaction kettle 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 this MXene material is (Mo2Sc)C2Tx. After the feeding was completed, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to exhaust the residual air in the reaction kettle. Subsequently, the temperature was raised. After the raw materials melted at 150 °C, mechanical stirring was started. Subsequently, the temperature in the reaction kettle was gradually raised to 200 °C, and the pressure in the reaction kettle was gradually reduced. When the distillation amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was terminated and transferred to the polycondensation stage.

[0098] Subsequently, the temperature in the reaction kettle was further increased to 260 °C, and the pressure in the reaction kettle was evacuated to 20 Pa within 30 min. After the polycondensation was completed, a bio-based polycarbonate was obtained, and its structure was as shown in formula (VII): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0099] After testing, the molecular weight M of the polycarbonate obtained in this example w was approximately 86,871, the light transmittance was approximately 90%, and the glass transition temperature (T g ) was approximately 158 °C.

[0100] Example 13 Diphenyl carbonate, isosorbide and dimethylbicyclopentanediol were added to the reaction kettle 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 this MXene material was Ti3C2T x . After the feeding was completed, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to exhaust the residual air in the reaction kettle. After the feeding was completed, the air in the reaction kettle was evacuated, and then high-purity N2 was introduced. This was repeated three times or more to exhaust the residual air in the reaction kettle. Subsequently, the temperature was increased. After the raw materials melted at 150 °C, mechanical stirring was started, and then the temperature in the reaction kettle was gradually increased to 200 °C, and the pressure in the reaction kettle was gradually decreased. When the distillation amount of phenol reached more than 90% of the theoretical mass, the transesterification reaction was terminated and transferred to the polycondensation stage.

[0101] Subsequently, the temperature in the reaction kettle was further increased to 260 °C, and the pressure in the reaction kettle was evacuated to 20 Pa within 30 min. After the polycondensation was completed, a bio-based polycarbonate was obtained, and its structure was as shown in formula (VIII): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0102] After testing, the molecular weight M of the polycarbonate obtained in this example w was approximately 86,871, the light transmittance was approximately 90%, and the glass transition temperature (T g ) was approximately 155 °C.

[0103] Example 14 Diphenyl carbonate, isosorbide and 2,3,5,6-tetrafluoroterephthalyl alcohol were added to the reaction kettle 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 this MXene material was Ti4C3T xAfter the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2. Repeat this process three times or more to exhaust the residual air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 200°C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 220°C and gradually reduce the pressure in the reaction kettle. When the distillate amount of phenol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0104] Subsequently, further increase the temperature in the reaction kettle to 280°C and evacuate to a pressure of 20 Pa in the reaction kettle within 30 minutes. After the polycondensation is completed, a bio-based polycarbonate is obtained, and its structure is as shown in formula (IX): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0105] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 82541, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 172°C.

[0106] Example 15 Add diphenyl carbonate, isosorbide, and polycyclic aromatic diol to the reaction kettle according to a molar ratio of 1:0.7:0.3, and add 100 ppm of MXene material as a catalyst. The chemical formula of this MXene material is Ti2CT x After the feeding is completed, evacuate the air in the reaction kettle, and then introduce high-purity N2. Repeat this process three times or more to exhaust the residual air in the reaction kettle. Subsequently, start heating. After the raw materials are melted at 150°C, start mechanical stirring. Then, gradually increase the temperature in the reaction kettle to 200°C and gradually reduce the pressure in the reaction kettle. When the distillate amount of phenol reaches more than 90% of the theoretical mass, end the transesterification reaction and transfer to the polycondensation stage.

[0107] Subsequently, further increase the temperature in the reaction kettle to 280°C and evacuate to a pressure of 20 Pa in the reaction kettle within 30 minutes. After the polycondensation is completed, a bio-based polycarbonate is obtained, and its structure is as shown in formula (X): ; wherein, x and y are integers from 1 to 10, and z is an integer from 10 to 1000.

[0108] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 70582, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 178°C.

[0109] Comparative Example 1 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.

[0110] After testing, the molecular weight M of the polycarbonate obtained in this comparative example w is about 49429, the light transmittance is about 87%, and the glass transition temperature (T g ) is about 123 °C.

[0111] Comparative Example 2 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.

[0112] After testing, the molecular weight M of the polycarbonate obtained in this comparative example w is about 9812, the light transmittance is about 81%, and the glass transition temperature (T g ) is about 120 °C. The molecular weight is relatively low, and the polymer state is hard and brittle, making it difficult to form a film.

[0113] Comparative Example 3 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.

[0114] After testing, the molecular weight M of the polycarbonate obtained in this comparative example w is about 41023, the light transmittance is about 86%, and the glass transition temperature (T g ) is about 121 °C.

[0115] Comparative Example 4 The synthesis method of this comparative example is basically the same as that of Example 6, except that the diol only uses 1,4-cyclohexanedimethanol, and other conditions remain unchanged.

[0116] After testing, the molecular weight M of the polycarbonate obtained in this comparative example w is about 150651, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 26 °C, making it difficult to be used in an environment above room temperature.

[0117] Comparative Example 5 The synthesis method of this example is basically the same as that of Example 6, except that 1,4-cyclohexanedimethanol is replaced with the same molar amount of 1,4-butanediol, and other conditions remain unchanged.

[0118] After testing, the molecular weight M of the polycarbonate obtained in this example w is about 105263, the light transmittance is about 90%, and the glass transition temperature (T g ) is about 93 °C.

