Unsaturated polycarbonate and post-polymerization method thereof

Abstract

The invention discloses unsaturated polycarbonate and a post-polymerization method thereof, and belongs to the technical field of high polymer materials. A double-bond-containing compound is randomly copolymerized on a polycarbonate chain, and the double-bond-containing compound is one or two of a double-bond-containing epoxy compound and a double-bond-containing cyclic anhydride. According to the invention, double bonds are introduced into polycarbonate / polyester through a copolymerization reaction, and carbon dioxide and an unsaturated comonomer are subjected to a copolymerization reaction under the action of a catalyst and an initiator to generate polycarbonate / polyester containing unsaturated double bonds. Due to the existence of the unsaturated double bonds, the material can be subjected to free radical crosslinking, the heat resistance and the mechanical strength of the material are improved, and the material can be used as thermosetting engineering plastic.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and particularly relates to an unsaturated polycarbonate and a post-polymerization method thereof. Background Art

[0002] With the widespread application of polycarbonate materials in various industrial fields, the research and development of new polycarbonates and their manufacturing methods have become important scientific research directions. However, existing polycarbonate materials still have some problems in practical applications. For example, polycarbonates currently on the market generally do not contain unsaturated double bonds, making them incapable of free radical crosslinking. This makes it difficult to further improve the performance of some materials under certain conditions, such as heat resistance and mechanical strength.

[0003] To further enhance the performance of polycarbonate, some manufacturers and research institutions have attempted to improve the overall performance of the material through copolymerization, modification, and other methods. However, these methods often have certain limitations and make it difficult to achieve multifunctionality while maintaining basic performance.

[0004] Publication No. CN115433350B discloses a method for preparing a hyperbranched polysiloxane co-polycarbonate. This invention relates to a method for preparing a hyperbranched polysiloxane co-polycarbonate, wherein a hyperbranched polysiloxane-polycarbonate copolymer is prepared via interfacial oligomerization and chain extension reactions. While this copolymer can significantly reduce torque and melt temperature during processing, it lacks unsaturated double bonds and cannot undergo free radical crosslinking, limiting its application in certain high-performance materials applications.

[0005] Publication number CN109776783B discloses a method for preparing a weather-resistant and solvent-resistant copolycarbonate. This invention relates to a method for preparing a weather-resistant and solvent-resistant copolycarbonate, using an interfacial oligomerization reaction and a chain extension reaction to prepare a polycarbonate-polyorganosiloxane-polyester copolymer. This copolymer exhibits excellent chemical resistance and weatherability, but also lacks unsaturated double bonds and cannot undergo free radical crosslinking, limiting its application in high-performance composite materials.

[0006] These issues demonstrate that existing polycarbonate copolymers have limitations in terms of functionality and performance. Therefore, the present invention provides an unsaturated polycarbonate and a polymerization method thereof. By introducing unsaturated double bonds to achieve free radical crosslinking, the material's heat resistance, mechanical strength, and multifunctionality are further enhanced to meet modern industry's demand for high-performance materials. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an unsaturated polycarbonate having heat resistance, mechanical strength and multifunctionality and a post-polymerization method thereof.

[0008] The technical solution adopted by the present invention to solve the technical problem is: an unsaturated polycarbonate, a double bond-containing compound randomly copolymerized on the polycarbonate chain, and the double bond-containing compound is one or both of a double bond-containing epoxy compound and a double bond-containing cyclic anhydride.

[0009] The double bonds in this invention are introduced into polycarbonate / polyester via copolymerization. Carbon dioxide and an unsaturated comonomer undergo copolymerization in the presence of a catalyst and an initiator to produce a polycarbonate / polyester containing unsaturated double bonds. The presence of these unsaturated double bonds enables free radical crosslinking, improving the material's heat resistance and mechanical strength, enabling its use as a thermosetting engineering plastic.

[0010] The structural formula of the above unsaturated polycarbonate is: ;

[0011] R, R' and R'' are one or more of methyl, ethyl, butyl, butoxymethyl, long-chain alkoxy and olefin groups, wherein at least one of R' and R'' is an olefin group; 1<x<200, 1<y<200, 1<z<50.

