Isosorbide type block copolycarbonate as well as preparation method and application thereof

Abstract

The invention discloses isosorbide type block copolycarbonate as well as a preparation method and application thereof, and belongs to the technical field of organic polymer materials. The problems that isosorbide polycarbonate in the prior art is low in molecular weight, deep in color and luster, fragile in material and the like are solved. The preparation method comprises the following steps: carrying out melt ester exchange polycondensation reaction on dihydric alcohol and isosorbide carbonate serving as raw materials to obtain dihydroxyl-terminated isosorbide ester glycol; rigid amorphous dihydroxyl-terminated isosorbide ester glycol and oligomeric flexible chain dihydric alcohol are connected together, and a molecular chain is reformed, arranged and branched to a certain extent, so that the isosorbide type block copolycarbonate is effectively synthesized. According to the method, the oligomeric flexible chain dihydric alcohol can be effectively introduced to improve the molecular weight and the mechanical property of the isosorbide polycarbonate, so that the problems that the isosorbide polycarbonate is too strong in structural rigidity, fragile in material, deep in color and the like in production and application are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic polymer materials, and specifically relates to an isosorbide type block copolycarbonate and a preparation method and application thereof. Background Art

[0002] In recent years, isosorbide (IS), as a bio-based renewable monomer, is non-toxic and harmless, and is currently the most promising key raw material for synthesizing polycarbonate to replace bisphenol A. The copolymerized isosorbide-type polycarbonate (IS-PC) synthesized by using diphenyl carbonate as a raw material has non-toxicity and excellent optical properties, scratch resistance, thermal stability, biodegradability and biocompatibility, and has shown good application prospects in packaging, automobiles, electronic appliances, biomedicine and other fields. However, DPC is prepared from DMC, which has a long process flow and its market price is much higher than DMC; at the same time, a large amount of high-boiling point byproduct phenol will be produced during the reaction, which will affect the material properties and endanger people's health; while the method of preparing IS-PC with DMC as raw material has the advantages of short process, low production cost and environmental friendliness. With the continuous innovation of catalytic technology and process, it will become the most promising and competitive preparation route of IS-PC. However, so far, there are still many difficulties in the preparation and modification of IS-PC by dimethyl carbonate. This is because its IS is easy to deliquesce, has large steric hindrance, has a large difference in the activity of internal and external hydroxyl groups, and dimethyl carbonate (DMC) has a low boiling point. At the same time, its carbonyl carbon and methyl carbon have strong electrophilicity, which leads to a large number of by-products in the ester exchange reaction process and poor condensation efficiency.

[0003] At present, the modification of isosorbide-type polycarbonate basically uses the melt transesterification polycondensation method. Although this method is simple and does not use toxic solvents, the soft chain diol used in this reaction process has low activity. At the same time, the reaction temperature of this method is high, the reaction time is long, and it is easy to cause side reactions, resulting in low molecular weight and dark color of its copolymerized isosorbide-type polycarbonate, which especially limits its application in the optical field. At the same time, although this method can regulate the mechanical properties of IS-PC, the content of the introduced soft chain diol is difficult to control. The introduction of less soft chain diol does not effectively improve its toughness, but instead leads to a significant decrease in the Tg of the copolymerized isosorbide-type polycarbonate, and the introduction of too many soft chains will also lead to a significant decrease in the mechanical strength of the copolymerized isosorbide-type polycarbonate.

[0004] Therefore, the synthesis of isosorbide-based block copolycarbonate using a melt / solution chain extension modification method has important scientific significance and research value. Summary of the invention

[0005] Aiming at the problems of low molecular weight, dark color, brittle material and the like in the prior art of preparing isosorbide type polycarbonate by DMC method, the present invention provides an isosorbide type block copolycarbonate and a preparation method and application thereof.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An isosorbide-based block copolycarbonate, the structural formula of which is as follows:

[0008]

[0009] Wherein, m and n are both natural numbers greater than 0, and R represents at least one functional group.

