A chain extender for polyglycolic acid and a preparation method and application thereof, and a polyglycolic acid modification method

Abstract

The application belongs to the field of polymer material preparation, and relates to a chain extender for polyglycolic acid modification and a preparation method and application thereof, and a polyglycolic acid modification method. The chain extender contains structural units shown in formula (1), formula (2) and formula (3); in formula (3), X is selected from C1-C6 alkyl, preferably C3-C5 alkyl. The application introduces styrene structural units and silicon-containing monomers into the macromolecular structure of glycidyl methacrylate, the introduction of the silicon-containing monomers can improve the toughness of the modified polyglycolic acid, so that the modified polyglycolic acid has plasticity, the bulk density is increased, and then the compressive strength of the polyglycolic acid as a temporary plugging agent is improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation, specifically relating to a chain extender for polyglycolic acid modification, its preparation method and application, and a method for polyglycolic acid modification. Background Technology

[0002] Polyglycolic acid (PGA) is a synthetic polymer material with good biodegradability and biocompatibility. Unlike traditional polymer materials such as synthetic resins, rubber, and fibers, PGA's biodegradability is similar to that of natural cellulose. It can degrade under composting conditions for 3-4 months, breaking down into water and carbon dioxide that are harmless to humans, animals, plants, and the natural environment. PGA molecules are unbranched, with regular and dense chain arrangement and a well-defined crystalline structure, resulting in high mechanical properties, making it suitable as a high-strength, pressure-resistant material for applications such as oil and gas extraction.

[0003] Polyglycolic acid (PEG) is mainly used in oil and gas extraction as a temporary plugging agent and plugging ball. Its excellent mechanical properties result in high compressive strength, which can effectively seal formation channels and blast holes. However, due to its high strength and brittleness, PEG fracture during application will significantly affect its compressive strength, leading to a short effective working time. Summary of the Invention

[0004] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a chain extender for modifying polyglycolic acid and its preparation method, which can effectively improve the mechanical properties of polyglycolic acid, thereby extending its degradation time and expanding its application in the field of oil and gas extraction.

[0005] To achieve the above objectives, a first aspect of the present invention provides a chain extender for modifying polyglycolic acid, the chain extender comprising the structural units shown in formula (1), formula (2) and formula (3);

[0006]

[0007] In formula (3), X is selected from C1-C6 alkyl groups, preferably C3-C5 alkyl groups.

[0008] A second aspect of the present invention provides a method for preparing a chain extender for polyglycolic acid modification, comprising the following steps:

[0009] Step 1: Add the monomers with the structures shown in formula (4), formula (5) and formula (6) into the polymerization reactor and stir to mix evenly;

[0010] Step 2: Add the accelerator to the polymerization reactor, stir to dissolve, and obtain a stable solution;

[0011] Step 3: Add the initiator to the polymerization reactor, stir and mix evenly, and heat to the first reaction condition to carry out the reaction;

[0012] Step 4: Continue heating to the second reaction conditions to carry out the reaction and obtain the chain extender;

[0013]

[0014] In formula (6), X is selected from C1-C6 alkyl groups, preferably C3-C5 alkyl groups.

[0015] A third aspect of the present invention provides a chain extender for polyglycolic acid modification prepared by the aforementioned preparation method.

[0016] A fourth aspect of the invention provides the application of the chain extender described above for polyglycolic acid modification in the modification of polyglycolic acid.

[0017] A fifth aspect of the present invention provides a method for modifying polyglycolic acid, comprising: mixing polyglycolic acid with a chain extender, wherein the chain extender is the chain extender described above for modifying polyglycolic acid.

[0018] The present invention has the following effects:

[0019] This invention introduces styrene structural units and silicon-containing monomers into the macromolecular structure of glycidyl methacrylate. The introduction of silicon-containing monomers can improve the toughness of modified polyglycolic acid, making it plastic, increasing the bulk density, and thus improving the compressive strength of polyglycolic acid as a temporary plugging agent.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] To achieve the above objectives, a first aspect of the present invention provides a chain extender for modifying polyglycolic acid, the chain extender comprising the structural units shown in formula (1), formula (2) and formula (3);

[0023]

[0024] In formula (3), X is selected from C1-C6 alkyl groups, preferably C3-C5 alkyl groups.

