BPA-PC degradation method and application of BPA-PC degradation method in preparation of epoxy thermosetting resin

Abstract

The invention discloses a BPA-PC degradation method and application of the BPA-PC degradation method in preparation of epoxy thermosetting resin, and belongs to the technical field of polymer composite material depolymerization and recycling. According to the method, degradation of BPA-PC and synthesis of epoxy thermosetting resin are coupled, efficient upgrading and recycling of BPA-PC plastic are achieved, and a new way is developed for chemical recycling of waste plastic. According to the invention, diphenyl carbonate is used as a depolymerization reagent to realize depolymerization of BPA-PC, and the obtained depolymerization product is directly used as a curing agent of epoxy resin without separation and purification to prepare high-performance and recoverable epoxy thermosetting resin. The process does not involve excessive reaction reagents, and a depolymerization product can be directly reused, so that 100% of atom utilization rate is realized. In addition, the prepared epoxy thermosetting resin has good comprehensive performance such as mechanical performance, thermal performance and dynamic performance, meanwhile, carbonic ester bonds are reserved in the structure of the epoxy thermosetting resin, and chemical circulation can be achieved.

Description

Technical Field

[0001] The invention relates to a BPA-PC degradation method and application thereof in manufacturing epoxy thermosetting resin, belonging to the technical field of depolymerization, recovery and reuse of polymer composite materials. Background Art

[0002] Bisphenol A polycarbonate (BPA-PC), as an important engineering plastic, is widely used in various fields such as packaging and automotive parts, and is used in huge quantities worldwide. However, since waste BPA-PC will slowly release eco-toxic bisphenol A into the environment, the recycling of BPA-PC is extremely important.

[0003] Chemical recycling is an effective means to achieve the recycling of BPA-PC. However, in previous reports on the chemical recycling of BPA-PC, nucleophilic reagents were mostly used to attack carbonate bonds, and they were used as a green source of carbonyl groups to synthesize carbonyl-containing chemicals, accompanied by the generation of polymerized monomer bisphenol A. For example, patent CN 113912559 B reported that the product oxazolidinone can be obtained by alcoholysis of ethanolamine, a highly nucleophilic reagent. Although these carbonyl-containing depolymerization products are said to have high added value, their real application market needs further consideration, and whether the recycling process is truly economical compared to the conventional production methods of these chemicals has not been tested. Therefore, it is very necessary to provide a method that does not require a complicated separation process and does not require additional excess reaction reagents, and the depolymerization products can be efficiently reused, thereby achieving efficient upgrading and recycling of BPA-PC plastics. Summary of the invention

[0004] Aiming at the problem of efficient upgrading and recycling of existing BPA-PC plastics, the present invention provides a method for preparing epoxy thermosetting resin using degradation products of BPA-PC, and couples the degradation of BPA-PC with the synthesis of epoxy thermosetting resin to achieve efficient upgrading and recycling of BPA-PC plastics.

[0005] The technical solution of the present invention:

[0006] One of the purposes of the present invention is to provide a BPA-PC degradation method, which comprises mixing BPA-PC with diphenyl carbonate, adding a depolymerization catalyst, heating the mixture to react, and obtaining a depolymerization product, which is used as an epoxy resin curing agent.

[0007] Further defined, the number average molecular weight of BPA-PC is 10 2 ~10 7 g / mol.

[0008] It is further defined that the amount of diphenyl carbonate is 10 to 100% of the amount of BPA-PC.

[0009] It is further defined that the depolymerization catalyst is one or more combinations of sodium hydroxide, potassium hydroxide, sodium phenolate, and potassium phenolate.

[0010] It is further defined that the amount of the depolymerization catalyst is 0.01 to 1% of the molar amount of the BPA-PC repeating unit.

[0011] It is further defined that the heating reaction temperature is 100 to 250° C. and the time is 1 to 24 hours.

[0012] The second object of the present invention is to provide an application of the above-mentioned BPA-PC degradation method in the manufacture of epoxy thermosetting resin, and the application method comprises the following steps:

[0013] (1) mixing BPA-PC and diphenyl carbonate, adding a depolymerization catalyst, heating and reacting to obtain a depolymerization product;

[0014] (2) The depolymerization product, epoxy resin and curing catalyst are mixed and heated to obtain epoxy thermosetting resin.

[0015] It is further defined that the curing catalyst in (2) is 4-dimethylaminopyridine DMAP or pyridine, and the mass of the curing catalyst added is 0.01-1% of the mass of the epoxy resin.