[0010] After adopting the technical scheme, the isosorbide type block copolycarbonate provided by the present invention has good mechanical properties, thereby solving the problems of too strong structural rigidity, brittle material, dark color, etc. in the production and application of isosorbide type polycarbonate.

[0011] Preferably, the preparation raw materials include: isosorbide carbonate, diol, oligomeric diol, catalyst and chain extender.

[0012] Preferably, the molar ratio of isosorbide carbonate to diol is 1:(1-2), and the mass ratio of isosorbide carbonate to catalyst is 100:(0.01-1);

[0013] Isosorbide carbonate reacts with diol to obtain dihydroxy-terminated isosorbide diol, wherein the molar ratio of the dihydroxy-terminated isosorbide diol to the oligomeric diol is 1:(0.1-0.5), and the molar ratio of the terminal hydroxyl group of the isosorbide diol to the chain extender is 1:(1-2).

[0014] Preferably, the molar ratio of isosorbide carbonate to diol is 1:(1-1.5).

[0015] Preferably, the molecular weight of the dihydroxy-terminated isosorbide diol is 1000-6000 g / mol, and more preferably 1000-3000 g / mol.

[0016] Preferably, the diol is a straight-chain diol, an ester ring diol, or an aromatic diol, preferably one or more of ethylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, cyclohexanediol, tricyclododecanedimethanol, dodecanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, spirocyclic diol, hydroquinone bis(hydroxyethyl) ether, resorcinol bis(hydroxyethyl) ether, bisphenol A, terephthalene alcohol, bisether fluorene, and bisphenol fluorene;

[0017] The oligomeric diol is one or more of polycarbonate diol, polyethylene glycol, polypropylene glycol, polypentylene glycol, polyethylene glycol, polyheptylene glycol, polyoctanediol, polytetramethylene ether glycol, polylactide, polyglycolide, polycaprolactone, and polytetrahydrofuran;

[0018] The chain extender is one of hexamethylene diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane-4,4-diisocyanate, hydrogenated xylylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-pentane diisocyanate, 1,4-phenylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, norbornane dimethylene isocyanate, lysine diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4-diisocyanate, lysine diisocyanate, methylcyclohexyl diisocyanate and cyclohexane dimethyl diisocyanate;

[0019] The catalyst is a solid base catalyst.

[0020] A method for preparing an isosorbide-based block copolycarbonate comprises the following steps:

[0021] S1: subjecting isosorbide carbonate and diol to a melt transesterification polycondensation reaction under the action of a catalyst to obtain dihydroxy-terminated isosorbide ester diol;

[0022]

[0023] S2: The obtained dihydroxy-terminated isosorbide ester diol and oligomeric diol are subjected to melt / solution chain extension under the action of a chain extender to synthesize an isosorbide-type block copolycarbonate.

[0024]

[0025] After adopting the technical scheme, the present invention uses the melt / solution chain extension method to synthesize isosorbide type block copolycarbonate for the first time. This method can effectively reduce the reaction temperature and shorten the reaction time, while also increasing the reaction rate and reducing the occurrence of side reactions. Under the action of the chain extender, this method connects the rigid amorphous dihydroxy-terminated isosorbide ester diol and the oligomeric flexible chain diol to effectively synthesize isosorbide type block copolycarbonate. This method can increase the molecular weight of isosorbide type polycarbonate by introducing the oligomeric flexible chain diol through the chain extender, and reorganize and arrange its molecular chain and branch it to a certain extent, effectively improving the mechanical properties of the material.

[0026] Preferably, the temperature of the ester exchange reaction in the melt ester exchange polycondensation reaction in S1 is 90-180°C, and the temperature time of the ester exchange reaction is 1-5h; it can be further preferably that the temperature of the ester exchange reaction is 130-160°C, and the temperature time of the ester exchange reaction is 2-4h.

[0027] The temperature of the polycondensation reaction is 170-220°C, and the polycondensation reaction time is 1-5h; it may be further preferred that the temperature of the polycondensation reaction is 180-200°C, and the polycondensation reaction time is 1-2h;

[0028] The stirring speed of the reaction is 100-400 rpm, and more preferably 200 rpm.

