Post-treatment method of polymer and polymer prepared by post-treatment method

Abstract

The application relates to the field of high polymer materials, and discloses a post-treatment method of a polymer and a polymer prepared by the post-treatment method. The post-treatment method comprises the following steps: (1) mixing an initiator with a polymer fluid and then performing first devolatilization; and (2) performing second devolatilization on the product after the first devolatilization in a double-screw extruder to obtain a purified polymer; wherein the initiator is selected from at least one of compounds shown in formula I, formula II and formula III, and the post-treatment method can significantly reduce the content of volatile organic compounds in the product.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more specifically, to a post-processing method for a polymer and a polymer obtained by the post-processing method. Background Technology

[0002] Polymer devolatilization, the removal of small molecules from polymers, is a crucial step in the synthesis and production of polymer materials, second only to the polymerization reaction in importance. Effective devolatilization treatment can help improve product quality and is highly valued by petrochemical giants. In typical polymer production processes, the volatile organic compounds (VOCs) content in the polymer fluid entering the industrial devolatilizer from the polymerization unit generally ranges from 10% to 80%. Depending on the product's application, the devolatilization process typically aims to reduce the VOC levels in the polymer product to several thousand mg / kg or even tens of mg / kg. The energy consumption of the devolatilization process often accounts for more than 60% of the total energy consumption.

[0003] Industrially, polymer devolatilization processes can generally be divided into three different stages. (1) Flash devolatilization occurs when the polymer system has a high content of small molecule volatiles, relatively low viscosity, and relatively high heat and mass transfer efficiency. The process is mainly controlled by phase equilibrium, and a preheater with a large heat exchange area is set up in the flash devolatilization stage. (2) Foaming devolatilization is achieved by the continuous formation, growth, movement, deformation, aggregation and merging, and rupture of bubbles inside the polymer system. The most significant factors affecting foaming devolatilization are the viscoelasticity of the system and the supersaturation of volatiles, while the devolatilization effect depends on the magnitude of the gas-liquid two-phase mass transfer rate. (3) Diffusion devolatilization is usually carried out under negative pressure. Temperature and vacuum are the main factors affecting the devolatilization process. Increasing the devolatilization temperature and vacuum is an effective means to enhance the process. A high-efficiency static mixer needs to be inserted into the preheater to enhance heat transfer, and internal components need to be introduced into the devolatilization tank to increase the film-forming area.

[0004] Polymethyl methacrylate (PMMA), commonly known as plexiglass or acrylic, is a polymer compound formed by the polymerization of methacrylate and other monomers. Polymerization processes include suspension polymerization, solution polymerization, and bulk polymerization. Regardless of the process used, a devolatilization process is necessary to remove residual solvents, additives, and unreacted monomers from the polymer to obtain a relatively pure polymer. Currently, bulk polymerization is mainly used to synthesize optical-grade PMMA products. However, in the later stages of polymerization, when the monomer conversion rate reaches over 80%, the system viscosity becomes extremely high, resulting in poor mass and heat transfer, making the removal of unreacted monomers difficult. Conventional twin-screw devolatilization processes involve harsh operating conditions; polymer devolatilization is typically carried out at high temperatures, making it prone to discoloration and degradation, and the residence time cannot be too long. Therefore, it is difficult to obtain products with low VOC content (<0.2%) while maintaining optical performance, which to some extent limits the application areas of optical-grade PMMA products. Therefore, developing new devolatilization technologies and processes to achieve low VOC content products while ensuring optical performance is of great significance for expanding the application range of optical-grade PMMA. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of high volatile organic compound content in products in the prior art, and to provide a polymer post-processing method and a polymer obtained by the post-processing method. This post-processing method can significantly reduce the volatile organic compound content in the product.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for polymer post-processing, wherein the post-processing method includes the following steps:

[0007] (1) The initiator is mixed with the polymer fluid and then subjected to the first devolatilization;

[0008] (2) In a twin-screw extruder, the product after the first devolatilization is subjected to a second devolatilization to obtain the purified polymer;

[0009] The initiator is selected from at least one of the compounds shown in Formula I, Formula II and Formula III.

[0010]

[0011] Preferably, the polymer fluid is obtained by free radical polymerization, wherein, based on the total weight of the polymer fluid, the content of volatile organic compounds in the polymer fluid is ≤40% by weight.

[0012] The second aspect of the present invention provides a polymer obtained by the post-processing method described in the first aspect above.