[0016] It is further defined that the molar ratio of the epoxy groups of the epoxy resin to the carbonate groups in the depolymerization product in (2) is 1:1.

[0017] It is further defined that the epoxy resin in (2) is a compound containing two or more epoxy groups in its molecular structure.

[0018] Further limiting, the epoxy resin is bisphenol A diglycidyl ether, the structure of which is shown below:

[0019]

[0020] It is further defined that the curing temperature in (2) is 80 to 250° C. and the curing time is 1 to 24 hours.

[0021] Beneficial effects:

[0022] The present invention couples the degradation of BPA-PC with the synthesis of epoxy thermosetting resin, realizes the efficient conversion of BPA-PC into epoxy thermosetting material, and opens up a new way for the chemical recycling of waste plastics. At the same time, this process does not require the separation and purification of the degradation products of BPA-PC, and does not involve excessive reaction reagents. The depolymerization products can be directly and efficiently reused, achieving 100% atomic utilization. In addition, the epoxy thermosetting resin prepared by the present invention has good comprehensive properties such as mechanical properties, thermal properties, and dynamic properties. At the same time, the carbonate bond is retained in its structure, and chemical recycling can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram showing the dynamic thermomechanical analysis test results of the thermosetting epoxy resin obtained in Example 1;

[0024] Figure 2 The stress-strain curve result diagram of the thermosetting epoxy resin obtained in Example 1;

[0025] Figure 3 This is a graph showing the thermal gravimetric analysis test results of the thermosetting epoxy resin obtained in Example 1. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0029] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art, and the purity of the solid and liquid reagents used is analytically pure.

[0030] Example 1

[0031] The reaction process of preparing epoxy thermosetting resin using the degradation product of BPA-PC in this embodiment is as follows:

[0032]

[0033] The specific operation process is as follows:

[0034] PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) was weighed and added into a 50 mL round-bottom flask; BPA-PC pellets (molecular weight 21000 g / mol, molecular weight distribution 2.3) (10 g, 0.039 mol, 1 equiv.) and DPC (8.43 g, 0.039 mol, 1 equiv.) were weighed and added into the flask, and the reaction was stirred at 200° C. for 4 h to obtain the depolymerization product DPC-PC.

[0035] Weigh DPC-PC (6 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved until the system is a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by staged temperature rise to obtain a thermosetting epoxy resin. Curing conditions: under argon atmosphere, 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) → 200°C (2h) → 220°C (2h).

[0036] The obtained thermosetting epoxy resin was tested for properties by dynamic thermomechanical analyzer. The results are as follows: Figure 1 As shown in Figure 2, its glass transition temperature is 146°C, the storage modulus at room temperature is 2.9 GPa, and the crosslinking density is 2170 mol / m 3 The stress-strain curve was analyzed by tensile test. The test results are as follows: Figure 2 As shown, the breaking strength is 71MPa and the breaking elongation is 9.5%. Through thermogravimetric analysis, the test results are as follows Figure 3 As shown, the 5% mass loss temperature was measured to be 352°C.

[0037] Example 2

[0038] The difference between this embodiment and embodiment 1 is that a BPA-PC water bucket (molecular weight 25500 g / mol, molecular weight distribution 2.5) is used to replace the BPA-PC pellets.

[0039] The specific operation process is as follows:

[0040] Weigh PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) and add it into a 50 mL round-bottom flask; weigh BPA-PC (molecular weight 25500 g / mol, molecular weight distribution 2.5) (10 g, 0.039 mol, 1 equiv.) and DPC (8.43 g, 0.039 mol, 1 equiv.) and add them into the flask, stir and react at 200 °C for 8 h to obtain the depolymerization product DPC-PC.

[0041] Weigh DPC-PC (6 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved until the system is a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by staged temperature rise to obtain a thermosetting epoxy resin. Curing conditions: under argon atmosphere, 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) → 200°C (2h) → 220°C (2h).

[0042] The obtained thermosetting epoxy resin was tested for properties. The dynamic thermomechanical analyzer showed that its glass transition temperature was 145°C, the storage modulus at room temperature was 2.8 GPa, and the crosslinking density was 2180 mol / m 3 ; The stress-strain curve was analyzed by tensile test, and the breaking strength was measured to be 70MPa and the breaking elongation was 9.8%. The 5% mass loss temperature was measured to be 355℃ by thermogravimetric analysis.

[0043] Example 3

[0044] The difference between this embodiment and embodiment 1 is that BPA-PC discs (molecular weight 14500 g / mol, molecular weight distribution 2.3) are used to replace BPA-PC pellets.

