Heat-resistant AMSAN resin with double-layer structure as well as preparation method and application of heat-resistant AMSAN resin

Abstract

The invention provides heat-resistant AMSAN resin with a double-layer structure as well as a preparation method and application of the heat-resistant AMSAN resin. The preparation method comprises the following steps: preparing a macromolecular RAFT reagent PEGn-RAFT from an RAFT reagent and methoxypolyethylene glycol (mPEG-OH), and then carrying out PEGn-RAFT mediated copolymerization on acrylonitrile and alpha-methyl styrene, so as to obtain the segmented copolymer PEGn-b-(PaMS-co-PAN). The block copolymer prepared by the method disclosed by the invention has amphipathy and can be self-assembled in a solvent to finally obtain a structure in which the PaMS-co-PAN is arranged inside and the PEGn is arranged outside. The high-thermal-stability heat-resistant AMSAN resin with the double-layer structure prepared by the preparation method disclosed by the invention has excellent thermal stability and high heat resistance, and also has relatively high impact strength.

Description

Technical Field

[0001] The invention belongs to the field of polymers, and in particular relates to a double-layer heat-resistant AMSAN resin and a preparation method and application thereof. Background Art

[0002] ABS resin has good comprehensive properties and is widely used in many fields. However, the heat resistance of ABS resin limits its application in major automotive parts, home appliances, office automation equipment and other fields. Almost all high-quality heat-resistant ABS resins in the domestic market need to be imported to meet demand.

[0003] The heat resistance of ABS can be improved by preparing ABS alloy or blending it with heat-resistant SAN. PC / ABS alloy can be used to prepare high-heat-resistant ABS, but its cost is generally high due to the price of PC; although the chemical synthesis method of preparing heat-resistant base materials by copolymerization with heat-resistant monomers has a relatively complex synthesis route, it is more economical. At the end of the 20th century, the United States, Japan, Germany and other countries conducted a lot of research on chemical modification to improve the heat resistance of plastics such as ABS. The results showed that related polymers such as α-methylstyrene (AMS), p-methylstyrene (PMS), maleic anhydride (MA) and nitrogen-substituted maleimide (such as N-phenylmaleimide, NPMI) have good heat resistance. The use of the above monomers to copolymerize to prepare heat-resistant AMSAN resin instead of ordinary SAN resin can effectively improve the heat resistance of ABS. Its maximum heat deformation temperature can reach 120°C, which can be used in the field of transparent resins with high heat resistance requirements, making up for the heat resistance defects of ordinary SAN resin. However, the heat-resistant AMSAN resin is very susceptible to thermal degradation at high temperatures, which causes its molecular chain to break and its molecular weight to drop sharply, causing its heat resistance and impact strength to be affected to varying degrees, seriously affecting its actual use.

[0004] In summary, the introduction of AMS has improved the heat resistance of SAN to a certain extent, but the poor thermal stability of heat-resistant AMSAN resin has seriously affected its subsequent use. Therefore, it is still necessary to develop a heat-resistant AMSAN resin with high thermal stability. Summary of the invention

[0005] In view of the above problems existing in the prior art, one of the objectives of the present invention is to provide a double-layer heat-resistant AMSAN resin with high thermal stability, which can significantly improve the thermal stability while maintaining high heat resistance and impact strength.

[0006] Another object of the present invention is to provide a preparation method and application of the high thermal stability double-layer heat-resistant AMSAN resin.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a double-layer heat-resistant AMSAN resin, comprising preparing a macromolecular RAFT agent (PEG) by using a RAFT agent and polyethylene glycol monomethyl ether (mPEG-OH) n -RAFT), and then mediated the copolymerization of acrylonitrile and α-methylstyrene to form an amphiphilic block copolymer, which was self-assembled in solution to obtain a double-layer structure of heat-resistant AMSAN resin PEG n -b-(PaMS-co-PAN) step, wherein n is preferably 20 to 40, for example, 20, 22, 23, 25, 26, 28, 30, 32, 35, 36, 38, 40, etc.