[0013] Through the above technical solution, the present invention uses a specific initiator to mix with a polymer fluid and then sequentially perform a first devolatilization and a second devolatilization, which can significantly reduce the content of volatile organic compounds in the polymer. Detailed Implementation

[0014] 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.

[0015] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this invention are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0016] In this invention, unless otherwise specified, "first" and "second" do not indicate a sequence or limit the specific materials or steps; they are merely used to distinguish that these are not the same material or step. For example, in "first devolatilization" and "second devolatilization," "first" and "second" are used only to indicate that these are not the same devolatilization process.

[0017] The first aspect of the present invention provides a method for polymer post-processing, wherein the post-processing method includes the following steps:

[0018] (1) The initiator is mixed with the polymer fluid and then subjected to the first devolatilization;

[0019] (2) In a twin-screw extruder, the product after the first devolatilization is subjected to a second devolatilization to obtain the purified polymer;

[0020] The initiator is selected from at least one of the compounds shown in Formula I, Formula II and Formula III.

[0021]

[0022] This invention employs a specific initiator mixed with a polymer fluid, followed by sequential first and second devolatilization, which significantly reduces the content of volatile organic compounds (VOCs) in the polymer. Specifically, this invention uses compounds represented by Formulas I, II, and III as initiators, which can further initiate the polymerization of unreacted monomers in the polymer fluid, thereby reducing the VOC content in the final polymer due to the presence of unreacted monomers.

[0023] In the devolatilization process, this initiator can effectively reduce the residual monomer content in the polymer solution and reduce the residual amount of volatile organic compounds in the polymer.

[0024] According to the present invention, preferably, the amount of the initiator is 0.005-0.02% by weight, based on the total weight of the polymer fluid. The present invention uses an initiator within the above-mentioned content range, which is beneficial to the polymerization reaction and reduces the content of volatile organic compounds in the polymer. More preferably, it is 0.01-0.02% by weight.

[0025] According to the present invention, preferably, the polymer fluid is obtained by free radical polymerization, wherein, based on the total weight of the polymer fluid, the content of volatile organic compounds in the polymer fluid is ≤40% by weight. The lower the content of volatile substances in the polymer fluid, the less unreacted monomers or other volatile substances are present in the system. More preferably, the content of volatile organic compounds in the polymer fluid is ≤30% by weight.

[0026] In this invention, the content of volatile organic compounds in the methyl methacrylate polymer is determined by measuring the hydrogen spectrum of the polymer using a Swiss Bruker AV 300 nuclear magnetic resonance spectrometer, and the content of volatile organic compounds, i.e., VOC content, is calculated based on the integral area of ​​the hydrogen spectrum.

[0027] It should be noted that the present invention does not particularly limit the mixing method and conditions described in step (1). As long as it is conducive to uniformly mixing the initiator and the polymer fluid, those skilled in the art can make the selection according to actual needs, such as stirring.

[0028] This invention does not particularly limit the type of polymer fluid, as long as it meets the requirements of this invention. Those skilled in the art can select according to actual needs. Preferably, the polymer is selected from homopolymers and / or copolymers of the following monomers:

[0029] At least one of methyl methacrylate, ethyl methacrylate, ethyl acrylate, styrene, butyl acrylate, butyl methacrylate, tert-butyl methacrylate, tert-butyl acrylate, acrylamide, acrylic acid, sodium acrylate and 2-acrylamido-2-methylpropanesulfonic acid.

[0030] It should be noted that when the polymer is selected from copolymers of the above monomers, the present invention does not particularly limit the content of each monomer in the copolymer. According to a specific embodiment of the present invention, preferably, based on the total weight of the copolymer, the content of methyl methacrylate is 80-100% by weight, and the content of styrene, ethyl methacrylate, and tert-butyl methacrylate is 0-20% by weight, respectively.

[0031] Furthermore, based on the total weight of the copolymer, the content of methyl methacrylate is 90-100% by weight, and the content of styrene, ethyl methacrylate, and tert-butyl methacrylate is 0-10% by weight, respectively.

[0032] The present invention does not particularly limit the source of the polymer fluid, and those skilled in the art can select it according to actual needs. Preferably, the polymer fluid comes from bulk polymerization or solution polymerization.

[0033] The present invention does not particularly limit the method and equipment for implementing step (1), as long as the initiator and polymer fluid can react fully. Preferably, step (1) is carried out in a horizontal self-cleaning devolatilizer.