[0025] According to the present invention, preferably, based on the total weight of the chain extender, the content of the structural unit shown in formula (1) is 50.6-54% by weight, the content of the structural unit shown in formula (2) is 18-28% by weight, and the content of the structural unit shown in formula (3) is 20-28% by weight.

[0026] More preferably, based on the total weight of the chain extender, the content of the structural unit shown in formula (1) is 50.6-53.6% by weight, the content of the structural unit shown in formula (2) is 22-25% by weight, and the content of the structural unit shown in formula (3) is 23-26% by weight.

[0027] A second aspect of the present invention provides a method for preparing a chain extender for polyglycolic acid modification, comprising the following steps:

[0028] Step 1: Add the monomers with the structures shown in formula (4), formula (5) and formula (6) into the polymerization reactor and stir to mix evenly;

[0029] Step 2: Add the accelerator to the polymerization reactor, stir to dissolve, and obtain a stable solution;

[0030] Step 3: Add the initiator to the polymerization reactor, stir and mix evenly, and heat to the first reaction condition to carry out the reaction;

[0031] Step 4: Continue heating to the second reaction conditions to carry out the reaction and obtain the chain extender;

[0032]

[0033] In formula (6), X is selected from C1-C6 alkyl groups, preferably C3-C5 alkyl groups.

[0034] According to the present invention, preferably, before step 1, the monomers with the structures shown in formula (4), formula (5) and formula (6) are purified by vacuum distillation and cooled to 0-10°C.

[0035] In this invention, a specially designed polymerization reactor is equipped with a high-torque stirring paddle to enhance mass and heat transfer, prevent coking, and ensure smooth material discharge; at the same time, a gas phase condenser is installed at the top of the polymerization reactor to achieve precise temperature control of bulk polymerization.

[0036] According to the present invention, preferably, in the first step, based on the total mass percentage of the reactant monomers being 100%, the amount of monomers added to the structure shown in formula (4) is 50.6-54% by weight, the amount of monomers added to the structure shown in formula (5) is 18-28% by weight, and the amount of monomers added to the structure shown in formula (6) is 20-28% by weight.

[0037] More preferably, based on the total mass percentage of the reacting monomers being 100%, the amount of monomers added to the structure shown in formula (4) is 50.6-53.6% by weight, the amount of monomers added to the structure shown in formula (5) is 22-25% by weight, and the amount of monomers added to the structure shown in formula (6) is 23-26% by weight.

[0038] According to the present invention, preferably, in step 2, the accelerator is 1,3-bis(trimethoxyurea).

[0039] In this invention, the introduction of a silicon-containing promoter into the polymerization system can improve the activity of monomers in free molecular polymerization, causing them to be randomly and uniformly distributed on the macromolecular chain, further increasing the glass transition temperature of the polymer product, and obtaining a polymerizable chain extender, which is beneficial for improving the modification and processing of polyglycolic acid.

[0040] According to the present invention, preferably, the amount of the accelerator added is 0.1%-0.3% of the total mass of the reactants.

[0041] According to the present invention, preferably, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, benzoyl peroxide, tert-butyl peroxide, and dicumyl peroxide.

[0042] According to the present invention, preferably, the amount of the initiator added is 0.7%-1.5% of the total mass of the reactants.

[0043] According to the present invention, preferably, in step 3, before adding the initiator, nitrogen gas is first bubbled into the polymerization reactor and maintained for at least 30 minutes.

[0044] According to the present invention, preferably, the first reaction conditions include: a temperature of 90-110°C, more preferably 98-106°C, and a time of 30-60 minutes, more preferably 40-50 minutes.

[0045] According to the present invention, preferably, step 4 further includes pulverizing the polymer obtained from the reaction to obtain the chain extender.

[0046] According to the present invention, preferably, in step 4, the second reaction conditions include: a temperature of 130-145°C, more preferably 135-142°C, and a time of 120-150 minutes, more preferably 132-146 minutes.