[0012] The unsaturated polycarbonate comprises carbon dioxide and at least one unsaturated comonomer, wherein the unsaturated comonomer is one or both of a double-bond epoxy compound and a double-bond cyclic anhydride. The introduction of the unsaturated epoxy compound and the unsaturated cyclic anhydride not only increases the material's reactivity but also facilitates the formation of a complex three-dimensional network structure, further enhancing the material's mechanical properties and thermal stability.

[0013] Specifically, the structural formula includes: 、

[0014] 、

[0015] or

[0016] , where 1<a<200, 1<b<200, 1<c<50, 1<x<200, 1<y<200, 1<z<50.

[0017] Preferably, the double-bond epoxy compound includes one or both of allyl glycidyl ether and 1,2-epoxy-4-vinylcyclohexane. These unsaturated epoxy compounds can effectively react with carbon dioxide during copolymerization to form polycarbonates / polyesters with unsaturated double bonds. The inclusion of allyl glycidyl ether and 1,2-epoxy-4-vinylcyclohexane enhances the material's reactivity and crosslinking density, thereby improving its heat resistance and mechanical strength.

[0018] Preferably, the double-bond cyclic anhydride is at least one of maleic anhydride, citraconic anhydride, nadic anhydride, halogenated maleic anhydride, dimethylmaleic anhydride, dodecenylsuccinic anhydride, itaconic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. These unsaturated cyclic anhydrides can form stable copolymers with carbon dioxide and unsaturated epoxy compounds during the copolymerization process. The introduction of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and maleic anhydride not only increases the reactivity of the material but also helps to form a complex three-dimensional network structure, further improving the mechanical properties and thermal stability of the material.

[0019] A method for preparing the above-mentioned unsaturated polycarbonate, the synthesis route is:

[0020]

[0021] Wherein, R1, R3, and R4 are one or more of methyl, ethyl, butyl, butoxymethyl, and long-chain alkoxy groups, and R2 is an olefin group; R5 and R6 are one or more of methyl, ethyl, butyl, butoxymethyl, long-chain alkoxy groups, and olefin groups, and at least one of R5 and R6 is an olefin group; R is R1 or R2, R' is R3 or R5, and R'' is R4 or R6. It is a saturated cyclic anhydride; It is an unsaturated cyclic anhydride.

[0022] The above preparation method comprises the following steps:

[0023] 1) Add catalyst, initiator and comonomer into the autoclave and react for 4-10 hours under the conditions of carbon dioxide pressure of 1.5MPa-2.5MPa, reaction temperature of 60℃-70℃ and stirring;

[0024] 2) The reaction product is diluted with a solvent and precipitated in ethanol, and then washed to obtain an unsaturated polycarbonate.

[0025] The product after the polymerization is stored in a sol state without undergoing devolatilization and granulation to facilitate subsequent functional modification or cross-linking.

[0026] Preferably, in the above preparation method, the catalyst in step 1) is a metal catalyst or an organoborane catalyst, and the initiator is an aliphatic or aromatic unsaturated organic acid onium salt.

[0027] The catalyst is more preferably an organoborane catalyst to avoid metal residue. The initiator is more preferably tetra-n-butylammonium acetate, tetra-n-butylammonium propionate or tetra-n-butylammonium butyrate.

[0028] The solvent in step 2) is acetone or methanol.

[0029] Preferably, in the above preparation method, the molar ratio of the saturated epoxy compound, saturated cyclic anhydride, double-bond-containing cyclic anhydride, and double-bond-containing epoxy compound in the comonomers described in step 1) is 40-50:0-5:1-20:0-10. By controlling the double bond density in the copolymer through the monomer ratio, the material's hardness can be maintained while avoiding excessive brittleness.