[0034] According to the present invention, preferably, the first devolatilization in step (1) is carried out under stirring conditions.

[0035] According to the present invention, preferably, the conditions for the first devolatilization in step (1) include: a reaction temperature of 150-180°C, a reaction time of 10-25 minutes, a stirring rate of 5-10 rpm, and a reaction pressure of 200-500 Pa.

[0036] Further, the conditions for the first devolatilization in step (1) include: a reaction temperature of 160-170°C, a reaction time of 15-25 minutes, and a reaction pressure of 200-300 Pa.

[0037] It should be noted that the reaction pressure in this invention is absolute pressure.

[0038] In this invention, the first devolatilization not only removes volatile organic compounds, but also further initiates the polymerization of unreacted monomers in the polymer fluid, thereby reducing the content of volatile organic compounds in the final polymer due to the presence of unreacted monomers.

[0039] According to the present invention, preferably, in the first devolatilization product, the content of volatile organic compounds in the methyl methacrylate polymer is ≤2% by weight, based on the total weight of the methyl methacrylate polymer.

[0040] In this invention, the content of volatile organic compounds in the methyl methacrylate polymer is determined by measuring the hydrogen spectrum of the polymer using a Swiss Bruker AV 300 nuclear magnetic resonance spectrometer, and the content of volatile organic compounds, i.e., VOC content, is calculated based on the integral area of ​​the hydrogen spectrum.

[0041] According to the present invention, preferably, the post-processing method further includes: conveying the first devolatilized product through twin-screw extruder I to twin-screw extruder II.

[0042] According to the present invention, preferably, the conditions of the twin-screw extruder I include: temperature 180-200°C and rotation speed 10-20 rpm.

[0043] According to the present invention, preferably, the second devolatilization in step (2) is carried out under stirring conditions.

[0044] According to the present invention, preferably, the conditions for the second devolatilization in step (2) include: a reaction temperature of 200-250°C, a reaction pressure of ≤10Pa, and a rotation speed of 100-180rpm.

[0045] Furthermore, in step (2), the rotational speed of the second devolatilization is more preferably 120-140 rpm.

[0046] According to the present invention, preferably, the temperature is controlled in stages during the second devolatilization process in step (2).

[0047] The present invention does not have a particular limitation on the number of segments in the second devolatilization process in step (2), as long as it can meet the reaction requirements. Those skilled in the art can select according to actual needs. Preferably, the second devolatilization process in step (2) is divided into 4-8 segments for temperature control, and more preferably 5-6 segments.

[0048] The present invention does not particularly limit the temperature of each stage in the second devolatilization in step (2), as long as the reaction can proceed fully. Those skilled in the art can select according to actual needs. According to a preferred embodiment of the present invention, the second devolatilization in step (2) is temperature controlled in 6 stages. The temperature of the first stage is more preferably 200-210℃, the temperature of the second stage is more preferably 200-220℃, the temperature of the third stage is more preferably 210-230℃, the temperature of the fourth stage is more preferably 215-235℃, the temperature of the fifth stage is more preferably 220-240℃, and the temperature of the sixth stage is more preferably 230-250℃.

[0049] The present invention combines the first devolatilization in step (1) and the second devolatilization in step (2), which is more conducive to reducing the content of volatile organic compounds in the product.

[0050] According to the present invention, preferably, step (2) further includes extrusion, stranding, cooling, pelletizing and drying after the second devolatilization to obtain polymer pellets.

[0051] This invention does not impose any particular limitations on the conditions and equipment for extrusion, stretching, cooling, pelletizing, and drying; those skilled in the art can select the appropriate equipment according to their actual needs.

[0052] It should be noted that the main purpose of the devolatilization process in this invention is to reduce the content of volatile organic compounds in the polymer. However, while achieving the goal of reducing volatility, the devolatilization operation will have a slight impact on some performance indicators of the polymer, such as weight-average molecular weight and melt index. However, from the perspective of overall process consideration and comprehensive product performance balance, the impact is limited and within an acceptable range.

[0053] The second aspect of the present invention provides a polymer obtained by the post-processing method described in the first aspect above.

[0054] According to the present invention, preferably, the content of volatile organic compounds in the polymer is ≤0.2% by weight, based on the total weight of the polymer.

