CN115703857A - Polyacrylate/polyacrylamide polymer and polymerization process thereof - Google Patents

Abstract

The application relates to the field of polymer polymerization, and specifically discloses a polyacrylate/polyacrylamide polymer and a polymerization process thereof. The polymerization process includes: in an organic solvent, using acrylate/acrylamide compounds as monomer raw materials, using alkali metal alkoxide as an initiator, adding a regulator tetraalkylammonium salt, and polymerizing at a temperature of 0-60°C The reaction is carried out for more than 5 minutes to obtain a polyacrylate/polyacrylamide polymer. The molecular weight of the polyacrylate/polyacrylamide polymer obtained by the polymerization process of the present application is between 5000-300000g/mol, the molecular weight distribution is narrow (1.6-3.4), the monomer conversion rate is as high as 99%, and the syndiotacticity is greater than 40 % advantages, cheap raw materials, short reaction time, so as to achieve low-cost, large-scale industrial production.

Description

Polyacrylate/polyacrylamide polymer and its polymerization process

technical field

This application relates to the field of polymer polymerization, more specifically, it relates to a polyacrylate/polyacrylamide polymer and its polymerization process.

Background technique

Traditional polyacrylate polymers and polyacrylamide polymers are mainly based on free radical polymerization, and the termination type is diradical disproportionation termination, which makes it difficult to control the molecular weight and molecular weight distribution of polymerized products. Moreover, gel effect will occur with the increase of system viscosity during the polymerization process, making the molecular weight distribution more difficult to control. In free radical polymerization, the polymerization process is generally regulated by means of low conversion rate control, temperature program control or feed control to reduce the viscosity of the polymerization system, thereby reducing the molecular weight distribution coefficient of the polymer. However, the degree of chain transfer in the free radical polymerization process is large, which makes it difficult to control the molecular weight, distribution, and molecular structure regularity of the generated products. At present, free radical polymerization is difficult to meet the growing demand for high-performance polyacrylate polymers and polyacrylamide polymers.

In order to better control its molecular weight distribution and molecular structure regularity, anionic polymerization is usually used. The anionic polymerization of this type of compound has characteristics that cannot be compared with other living polymerization methods: First, there are many monomers suitable for anionic polymerization, which can be divided into There are four types of monomers: non-polar monomers, polar monomers, cyclic monomers and functional monomers; second, a wide range of solvent choices and a wide range of polymerization temperatures are also a major feature of anionic polymerization; third, anionic polymerization active species Good stability, fast polymerization rate and simple polymerization system.

However, the anionic polymerization reaction of acrylate compounds and acrylamide compounds is basically carried out at low temperature. For example, most anionic polymerizations of methyl methacrylate (MMA) are below -78°C, and the reaction temperature is harsh. Although there are a few experiments carried out under the condition of 0 ℃, the experiments are all unsatisfactory. The main performance is that the molecular weight distribution of the prepared polymethyl methacrylate (PMMA) is as wide as 4.0, and the monomer conversion rate≤50%. The rate is lower. Therefore, the synthesis of PMMA by MMA through anionic polymerization is limited by the reaction temperature and it is difficult to realize low-cost, large-scale industrial production, and the same is true for other acrylate compounds and acrylamide compounds. In order to make new materials better applied to actual production and realize low-cost, large-scale industrial production, further improvements are urgently needed.

Contents of the invention

In order to synthesize polyacrylate/polyacrylamide polymers through anionic polymerization to achieve low-cost, large-scale industrial production, the present application provides a polyacrylate/polyacrylamide polymer and a polymerization process thereof.

In the first aspect, the application provides a polyacrylate/polyacrylamide polymer polymerization process, which adopts the following technical scheme:

A polymerization process for polyacrylate/polyacrylamide polymers, in an organic solvent, using acrylate/acrylamide compounds as monomer raw materials, using alkali metal alkoxide as an initiator, and adding a regulator tetradecane Ammonium salts, react at a polymerization temperature of 0-60°C for more than 5 minutes to obtain crude polyacrylate/polyacrylamide polymers, wherein the concentration of the acrylate/acrylamide compounds in the organic solvent 0.3-16mol/L, the molar ratio between the acrylate/acrylamide compound, tetraalkylammonium salt and alkali metal alkoxide is (100-500):(0.02-0.5):(0.01-0.25 ).