[0029] Preferably, the temperature of the melt chain extension in S2 is 90-180°C, the reaction time is 10-60 min, and the reaction stirring speed is 100-400 rpm. It may be further preferred that the temperature of the melt chain extension is 130-150°C, the reaction time is 10-20 min, and the reaction stirring speed is 200 rpm.

[0030] Preferably, the solvent used for chain extension in the solution in S2 is one of tetrahydrofuran, toluene, chloroform, tetrachloromethane, and NN-dimethylformamide;

[0031] The temperature of the solution chain extension is 50-130° C., the reaction time is 1-6 hours, and the reaction stirring speed is 10-100 rpm.

[0032] It is further preferred that the temperature of the solution chain extension is 60-120° C., the reaction time is 2-4 h, and the reaction stirring speed is 20 rpm.

[0033] The invention discloses an application of isosorbide type block copolycarbonate in optical film or food packaging.

[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] 1. The preparation method of the dihydroxy-terminated polyisosorbide carbonate diol of the present invention is a melt transesterification polycondensation method. The method uses isosorbide carbonate diol and diols of different structures as raw materials to synthesize polyisosorbide carbonate diols of different hydroxyl groups. Isosorbide carbonate can effectively improve the problems of poor reaction rate in the polymerization process caused by isosorbide due to its easy deliquescence and low activity. By introducing diols of different structures, the structure of polyisosorbide carbonate diol can be designed, laying a foundation for regulating the performance of isosorbide-type block copolycarbonate.

[0036] 2. The present invention uses the method of melt / solution chain extension to modify isosorbide-type polycarbonate for the first time. This invention can effectively reduce the reaction temperature and shorten the reaction time, while also increasing the reaction rate and reducing the occurrence of side reactions; under the action of a chain extender, this method connects the rigid amorphous polyisosorbide carbonate diol and the oligomeric flexible chain diol and reorganizes and arranges the molecular chain and branches it to a certain extent, effectively synthesizing isosorbide-type block copolycarbonate. This method can effectively introduce oligomeric flexible chain diols to increase the molecular weight and mechanical properties of isosorbide-type polycarbonate, thereby solving the problems of too strong structural rigidity, brittle materials, and dark color in the production and application of isosorbide-type polycarbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The raw material isosorbide carbonate used in the present invention is 1 H-NMR spectrum;

[0038] Figure 2 The raw material isosorbide carbonate used in the present invention is 13 C-NMR spectrum;

[0039] Figure 3 is the mass spectrum of isosorbide carbonate, a raw material used in the present invention;

[0040] Figure 4 The isosorbide type block copolycarbonate obtained by using 1,4-cyclohexane as diol and polyethylene glycol 1000 as oligomeric diol in the present invention is 1 H-NMR spectrum. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0042] The raw material isosorbide carbonate in the following examples and comparative examples is homemade in the laboratory, and its preparation method is as follows:

[0043] Under nitrogen atmosphere, 5 g of isosorbide (Jinan Yuteng Pharmaceutical Co., Ltd.), 30 g of dimethyl carbonate (Chengdu Longke Chemical Co., Ltd.) (the molar ratio of isosorbide to dimethyl carbonate is 1:10) and 0.01 g of catalyst 40%-KF / MgO-500°C were added into a three-necked flask equipped with a magnetic stirrer, and the reaction was carried out for 6 hours at an ester exchange temperature of 120 degrees Celsius and a stirring speed of 20 rpm. The ester exchange reaction liquid was filtered and distilled under reduced pressure to obtain isosorbide carbonate, the structural formula of which is as follows:

[0044]

[0045] The hydrogen spectrum, carbon spectrum and mass spectrum were tested and the results were as follows: Figure 1-3 As shown, where:

[0046] 1 HNMR (400MHz, CDCl3): d=5.09–5.04(m,2H),4.87(t,1H),4.53(d,1H),4.08–4.00(m,2H),3.93–3.85(m,2H),3.80(s,3H),3.78ppm(s,3H);

[0047] 13 C NMR (400MHz, CDCl3): d=155.14,154.82,85.88,81.25,80.90,76.81,73.26,70.52,55.18,55.14ppm;

[0048] HRMS (ESI) m / z: 262.07;

[0049] Combination Figure 1 The hydrogen spectrum of Figure 2 The carbon spectrum and Figure 3 The mass spectrum of isosorbide carbonate was proved to be synthesized, and its molecular formula is: 10 H 14 O8.