[0055] The present invention does not particularly limit the type of polymer obtained. According to a specific embodiment of the present invention, preferably, the polymer is a methyl methacrylate polymer.

[0056] This invention does not impose any particular limitation on the weight-average molecular weight of the methyl methacrylate polymer; the weight-average molecular weight of the methyl methacrylate polymer is generally within the range of 12 × 10⁻⁶. 4 -15×10 4 g / mol, more preferably 12.8 × 10 g / mol. 4 -14.4×10 4 g / mol.

[0057] This invention uses gel permeation chromatography (PL-GPC20) to measure the weight-average molecular weight of polymers.

[0058] The present invention does not particularly limit the melt index of the methyl methacrylate polymer. Preferably, the melt index of the methyl methacrylate polymer at 230°C and 3.8 kg is 3-5 g / 10 min, more preferably 3.3-4.5 g / 10 min.

[0059] The polymer melt index was tested according to ISO 1133-1:2022 at 230°C and 3.8 kg.

[0060] The present invention will be described in detail below through embodiments.

[0061] Unless otherwise specified, all examples and comparative examples below are based on conventional methods; and all reagents and materials used, unless otherwise specified, are commercially available and / or prepared using methods known in the art.

[0062] In the following examples and comparative examples, the weight-average molecular weight of the polymers was measured using gel permeation chromatography (PL-GPC20).

[0063] In the following examples and comparative examples, the transmittance of the polymer was determined according to ISO 13468-2:2021 and the haze of the polymer was determined according to ISO 14782:2021.

[0064] In the following examples and comparative examples, the polymer melt index was tested according to ISO 1133-1:2022 at 230°C and 3.8 kg.

[0065] In the following examples and comparative examples, the proton NMR spectra of the polymers were measured using a Swiss Bruker AV 300 nuclear magnetic resonance spectrometer, and the VOC content of the polymers was calculated based on the integral area of ​​the proton NMR spectra.

[0066] Example 1

[0067] Add 2g of the initiator shown in Formula I to 20kg of methyl methacrylate bulk polymerization to obtain a polymer fluid, stir and mix evenly. At this time, based on the total mass of the polymer fluid, the VOC (methyl methacrylate) content is 15.5% by weight.

[0068] The polymer fluid is injected into the upper right inlet of the horizontal self-cleaning devolatilizer by a pump. The reactor temperature is 160℃, the stirring rate is 7rpm, and the residence time is 20min. After the first devolatilization, the pressure is 220Pa≤250Pa. At this time, based on the total mass of the polymer fluid, the VOC (methyl methacrylate) content in the methyl methacrylate polymer is 1.2% by weight.

[0069] The material is discharged from the lower left outlet of the reactor via twin-screw extruder I and continuously fed into the devolatilization section of twin-screw extruder II for secondary devolatilization. The temperature of twin-screw extruder I is 180℃, and the devolatilization temperatures of twin-screw extruder II are 200℃, 210℃, 215℃, 220℃, 225℃, and 235℃. The pressure in the devolatilization section is 2Pa ≤ ≤ 10Pa. The speed of twin-screw extruder I is 12 rpm, and the devolatilization speed of twin-screw extruder II is 140 rpm.

[0070] After devolatilization, the polymer pellets are obtained by extrusion through port II of a twin-screw extruder, followed by stranding, cooling, pelletizing, and drying. The properties are shown in Table 1.

[0071] Example 2

[0072] Add 3g of the initiator shown in Formula II to 25kg of methyl methacrylate / styrene (the weight ratio of methyl methacrylate to styrene is 4:1) bulk copolymerization to obtain a polymer fluid, stir and mix evenly. At this time, based on the total mass of the polymer fluid, the VOC (methyl methacrylate / styrene) content is 20.3%.

[0073] The polymer fluid was injected into the upper right inlet of the horizontal self-cleaning devolatilizer by a pump. The reactor temperature was 165℃, the stirring rate was 10 rpm, and the residence time was 25 min. After the first devolatilization, the pressure was 270 Pa ≤ 300 Pa. At this time, the VOC content in the methyl methacrylate copolymer was 1.4% by weight.

[0074] The material is discharged from the lower left outlet of the reactor via twin-screw extruder I and continuously fed into the devolatilization section of twin-screw extruder II for secondary devolatilization. The temperature of twin-screw extruder I is 195℃, and the devolatilization temperatures of twin-screw extruder II are 200℃, 210℃, 220℃, 230℃, 240℃, and 250℃. The pressure in the devolatilization section is 2Pa ≤ ≤ 10Pa. The speed of twin-screw extruder I is 15rpm, and the devolatilization speed of twin-screw extruder II is 180rpm.