[0009] In one embodiment of the present invention, the preparation method comprises the following steps:

[0010] S1. Mix anhydrous toluene with polyethylene glycol monomethyl ether (mPEG-OH), other additives, and RAFT agent, heat preservation, precipitation, and suction filtration to obtain a macromolecular RAFT agent PEG n -RAFT;

[0011] S2, blending an antioxidant, an initiator, α-methylstyrene and acrylonitrile monomers to obtain a mixed solution S2;

[0012] S3, solvent and macromolecular RAFT agent PEG n -RAFT was added to the reactor, the temperature was raised and stirred until the macromolecular RAFT agent was completely dissolved, and then the S2 mixed solution was added thereto, reacted, and kept warm to prepare PEG n -b-(PaMS-co-PAN).

[0013] In one embodiment of the present invention, the other auxiliary agent in S1 is dicyclohexylcarbodiimide (DCC) or 4-dimethylaminopyridine (DMAP).

[0014] In one embodiment of the present invention, S1 contains 80-90 parts by weight of anhydrous toluene, for example, 81, 82, 83, 84, 85, 86, 87, 88, and 89 parts by weight; 10-20 parts by weight of polyethylene glycol monomethyl ether, for example, 11, 12, 13, 14, 15, 16, 18, and 19 parts by weight; 1-1.5 parts by weight of DCC, for example, 1.1, 1.2, 1.3, and 1.4 parts by weight; 1-1.5 parts by weight of DMAP, for example, 1.1, 1.2, 1.3, and 1.4 parts by weight; and 0.3-0.5 parts by weight of RAFT agent, for example, 0.35, 0.4, and 0.45 parts by weight.

[0015] In one embodiment of the present invention, the RAFT agent has a structure as shown in formula (1):

[0016]

[0017] In formula (1), R1 represents any one of an alkyl group, an aryl group, an aramid group, a sulfanyl group, an amino group, an alkoxy group, and an aryloxy group;

[0018] In formula (1), R2 represents the leaving group of the RAFT agent, which is usually a group connected via C, for example, any one selected from styrene, methacrylate, acrylonitrile, acrylamide, etc.

[0019] In one embodiment of the present invention, the insulation temperature in S1 is 40-100°C, for example, 50°C, 60°C, 70°C, 80°C, 90°C, etc.

[0020] In one embodiment of the present invention, the precipitant used in the precipitation in S1 is one or more of methanol, ethanol, n-propanol, isopropanol, and n-butanol. The amount of the precipitant added is not particularly limited, for example, 50-90 parts by weight. The precipitant mainly acts to convert the macromolecular RAFT agent PEG n -RAFT precipitation into solid form.

[0021] In one embodiment of the present invention, the filtration time in S1 is 30-90 min, for example, 40 min, 50 min, 60 min, 70 min, 80 min, etc., but is not limited thereto.

[0022] In one embodiment of the present invention, the antioxidant in S2 is preferably a hindered phenol antioxidant, preferably one or more of monophenol antioxidant 1076, antioxidant 246, antioxidant 1135, bisphenol antioxidant 2246, antioxidant 702, polyphenol antioxidant 330, antioxidant 1010, and antioxidant 3114.

[0023] In one embodiment of the present invention, the antioxidant in S2 is 0.2-0.4 parts by weight, for example 0.3 parts by weight.

[0024] In one embodiment of the present invention, the initiator in S2 is an organic peroxide, preferably one or more of a monofunctional organic peroxide and a multifunctional organic peroxide; more preferably, the multifunctional organic peroxide is selected from one or more of 1,1-bis(tert-butylperoxy)-2-methylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, and 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; the monofunctional organic peroxide is selected from one or more of di-tert-butyl peroxide, diisopropyl peroxide and di-tert-butyl isopropyl peroxide.

[0025] In one embodiment of the present invention, the initiator in S2 is 0.1-0.3 parts by weight, for example 0.2 parts by weight.

[0026] In one embodiment of the present invention, the acrylonitrile monomer in S2 is one or more of acrylonitrile, methacrylonitrile and ethacrylonitrile.