[0030] A post-polymerization method for unsaturated polycarbonate comprises the following steps:

[0031] 1) Add 0-1.0‰ mass fraction of free radical initiator to the above unsaturated polycarbonate, stir and mix at 5°C-40°C to obtain a rubber compound;

[0032] 2) The cross-linked polycarbonate material is obtained by hot pressing.

[0033] The temperature for hot pressing is 150°C to 220°C, which can be adjusted based on the heat deformation temperature of the copolymer obtained from different comonomers. When the material is used as a thermosetting engineering plastic, hot pressing is preferably performed. During the hot pressing process, crosslinking can be achieved through high-temperature-induced free radical polymerization. The addition of a small amount of a high-temperature free radical initiator, such as aryl peroxide (DCBP), can also accelerate the efficiency of crosslinking and curing.

[0034] The present invention significantly improves the material's heat resistance and mechanical strength by introducing unsaturated double bonds to achieve free radical crosslinking. The introduction of unsaturated epoxy compounds and unsaturated cyclic anhydrides increases the material's reactivity, forming a three-dimensional network structure after crosslinking and curing, further enhancing the material's mechanical properties and thermal stability. The preparation method of the present invention is simple, operates under mild reaction conditions, is amenable to large-scale production, and is highly practical and economical.

[0035] In each of the above preparation methods, the vacuum drying process is preferably performed at a temperature of 30°C to 35°C, a vacuum degree of ≤10 Pa, and a drying time of 5 to 6 hours. The primary purpose of preparing a powder by vacuum drying is to facilitate storage and transportation. The powder can be more easily transported to downstream hot pressing companies for production into various finished engineering plastics.

[0036] Compared with the prior art, the present invention has the following beneficial effects: By introducing unsaturated double bonds, the present invention achieves free radical crosslinking, significantly improving the heat resistance and mechanical strength of the material, allowing it to maintain good performance under high temperature and high stress conditions. The introduction of unsaturated epoxy compounds and unsaturated cyclic anhydrides increases the reactivity of the material, helps to form a complex three-dimensional network structure, further improves the mechanical properties and thermal stability of the material, and gives it broad application prospects in the field of high-performance composite materials. The preparation method of the present invention is simple, the reaction conditions are mild, and it is easy to mass-produce. It has strong practicality and economy, and can meet the needs of modern industry for high-performance materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the NMR spectrum of unsaturated polycarbonate copolymerized by EO, MA and CO2.

[0038] Figure 2 This is the NMR spectrum of unsaturated polycarbonate copolymerized by PO, AGE and CO2.

[0039] Figure 3 This is the NMR spectrum of unsaturated polycarbonate copolymerized by PO, PA, THPA and CO2. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below by way of examples. Unless otherwise specified, all raw materials used are commercially available.

[0041] Example 1

[0042] 1) Triethylborane, tetra-n-butylammonium acetate, and a comonomer were added to an autoclave, wherein the molar ratio of propylene oxide, phthalic anhydride, maleic anhydride, and allyl glycidyl ether in the comonomer was 47:2:13:3; and the reaction was carried out under a carbon dioxide pressure of 2.0 MPa, a reaction temperature of 65°C, and stirring for 7 hours;

[0043] 2) diluting the reaction product with methanol and precipitating it in ethanol, and washing it with ethanol to obtain an unsaturated polycarbonate;

[0044] 3) adding 0.5‰ mass fraction of DCBP to the obtained unsaturated polycarbonate, stirring and mixing at 10°C to obtain a rubber compound, and vacuum drying the rubber compound at 30°C and a vacuum degree of 12 Pa for 5.5 hours to obtain a powder;

[0045] 4) The powder is hot-pressed at 180° C. to obtain a molded cross-linked polycarbonate sample.

[0046] Example 2

[0047] 1) Triethylborane, tetra-n-butylammonium acetate, and a comonomer were added to an autoclave, wherein the molar ratio of propylene oxide, phthalic anhydride, and maleic anhydride was 50:2:13. The reaction was continued under stirring at a carbon dioxide pressure of 2.0 MPa, a reaction temperature of 65°C, and a reaction temperature of 65°C for 7 hours.