[0075] After devolatilization, the polymer pellets are obtained by extrusion through port II of a twin-screw extruder, followed by stranding, cooling, pelletizing, and drying. The properties are shown in Table 1.

[0076] Example 3

[0077] 2.5 g of the initiator shown in Formula III was added to 25 kg of methyl methacrylate / ethyl methacrylate (the weight ratio of methyl methacrylate to ethyl methacrylate is 9:1) bulk copolymerization to obtain a polymer fluid. The mixture was stirred and mixed evenly. At this time, based on the total mass of the polymer fluid, the VOC (methyl methacrylate / ethyl methacrylate) content was 12.6%.

[0078] The polymer fluid was injected into the upper right inlet of the horizontal self-cleaning devolatilizer by a pump. The reactor temperature was 180℃, the stirring rate was 5 rpm, and the residence time was 25 min. After the first devolatilization, the pressure was 210 Pa ≤ 250 Pa. At this time, the VOC content in the methyl methacrylate copolymer was 1.4% by weight.

[0079] The material is discharged from the lower left outlet of the reactor via twin-screw extruder I and continuously fed into the devolatilization section of twin-screw extruder II for secondary devolatilization. The temperature of twin-screw extruder I is 190℃, and the devolatilization temperatures of twin-screw extruder II are 200℃, 210℃, 215℃, 220℃, 230℃, and 240℃. The pressure in the devolatilization section is 2Pa ≤ ≤ 10Pa. The speed of twin-screw extruder I is 20rpm, and the devolatilization speed of twin-screw extruder II is 160rpm.

[0080] After devolatilization, the polymer pellets are obtained by extrusion through port II of a twin-screw extruder, followed by stranding, cooling, pelletizing, and drying. The properties are shown in Table 1.

[0081] Example 4

[0082] Add 5g of the initiator shown in Formula II to 25kg of methyl methacrylate / tert-butyl methacrylate (the weight ratio of methyl methacrylate and tert-butyl methacrylate is 19:1) bulk copolymerization to obtain a polymer fluid, stir and mix evenly. At this time, based on the total mass of the polymer fluid, the VOC (methyl methacrylate / tert-butyl methacrylate) content is 22.8%.

[0083] The polymer fluid was injected into the upper right inlet of the horizontal self-cleaning devolatilizer by a pump. The reactor temperature was 150℃, the stirring rate was 8 rpm, and the residence time was 10 min. After the first devolatilization, the pressure was 460 ≤ pressure ≤ 500 Pa. At this time, the VOC content in the methyl methacrylate copolymer was 1.3% by weight.

[0084] The material is discharged from the lower left outlet of the reactor via twin-screw extruder I and continuously fed into the devolatilization section of twin-screw extruder II for secondary devolatilization. The temperature of twin-screw extruder I is 190℃, and the devolatilization temperatures of twin-screw extruder II are 210℃, 215℃, 220℃, 225℃, 235℃, and 245℃. The pressure in the devolatilization section is 2Pa ≤ ≤ 10Pa. The speed of twin-screw extruder I is 10rpm, and the devolatilization speed of twin-screw extruder II is 100rpm.

[0085] After devolatilization, the polymer pellets are obtained by extrusion through port II of a twin-screw extruder, followed by stranding, cooling, pelletizing, and drying. The properties are shown in Table 1.

[0086] Example 5

[0087] The method of Example 1 is followed, except that the amount of initiator shown in Formula I added is 1g. After the first devolatilization, based on the total mass of the polymer fluid, the VOC (methyl methacrylate) content in the methyl methacrylate polymer is 1.6% by weight, and the properties are shown in Table 1.

[0088] Example 6

[0089] The method is the same as in Example 1, except that the VOC content in the methyl methacrylate polymer before the first devolatilization is 35.8 wt%, and after the first devolatilization, the VOC (methyl methacrylate) content in the methyl methacrylate polymer is 1.9 wt% based on the total mass of the polymer fluid. The properties are shown in Table 1.