[0119] It can be concluded from the above examples and comparative examples that the MXene catalyst has high catalytic activity compared with the alkali metal catalyst, and the finally obtained polycarbonate M w ≥60000. And the surface of the MXene material has various functional groups such as -OH, -F, -O, -Cl, etc., which can quickly catalyze the transesterification and polycondensation reactions, control the high-temperature polycondensation time within 1 h, thereby reducing the occurrence of side reactions and thermal degradation. The prepared polycarbonate has a low color value, and the film transmittance at a wavelength of 700 nm is ≥90%.

[0120] The bio-based polycarbonate prepared by the above method can be further processed into the required polycarbonate products according to actual needs in a manner known in the art through a series of processing methods, including but not limited to extrusion granulation, injection molding, film forming, spinning, etc.

[0121] Exemplarily, the bio-based high molecular weight and high transparency polycarbonate prepared in the above example can be input into a co-rotating twin-screw extruder for melt extrusion and granulation; wherein, the working parameters of the co-rotating twin-screw extruder include: the barrel temperature is 215°C to 250°C, and the die head temperature is 215°C to 250°C.

[0122] For example, the bio-based high molecular weight and high transparency 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 finally obtained polycarbonate particles are colorless and transparent.

[0123] Exemplarily, the bio-based high molecular weight and high transparency polycarbonate prepared in the above example can also be prepared into a film or a sheet. Specifically, the bio-based high molecular weight and high transparency polycarbonate can be input into a twin-screw extruder and melt-extruded at 215°C to 250°C. The temperature of the melt transfer pump is 215 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 longitudinally stretched 3 to 4 times, and then preheated to 85~170°C again and transversely stretched 3 to 4.5 times to obtain a polycarbonate film.

[0124] For example, the biobased high molecular weight and high transparency polycarbonate prepared in Example 1 can be fed into a twin-screw extruder and melt-extruded at about 230 °C. Set the temperature of the melt transfer pump to about 220 °C, and allow the molten fluid to flow-cast onto a cooling drum rotating at a low speed (rotation speed about 50 rpm) to obtain a cast sheet with a thickness of about 2 mm. Then, preheat the cast sheet to about 120 °C and longitudinally stretch it 3 times, and then preheat it again to about 120 °C and transversely stretch it 4 times to obtain a polycarbonate film, which 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 about 2500 pa.

[0125] Although the embodiments of the present application have been described in detail above, once those skilled in the relevant art know the creative content and concepts therein, they can make deletions and changes to them, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

[0126] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

Claims

1. A preparation method of a biobased high molecular weight and high transparency polycarbonate, characterized in that, Comprising: In the presence of a catalyst, at least a diester carbonate and one or more diols are successively subjected to melt transesterification reaction and polycondensation reaction to obtain the polycarbonate, wherein the molecular weight Mw of the polycarbonate is ≥60,000, and the visible light transmittance is ≥90%; Among them, the catalyst includes an MXene material with the chemical formula M m X n T x , where M includes one or a combination of two of Ti, Mo, Sc, Nb, Cr, and V, X includes carbon and / or nitrogen, m is any integer from 2 to 4, n is any integer from 1 to 4, and T x includes O, -OH, -F, or -Cl; The diol includes isosorbide.

2. The preparation method according to claim 1, characterized in that: The diester carbonate 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, characterized in that: The diol also includes cyclic diols and / or aliphatic diols other than isosorbide.

4. The preparation method according to claim 3, characterized in that: The diol also includes a combination of one or more of the following diols: 。 5. The preparation method according to claim 1, characterized in that: The surface groups of the MXene material include one or a combination of two or more of -OH, -O, -F, and -Cl.

6. The preparation method according to claim 1, characterized in that: The molar ratio of the diester carbonate to the diol is 0.9 - 10:1; and / or, the molar ratio of isosorbide to the diester carbonate is 0.1 - 1:1; and / or, the addition amount of the catalyst is 1 ppm - 1000 ppm of the theoretical product mass of the preparation method.

7. The preparation method according to claim 1, characterized in that, The reaction conditions of the melt transesterification reaction include: the melting temperature is 80 - 200 °C, the reaction temperature is 90 - 220 °C, and the reaction time is 0.5 - 8 h; and / or, the reaction conditions of the polycondensation reaction include: the reaction temperature is 160 °C - 280 °C, the reaction pressure is 5 Pa - 1000 Pa, and the reaction time is 0.5 h - 8 h.

8. The preparation method according to any one of claims 1 to 7, characterized in that, Specifically including: A polymerization reaction system containing uniformly mixed diester carbonate, isosorbide, optionally added or not added other diols, and a catalyst is successively subjected to the melt transesterification reaction and the polycondensation reaction.

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

10. Use of the bio-based high molecular weight and high transparency polycarbonate according to claim 9 in the preparation of fire-fighting equipment, baby bottles, water cups, kitchen electrical products, food packaging materials, hot-filled beverage bottles, optical base films, decorative materials, or automotive parts.

11. A polycarbonate processing method, characterized in that, Including: Feeding the bio-based high molecular weight and high transparency polycarbonate according to claim 9 into a co-rotating twin-screw extruder for melt extrusion and granulation; wherein, the working parameters of the co-rotating twin-screw extruder include: the barrel temperature is 215 °C - 250 °C, and the die head temperature is 215 °C - 250 °C.

12. A processing method of a polycarbonate film, characterized in that, Including: Feeding the bio-based high molecular weight and high transparency polycarbonate according to claim 9 into a twin-screw extruder, melt extruding at 215 °C - 250 °C, the melt transfer pump temperature is 215 - 250 °C, and the molten fluid is cast onto a rotating cooling drum to obtain a cast sheet with a thickness of 500 μm - 5500 μm; Preheating the cast sheet to 85 - 170 °C and then longitudinally stretching it by 3 - 4 times, and then preheating it again to 85 - 170 °C and transversely stretching it by 3 - 4.5 times to obtain a polycarbonate film.

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