[0050] Preparation method of the solid base catalyst used:

[0051] 4g of KF (Shanghai Adamas Reagent Co., Ltd.) was added to 6g of nano-MgO (Shanghai Dibai Biotechnology Co., Ltd.), and 10g of deionized water was added. After magnetic stirring for three hours, it was placed in a 100°C oven and dried for 12 hours to obtain a solid. After grinding, the solid powder was placed in a muffle furnace and calcined at a set temperature of 500°C for 5 hours to obtain the catalyst 40%-KF / MgO-500°C.

[0052] Example 1

[0053] An isosorbide type block copolycarbonate, the preparation method of which is as follows: comprising the following steps:

[0054] S1: Add isosorbide carbonate and 1,4-cyclohexanedimethanol (Shanghai Aladdin Biochemical Technology Co., Ltd.) in a molar ratio of 1:1.2 into a three-necked flask, and add the above-prepared KF / MgO as a catalyst (the dosage is 0.05%wt), start the ester exchange at 130°C, and heat to 180°C after 4 hours of reaction; carry out polycondensation at 180°C, slowly reduce the pressure during the polycondensation reaction until the pressure drops to 100pa, react for 1 hour, wash out the precipitate, and obtain dihydroxy-terminated isosorbide ester diol. The number average molecular weight of dihydroxy-terminated isosorbide ester diol obtained by gel chromatography is: 1279g / mol.

[0055] S2: Melt chain extension reaction: The dihydroxy-terminated isosorbide diol and polyethylene glycol 1000 (Wuxi Yatai United Chemical Co., Ltd.) obtained in S1 were added to a glass bottle at a molar ratio of 7:3, replaced with N2 gas three times, and heated to 160°C under N2 atmosphere. After the mixture was completely melted, it was opened and operated at 200 rpm for 10 minutes to mix the two hydroxyl-terminated prepolymers evenly, and then a predetermined amount (molar ratio of hydroxyl to chain extender 1:1.2) of chain extender (hexamethylene diisocyanate) was added to the flask, and the mechanical stirring rate was maintained at 150-300 r / min. After vigorous stirring and reaction for 10 minutes, isosorbide-type block copolycarbonate was obtained. The obtained product was dissolved in dichloromethane, and then coprecipitated and purified twice with methanol, and then placed in a vacuum oven at 80°C for drying for more than 4 hours until constant weight. The weight average molecular weight of the isosorbide type block copolycarbonate was measured by gel chromatography to be 57965 g / mol, and its molecular formula was:

[0056]

[0057] like Figure 4 The results show that the synthesis of isosorbide-based block copolycarbonate ( Figure 4 The letters in the formula correspond to the letters in the molecular formula one by one), where: 1H NMR (400MHz, CDCl3, d, ppm): 0.91–2.01 (m, 10H,), 3.6 (m, 4H, PEG), 3.84–4.14 (m, 8H, isosorbide-ring, H1, H6,), 4.48–4.62 (m, 1H, H4, isosorbide), 4.88 (m, 1H, H3, isosorbide), 5.06–5.16 (m, 2H, H2, H5, isosorbide).

[0058] Example 2

[0059] This embodiment is basically the same as embodiment 1, except that: this embodiment adopts solution chain extension, specifically as follows: the dihydroxy-terminated isosorbide ester diol obtained in S1 and polyethylene glycol 1000 are dissolved in 10 ml of tetrahydrofuran at a molar ratio of 7:3, replaced with N2 gas three times, and heated to 55°C under N2 atmosphere. After the mixture is completely dissolved in the organic solvent, the magnetic stirring of 30prm is turned on to make the mixture evenly mixed, and then a predetermined amount (molar ratio of hydroxyl to chain extender 1:1.2) of chain extender (hexamethylene diisocyanate) is added, and after reacting for 2 hours, methanol is used for coprecipitation to obtain isosorbide-type block copolycarbonate, which is placed in a vacuum oven at 80°C and dried for more than 4 hours until constant weight, and its weight average molecular weight is measured by gel chromatography test to be 59840g / mol.