[0090] Example 7

[0091] The method is the same as in Example 1, except that during the first devolatilization, the pressure is 400Pa≤450Pa. After the first devolatilization, based on the total mass of the polymer fluid, the VOC (methyl methacrylate) content in the methyl methacrylate polymer is 1.8% by weight, and the properties are shown in Table 1.

[0092] Example 8

[0093] The method is the same as in Example 1, except that the first devolatilization temperature is 150°C, and the VOC content in the methyl methacrylate polymer after the first devolatilization is 1.5% by weight, and the properties are shown in Table 1.

[0094] Example 9

[0095] The method is the same as in Example 1, except that the second devolatilization speed is 180 rpm, and the performance is shown in Table 1.

[0096] Comparative Example 1

[0097] The method of Example 1 was followed, except that the initiator was replaced with an equal amount of tert-butyl peroxide, and the properties are shown in Table 1.

[0098] Comparative Example 2

[0099] The method is the same as in Example 1, except that no initiator is used.

[0100] Comparative Example 3

[0101] The method is the same as in Example 1, except that a first devolatilization is not used.

[0102] Comparative Example 4

[0103] The method is the same as in Example 1, except that a second devolatilization is not used.

[0104] Table 1

[0105]

[0106]

[0107] In Table 1, VOC represents the content of volatile organic compounds in the methyl methacrylate polymer after two devolatilization processes.

[0108] As can be seen from the results in Table 1, compared with the comparative example, the present invention uses a specific initiator to mix with the polymer fluid and then sequentially perform the first and second devolatilization, which has a significantly better effect on removing the content of volatile organic compounds in the polymer.

[0109] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for polymer post-processing, characterized in that, The post-processing method includes the following steps: (1) The initiator is mixed with the polymer fluid and then subjected to the first devolatilization; (2) In a twin-screw extruder, the product after the first devolatilization is subjected to a second devolatilization to obtain the purified polymer; The initiator is selected from at least one of the compounds shown in Formula I, Formula II and Formula III.

2. The post-processing method according to claim 1, wherein, Based on the total weight of the polymer fluid, the amount of the initiator is 0.005-0.02% by weight, preferably 0.01-0.02% by weight; And / or, the polymer fluid is derived from a free polymerization reaction, wherein, based on the total weight of the polymer fluid, the content of volatile organic compounds in the polymer fluid is ≤40% by weight.

3. The post-processing method according to claim 1 or 2, wherein, The polymer is selected from the following monomer homopolymers and / or copolymers: At least one of methyl methacrylate, ethyl methacrylate, ethyl acrylate, styrene, butyl acrylate, butyl methacrylate, tert-butyl methacrylate, tert-butyl acrylate, acrylamide, acrylic acid, sodium acrylate and 2-acrylamido-2-methylpropanesulfonic acid.

4. The post-processing method according to any one of claims 1-3, wherein, The polymer fluid originates from bulk polymerization or solution polymerization.

5. The post-processing method according to any one of claims 1-4, wherein, Step (1) is carried out in a horizontal self-cleaning reactive devolatilizer; And / or, the first devolatilization in step (1) is carried out under stirring conditions; And / or, the conditions for the first devolatilization in step (1) include: a reaction temperature of 150-180℃, a reaction time of 10-25 minutes, a stirring rate of 5-10 rpm, and a reaction pressure of 200-500 Pa.

6. The post-processing method according to any one of claims 1-5, wherein, In the first devolatilization product, based on the total weight of the methyl methacrylate polymer, the content of volatile organic compounds in the methyl methacrylate polymer is ≤2% by weight.

7. The post-processing method according to any one of claims 1-6, wherein, The post-processing method further includes: conveying the first devoured product through twin-screw extruder I to twin-screw extruder II; Preferably, the conditions of the twin-screw extruder I include: temperature 180-200℃ and rotation speed 10-20 rpm.

8. The post-processing method according to any one of claims 1-7, wherein, In step (2), the second devolatilization is carried out under stirring conditions; And / or, the conditions for the second devolatilization in step (2) include: a reaction temperature of 200-250℃, a reaction pressure of ≤10Pa, and a rotation speed of 100-180rpm; And / or, the temperature is controlled in stages during the second devolatilization process in step (2); Preferably, the second devolatilization process is divided into 4-8 stages for temperature control.

9. A polymer obtained by the post-processing method according to any one of claims 1-8.

10. The polymer according to claim 9, wherein, Based on the total weight of the polymer, the content of volatile organic compounds in the polymer is ≤0.2% by weight.

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