[0045] The specific operation process is as follows:

[0046] Weigh PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) and add it into a 50 mL round-bottom flask; weigh BPA-PC disc (molecular weight 14500 g / mol, molecular weight distribution 2.3) (10 g, 0.039 mol, 1 equiv.) and DPC (8.43 g, 0.039 mol, 1 equiv.) and add them into the flask, stir and react at 200 ° C for 8 h to obtain the depolymerization product DPC-PC.

[0047] Weigh DPC-PC (6 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved until the system is a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by staged temperature rise to obtain a thermosetting epoxy resin. Curing conditions: under argon atmosphere, 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) → 200°C (2h) → 220°C (2h).

[0048] The obtained thermosetting epoxy resin was tested for properties. The dynamic thermomechanical analyzer showed that its glass transition temperature was 141°C, the storage modulus at room temperature was 2.7 GPa, and the crosslinking density was 1970 mol / m 3 ; The stress-strain curve was analyzed through tensile test, and its breaking strength was measured to be 68MPa and the breaking elongation was 8.3%; through thermogravimetric analysis, its 5% mass loss temperature was measured to be 348℃.

[0049] Example 4

[0050] The difference between this example and Example 1 is that the amount of DPC used is 0.020 mol (4.22 g, 0.5 equiv.).

[0051] The specific operation process is as follows:

[0052] PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) was weighed and added into a 50 mL round-bottom flask; BPA-PC pellets (molecular weight 21000 g / mol, molecular weight distribution 2.3) (10 g, 0.039 mol, 1 equiv.) and DPC (4.22 g, 0.020 mol, 0.5 equiv.) were weighed and added into the flask, and the reaction was stirred at 200 ° C for 8 h to obtain the depolymerization product DPC-PC-2.

[0053] Weigh DPC-PC-2 (6.16 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved until the system is a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by step-by-step temperature increase to obtain a thermosetting epoxy resin. Curing conditions: under argon atmosphere, 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) → 200°C (2h) → 220°C (2h).

[0054] The obtained thermosetting epoxy resin was tested for properties. The dynamic thermomechanical analyzer showed that its glass transition temperature was 149°C, the storage modulus at room temperature was 2.8 GPa, and the crosslinking density was 2210 mol / m 3 ; Through tensile test, the stress-strain curve was analyzed and its breaking strength was measured to be 69MPa and the breaking elongation was 8.9%; through thermogravimetric analysis, its 5% mass loss temperature was measured to be 357℃.

[0055] Example 5

[0056] The difference between this embodiment and embodiment 1 is that the depolymerization temperature is 180° C. and the depolymerization time is 8 h.

[0057] The specific operation process is as follows:

[0058] PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) was weighed and added into a 50 mL round-bottom flask; BPA-PC pellets (molecular weight 21000 g / mol, molecular weight distribution 2.3) (10 g, 0.039 mol, 1 equiv.) and DPC (8.43 g, 0.039 mol, 1 equiv.) were weighed and added into the flask, and the reaction was stirred at 180 ° C for 8 h to obtain the depolymerization product DPC-PC.

[0059] Weigh DPC-PC (6 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved until the system is a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by staged temperature rise to obtain a thermosetting epoxy resin. Curing conditions: under argon atmosphere, 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) → 200°C (2h) → 220°C (2h).

[0060] The obtained thermosetting epoxy resin was tested for properties. The dynamic thermomechanical analyzer showed that its glass transition temperature was 143°C, the storage modulus at room temperature was 2.7 GPa, and the crosslinking density was 2310 mol / m 3 ; The stress-strain curve was analyzed through tensile test, and its breaking strength was measured to be 68MPa and the breaking elongation was 8.1%; through thermogravimetric analysis, its 5% mass loss temperature was measured to be 346℃.

[0061] Example 6

[0062] The difference between this embodiment and embodiment 1 is that the depolymerization temperature is 160° C. and the depolymerization time is 15 h.

[0063] The specific operation process is as follows:

[0064] PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) was weighed and added into a 50 mL round-bottom flask; BPA-PC pellets (molecular weight 21000 g / mol, molecular weight distribution 2.3) (10 g, 0.039 mol, 1 equiv.) and DPC (8.43 g, 0.039 mol, 1 equiv.) were weighed and added into the flask, and the reaction was stirred at 160 ° C for 15 h to obtain the depolymerization product DPC-PC.

[0065] Weigh DPC-PC (6 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved until the system is a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by staged temperature rise to obtain a thermosetting epoxy resin. Curing conditions: under argon atmosphere, 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) → 200°C (2h) → 220°C (2h).

