Application of a polysulfone cyclic oligomer in resin modification

Abstract

This invention belongs to the field of polymer materials technology, specifically relating to the application of polysulfone cyclic oligomers in resin modification. This invention applies polysulfone cyclic oligomers to resin modification, which can increase the melt index of the modified resin, thus improving its flowability during injection molding. Simultaneously, this invention transforms polysulfone cyclic oligomers into a valuable resource, realizing the usability of waste materials. The preparation method of polysulfone cyclic oligomers provided by this invention separates the polysulfone cyclic oligomers from polysulfone, reducing the content of polysulfone cyclic oligomers in polysulfone, optimizing the performance of polysulfone, and improving product quality. Furthermore, the separation of polysulfone cyclic oligomers from polysulfone solves the problem of polysulfone crystallization during ultrafiltration membrane casting.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to the application of a polysulfone cyclic oligomer in resin modification. Background Technology

[0002] Currently, the most advanced production process for polysulfone polymers is a one-step synthesis method. This method polymerizes the main raw material, 4,4'-dichlorodiphenyl sulfone, monomers, and alkali metal salts (potassium carbonate or potassium bicarbonate), in a solvent. Commonly used solvents include dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone. Toluene and xylene can be used as dehydrating agents. After polymerization, water, ethanol, or methanol is used as a precipitant. Under the action of the precipitant, the polysulfone separates from the polymer solution. The separated polysulfone is then purified, dried, granulated, and packaged to obtain the polysulfone material. However, the polysulfone material obtained by this one-step synthesis method contains 1–5 wt% cyclic compounds (polysulfone cyclic oligomers), which adversely affects the product quality.

[0003] Polysulfone cyclic oligomers in polysulfone solutions slowly crystallize in polar aprotic solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAC), causing crystallization precipitation problems during the preparation of solvent-based polymers for polysulfone products, such as the casting of ultrafiltration membranes. Furthermore, these cyclic oligomers deposit as hard scale on the walls of polysulfone solution storage containers. Once formed, this scale is extremely difficult to dissolve, insoluble in organic solvents, and difficult to remove even at temperatures up to 400°C, affecting the storage and use of polysulfone materials.

[0004] Currently, research on polysulfone cyclic oligomers mainly focuses on how to remove or reduce the content of polysulfone cyclic oligomers in polysulfone materials, and there are no reports on how to use polysulfone cyclic oligomers. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide an application of polysulfone cyclic oligomers in resin modification. Applying polysulfone cyclic oligomers to resin modification can increase the melt index of the modified resin, which is beneficial for improving the flowability during injection molding.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides an application of polysulfone cyclic oligomers in resin modification.

[0008] Preferably, the application includes the following steps:

[0009] A blend is obtained by mixing polysulfone cyclic oligomers, resins, and additives; the resin includes one or more of polyethersulfone resins, polyphenylene sulfone resins, and polyetheretherketone resins.

[0010] After the blend is dried, it is injection molded.

[0011] Preferably, the additives include fibers and / or pigments.

[0012] Preferably, when the additive is fiber, the blend comprises the following components by mass fraction: 2-5% polysulfone cyclic oligomer, 15-28% fiber, and 70-80% resin.

[0013] Preferably, when the additive is a pigment, the blend comprises the following components by mass fraction: 2-5% polysulfone cyclic oligomer, 0.1-0.5% pigment, and 94.5-97.5% resin.

[0014] Preferably, the polysulfone cyclic oligomer is prepared by a method comprising the following steps:

[0015] The second mixture is added dropwise to the first mixture and refluxed to remove water, and then a polymerization reaction is carried out to obtain a polymer mixture. The first mixture contains bisphenol A, alkali metal substances, dehydrating agents and part of the solvent, and the second mixture contains aromatic dihalogen sulfone monomer and the remaining solvent.

[0016] The polymer mixture was concentrated and then mixed with a precipitation solvent, followed by acidification, solid-liquid separation, washing and drying to obtain a cyclic mixture.