[0048] 2) diluting the reaction product with methanol and precipitating it in ethanol, and washing it with ethanol to obtain an unsaturated polycarbonate;

[0049] 3) adding 0.5‰ mass fraction of DCBP to the obtained unsaturated polycarbonate, stirring and mixing at 10°C to obtain a rubber compound, and vacuum drying the rubber compound at 30°C and a vacuum degree of 12 Pa for 5.5 hours to obtain a powder;

[0050] 4) The powder is hot-pressed at 180° C. to obtain a molded cross-linked polycarbonate sample.

[0051] Example 3

[0052] 1) Triethylborane, tetra-n-butylammonium acetate, and a comonomer were added to an autoclave, wherein the molar ratio of propylene oxide, 1,2-epoxydodecane, phthalic anhydride, and maleic anhydride was 47:3:2:13. The reaction was continued under a carbon dioxide pressure of 2.0 MPa, a reaction temperature of 65°C, and stirring for 7 hours.

[0053] 2) diluting the reaction product with methanol and precipitating it in ethanol, and washing it with ethanol to obtain an unsaturated polycarbonate;

[0054] 3) adding 0.5‰ by mass of DCBP to the obtained unsaturated polycarbonate, stirring and mixing at 10°C to obtain a rubber compound;

[0055] 4) The rubber compound was directly hot-pressed at 180°C to obtain a molded cross-linked polycarbonate sample.

[0056] Example 4

[0057] 1) Add tributyl boron, tetra-n-butylammonium propionate, and a comonomer to an autoclave, wherein the molar ratio of ethylene oxide, nadic anhydride, and 1,2-epoxy-4-vinylcyclohexane in the comonomer is 50:1:10; and react for 4 hours under a carbon dioxide pressure of 2.5 MPa, a reaction temperature of 60°C, and stirring;

[0058] 2) The reaction product is diluted with methanol and precipitated in ethanol, and then washed to obtain unsaturated polycarbonate.

[0059] 3) The obtained unsaturated polycarbonate was stirred and mixed at 5°C to obtain a rubber compound, and the rubber compound was vacuum dried at 30°C and a vacuum degree of ≤10Pa for 6 hours to obtain a powder;

[0060] 4) The powder is hot-pressed at 150° C. to obtain a molded cross-linked polycarbonate sample.

[0061] Example 5

[0062] 1) Add trimethylboron, tetra-n-butylammonium bromide and a comonomer into an autoclave, wherein the molar ratio of 1,2-butylene oxide, 1,2-epoxydodecane and citraconic anhydride in the comonomer is 30:20:20; react for 10 hours under a carbon dioxide pressure of 1.5 MPa, a reaction temperature of 70°C and stirring;

[0063] 2) The reaction product is diluted with methanol and precipitated in ethanol, and then washed to obtain unsaturated polycarbonate.

[0064] 3) adding 1.0‰ by mass of DCBP to the obtained unsaturated polycarbonate, stirring and mixing at 40°C to obtain a rubber compound;

[0065] 4) The rubber compound was directly hot-pressed at 220°C to obtain a molded cross-linked polycarbonate sample.

[0066] The cross-linked polycarbonate plastic samples prepared in each example were subjected to performance testing. The test results are shown in Table 1. Heat deformation temperature was determined in accordance with GB / T 1634.2, under a load of 1.82 MPa. Thermogravimetric analysis (TGA) was performed under a nitrogen atmosphere at a heating rate of 10°C / min. Tensile strength and elongation at break were determined in accordance with GB / T 1040.2, and flexural strength and modulus were determined in accordance with GB / T 9341. Rockwell hardness was determined in accordance with GB / T 3398.2. Gel content was determined using Soxhlet extraction with toluene solvent and reflux at 80°C for 24 hours.

[0067] Swelling method: Calculate the swelling rate of the sample after the gel content test.

[0068] Table 1 Example test results

[0069] .