[0066] The obtained thermosetting epoxy resin was tested for properties. The dynamic thermomechanical analyzer showed that its glass transition temperature was 149°C, the storage modulus at room temperature was 2.9 GPa, and the crosslinking density was 2290 mol / m 3 ; The stress-strain curve was analyzed through tensile test, and its breaking strength was measured to be 70MPa and the breaking elongation was 8.3%; through thermogravimetric analysis, its 5% mass loss temperature was measured to be 353℃.

[0067] Example 7

[0068] The difference between this embodiment and embodiment 1 is that the curing conditions of this embodiment are: under argon atmosphere, 80℃(4h)→120℃(2h)→140℃(2h)→160℃(2h)→180℃(2h).

[0069] The specific operation process is as follows:

[0070] PhONa (2.28 mg, 0.02 mmol, 0.05% equiv.) was weighed and added into a 50 mL round-bottom flask; BPA-PC pellets (molecular weight 21000 g / mol, molecular weight distribution 2.3) (10 g, 0.039 mol, 1 equiv.) and DPC (8.43 g, 0.039 mol, 1 equiv.) were weighed and added into the flask, and the reaction was stirred at 180 ° C for 8 h to obtain the depolymerization product DPC-PC.

[0071] Weigh DPC-PC (6 g, 12.8 mmol, 1 equiv.) and DGEBA (4.36 g, 12.8 mmol, 1 equiv.) into a round-bottom flask, add 31 g of anhydrous THF and dissolve evenly to make a 25% wt solution, weigh DMAP (10.9 mg, 0.25% wt epoxy) into the flask, and after DMAP is completely dissolved to form a homogeneous solution, cast the solution into a tetrafluoroethylene mold, and after the THF solvent evaporates and dries, place the sample in a vacuum drying oven at 60°C for 12 hours to degas; after the degassing is completed, the sample is cured by step-by-step temperature rise to obtain a thermosetting epoxy resin. Curing conditions: 80°C (4h) → 120°C (2h) → 140°C (2h) → 160°C (2h) → 180°C (2h) under argon atmosphere.

[0072] The obtained thermosetting epoxy resin was tested for properties. The dynamic thermomechanical analyzer showed that its glass transition temperature was 136°C, the storage modulus at room temperature was 2.5 GPa, and the crosslinking density was 1850 mol / m 3 ; The stress-strain curve was analyzed through tensile test, and its breaking strength was measured to be 64MPa and the breaking elongation was 5.7%; through thermogravimetric analysis, its 5% mass loss temperature was measured to be 333℃.

[0073] Although the present invention has been disclosed as above in the preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A BPA-PC degradation method, characterized in that: BPA-PC is mixed with diphenyl carbonate, a depolymerization catalyst is added, and the mixture is heated for reaction to obtain a depolymerization product, which is used as an epoxy resin curing agent.

2. The BPA-PC degradation method according to claim 1, characterized in that: The number average molecular weight of BPA-PC is 10 2 ~10 7 g / mol.

3. The BPA-PC degradation method according to claim 1, characterized in that: The amount of diphenyl carbonate is 10 to 100% of the amount of BPA-PC.

4. The BPA-PC degradation method according to claim 1, characterized in that: The depolymerization catalyst is one or more combinations of sodium hydroxide, potassium hydroxide, sodium phenolate and potassium phenolate.

5. The BPA-PC degradation method according to claim 1 or 4, characterized in that: The amount of the depolymerization catalyst is 0.01 to 1% of the molar amount of the BPA-PC repeating unit.

6. The BPA-PC degradation method according to claim 1 or 4, characterized in that: The heating reaction temperature is 100-250°C and the time is 1-24h.

7. A method for preparing an epoxy thermosetting resin, characterized in that: include: (1) using the BPA-PC degradation method described in claim 1 to obtain a depolymerized product; (2) The depolymerization product, epoxy resin and curing catalyst are mixed and heated to obtain epoxy thermosetting resin.

8. The method for preparing the epoxy thermosetting resin according to claim 7, characterized in that: (2) The curing catalyst is 4-dimethylaminopyridine DMAP or pyridine, and the mass of the curing catalyst added is 0.01-1% of the mass of the epoxy resin.

9. The method for preparing the epoxy thermosetting resin according to claim 7, characterized in that: (2) The molar ratio of the epoxy groups of the epoxy resin to the carbonate groups in the depolymerization product is 1:

1.

10. The method for preparing the epoxy thermosetting resin according to claim 7, characterized in that: (2) Epoxy resins are compounds containing two or more epoxy groups in their molecular structure.

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