[0017] The cyclic mixture was mixed with dichloromethane and then separated by chromatography to obtain the polysulfone cyclic oligomer.

[0018] Preferably, the aromatic dihalogen sulfone monomer comprises 4,4'-dichlorodiphenyl sulfone and / or 4,4'-difluorodiphenyl sulfone.

[0019] Preferably, the alkali metal-containing substance includes alkali metal hydroxides or alkali metal salts.

[0020] Preferably, the dehydrating agent includes one or more of toluene, xylene, ethylbenzene, and chlorobenzene.

[0021] Preferably, the polysulfone cyclic oligomer is prepared by a method comprising the following steps:

[0022] Bisphenol A, aromatic dihalogen sulfone monomer, dehydrating agent, alkali metal substance and first solvent are mixed and refluxed to remove water, and then a polymerization reaction is carried out to obtain polymer mixture.

[0023] The polymer mixture was subjected to desalting, dispersion precipitation, washing and drying in sequence to obtain the polymer;

[0024] After mixing the polymer and the second solvent, the mixture was allowed to stand and then subjected to solid-liquid separation to obtain an insoluble substance.

[0025] The insoluble substance was mixed with dichloromethane and then separated by chromatography to obtain the polysulfone cyclic oligomer.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention applies polysulfone cyclic oligomers to resin modification. The high fluidity of polysulfone cyclic oligomers can increase the melt flow index (melt mass flow rate) of the modified resin, which is beneficial for improving flowability during injection molding. Simultaneously, this invention transforms polysulfone cyclic oligomers into a valuable resource, realizing the usability of waste materials.

[0028] Furthermore, the method for preparing polysulfone cyclic oligomers provided by the present invention involves mixing the polymer with a second solvent, followed by sequential standing and solid-liquid separation to separate the polysulfone cyclic oligomers from the polysulfone. This reduces the content of polysulfone cyclic oligomers in the polysulfone, optimizes the performance of the polysulfone, and improves product quality. At the same time, separating the polysulfone cyclic oligomers from the polysulfone solves the problem of polysulfone crystallization during ultrafiltration membrane casting. Detailed Implementation

[0029] This invention provides an application of polysulfone cyclic oligomers in resin modification.

[0030] Unless otherwise specified, all materials and equipment used in this invention are commercially available products in the field.

[0031] In this invention, the polysulfone cyclic oligomer is a product of the synthesis of bisphenol A type polysulfone (PSU). The polysulfone cyclic oligomer preferably includes polysulfone cyclic dimers and polysulfone cyclic tetramers. The content of the polysulfone cyclic dimer is preferably greater than 90 wt%. The structural formula of the polysulfone cyclic dimer is shown in Formula I.

[0032]

[0033] In this invention, the polysulfone cyclic oligomer is preferably prepared by preparation method one or preparation method two, wherein preparation method one preferably includes the following steps:

[0034] The second mixture is added dropwise to the first mixture and refluxed to remove water, and then a polymerization reaction is carried out to obtain a polymer mixture. The first mixture contains bisphenol A, alkali metal substances, dehydrating agents and part of the solvent, and the second mixture contains aromatic dihalogen sulfone monomer and the remaining solvent.

[0035] The polymer mixture was concentrated and then mixed with a precipitation solvent, followed by acidification, solid-liquid separation, washing and drying to obtain a cyclic mixture.

[0036] The cyclic mixture was mixed with dichloromethane and then separated by chromatography to obtain the polysulfone cyclic oligomer.

[0037] In this invention, a second mixture is added dropwise to a first mixture and refluxed to remove water, followed by a polymerization reaction to obtain a polymer mixture. The first mixture contains bisphenol A, an alkali metal substance, a dehydrating agent, and a portion of the solvent. The second mixture contains an aromatic dihalogen sulfone monomer and the remaining portion of the solvent.

[0038] In this invention, the aromatic dihalogen sulfone monomer preferably includes 4,4'-dichlorodiphenyl sulfone (DCPDS) and / or 4,4'-difluorodiphenyl sulfone (DFDPS).

