Synthesis of low molecular weight polystyrene based on anionic chain transfer polymerization method and method of preparation thereof

Abstract

The application relates to a low-molecular-weight polystyrene synthesized based on an anion chain transfer polymerization method and a preparation method thereof, and belongs to the technical field of polymer preparation. First, in a high-purity argon environment free of water and oxygen, an organic monomer, an organic solvent, a polarity regulator, a chain transfer agent and an initiator are sequentially added into a reaction container, anion polymerization is initiated by the initiator, and the reaction container is sealed by a gland; the chain transfer agent is a derivative with a lively metal-carbon bond; secondly, a terminating agent is added into a polymer system after reaction to terminate the reaction; finally, the polymer system after termination is subjected to gel precipitation, filtration, washing and vacuum drying to obtain a low-molecular-weight polymer. The application adds the chain transfer agent with the lively metal-carbon bond structure into a polymerization system to obtain low-molecular-weight polystyrene, which can be applied to the fields of electronics, medical treatment and the like. Compared with the current technology, the application can not only save initiator cost, but also simplify a process flow, is environment-friendly and is beneficial to industrialized production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polymer preparation, and since the polymerization rate of styrene is fast and difficult to control, the rate curve is in an "S" shape, so that the molecular weight is difficult to control. BACKGROUND

[0002] Living polymerization refers to a polymerization reaction under appropriate synthesis conditions, no chain termination and chain transfer reaction, the concentration of active center remains constant for several times longer than the time required for the completion of the reaction, and its typical representative is anion polymerization.

[0003] In recent years, low molecular weight polymer materials have extremely high research value due to their excellent performance and wide application fields, and have attracted widespread attention from the industry and academia, and have become one of the hotspots in the field of high polymer material research.

[0004] In 1920, Staudinger in Germany carried out the polymerization of styrene, and proposed that polystyrene is a linear polymer formed by connecting styrene monomers together, thereby establishing the theory of high polymers. In 1933, the research on synthetic rubber in Germany succeeded in preparing butadiene-styrene copolymer to prepare butadiene-styrene rubber, which was valued as a strategic material, thereby quickly promoting the industrialization of styrene. In 1934, the synthesis of styrene from ethylbenzene by dehydrogenation was successful, and in 1935, one year later, the industrialization of polystyrene was also successful. This opened the era of polystyrene industrialization.

[0005] With the advent of the information age, the preparation of materials for electronic components has become a new problem. Such polymers have good electrochemical properties and dielectric properties and can be applied in the fields of transistors and diodes. SUMMARY

[0006] In view of the problems existing in the prior art, the application provides a low molecular weight polystyrene synthesized based on an anionic chain transfer polymerization method and a preparation method thereof. The application adopts living anion polymerization, reduces the molecular weight of polystyrene under the action of a certain chain transfer agent, so that it is within the control range, and through the comparison of the amount of the chain transfer agent and the amount of the polarity regulator, the best one is found under a certain combination, which is endowed with unique properties to meet the application in different fields.

[0007] In order to achieve the above purpose, the technical scheme adopted by the application is as follows:

[0008] A preparation method of low molecular weight polystyrene synthesized based on an anionic chain transfer polymerization method, comprising the following steps:

[0009] (1) In an anhydrous and oxygen-free high-purity argon environment, organic monomers, organic solvents, polarity modifiers, chain transfer agents and initiators are added to the reaction vessel in sequence. After the anionic polymerization is initiated by the initiator, the reaction vessel is sealed with a pressure cap.

[0010] The chain transfer agent is a derivative with an active metal-carbon bond, including dibutylmagnesium, benzyl magnesium bromide, and ethyl magnesium bromide;

[0011] The organic monomers mentioned include styrene, isoprene, etc.

[0012] The organic solvents mentioned include cyclohexane, methylcyclohexane, benzene, etc.

[0013] The polarity modifiers include tetrahydrofuran (THF), tetramethylethylenediamine (TMEDA), dimethoxyethane (DME), diethylene glycol diethyl ether (2G), and triethylamine.

[0014] The initiators include alkyllithium, alkyl alkali metal oxides, or sodium naphthalene.

[0015] The anionic polymerization temperature is 25℃~60℃, and the time is 2~3h;

[0016] The mass ratio of organic solvent to organic monomer in the reaction system is 5-10:1, and the amount of initiator is 0.305% of the mass of organic monomer; the molar ratio of chain transfer agent to initiator is 1-3:1; when the polarity modifier is TMEDA, the equivalence ratio is 1-2:1; when the polarity modifier is THF, the equivalence ratio is 173-693:1.