[0027] In one embodiment of the present invention, the acrylonitrile monomer in S2 is 20-40 parts by weight, for example, 25, 30, or 35 parts by weight.

[0028] In one embodiment of the present invention, S2 contains 60-80 parts by weight of α-methylstyrene, for example, 65, 70, or 75 parts by weight.

[0029] In one embodiment of the present invention, the solvent in S3 is selected from any one of p-xylene, chlorobenzene and o-dichlorobenzene.

[0030] In one embodiment of the present invention, the amount of solvent added to S3 is 40-60 parts by weight, such as 45, 50, or 55 parts by weight; the amount of mixed solution added to S2 is 60-40 parts by weight, such as 55, 50, or 45 parts by weight, and the macromolecular RAFT agent PEG n -RAFT is added in an amount of 0.5-1 part by weight, such as 0.6, 0.7, 0.8, 0.9 part by weight.

[0031] In one embodiment of the present invention, the mixed solution of S2 is added to the reactor in S3 by dropwise addition.

[0032] In one embodiment of the present invention, the dropwise addition time of the S2 mixed solution in S3 is 2-4 h, such as 2.5, 3, 3.5 h, etc., preferably 2-3 h, and more preferably 2-2.5 h.

[0033] In one embodiment of the present invention, the insulation temperature in S3 is 110-125°C, such as 115°C, 120°C, 125°C, etc.; the insulation time is 1-5h, such as 2h, 3h, 4h, etc., preferably 2-4h, more preferably 3-4h.

[0034] In one embodiment of the present invention, the random copolymer PaMS-co-PAN formed by the reaction is reacted with a solvophilic segment PEG n The double-layer structure of block copolymer PEG was obtained by coating n -b-(PaMS-co-PAN).

[0035] Another aspect of the present invention is a double-layer heat-resistant AMSAN resin PEG n -b-(PaMS-co-PAN), prepared by the aforementioned preparation method, the resin has a double-layer structure.

[0036] A heat-resistant AMSAN prepared by reactive controlled radical (RAFT) polymerization has a higher conversion rate of the polymerization reaction, a narrower molecular weight distribution and better heat resistance of the product due to the characteristics of RAFT polymerization.

[0037] Another aspect of the present invention is a double-layer heat-resistant AMSAN resin PEG n -b-(PaMS-co-PAN) is used in the preparation of heat-resistant ABS, especially in the fields of home appliances, office supplies and automobiles.

[0038] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0039] In the preparation method of the present invention, the random copolymer PaMS-co-PAN formed by the reaction is reacted with the solvent-philic segment PEG n The double-layer structure of block copolymer PEG was obtained by coating n -b-(PaMS-co-PAN).

[0040] The present invention effectively protects the heat-resistant AMSAN (PaMS-co-PAN), and the AMSAN resin prepared therefrom has excellent thermal stability, improves the heat resistance of the resin (Tg>126°C), and maintains its impact resistance (reaching 34kg / cm 2 ). DETAILED DESCRIPTION

[0041] In order to better understand the technical solution of the present invention, the content of the present invention is further described below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0042] At present, the common problem of heat-resistant AMSAN is poor thermal stability. It will undergo degradation reaction in a high temperature environment, especially during the devolatilization process, which will cause degradation due to high temperature and cause a sudden drop in molecular weight. The mechanism of thermal degradation of heat-resistant AMSAN is as follows:

[0043] The degradation of polymers is an important aspect of the study of their structural properties. Macromolecular chains may degrade under the action of heat, mechanical force or chemical energy. There are three main steps in the degradation: 1) free radicals are generated through chain end, middle or random scission; 2) β-shearing produces smaller molecular weight products; 3) free radicals are terminated by coupling, disproportionation or H-abstraction chain transfer.

[0044] When AMS / SM / AN free radicals are polymerized, they generally undergo random copolymerization in the form of -AABCABCCB- chain segments.