[0070] The HDT of each example of the present invention is >140°C, with Example 4, containing nadic anhydride, reaching 160°C. Its tensile strength (65-70 MPa) and flexural strength (95-105 MPa) exceed those of general-purpose engineering plastics. A gel content of >96% and a low degree of swelling (<25%) demonstrate a dense cross-linked structure and strong resistance to solvent attack. Example 3, which incorporates a long-chain epoxy monomer (1,2-epoxydodecane), achieves an elongation at break of 15%, maintaining strength while improving toughness, making it suitable for impact-resistant components. Due to their rigid ring structures, Examples 4 (nadic anhydride) and 5 (citraconic anhydride) achieve Td5% >300°C, making them suitable for high-temperature environments.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. An unsaturated polycarbonate, characterized in that A double bond-containing compound is randomly copolymerized on the polycarbonate chain, and the double bond-containing compound is one or both of a double bond-containing epoxy compound and a double bond-containing cyclic acid anhydride.

2. The unsaturated polycarbonate according to claim 1, characterized in that: The structural formula is: ; R, R' and R'' are one or more of methyl, ethyl, butyl, butoxymethyl, long-chain alkoxy and olefin groups, wherein at least one of R' and R'' is an olefin group; 1<x<200, 1<y<200, 1<z<50.

3. The unsaturated polycarbonate according to claim 2, characterized in that: The structural formula includes: 、 、 or , where 1<a<200, 1<b<200, 1<c<50, 1<x<200, 1<y<200, 1<z<50.

4. The unsaturated polycarbonate according to claim 1, characterized in that: The molar ratio of the double bond-containing compound in all comonomers of the polycarbonate is 1% to 25%; the double bond-containing epoxy compound includes one or two of allyl glycidyl ether and 1,2-epoxy-4-vinylcyclohexane.

5. The unsaturated polycarbonate according to claim 1, characterized in that: The double bond-containing cyclic anhydride is at least one of maleic anhydride, citraconic anhydride, nadic anhydride, halogenated maleic anhydride, dimethylmaleic anhydride, dodecenylsuccinic anhydride, itaconic anhydride, cis-1,2,3,6-tetrahydrophthalic anhydride and methyltetrahydrophthalic anhydride.

6. The unsaturated polycarbonate according to claim 1, characterized in that: The synthetic route is: ; wherein R1, R3, and R4 are one or more of methyl, ethyl, butyl, butoxymethyl, and long-chain alkoxy groups, and R2 is an olefin group; R5 and R6 are one or more of methyl, ethyl, butyl, butoxymethyl, long-chain alkoxy groups, and olefin groups, and at least one of R5 and R6 is an olefin group; R is R1 or R2, R' is R3 or R5, and R'' is R4 or R6, It is a saturated cyclic anhydride; It is an unsaturated cyclic anhydride.

7. The unsaturated polycarbonate according to claim 6, characterized in that: The preparation method comprises the following steps: 1) Add catalyst, initiator and comonomer into the autoclave and react for 4-10 hours under the conditions of carbon dioxide pressure of 1.5MPa-2.5MPa, reaction temperature of 60℃-70℃ and stirring; 2) The reaction product is diluted with a solvent and precipitated in ethanol, and then washed to obtain an unsaturated polycarbonate.

8. The method for preparing an unsaturated polycarbonate according to claim 7, wherein: The catalyst in step 1) is a metal catalyst or an organic borane catalyst; the initiator is an aliphatic or aromatic unsaturated organic acid onium salt.

9. The method for preparing an unsaturated polycarbonate according to claim 7, wherein: The molar ratio of the saturated epoxy compound, the saturated cyclic anhydride, the double-bond-containing cyclic anhydride and the double-bond-containing epoxy compound in the comonomer described in step 1) is 40-50:0-5:1-20:0-10.

10. A post-polymerization method for unsaturated polycarbonate, characterized in that: The following steps are involved: 1) adding 0-1.0‰ mass fraction of a free radical initiator to the unsaturated polycarbonate obtained according to any one of claims 7-9, stirring and mixing at 5°C-40°C to obtain a rubber compound; 2) The cross-linked polycarbonate material is obtained by hot pressing.

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