[0017] (2) A terminator is added to the polymer system after the reaction to terminate the reaction; the terminator is methanol.

[0018] (3) The terminated polymer system is subjected to precipitation, filtration, washing, and vacuum drying to obtain a low molecular weight polymer.

[0019] The vacuum drying temperature is 25℃~40℃, and the time is 18h~48h.

[0020] The amounts added were in gradients of 1.5 Li equivalent, 2 Li equivalent, and 3 Li equivalent for comparison.

[0021] The amounts added were 173 equivalents, 277 equivalents, 555 equivalents, and 693 equivalents, and were compared.

[0022] The reaction mechanism of this invention is as follows: the initiator initiates the polymerization of styrene, making styrene an active species, while the added chain transfer agent rapidly participates in the reaction, becoming an active species and continuing to grow. At this point, the initiation end is no longer the initiator, but the chain transfer agent or the monomeric styrene.

[0023] A method for synthesizing low molecular weight polystyrene based on anionic chain transfer polymerization is characterized in that the low molecular weight polymer has a molecular weight of 3000-16000. w / M n The value ranges from 1.03 to 1.66.

[0024] Compared with simple styrene polymerization, the beneficial effects of this invention are as follows:

[0025] (1) The addition of chain transfer agents, polarity modifiers and initiators can yield polymers with lower molecular weight and narrower distribution, which have great research and development value.

[0026] (2) The amount of initiator used is greatly reduced, saving costs and making it easier to remove metal impurities from the initiation end.

[0027] (3) This method has a high yield. Attached Figure Description

[0028] Figure 1 The GPC spectra of polystyrene without chain transfer agent in Comparative Example 1 and polystyrene with chain transfer agent dibutylmagnesium in Example 1 are compared.

[0029] Figure 2 The NMR spectra of polystyrene without chain transfer agent in Comparative Example 1 and polystyrene with chain transfer agent dibutylmagnesium in Example 1 are compared.

[0030] Figure 3 Examples 6, 9, and 12 show a comparison of the GPC spectra of polystyrene with different equivalents of dibutylmagnesium under the same polarity modifier THF, using styrene as the monomer.

[0031] Figure 4 The comparison of the 1H NMR spectra of polystyrene with different equivalents of dibutylmagnesium under the same polarity modifier THF is shown in Examples 6, 9, and 12.

[0032] Figure 5 The image shows the MALDI-TOF MS spectrum of Example 6.

[0033] Figure 6 The GPC spectra of polystyrene with different equivalents of polar modifier THF are compared for Examples 15, 18, and 21, using styrene as the monomer and under the same equivalent of dibutylmagnesium.

[0034] Figure 7 The GPC spectrum for Example 24 is obtained using styrene as a monomer and tetramethylethylenediamine (TMEDA) as a polarity modifier. Detailed Implementation

[0035] The present invention provides the following embodiments as further illustration, but these are not intended to limit the scope of protection of the claims. The molecular weight and molecular weight distribution index (PDI) of the polymer were analyzed using gel permeation chromatography.

[0036] Anionic polymerization is carried out by sequentially adding monomers, organic solvents, polarity modifiers, chain transfer agents, and initiators to the system.

[0037] Example 1

[0038] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0039] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0040] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0041] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 16,000 and a PDi of 1.16.

[0042] Example 2

[0043] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, add 50g of cyclohexane as a solvent, add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 40℃ for two and a half hours.

[0044] (2) After the reaction has been going on for two and a half hours, the sealed container was removed from the glove box and 2 ml of isopropanol was drawn into the reaction container by a 2 ml syringe that had been repeatedly blown with high-purity argon gas to terminate the reaction.

[0045] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0046] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 15300 and a PDi of 1.14.

[0047] Example 3

[0048] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0049] (2) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0050] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0051] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 14,500 and a PDi of 1.12.

[0052] Example 4

[0053] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0054] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0055] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0056] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 96% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3497 and a PDi of 1.37.

[0057] Example 5

[0058] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir and react in a sand bath at 40℃ for two and a half hours.

[0059] (2) After the reaction has been going on for two and a half hours, the sealed container was removed from the glove box and 2 ml of isopropanol was drawn into the reaction container by a 2 ml syringe that had been repeatedly blown with high-purity argon gas to terminate the reaction.

[0060] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0061] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 96% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3289 and a PDi of 1.30.

[0062] Example 6

[0063] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0064] (2) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0065] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0066] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 96% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3081 and a PDi of 1.25.

[0067] Example 7

[0068] (1) Select a 100ml capped polymerization bottle and place it in the transition chamber of the glove box. Use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times and then take it into the glove box. Add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 2 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0069] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0070] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0071] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3185 and a PDi of 1.36.