[0045] Wherein, the structural unit of AMSAN copolymer is shown in formula (a):

[0046]

[0047] However, due to the characteristics of AMS's own structure, when the end of the growing chain is an AMS free radical, it is easier to undergo a termination reaction with another free radical or a chain transfer reaction with a monomer than to continue growing. The AMS unit will exist in the middle of the molecular chain in the form of an end group (caused by chain transfer or disproportionation termination) or in the form of a head-to-head structure (caused by coupling termination).

[0048] Among them, the possible existence form of the AMSAN structural unit in the copolymer is shown in formula (b):

[0049]

[0050] The head-to-head structure formed by coupling and termination is easily degraded to produce free radicals, which further trigger various degradation reactions. The free radical scavenger DPPH and carbon spectrum analysis can determine that the chain break occurs at the above-mentioned weak bond; after the free radical is generated, it will produce monomers and short-chain free radicals through β-shearing reaction; free radical termination can be achieved through coupling, disproportionation or H abstraction reaction.

[0051] Among them, the chain breaking process of the AMSAN structural unit is shown in formula (c):

[0052]

[0053] In addition, the peroxide initiator remaining in the system after the polymerization is completed will form peroxide free radicals and capture hydrogen on the secondary carbon of the polymer main chain, accelerating the decomposition of the polymer.

[0054] The peroxidation initiator induces the polymer degradation process as shown in formula (d):

[0055]

[0056] The block copolymer PEG prepared by the present invention n -b-(PaMS-co-PAN), external structure PEG n The thermally cracked free radicals are isolated from the internal structure PaMS-co-PAN and the external structure PEG n It can also effectively reduce the impact of heat energy on the internal structure. This effective insulation effect protects the internal PaMS-co-PAN very well. n -b-(PaMS-co-PAN) maintains excellent heat resistance (Tg>126℃) and impact resistance (reaching 34kg / cm 2 ).

[0057] In the present invention, a method for preparing a double-layer heat-resistant AMSAN resin comprises the following steps: preparing a macromolecular RAFT agent (PEG) by using a RAFT agent and polyethylene glycol monomethyl ether (mPEG-OH); n -RAFT), and then mediated the copolymerization of acrylonitrile and α-methylstyrene to form an amphiphilic block copolymer, which was self-assembled in solution to obtain a double-layer structure of heat-resistant AMSAN resin PEG n -b-(PaMS-co-PAN).

[0058] Specifically, the preparation method comprises the following steps:

[0059] S1. Mix anhydrous toluene with polyethylene glycol monomethyl ether (mPEG-OH), other additives, and RAFT agent, heat preservation, precipitation, and suction filtration to obtain a macromolecular RAFT agent PEG n -RAFT;

[0060] S2, blending an antioxidant, an initiator, α-methylstyrene and acrylonitrile monomers to form a mixed solution S2;

[0061] S3, solvent and macromolecular RAFT agent PEG n -RAFT was added to the reactor, the temperature was raised and stirred until the macromolecular RAFT agent was completely dissolved, and then the S2 mixed solution was added thereto, reacted, and kept warm to prepare PEG n -b-(PaMS-co-PAN).

[0062] The technical solution of the present invention is further explained below through more specific embodiments, but does not constitute any limitation.

[0063] Unless otherwise specified, the raw materials used in the following examples and comparative examples of the present invention are obtained from commercial channels.

[0064] Thiobenzoylthioglycolic acid, 97%, purchased from TCI;

[0065] Bis(diethylthiocarbamyl) disulfide, 97%, purchased from TCI;

[0066] 3-Benzylsulfanylthiocarbonylsulfanylpropionic acid, 98%, purchased from TCI;

[0067] Cyanomethyldodecyl trithiocarbonate, 98%, purchased from TCI;

[0068] 4-Cyano-4-[(phenylthiocarbonyl)thio]pentanoic acid-2,5-dioxapyrrolidin-1-yl ester, 98%, purchased from TCI;

[0069] Polyethylene glycol monomethyl ether, 97%, purchased from Sigma-Aldrich;

[0070] Anhydrous toluene, 99%, purchased from Aladdin;

[0071] o-Xylene, 97%, purchased from Sigma-Aldrich;

[0072] Dicyclohexylcarbodiimide, 98%, purchased from Sigma-Aldrich;

[0073] 4-Dimethylaminopyridine, 98%, purchased from Sigma-Aldrich;

[0074] Acrylonitrile, 99%, purchased from Aladdin;

[0075] Methacrylonitrile, 99%, purchased from Aladdin;

[0076] Ethyl acrylonitrile, 99%, purchased from Aladdin;

[0077] α-Methylstyrene, 99%, was purchased from Aladdin.