[0039] In this invention, the molar ratio of bisphenol A to aromatic dihalogen sulfone monomer is preferably 1 to 1.05:1, more preferably 1:1.

[0040] In this invention, the alkali metal-containing substance preferably includes alkali metal hydroxides or alkali metal salts, the alkali metal hydroxides preferably include sodium hydroxide and / or potassium hydroxide, and the alkali metal salts preferably include one or more of sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, and sodium hydride.

[0041] In this invention, the molar ratio of the alkali metal substance and bisphenol A is preferably 1.0 to 2.0:1, more preferably 1.05:1.

[0042] In this invention, the water-removing agent preferably includes one or more of toluene, xylene, ethylbenzene and chlorobenzene, more preferably toluene.

[0043] In this invention, the volume ratio of the water-removing agent to the solvent is preferably 5 to 100:100, the solvent includes a partial solvent and a remaining partial solvent, and the mass ratio of the partial solvent to the remaining partial solvent is preferably 5 to 10:1, more preferably 2000.7458:325.0000.

[0044] In this invention, the solvent is preferably an aprotic polar solvent, which preferably includes one or more of dimethyl sulfoxide (DMSO), dimethyl sulfone, diphenyl sulfone (DPS), diethylene sulfoxide, sulfolane, tetrahydrothiophene-1-oxide, N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and 1,3-dimethyl-2-imidazolinone (DMI).

[0045] In this invention, the step of adding the first mixture preferably includes purging the first mixture with nitrogen and performing a first reflux to remove water. The nitrogen purging time is preferably 15 to 30 minutes, the temperature of the first reflux to remove water is preferably 150°C, and the time is determined by the point at which no more water is produced.

[0046] In this invention, the dripping rate is preferably 1 to 3 drops / s, the dripping can make the reaction more complete, and the dripping time is preferably 3 hours; the dripping is preferably carried out in a reflux dehydration state, the reflux dehydration temperature is preferably 162°C, and the reflux dehydration is stopped after the dripping is completed.

[0047] In this invention, the temperature of the polymerization reaction is preferably 150-170°C, more preferably 162°C, and the time is preferably 6 hours.

[0048] In this invention, the solid content of the polymer mixture is preferably below 1%, and the polymer in the polymer mixture after the polymerization reaction is mainly polysulfone cyclic oligomers.

[0049] After obtaining the polymer mixture, the present invention concentrates the polymer mixture and mixes it with a precipitation solvent, and then performs acidification, solid-liquid separation, washing and drying in sequence to obtain a cyclic mixture.

[0050] In this invention, the solid content of the concentrated polymer mixture is preferably 60-80%.

[0051] In this invention, the precipitation solvent preferably includes one or more of methanol, ethanol, and water.

[0052] In this invention, the volume ratio of the concentrated polymer mixture to the precipitating solvent is preferably 1:5, and the cyclic mixture precipitates out in the form of a precipitate after the addition of the precipitating solvent.

[0053] In this invention, the acidifying reagent is preferably hydrochloric acid, the concentration of the hydrochloric acid is preferably 36-38%, the volume ratio of the hydrochloric acid to the precipitation solvent is preferably 1:100, and the purpose of acidification is to demulsify.

[0054] In this invention, the acidification process preferably includes a settling period, during which a precipitate forms. This invention does not have any special requirements for the solid-liquid separation method, such as filtration or vacuum filtration, and the obtained solid is washed and dried sequentially.

[0055] In this invention, the washing reagent is preferably pure water, and the washing is preferably performed 8 times.

[0056] In this invention, the drying temperature is preferably 150°C and the drying time is preferably 2 hours.

[0057] After obtaining the cyclic mixture, the present invention mixes the cyclic mixture with dichloromethane and separates them by passing through a chromatography column to obtain the polysulfone cyclic oligomer.