[0072] Example 8

[0073] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 2 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir and react in a sand bath at 45℃ for two and a half hours.

[0074] (2) After the reaction has been going on for two and a half hours, the sealed container was removed from the glove box and 2 ml of isopropanol was drawn into the reaction container by a 2 ml syringe that had been repeatedly blown with high-purity argon gas to terminate the reaction.

[0075] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0076] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3081 and a PDi of 1.34.

[0077] Example 9

[0078] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 2 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0079] (2) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0080] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0081] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.26.

[0082] Example 10

[0083] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 3 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0084] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0085] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0086] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.31.

[0087] Example 11

[0088] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 3 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir and react in a sand bath at 40℃ for two and a half hours.

[0089] (2) After the reaction has been going on for two and a half hours, the sealed container was removed from the glove box and 2 ml of isopropanol was drawn into the reaction container by a 2 ml syringe that had been repeatedly blown with high-purity argon gas to terminate the reaction.

[0090] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0091] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.30.

[0092] Example 12

[0093] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 173 equivalents of THF as a polarity regulator, then add 3 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0094] (2) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0095] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0096] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2873 and a PDi of 1.21.

[0097] Example 13

[0098] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 277 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0099] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0100] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0101] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3603 and a PDi of 1.23.

[0102] Example 14

[0103] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 277 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir and react in a sand bath at 40℃ for two and a half hours.

[0104] (2) After the reaction has been going on for two and a half hours, the sealed container was removed from the glove box and 2 ml of isopropanol was drawn into the reaction container by a 2 ml syringe that had been repeatedly blown with high-purity argon gas to terminate the reaction.

[0105] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0106] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3499 and a PDi of 1.20.

[0107] Example 15

[0108] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 277 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0109] (2) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0110] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0111] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3395 and a PDi of 1.20.

[0112] Example 16

[0113] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 555 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0114] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0115] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0116] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3081 and a PDi of 1.57.

[0117] Example 17

[0118] (4) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 555 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir and react in a sand bath at 40℃ for two and a half hours.

[0119] (5) After the reaction has been going on for two and a half hours, remove the sealed container from the glove box and inject 2 ml of isopropanol into the reaction container using a 2 ml syringe that has been repeatedly blown with high-purity argon to terminate the reaction.

[0120] (6) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0121] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 3081 and a PDi of 1.51.

[0122] Example 18

[0123] (7) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 555 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0124] (8) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly purged with high-purity argon to draw 2ml of isopropanol into the reaction container to terminate the reaction.

[0125] (9) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0126] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.50.

[0127] Example 19

[0128] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 693 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0129] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0130] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0131] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.66.

[0132] Example 20

[0133] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 693 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir and react in a sand bath at 40℃ for two and a half hours.

[0134] (2) After the reaction has been going on for two and a half hours, the sealed container was removed from the glove box and 2 ml of isopropanol was drawn into the reaction container by a 2 ml syringe that had been repeatedly blown with high-purity argon gas to terminate the reaction.

[0135] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0136] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.50.

[0137] Example 21

[0138] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 693 equivalents of THF as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0139] (2) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0140] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0141] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 2977 and a PDi of 1.41.

[0142] Example 22

[0143] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 2 equivalents of TMEDA as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 25℃ for three hours.

[0144] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0145] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0146] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 6775 and a PDi of 1.27.

[0147] Example 23

[0148] (4) Select a 100ml capped polymerization bottle and place it in the transition chamber of the glove box. Use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times and then take it into the glove box. Add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 2 equivalents of TMEDA as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir and react in a sand bath at 40℃ for two and a half hours.

[0149] (5) After the reaction has been going on for two and a half hours, remove the sealed container from the glove box and inject 2 ml of isopropanol into the reaction container using a 2 ml syringe that has been repeatedly blown with high-purity argon to terminate the reaction.

[0150] (6) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0151] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 6567 and a PDi of 1.22.

[0152] Example 24

[0153] (7) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, then add 50g of cyclohexane as a solvent, then add 2 equivalents of TMEDA as a polarity regulator, then add 1.5 equivalents of dibutylmagnesium as a chain transfer agent, and then add 170μL of sec-butyllithium initiator (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for two hours.

[0154] (8) After two hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly purged with high-purity argon to draw 2ml of isopropanol into the reaction container to terminate the reaction.

[0155] (9) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0156] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 99% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 6255 and a PDi of 1.14.