[0078] Preparation Example Preparation of macromolecular RAFT agent PEG n -TBTAC:

[0079] Take a 500mL three-necked flask, add 400mL of anhydrous toluene, then add 50g of polyethylene glycol monomethyl ether (mPEG-OH) solid and stir at 50°C until the solid is completely dissolved. Then add 9.5g of dicyclohexylcarbodiimide (DCC) and 5.5g of 4-dimethylaminopyridine (DMAP), raise the temperature to 70°C, and after the above two solids are completely dissolved, add 1.7g of RAFT agent thiobenzoylthioglycolic acid (TBTAC) to the three-necked flask, and keep the solution in the three-necked flask in a stirring state until the powdered RAFT agent is completely dissolved. After that, place the three-necked flask in an oil bath at 90°C and let it react for 24h. Then use anhydrous ethanol to precipitate and purify the product, then filter the precipitate, and dry it to obtain the final product macromolecular RAFT agent.

[0080] The above preparation routes were used to prepare the following macromolecular RAFT agents: PEG 30 -TBTAC, PEG 60 -TBTAC, bis(diethylthiocarbamoyl) disulfide macromolecular RAFT agent PEG 30 -TTDS, PEG 40 -TTDS, 3-benzylsulfanylthiocarbonylsulfanylpropionic acid type macromolecular RAFT agent PEG30 -BCTTP, PEG 40 -BCTTP, cyanomethyl dodecyl trithiocarbonate type macromolecular RAFT agent PEG 30 -CDTC, PEG 40 -CDTC, 4-cyano-4-[(phenylthiocarbonyl)thio]pentanoic acid-2,5-dioxapyrrolidine-1-ester type macromolecular RAFT agent PEG 30 -SCPCP, PEG 40 -SCPCP.

[0081] Example 1

[0082] 50 g of o-dichlorobenzene was added to the reactor, and N2 was continuously passed through the reactor to deoxygenate it. The stirring of the reactor was started, and the reactor was heated to 70°C. 0.5 g of the macromolecular RAFT agent PEG was added. 30 -TBTAC was added to the reactor and stirred until it was completely dissolved. The reactor was then heated to 110°C, and a mixture of 0.25g antioxidant 1076, 0.15g initiator 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 15g acrylonitrile and 35g α-methylstyrene was dripped into the reactor for 2h. The mixture was kept warm for 3h, and the reactor was cooled in a water bath with water to obtain heat-resistant AMSAN resin after purification.

[0083] Example 2

[0084] 60 g of chlorobenzene was added to the reactor, N2 was continuously passed through the reactor to deoxygenate, and stirring of the reactor was started. The reactor was heated to 70°C, and 0.7 g of the macromolecular RAFT agent PEG was added. 30 -TTDS was added to the reactor and stirred until it was completely dissolved. The reactor was then heated to 115°C, and a mixture of 0.2g antioxidant 1076, 0.1g antioxidant 1010, 0.2g initiator 1,1-bis(tert-butylperoxy)-2-methylcyclohexane, 8g methacrylonitrile and 32g α-methylstyrene was dripped into the reactor for 2.5h. The mixture was kept warm for 4h, and the reactor was cooled in a water bath with water to obtain heat-resistant AMSAN resin after purification.

[0085] Example 3

[0086] 40 g of p-xylene was added to the reactor, N2 was continuously passed through the reactor to deoxygenate, and stirring of the reactor was started. The reactor was heated to 70°C, and 0.8 g of the macromolecular RAFT agent PEG was added. 30-CDTC was added to the reactor and stirred until it was completely dissolved. The reactor was then heated to 120°C, and a mixture of 0.15g antioxidant 1135, 0.15g antioxidant 3114, 0.3g initiator 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 24g ethyl acrylonitrile and 36g α-methylstyrene was dripped into the reactor for 2h. The mixture was kept warm for 3.5h, and the reactor was cooled in a water bath with water. Heat-resistant AMSAN resin was obtained after purification.