[0058] In this invention, the cyclic mixture preferably includes polysulfone cyclic oligomers, polysulfone cyclic polymers, and unreacted monomers. The solid content of the solution after mixing the cyclic mixture with dichloromethane is preferably 20-30%, and the amount of dichloromethane used is sufficient to completely dissolve the cyclic mixture.

[0059] In this invention, the packing material of the chromatography column is preferably fluorescent silica gel (silica gel GF254). The solution obtained by mixing the cyclic compound mixture with dichloromethane is poured into the chromatography column and eluted with dichloromethane. The resulting eluent is then subjected to solvent removal and drying to obtain the polysulfone cyclic oligomer. This invention does not have special requirements for the solvent removal and drying methods; methods commonly used by those skilled in the art can be employed.

[0060] In this invention, the second preparation method preferably includes the following steps:

[0061] Bisphenol A, aromatic dihalogen sulfone monomer, dehydrating agent, alkali metal substance and first solvent are mixed and refluxed to remove water, and then a polymerization reaction is carried out to obtain polymer mixture.

[0062] The polymer mixture was subjected to desalting, dispersion precipitation, washing and drying in sequence to obtain the polymer;

[0063] After mixing the polymer and the second solvent, the mixture was allowed to stand and then subjected to solid-liquid separation to obtain an insoluble substance.

[0064] The insoluble substance was mixed with dichloromethane and then separated by chromatography to obtain the polysulfone cyclic oligomer.

[0065] In this invention, bisphenol A, aromatic dihalogen sulfone monomer, dehydrating agent, alkali metal substance and first solvent are mixed and refluxed to remove water, and then a polymerization reaction is carried out to obtain polymer mixture.

[0066] In this invention, the types of bisphenol A, aromatic dihalogen sulfone monomer, dehydrating agent, and alkali metal substance are preferably the same as those in preparation method one, and will not be repeated here; the molar ratio of bisphenol A and aromatic dihalogen sulfone monomer is preferably 1:1.0 to 1.2; the volume ratio of dehydrating agent to first solvent is preferably 5 to 100:100; and the molar ratio of alkali metal substance to bisphenol A is preferably 1.0 to 2.0:1.

[0067] In this invention, the type of the first solvent is preferably the same as that of the solvent in preparation method one, and will not be repeated here.

[0068] In this invention, nitrogen purging is included before the reflux water removal, and the nitrogen purging time is preferably 15 to 30 minutes; the temperature of the reflux water removal is preferably 150°C, and the time is preferably stopped when the water output reaches the theoretical value.

[0069] In this invention, the polymerization reaction temperature is preferably 165°C, and the time is preferably adjusted according to the molecular weight of the polysulfone product to be prepared, preferably 4 to 12 hours.

[0070] After obtaining the polymer mixture, the present invention sequentially performs desalting, dispersion precipitation, washing and drying on the polymer mixture to obtain the polymer.

[0071] The present invention does not have any special requirements for the methods of desalination, dispersion precipitation, washing and drying; methods commonly used by those skilled in the art can be used.

[0072] After obtaining the polymer, the present invention mixes the polymer with the second solvent, and then performs static standing and solid-liquid separation in sequence to obtain the insoluble substance.

[0073] In this invention, the second solvent is preferably N,N-dimethylacetamide, and the polymer content in the solution after the polymer and the second solvent are mixed is preferably 20 wt%. After the polymer and the second solvent are mixed, bisphenol A type polysulfone dissolves, and the precipitate is mainly polysulfone cyclic oligomer.

[0074] In this invention, the settling time is preferably 24 hours, and the purpose of settling is to allow the insoluble matter to precipitate completely.

[0075] In this invention, the solid-liquid separation method is preferably vacuum filtration, and the solid-liquid separation preferably further includes washing and drying in sequence. This invention does not have any special requirements for the washing and drying methods.

[0076] After obtaining the insoluble material, the present invention mixes the insoluble material with dichloromethane and separates them by passing through a chromatography column to obtain the polysulfone cyclic oligomer.