[0047] In this invention, the two-step reaction is crucial for improving the monomer conversion rate during the reaction and can effectively avoid phenomena such as explosive polymerization during the polymerization process.

[0048] A third aspect of the present invention provides a chain extender for polyglycolic acid modification prepared by the aforementioned preparation method.

[0049] A fourth aspect of the invention provides the application of the chain extender described above for polyglycolic acid modification in the modification of polyglycolic acid.

[0050] A fifth aspect of the present invention provides a method for modifying polyglycolic acid, comprising: mixing polyglycolic acid with a chain extender, wherein the chain extender is the chain extender described above for modifying polyglycolic acid.

[0051] According to the present invention, preferably, the amount of chain extender added is 1 to 5% based on the total weight of the chain extender and the polyglycolic acid raw material.

[0052] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0053] The molecular weight of the polymer was measured using gel permeation chromatography (PL-gPC20); the glass transition temperature (Tg) of the polymer was tested using differential scanning calorimetry (DSC8500); and the degradation rate of polyglycolic acid was calculated using a hydrothermal reactor. The compressive strength and time of application of polyglycolic acid materials were determined by core displacement physical model test.

[0054] The polyglycolic acid raw material was purchased from Shanghai Pujing Chemical Technology Co., Ltd.

[0055] Component 1: Glycidyl methacrylate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0056] Component 2: Styrene was purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0057] Component 3: X is selected from C1-C6 alkyl groups and purchased from Shanghai Hongzuo Science and Trade Co., Ltd.

[0058] Example 1

[0059] Step 1: The three components purified by vacuum distillation are cooled to 4°C and metered into a specially designed polymerization reactor by a pump. The amount of component 1 added is 270g, the amount of component 2 added is 90g, and the amount of component 3 (X is C1 alkyl) added is 140g. The mixture is stirred thoroughly to dissolve and mix evenly.

[0060] Step 2: Add 0.5g of 1,3-bis(trimethoxyurea) to the polymerization reactor, stir to dissolve, and make it a stable solution;

[0061] Step 3: After blowing nitrogen gas into the polymerization reactor for 30 minutes, add 3.5g of dimethyl azobisisobutyrate, stir to mix evenly, heat the polymerization reactor to 90℃ to initiate polymerization, and turn on the high torque stirrer to react for 60 minutes.

[0062] Step 4: Heat the polymerization reactor to 145°C and react for 120 minutes.

[0063] Step 5: Remove the polymer and pulverize it to obtain a chain extender sample.

[0064] Step 6: The above chain extender and polyglycolic acid raw material are blended by screw compressor to obtain a modified sample with a particle size of 4 mm, wherein the amount of chain extender added is 2.5%.

[0065] The performance test results are shown in Table 1.

[0066] Example 2

[0067] Step 1: The three components purified by vacuum distillation are cooled to 8°C and metered into a specially designed polymerization reactor by a pump. The amount of component 1 added is 268g, the amount of component 2 added is 110g, and the amount of component 3 (X is C3 alkyl) added is 122g. The mixture is stirred thoroughly to dissolve and mix evenly.

[0068] Step 2: Add 1.25g of 1,3-bis(trimethoxysilylurea) to the polymerization reactor, stir to dissolve, and make it a stable solution;

[0069] Step 3: After blowing nitrogen gas into the polymerization reactor for 30 minutes, add 4.5g of azobisisobutyronitrile, stir to mix it evenly, heat the polymerization reactor to 103℃ to initiate polymerization, and turn on the high torque stirrer to react for 40 minutes.

[0070] Step 4: Heat the polymerization reactor to 139°C and react for 140 minutes.

[0071] Step 5: Remove the polymer and pulverize it to obtain a chain extender sample.

[0072] Step 6: The above chain extender and polyglycolic acid raw material are blended by screw compressor to obtain a modified sample with a particle size of 4 mm, wherein the amount of chain extender added is 2.5%.

[0073] The performance test results are shown in Table 1.

[0074] Example 3

[0075] Step 1: The three components purified by vacuum distillation are cooled to 5°C and metered into a specially designed polymerization reactor by a pump. The amount of component 1 added is 253g, the amount of component 2 added is 119g, and the amount of component 3 (X is C3 alkyl) added is 128g. The mixture is stirred thoroughly to dissolve and mix evenly.