[0060] Example 3

[0061] This embodiment is basically the same as embodiment 1, except that the molar ratio of dihydroxy-terminated isosorbide diol and polyethylene glycol 1000 is 8:2. The weight average molecular weight of the melt-extended product measured by gel chromatography is 78960 g / mol.

[0062] Example 4

[0063] This embodiment is basically the same as embodiment 2, except that the molar ratio of dihydroxy-terminated isosorbide diol and polyethylene glycol 1000 is 8:2. The weight average molecular weight of the solution chain extension was measured by gel chromatography and was 75130 g / mol.

[0064] Preparation Example 5

[0065] This embodiment is basically the same as embodiment 1, except that the molar ratio of dihydroxy-terminated isosorbide diol and polyethylene glycol 1000 is 9:1. The weight average molecular weight of the melt-extended product measured by gel chromatography is 59513 g / mol.

[0066] Example 6

[0067] This embodiment is basically the same as embodiment 2, except that the molar ratio of dihydroxy-terminated isosorbide diol and polyethylene glycol 1000 is 9:1. The weight average molecular weight of the solution chain extension was measured by gel chromatography and was 57950 g / mol.

[0068] Example 7

[0069] This preparation example is basically the same as Example 1, except that: the preparation of isosorbide diol uses 1,4-butanediol (Chengdu Cologne Chemicals Co., Ltd.) as the diol, potassium carbonate solid catalyst (Shanghai MacLean Biochemical Technology Co., Ltd.) as the catalyst, the molar ratio of isosorbide carbonate to 1,4-butanediol is 1:1.3, and the final weight average molecular weight obtained by melt chain extension is 72331 g / mol.

[0070] Example 8

[0071] This embodiment is basically the same as 7, except that the weight average molecular weight of the solution chain extension measured by gel chromatography is 78938 g / mol.

[0072] Example 9

[0073] This preparation example is basically the same as Example 1, except that the molar ratio of isosorbide carbonate to 1,4-phenylenediol (Shanghai Aladdin Biochemical Technology Co., Ltd.) is 1:1.2, and the final weight average molecular weight after melt chain extension is 56138 g / mol.

[0074] Example 10

[0075] This embodiment is basically the same as embodiment 1, except that: oligomeric diol-polycarbonate diol 2000 (Chengdu Kelong Chemical Co., Ltd.) is used, and the molar ratio of Chengdu dihydroxy-terminated isosorbide diol and polycarbonate diol 2000 is 9:1. The weight average molecular weight of the solution chain extension measured by gel chromatography is 65321 g / mol.

[0076] Embodiment 11

[0077] This embodiment is basically the same as embodiment 1, except that: oligomeric diol-polycaprolactone diol 2000 (Tianjin Xienen Biotechnology Co., Ltd.) is used, and the molar ratio of dihydroxy-terminated isosorbide diol and polycaprolactone diol 2000 is 8:2. The weight average molecular weight of the solution chain extension measured by gel chromatography is 59612 g / mol.

[0078] Comparative Example 1

[0079] An isosorbide type block copolycarbonate, the preparation method of which is as follows: comprising the following steps:

[0080] S1: Add isosorbide carbonate and 1,4-cyclohexanedimethanol in a molar ratio of 1:1.1 into a three-necked flask, add KF / MgO as a catalyst (dosage is 0.05%wt), start ester exchange at 130℃, and heat to 180℃ after 4 hours of reaction; carry out polycondensation at 180℃, slowly reduce pressure during the polycondensation until the pressure drops to 100pa, react for 1 hour, wash out the precipitate, and obtain dihydroxy-terminated isosorbide ester diol. The number average molecular weight of dihydroxy-terminated isosorbide ester diol obtained by gel chromatography is: 1384g / mol.