[0077] In this invention, the method of separating the insoluble matter and dichloromethane by passing them through a chromatography column is preferably the same as the method of separating the cyclic mixture and dichloromethane by passing them through a chromatography column in preparation method one, and will not be repeated here.

[0078] In this invention, the application preferably includes the following steps:

[0079] A blend is obtained by mixing polysulfone cyclic oligomers, resins, and additives; the resins include one or more of polyethersulfone resins (PES), polyphenylene sulfone resins (PPSU), and polyether ether ketone resins (PEEK).

[0080] After the blend is dried, it is injection molded.

[0081] The present invention involves mixing polysulfone cyclic oligomers, resins, and additives to obtain a blend; the resin preferably includes one or more of polyethersulfone resins, polyphenylene sulfone resins, and polyetheretherketone resins.

[0082] In this invention, the additive preferably includes fibers and / or pigments, wherein the fibers are preferably chopped fibers (1-15 mm in length), the diameter of the chopped fibers is preferably 9-13 μm, and the material of the chopped fibers preferably includes glass fibers and / or carbon fibers; the pigments preferably include one or more of orange inorganic pigments, yellow inorganic pigments, titanium dioxide, iron oxide pigments, and carbon black, more preferably titanium dioxide.

[0083] In this invention, when the additive is preferably fiber, the blend preferably comprises the following components by mass fraction: 2-5% polysulfone cyclic oligomer, 15-28% fiber and 70-80% resin; more preferably, it comprises the following components by mass fraction: 5% polysulfone cyclic oligomer, 20% fiber and 75% resin.

[0084] In this invention, when the additive is preferably a pigment, the blend preferably comprises the following components by mass fraction: 2-5% polysulfone cyclic oligomer, 0.1-0.5% pigment, and 94.5-97.5% resin; more preferably, it comprises the following components by mass fraction: 5% polysulfone cyclic oligomer, 0.2% pigment, and 94.8% resin.

[0085] In this invention, when the additive is preferably a mixture of fiber and pigment, the blend preferably comprises the following components by mass fraction: 2-5% polysulfone cyclic oligomer, 10-30% fiber, 0.1-0.5% pigment, and the balance being resin.

[0086] The present invention does not have any special requirements for the method of mixing the polysulfone cyclic oligomer, resin and additives. In specific embodiments of the present invention, such as mixing in a mixer.

[0087] After obtaining the blend, the present invention dries the blend and then performs injection molding.

[0088] In this invention, the drying temperature is preferably 100-120°C, more preferably 110°C, and the drying time is preferably 2-12 hours.

[0089] In this invention, the drying process preferably includes extrusion granulation to obtain blend particles, wherein the extrusion temperature for granulation is preferably 320–350°C, more preferably 330–340°C.

[0090] In this invention, the injection molding temperature is preferably 320-350°C, more preferably 330-340°C. This invention does not have any special requirements for the injection molding method; any method commonly used by those skilled in the art can be adopted.

[0091] To further illustrate the present invention, the application of the polysulfone cyclic oligomers of the present invention in resin modification is described in detail below with reference to the embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0092] Example 1

[0093] Add 100 mL of toluene, 7.6281 g of potassium carbonate, 12.0000 g (0.0526 mol) of bisphenol A and 2000.7458 g of DMAC to a 3000 mL four-necked glass flask equipped with a stirrer, nitrogen tube, constant pressure funnel, and water separator with reflux condenser. Then add 15.0947 g (0.0526 mol) of 4,4'-dichlorodiphenyl sulfone and 325.0000 g of DMAC to the constant pressure funnel. Purge the system with nitrogen for 15 min and heat to 150 °C, maintaining a reflux state with water content until the water output reaches the theoretical value. Raise the temperature to 162 °C and continue maintaining a reflux state with water content. Begin adding the liquid from the constant pressure funnel dropwise into the system over 3 h. Maintain this temperature for 6 h of polymerization. Change the apparatus to a distillation apparatus and begin concentrating the liquid to 200 mL. The concentrated polymer solution was poured into a beaker containing 1000 mL of pure water for dispersion and precipitation. Then, 10 mL of concentrated hydrochloric acid was added to break the emulsion. After standing, the mixture was vacuum filtered to obtain a white solid. The separated white solid was then washed eight times with pure water, filtered again, and dried in an oven at 150 °C for 2 hours. The white solid was dissolved in dichloromethane until completely dissolved, and then separated using a silica gel column chromatography (the resulting solution was poured into the column and eluted with dichloromethane; the eluent was then subjected to solvent removal and drying sequentially) to obtain polysulfone cyclic oligomers.