[0076] Step 2: Add 1.05g of 1,3-bis(trimethoxyurea) to the polymerization reactor, stir to dissolve, and make it a stable solution;

[0077] Step 3: After blowing nitrogen gas into the polymerization reactor for 30 minutes, add 5.5g of azobisisobutyronitrile, stir to mix it evenly, heat the polymerization reactor to 98℃ to initiate polymerization, and turn on the high torque stirrer to react for 46 minutes.

[0078] Step 4: Heat the polymerization reactor to 142°C and react for 132 minutes.

[0079] Step 5: Remove the polymer and pulverize it to obtain a chain extender sample.

[0080] Step 6: The above chain extender and polyglycolic acid raw material are blended by screw compressor to obtain a modified sample with a particle size of 4 mm, wherein the amount of chain extender added is 2.5%.

[0081] The performance test results are shown in Table 1.

[0082] Example 4

[0083] Step 1: The three components purified by vacuum distillation are cooled to 10°C and metered into a specially designed polymerization reactor by a pump. The amount of component 1 added is 259g, the amount of component 2 added is 125g, and the amount of component 3 (X is C5 alkyl) added is 116g. The mixture is stirred thoroughly to dissolve and mix evenly.

[0084] Step 2: Add 0.8g of 1,3-bis(trimethoxysilylurea) to the polymerization reactor, stir to dissolve, and make it a stable solution;

[0085] Step 3: After blowing nitrogen into the polymerization reactor for 30 minutes, add 6.5g of dicumyl peroxide, stir to mix evenly, heat the polymerization reactor to 106℃ to initiate polymerization, and turn on the high torque stirrer to react for 50 minutes.

[0086] Step 4: Heat the polymerization reactor to 135°C and react for 146 minutes.

[0087] Step 5: Remove the polymer and pulverize it to obtain a chain extender sample.

[0088] Step 6: The above chain extender and polyglycolic acid raw material are blended by screw compressor to obtain a modified sample with a particle size of 4 mm, wherein the amount of chain extender added is 2.5%.

[0089] The performance test results are shown in Table 1.

[0090] Example 5

[0091] Step 1: The three components purified by vacuum distillation are cooled to 4°C and metered into a specially designed polymerization reactor by a pump. The amount of component 1 added is 260g, the amount of component 2 added is 140g, and the amount of component 3 (X is C6 alkyl) added is 100g. The mixture is stirred thoroughly to dissolve and mix evenly.

[0092] Step 2: Add 1.5g of 1,3-bis(trimethoxysilylurea) to the polymerization reactor, stir to dissolve, and make it a stable solution;

[0093] Step 3: After blowing nitrogen gas into the polymerization reactor for 30 minutes, add 7.5g of benzoyl peroxide, stir to mix evenly, heat the polymerization reactor to 110℃ to initiate polymerization, and turn on the high torque stirrer to react for 30 minutes.

[0094] Step 4: Heat the polymerization reactor to 130°C and react for 150 minutes.

[0095] Step 5: Remove the polymer and pulverize it to obtain a chain extender sample.

[0096] Step 6: The above chain extender and polyglycolic acid raw material are blended by screw compressor to obtain a modified sample with a particle size of 4 mm, wherein the amount of chain extender added is 2.5%.

[0097] The performance test results are shown in Table 1.

[0098] Comparative Example 1

[0099] Except for step 1, which only adds component one and component two, the amount of component two added is the same as in Example 3, the content of component one is adjusted accordingly, and the other steps are the same as in Example 3.

[0100] The performance test results are shown in Table 1.

[0101] Comparative Example 2

[0102] The only difference from Example 3 is that in step 1, component three is vinylsilane.

[0103] The performance test results are shown in Table 1.

[0104] Comparative Example 3

[0105] The only difference from Example 3 is that in step 2, 1,3-bis(trimethoxyurea) is replaced with dodecyl mercaptan.

[0106] Table 1

[0107]

[0108]

[0109] As can be seen from Table 1, compared with the blank example and the comparative example, the modified polyglycolic acid obtained in the example has a lower degradation rate after aging at 100°C for 4 hours and a longer pressure resistance time at 100°C and 35MPa, which expands the application of polyglycolic acid in the field of oil and gas extraction.