[0081] S2: Melt chain extension reaction: Add the dihydroxy-terminated isosorbide ester diol and polyethylene glycol 1000 obtained in S1 in a molar ratio of 1:1 into a glass bottle, replace with N2 gas three times, and heat to 160°C in an N2 atmosphere. After the mixture is completely melted, open and stir at 200rpm for 10min to mix the two hydroxyl-terminated prepolymers evenly, then add a predetermined amount (molar ratio of hydroxyl to chain extender 1:1.1) of chain extender (diphenylmethane diisocyanate) into the flask, and keep the mechanical stirring rate at 150-300r / min, stir vigorously and react for 35 minutes to obtain isosorbide-type block copolycarbonate. After dissolving the obtained product in dichloromethane, coprecipitate and purify it twice with methanol, put it in a vacuum oven at 80°C and dry it for more than 4h until constant weight. The weight average molecular weight of isosorbide-type block copolycarbonate measured by gel chromatography is 48690g / mol.

[0082] Comparative Example 2

[0083] This comparative example is basically the same as comparative example 1, except that: this example adopts solution chain extension, specifically as follows: the dihydroxy-terminated isosorbide ester diol obtained in S1 and polyethylene glycol 1000 are dissolved in 10 ml of tetrahydrofuran in a molar ratio of 1:1, replaced with N2 gas three times, and heated to 55°C under N2 atmosphere. After the mixture is completely dissolved in the organic solvent, turn on the magnetic stirring at 30rpm to make the two reactants mix evenly, then add a predetermined amount (molar ratio of hydroxyl to chain extender 1:1.1) of chain extender (diphenylmethane diisocyanate), react for 2h, and then coprecipitate with methanol to obtain isosorbide-type block copolycarbonate, put it into a vacuum oven at 80°C and dry it for more than 4h until constant weight, and its weight average molecular weight is measured by gel chromatography test to be 47890g / mol.

[0084] Comparative Example 3

[0085] This comparative example is basically the same as Example 1, except that: no oligomeric diol is used to modify it, and the dihydroxy-terminated isosorbide diol is directly added to the chain extender for melt chain extension. The weight average molecular weight of the solution chain extension is measured by gel chromatography and is 26985 g / mol.

[0086] Comparative Example 4

[0087] This comparative example is basically the same as Example 1, except that only the oligomeric diol-polyethylene glycol 1000 is used to directly add the chain extender for melt chain extension, and no dihydroxy-terminated isosorbide diol is added. The weight average molecular weight of the solution chain extension is measured by gel chromatography test to be 23654 g / mol.

[0088] The isosorbide block copolycarbonate prepared in Examples 1-11 and Comparative Examples 1-4 was used to prepare a film of modified isosorbide block copolycarbonate with a width of 2 cm and a thickness of 0.5 mm in accordance with ISO 527-1:2012. The elongation at break and tensile strength of the modified material were measured using an electronic universal testing machine (NKK 3010D). The parameter changes of Examples 1-11 and Comparative Examples 1-4 are shown in Table 1, and the test results are shown in Table 2:

[0089] Table 1

[0090]

[0091] Note: The diols used in the examples are 1,4-cyclohexanedimethanol, 1,4-butanediol, and 1,4-phenylenediol; the oligomeric diols are polyethylene glycol 1000, polycaprolactone diol, and polycarbonate diol; and the amount of the solid base catalyst used is 0.05%wt.

[0092] Table 2

[0093]

[0094]

[0095] As can be seen from Table 1 and Table 2, the use of melt / solution chain extension can effectively introduce a third monomer to modify isosorbide polycarbonate. The mechanical properties and molecular weight of block copolymer isosorbide polycarbonate can be regulated by controlling the content of end-capped hydroxyl groups, the types and proportions of diols and oligomeric diols, and the amount of chain extender. In general, the higher the molecular weight, the better the comprehensive performance of block copolymer isosorbide polycarbonate. The introduction of flexible chains within a certain range can significantly improve the elongation at break of the material, but excessive introduction will reduce the Tg of the material to below room temperature, making it impossible to measure its mechanical properties. The introduction of benzene rings will also reduce the light transmittance of the material.