[0094] Example 2

[0095] 243.0000 g (0.7674 mol) bisphenol A, 100 mL toluene, 215.0000 g (0.7487 mol) DCPDS, 155.2122 g (1.1231 mol) K2CO3, and 916.0000 g DMAC were added to a 3000 mL glass flask equipped with a stirrer, nitrogen tube, and a water separator with a reflux condenser. The reaction mixture was purged with nitrogen for 15 min and heated to 150 °C under reflux conditions until the water output reached the theoretical value, at which point reflux was stopped. After the toluene was completely removed, the temperature was rapidly increased to 165 °C and maintained until the desired molecular weight was achieved. The polymer was then desalted, and the desalted polymer solution was dispersed, precipitated, washed, and dried. The dried polymer was dissolved in DMAC with a solid content of 20%, and allowed to stand for 24 hours. After the insoluble matter was completely precipitated, it was vacuum filtered to separate the insoluble matter. After washing and drying, the insoluble matter was also dissolved in dichloromethane and then separated by a chromatography column to obtain polysulfone cyclic oligomers.

[0096] Examples 3-7 and Comparative Examples 1-5 all used the polysulfone cyclic oligomers (also known as cyclic products) prepared in Example 1.

[0097] Example 3

[0098] 5 wt% of cyclic compound (0.1 kg), 20 wt% of glass fiber (0.4 kg) and 75 wt% of PES resin (1.5 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C in an extrusion granulator to obtain blended granules. The blended granules were then injection molded in an injection molding machine.

[0099] Example 4

[0100] 5 wt% of cyclic compound (0.1 kg), 20 wt% of glass fiber (0.4 kg) and 75 wt% of PPSU resin (1.5 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C on an extrusion granulator to obtain blended granules. The blended granules were then injection molded on an injection molding machine.

[0101] Example 5

[0102] 5 wt% of cyclic compound (0.1 kg), 0.2 wt% of titanium dioxide (0.004 kg) and 94.8 wt% of PPSU resin (1.896 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C in an extrusion granulator to obtain blended granules. The blended granules were then injection molded in an injection molding machine.

[0103] Example 6

[0104] 5 wt% of cyclic compound (0.1 kg), 0.2 wt% of titanium dioxide (0.004 kg) and 94.8 wt% of PES resin (1.896 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C in an extrusion granulator to obtain blended granules. The blended granules were then injection molded in an injection molding machine.

[0105] Example 7

[0106] 5 wt% of cyclic compound (0.1 kg), 20 wt% of glass fiber (0.4 kg) and 75 wt% of PEEK resin (1.5 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C in an extrusion granulator to obtain blended granules. The blended granules were then injection molded in an injection molding machine.

[0107] Comparative Example 1

[0108] 20wt% glass fiber (0.4kg) and 80wt% PPSU resin (1.60kg) were mixed evenly in a mixer and dried in an oven at 110℃ for 2h. Then, the mixture was extruded at an extrusion temperature of 330℃ on an extrusion granulator to obtain blended granules. The blended granules were then injection molded on an injection molding machine.

[0109] Comparative Example 2

[0110] 0.2 wt% titanium dioxide (0.004 kg) and 99.8 wt% PES resin (1.996 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C on an extrusion granulator to obtain blended granules. The blended granules were then injection molded on an injection molding machine.