[0087] Example 4

[0088] 50 g of o-dichlorobenzene was added to the reactor, and N2 was continuously passed through the reactor to deoxygenate it. The stirring of the reactor was started, and the reactor was heated to 70°C. 0.9 g of the macromolecular RAFT agent PEG was added. 40 -SCPCP was added to the reactor and stirred until it was completely dissolved. The reactor was then heated to 125°C, and a mixed solution of 0.4g antioxidant 246, 0.1g initiator 1,1-bis(tert-butylperoxy)cyclohexane, 15g acrylonitrile and 35g α-methylstyrene was dripped into the reactor for 3h. The reactor was kept warm for 3h, and the reactor was cooled in a water bath with water to obtain heat-resistant AMSAN resin after purification.

[0089] Example 5

[0090] 40g of chlorobenzene was added to the reactor, N2 was continuously passed through the reactor to deoxygenate, and stirring of the reactor was started. The reactor was heated to 70°C and 1g of the macromolecular RAFT agent PEG was added. 40 -BCTTP was added to the reactor and stirred until it was completely dissolved. The reactor was then heated to 120°C, and a mixture of 0.2g of antioxidant 330, 0.2g of antioxidant 702, 0.18g of initiator 1,1-bis(tert-butylperoxy)cyclohexane, 21g of methacrylonitrile and 39g of α-methylstyrene was dripped into the reactor for 2h. The mixture was kept warm for 4h, and the reactor was cooled in a water bath with water to obtain heat-resistant AMSAN resin after purification.

[0091] Comparative Example 1

[0092] Compared with Example 1, the difference is that no macromolecular RAFT agent PEG is added 30 -TBTAC, other contents are the same as those in Example 1.

[0093] Comparative Example 2

[0094] Compared with Example 1, the difference is that the macromolecular RAFT agent PEG is not used 30 -TBTAC, replaced by the macromolecular RAFT agent PEG 60 -TBTAC, other contents are the same as those in Example 1.

[0095] According to the following steps, the heat-resistant AMSAN resin prepared in the examples and comparative examples was tested, and the test results are shown in Table 2:

[0096] The molecular weight was measured by gel chromatography; the thermal decomposition loss of the resin was determined by measuring the weight loss of the pellets placed on aluminum foil and heated in an oven at 250°C for 4 hours; and the glass transition temperature was obtained by differential scanning calorimetry (DSC) measurement.

[0097] The AMSAN resin was used to prepare various test specimens at 210° C. on an injection molding machine, and the impact strength of the AMSAN resin was obtained by testing according to ASTM D256 standard.

[0098] Table 1 Preparation formula of heat-resistant AMSAN

[0099]

[0100]

[0101] Table 2 Heat-resistant AMSAN performance

[0102]

[0103] It can be seen from the results of Example 1 and Comparative Example 1 that the heat-resistant AMSAN prepared by living controlled radical polymerization mediated by a macromolecular RAFT agent has greatly improved thermal stability.

[0104] Obviously, the above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. A method for preparing a double-layer heat-resistant AMSAN resin, characterized in that: The invention comprises preparing a macromolecular RAFT agent (PEG) by using a RAFT agent and polyethylene glycol monomethyl ether (mPEG-OH) n -RAFT), and then mediated the copolymerization of acrylonitrile and α-methylstyrene to form an amphiphilic block copolymer, which was self-assembled in solution to obtain a double-layer structure of heat-resistant AMSAN resin PEG n -b-(PaMS-co-PAN) step, wherein n is preferably 20 to 40.