[0096] The above-mentioned embodiments only express the specific implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the protection scope of the present application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the technical solution concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. An isosorbide-based block copolycarbonate, characterized in that: Its structural formula is as follows: Wherein, m and n are both natural numbers greater than 0, and R represents at least one functional group.

2. An isosorbide-based block copolycarbonate according to claim 1, characterized in that: The preparation raw materials include: isosorbide carbonate, diol, oligomeric diol, catalyst and chain extender.

3. An isosorbide-based block copolycarbonate according to claim 2, characterized in that: The molar ratio of isosorbide carbonate to diol is 1:(1-2), and the mass ratio of isosorbide carbonate to catalyst is 100:(0.01-1); Isosorbide carbonate reacts with diol to obtain dihydroxy-terminated isosorbide diol, wherein the molar ratio of the dihydroxy-terminated isosorbide diol to the oligomeric diol is 1:(0.1-0.5), and the molar ratio of the terminal hydroxyl group of the isosorbide diol to the chain extender is 1:(1-2).

4. An isosorbide-based block copolycarbonate according to claim 3, characterized in that: The molecular weight of the dihydroxy-terminated isosorbide diol is 1000-6000 g / mol.

5. An isosorbide-based block copolycarbonate according to any one of claims 2 to 4, characterized in that: The diol is one or more of a linear diol, an alicyclic diol, and an aromatic diol; The oligomeric diol is one or more of polycarbonate diol, polyethylene glycol, polypropylene glycol, polypentylene glycol, polyethylene glycol, polyheptylene glycol, polyoctanediol, polytetramethylene ether glycol, polylactide, polyglycolide, polycaprolactone, and polytetrahydrofuran; The chain extender is one of hexamethylene diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane-4,4-diisocyanate, diphenylmethane-2,4-diisocyanate, hydrogenated xylylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-pentane diisocyanate, 1,4-phenylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, norbornane diisocyanate, lysine diisocyanate, 1,4-cyclohexane diisocyanate, dicyclohexylmethane-4,4-diisocyanate, lysine diisocyanate, methylcyclohexyl diisocyanate and cyclohexane dimethyl diisocyanate; The catalyst is a solid base catalyst.

6. A method for preparing an isosorbide-based block copolycarbonate, characterized in that: The following steps are involved: S1: subjecting isosorbide carbonate and diol to a melt transesterification polycondensation reaction under the action of a catalyst to obtain dihydroxy-terminated isosorbide ester diol; S2: melt / solution chain extension is performed on the obtained dihydroxy-terminated isosorbide ester diol and oligomeric diol under the action of a chain extender to synthesize the isosorbide-based block copolycarbonate as described in any one of claims 1 to 5.

7. The method for preparing an isosorbide-based block copolycarbonate according to claim 6, characterized in that: The temperature of the ester exchange reaction in the melt ester exchange polycondensation reaction in S1 is 90-180°C, and the temperature and time of the ester exchange reaction is 1-5h; The temperature of the polycondensation reaction is 170-220°C, and the polycondensation reaction time is 1-5h; The stirring speeds for both the transesterification reaction and the polycondensation reaction were 100-400 rpm.

8. The method for preparing an isosorbide-based block copolycarbonate according to claim 6, characterized in that: The temperature of melt chain extension in S2 is 90-180°C, the reaction time is 10-60min, and the speed of reaction stirring is 100-400rpm.

9. The method for preparing an isosorbide-based block copolycarbonate according to claim 6, characterized in that: The solvent used for solution chain extension in S2 is one of tetrahydrofuran, toluene, chloroform, tetrachloromethane, and NN-dimethylformamide; The temperature of the solution chain extension is 50-130° C., the reaction time is 1-6 hours, and the reaction stirring speed is 10-100 rpm.

10. Use of the isosorbide type block copolycarbonate according to any one of claims 1 to 5 in optical films or food packaging.

Images