[0110] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0111] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A chain extender for modifying polyglycolic acid, characterized in that, The chain extender contains the structural units shown in formula (1), formula (2) and formula (3); In formula (3), X is selected from C1-C6 alkyl groups, preferably C3-C5 alkyl groups.

2. The chain extender for polyglycolic acid modification according to claim 1, wherein, Based on the total weight of the chain extender, the content of the structural unit shown in formula (1) is 50.6-54% by weight, the content of the structural unit shown in formula (2) is 18-28% by weight, and the content of the structural unit shown in formula (3) is 20-28% by weight. Preferably, based on the total weight of the chain extender, the content of the structural unit shown in formula (1) is 50.6-53.6% by weight, the content of the structural unit shown in formula (2) is 22-25% by weight, and the content of the structural unit shown in formula (3) is 23-26% by weight.

3. A method for preparing a chain extender for polyglycolic acid modification, characterized in that, Includes the following steps: Step 1: Add the monomers with the structures shown in formula (4), formula (5) and formula (6) into the polymerization reactor and stir to mix evenly; Step 2: Add the accelerator to the polymerization reactor, stir to dissolve, and obtain a stable solution; Step 3: Add the initiator to the polymerization reactor, stir and mix evenly, and heat to the first reaction condition to carry out the reaction; Step 4: Continue heating to the second reaction conditions to carry out the reaction and obtain the chain extender; In formula (6), X is selected from C1-C6 alkyl groups, preferably C3-C5 alkyl groups.

4. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, Before step 1, the monomers with the structures shown in formulas (4), (5) and (6) are purified by vacuum distillation and cooled to 0-10°C.

5. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, In step 1, the polymerization reactor is equipped with a high-torque stirring paddle and a gas phase condenser at the top.

6. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, In step 1, based on the total mass percentage of the reacting monomers being 100%, the amount of monomers added to the structure shown in formula (4) is 50.6-54% by weight, the amount of monomers added to the structure shown in formula (5) is 18-28% by weight, and the amount of monomers added to the structure shown in formula (6) is 20-28% by weight. Preferably, based on the total mass percentage of the reactants being 100%, the amount of monomer added to the structure shown in formula (4) is 50.6-53.6% by weight, the amount of monomer added to the structure shown in formula (5) is 22-25% by weight, and the amount of monomer added to the structure shown in formula (6) is 23-26% by weight.

7. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, In step 2, the accelerator is 1,3-bis(trimethoxysilylurea); The amount of the accelerator added is 0.1%-0.3% of the total mass of the reactants.

8. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, In step 3, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, benzoyl peroxide, tert-butyl peroxide, and dicumyl peroxide. The amount of initiator added is 0.7%-1.5% of the total mass of the reactants.

9. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, In step 3, before adding the initiator, nitrogen gas is first bubbled into the polymerization reactor and kept for at least 30 minutes; The first reaction conditions include: a temperature of 90-110℃, preferably 98-106℃, and a time of 30-60 minutes, preferably 40-50 minutes.

10. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, Step 4 also includes pulverizing the polymer obtained from the reaction to obtain the chain extender.

11. The method for preparing the chain extender for polyglycolic acid modification according to claim 3, wherein, In step 4, the second reaction conditions include: a temperature of 130-145°C, preferably 135-142°C, and a time of 120-150 minutes, preferably 132-146 minutes.

12. A chain extender for modifying polyglycolic acid prepared by the preparation method according to any one of claims 3-11.

13. The application of the chain extender for polyglycolic acid modification according to any one of claims 1-2 and 12 in the modification of polyglycolic acid.

14. A method for modifying polyglycolic acid, characterized in that, include: Polyglycolic acid is mixed with a chain extender, wherein the chain extender is the chain extender for polyglycolic acid modification as described in any one of claims 1-2 and 12.

15. The method for modifying polyglycolic acid according to claim 14, wherein, Based on the total weight of the chain extender and polyglycolic acid raw material, the amount of chain extender added is 1-5%.

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