[0111] Comparative Example 3

[0112] 0.4 kg of 20 wt% glass fiber and 1.60 kg of 80 wt% PEEK resin were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. The mixture was then extruded at 330°C in an extrusion granulator to obtain blended granules. The blended granules were then injection molded in an injection molding machine.

[0113] Comparative Example 4

[0114] 20wt% glass fiber (0.4kg) and 80wt% PES resin (1.60kg) were mixed evenly in a mixer and dried in an oven at 110℃ for 2h. Then, the mixture was extruded at an extrusion temperature of 330℃ on an extrusion granulator to obtain blended granules. The blended granules were then injection molded on an injection molding machine.

[0115] Comparative Example 5

[0116] 0.2 wt% titanium dioxide (0.004 kg) and 99.8 wt% PPSU resin (1.996 kg) were mixed evenly in a mixer and dried in an oven at 110°C for 2 hours. Then, the mixture was extruded at 330°C in an extrusion granulator to obtain blended granules. The blended granules were then injection molded in an injection molding machine.

[0117] The performance of the injection-molded samples from Examples 3-7 and Comparative Examples 1-5 was tested using a melt flow rate tester and a universal testing machine, respectively. The results are shown in Table 1.

[0118] Table 1 Comparison of changes in mechanical properties and melt flow index

[0119]

[0120] Note: All data were measured under the same experimental conditions, and resins of the same type are from the same batch.

[0121] As can be seen from the data in Table 1, the addition of polysulfone cyclic oligomers can enhance the fluidity of the modified resin. While increasing the melt flow index (melt mass flow rate), it does not affect other performance indicators, which is beneficial to improving the fluidity of the resin during injection molding.

[0122] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. The application of a polysulfone cyclic oligomer in resin modification, characterized in that, The application includes the following steps: After mixing 5 wt% polysulfone cyclic oligomer, 0.2 wt% titanium dioxide and 94.8 wt% PES resin evenly in a mixer, the mixture is dried in an oven at 110°C for 2 hours. Then, it is extruded on an extrusion granulator at an extrusion temperature of 330°C to obtain blend particles. The blend particles are then injection molded on an injection molding machine. The polysulfone cyclic oligomer includes a polysulfone cyclic dimer and a polysulfone cyclic tetramer, wherein the content of the polysulfone cyclic dimer is greater than 90 wt%, and the structural formula of the polysulfone cyclic dimer is shown in Formula I: Equation I; The method for preparing the polysulfone cyclic oligomer includes the following steps: Add 100 mL of toluene, 7.6281 g of potassium carbonate, 12.0000 g of bisphenol A, and 2000.7458 g of DMAC to a 3000 mL four-necked glass flask equipped with a stirrer, nitrogen tube, constant pressure funnel, and water separator with reflux condenser. Then add 15.0947 g of 4,4'-dichlorodiphenyl sulfone and 325.0000 g of DMAC to the constant pressure funnel. Purge the system with nitrogen for 15 min and heat to 150 °C, maintaining a reflux state with water content until the water output reaches the theoretical value. Raise the temperature to 162 °C and continue maintaining a reflux state with water content. Begin adding the liquid from the constant pressure funnel dropwise into the system over 3 h, maintaining this temperature for 6 h of polymerization. Change the apparatus to a distillation apparatus and begin concentrating the liquid to 200 mL. Pour the concentrated polymer solution into a beaker containing 1000 mL of pure water. The precipitate was dispersed, and then 10 mL of concentrated hydrochloric acid was added to break the emulsion. After standing, the mixture was vacuum filtered to obtain a white solid. The separated white solid was then washed 8 times with pure water, filtered again, and dried in an oven at 150°C for 2 hours. The white solid was dissolved in dichloromethane until it was completely dissolved, and then separated using a silica gel chromatography column. The silica gel chromatography column separation was performed by pouring the obtained solution into the chromatography column and eluting it with dichloromethane. The eluent was then subjected to solvent removal and drying to obtain polysulfone cyclic oligomers.

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