2. The preparation method according to claim 1, characterized in that: The following steps are involved: S1. Mix anhydrous toluene with polyethylene glycol monomethyl ether (mPEG-OH), other additives, and RAFT agent, heat preservation, precipitation, and suction filtration to obtain a macromolecular RAFT agent PEG n -RAFT; S2, blending an antioxidant, an initiator, α-methylstyrene and acrylonitrile monomers to obtain a mixed solution S2; S3, solvent and macromolecular RAFT agent PEG n -RAFT was added to the reactor, the temperature was raised and stirred until the macromolecular RAFT agent was completely dissolved, and then the S2 mixed solution was added thereto, reacted, and kept warm to prepare PEG n -b-(PaMS-co-PAN).

3. The preparation method according to claim 2, characterized in that: The other additives described in S1 are dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP); Preferably, the anhydrous toluene in S1 comprises 80-90 parts by weight, mPEG-OH 10-20 parts by weight, DCC 1-1.5 parts by weight, DMAP 1-1.5 parts by weight, and RAFT agent 0.3-0.5 parts by weight.

4. The preparation method according to any one of claims 1 to 3, characterized in that The RAFT agent has a structure as shown in formula (1): In formula (1), R1 represents any one of an alkyl group, an aryl group, an aramid group, a sulfanyl group, an amino group, an alkoxy group, and an aryloxy group; R2 represents a leaving group of a RAFT agent, preferably selected from any one of a styrene group, a methacrylate group, an acrylonitrile group, and an acrylamide group.

5. The preparation method according to claim 2, characterized in that: The antioxidant in S2 is a hindered phenol antioxidant, preferably one or more of monophenol antioxidant 1076, antioxidant 246, antioxidant 1135, bisphenol antioxidant 2246, antioxidant 702, polyphenol antioxidant 330, antioxidant 1010, antioxidant 3114; and / or, The initiator in S2 is selected from organic peroxides, preferably one or more of monofunctional organic peroxides and multifunctional organic peroxides; more preferably, the multifunctional organic peroxide is selected from one or more of 1,1-bis(tert-butylperoxy)-2-methylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, and 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; the monofunctional organic peroxide is selected from one or more of di-tert-butyl peroxide, diisopropyl peroxide and di-tert-butyl isopropyl peroxide.

6. The preparation method according to claim 2 or 5, characterized in that: The acrylonitrile monomer in S2 is one or more of acrylonitrile, methacrylonitrile and ethacrylonitrile; Preferably, S2 contains 0.2-0.4 parts by weight of antioxidant, 0.1-0.3 parts by weight of initiator, 60-80 parts by weight of α-methylstyrene, and 20-40 parts by weight of acrylonitrile monomer.

7. The preparation method according to claim 2, characterized in that: The solvent in S3 is selected from any one of p-xylene, chlorobenzene, and o-dichlorobenzene; Preferably, the S2 mixed solution in S3 is added dropwise; preferably, the dropwise addition time is 2-4h, more preferably 2-3h, and further preferably 2-2.5h; More preferably, the amount of solvent added to S3 is 40-60 parts by weight, the amount of mixed solution added to S2 is 60-40 parts by weight, and the macromolecular RAFT agent PEG n -RAFT is added in an amount of 0.5-1 parts by weight; Further preferably, the insulation temperature in S3 is 110-125° C., and the insulation time is 1-5 h, preferably 2-4 h, and more preferably 3-4 h.

8. The preparation method according to claim 1 or 2, characterized in that: The random copolymer PaMS-co-PAN formed by the reaction was PEGylated n Double-layer block copolymer PEG n -b-(PaMS-co-PAN).

9. A double-layer heat-resistant AMSAN resin PEG n -b-(PaMS-co-PAN), characterized in that The AMSAN resin is prepared by the preparation method according to any one of claims 1 to 8, and the resin has a double-layer structure.

10. Double-layer heat-resistant AMSAN resin PEG prepared by the preparation method according to any one of claims 1 to 8 n -b-(PaMS-co-PAN) or the double-layer heat-resistant AMSAN resin PEG described in claim 9 n -b-(PaMS-co-PAN) is used in the preparation of heat-resistant ABS, especially in the fields of home appliances, office supplies and automobiles.

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