[0157] Comparative Example 1

[0158] (1) Select a 100ml capped polymerization bottle, place it in the transition chamber of the glove box, and use a vacuum pump and high-purity argon to perform evacuation and gas replenishment operations. Repeat this three times, then take it into the glove box, add 10g of styrene monomer to the polymerization bottle, add 50g of cyclohexane as a solvent, and add 170μL of initiator sec-butyllithium (concentration of 1.3mol / L). Stir the reaction in a sand bath at 60℃ for three hours.

[0159] (2) After three hours of reaction, remove the sealed container from the glove box and use a 2ml syringe repeatedly blown with high-purity argon to draw 2ml of isopropanol and inject it into the reaction container to terminate the reaction.

[0160] (3) The terminated reaction mixture was slowly poured into a beaker containing 400 ml of anhydrous methanol for sedimentation. After stirring and standing overnight, it was filtered, washed and vacuum dried to finally obtain the powder product.

[0161] The low molecular weight polystyrene synthesized using the technology described in this embodiment had a monomer conversion rate of 98% obtained by gravimetric analysis. The molecular weight was measured using a Waters Alliance 2000 gel permeation chromatography system, yielding a number-average molecular weight of 69,738 and a PDi of 1.03.

[0162] The data shows that the molecular weight decreased significantly after adding the chain transfer agent, but remained around 16,000. However, after adding different equivalents of polar modifier, the molecular weight dropped to around 3,000. The higher the equivalent of polar modifier added, the better the chain transfer effect, indicating that the chain transfer agent and polar modifier must be added simultaneously to achieve better results. With the same equivalent of polar modifier, the higher the equivalent of chain transfer agent added, the better the chain transfer effect. Therefore, when preparing polymers of the same molecular weight, introducing the chain transfer agent of this invention can significantly reduce actual costs, i.e., the amount of initiator used, while still achieving the same effect. Furthermore, it simplifies the process and protects the environment.

[0163] The embodiments described above are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A production method of synthesizing low molecular weight polystyrene based on an anionic chain transfer polymerization method, characterized by, The method comprises the following steps: In the first step, under the condition of no water, no oxygen and high-purity argon, organic monomers, organic solvents, polarity regulators, chain transfer agents and initiators are sequentially added into a reaction container, and the anionic polymerization is initiated by the initiators, and then the reaction container is sealed by a gland; the chain transfer agent is a derivative with a labile metal-carbon bond; the temperature of the anionic polymerization is 25-60 DEG C, and the time is 2-3 hours; the chain transfer agent includes dibutyl magnesium, benzyl magnesium bromide and ethyl magnesium bromide; the amount of the initiator is 0.305% of the mass of the organic monomers; the molar ratio of the chain transfer agent to the initiator is 1-3:1; In the second step, a termination agent is added into the polymer system after the reaction to terminate the reaction; In the third step, the polymer system after termination is subjected to gel precipitation, filtration, washing and vacuum drying to obtain a low-molecular-weight polymer.

2. A process for the preparation of low molecular weight polystyrene based on anionic chain transfer polymerization method as claimed in claim 1, wherein, In the first step, the organic monomers are styrene.

3. The method for preparing low molecular weight polystyrene based on anionic chain transfer polymerization according to claim 1, characterized in that, In the first step, the polarity regulator includes tetrahydrofuran (THF), tetramethyl ethylenediamine (TMEDA), dimethoxyethane (DME), diethylene glycol diethyl ether and triethylamine; and the initiator includes alkyl lithium or naphthalene sodium.

4. The process for the preparation of low molecular weight polystyrene based on anionic chain transfer polymerization method as claimed in claim 1 wherein, In the first step, the mass ratio of the organic solvents to the organic monomers in the reaction system is 5-10:1; when the polarity regulator is TMEDA, the equivalent ratio is 1-2:1; and when the polarity regulator is THF, the equivalent ratio is 173-693:

1.

5. The method for preparing low molecular weight polystyrene based on anionic chain transfer polymerization according to claim 1, characterized in that, In the first step, the organic solvents include cyclohexane, methylcyclohexane and benzene.

6. The method for preparing low molecular weight polystyrene based on anionic chain transfer polymerization according to claim 1, characterized in that, In the second step, the termination agent is methanol.

7. The method for preparing low molecular weight polystyrene based on anionic chain transfer polymerization according to claim 1, characterized in that, In the third step, the temperature of the vacuum drying is 25-40 DEG C, and the time is 18-48 hours.

8. A low molecular weight polystyrene synthesized based on an anionic chain transfer polymerization method, characterized in that, The method is obtained by any one of claims 1-7.

9. A low molecular weight polystyrene synthesized based on an anionic chain transfer polymerization method according to claim 8, characterized in that, The low molecular weight polymer has a molecular weight of 3000 to 16000, M w / M n 1.03 to 1.66.

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