This application uses alkali metal alkoxide as initiator, under the action of tetraalkylammonium salt, with acrylate/acrylamide compound with (100-500): (0.02-0.5): (0.01-0.25) mole Specific reaction, so that acrylate/acrylamide compounds can undergo anionic polymerization reaction at a mild temperature, that is, 0-60°C to form polyacrylate/polyacrylamide polymers, from the beginning of the polymerization reaction to the loss of active species It only takes about 5 minutes to complete the activity or monomer conversion. The finally synthesized polyacrylate/polyacrylamide polymer has narrow molecular weight distribution range, high syndiotacticity and high monomer conversion rate. Compared with the existing anionic polymerization reaction, which can only obtain higher syndiotacticity, narrow molecular weight distribution range and higher monomer conversion rate at a temperature of -78°C, the anionic polymerization reaction of the present application has mild reaction conditions, The advantages of short reaction time and low cost of raw materials used enable the polymerization process of polyacrylate/polyacrylamide polymers to achieve large-scale and low-cost industrial production, which is very important for polyacrylate/polyacrylamide polymerization. The material processing industry has far-reaching significance.

Acrylate compounds include H ₂ C═CR ¹ COOR ² and lactones, R ₁ is H or alkyl, R ₂ is alkyl, aryl or five-membered heterocycle (furan). Examples: allyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, n-butyl acrylate, benzyl methacrylate, furfuryl methacrylate, and ɑ-methylene-γ-butyrol Esters etc.

The general formula of acrylamide compounds is H ₂ C=CR ³ CONR ⁴ R ⁵ , R ³ is hydrogen or alkyl, and R ⁴ and R ⁵ are alkyl. For example: N,N'-dimethylacrylamide and N,N'-dimethylmethacrylamide.

R₆、R₇、R₈和R₉为烷基，A^-为抗衡阴离子。例如：无氧抗衡阴离子(卤离子)、含氧抗衡阴离子(碳酸根、碳酸氢根、硫酸根、硫酸氢根、硝酸根、次氯酸根、高锰酸根等)以及有机抗衡阴离子(氰酸根、醋酸根、草酸根等)。The general formula of tetraalkylammonium salt is

R ₆ , R ₇ , R ₈ and R ₉ are alkyl groups, and A ^- is a counter anion. For example: anaerobic counteranions (halides), oxygen-containing counteranions (carbonate, bicarbonate, sulfate, bisulfate, nitrate, hypochlorite, permanganate, etc.) and organic counteranions (cyanate, acetate, oxalate, etc.).

R¹¹为烷基，R¹⁰和R¹²为H或烷基，M为常用的碱金属钠、钾。The general formula for alkali metal alkoxides is

R ¹¹ is an alkyl group, R ¹⁰ and R ¹² are H or an alkyl group, and M is commonly used alkali metal sodium or potassium.

The term "alkyl" is used in this application in the meaning known to those of ordinary skill in the art to refer to a monovalent residue consisting only of carbon and hydrogen atoms, the alkyl group forming a homogeneous series having the general formula _{CnH2n +1} . Alkyl can be straight chain or branched chain alkyl, for example, alkyl can be but not limited to secondary alkyl or tertiary alkyl, secondary alkyl is branched with a central carbon atom attached to two carbon residues; tertiary alkyl The group is a branched chain with a central carbon atom attached to 3 carbon residues. "Aryl" refers to a C ₆ -C ₁₀ aromatic hydrocarbon group, such as phenyl.

Preferably, the molar ratio of the acrylate/acrylamide compound, tetraalkylammonium salt and alkali metal alkoxide is 100:(0.06-0.25):(0.06-0.25).

Further selecting the molar ratio of the polyacrylate/polyacrylamide polymer, the tetraalkylammonium salt and the alkali metal alkoxide makes the polymerization reaction of the acrylate/acrylamide compound monomer more sufficient during the polymerization reaction. The monomer conversion rate is improved, and the molecular weight distribution range of polyacrylate/polyacrylamide polymers is further reduced, thereby improving the production efficiency of polyacrylate/polyacrylamide polymers, reducing production costs and The product quality of polyacrylate/polyacrylamide polymers is improved.

Preferably, the alkali metal alkoxide is potassium tert-butoxide or sodium tert-butoxide, and potassium tert-butoxide is further selected.

Since potassium tert-butoxide and sodium tert-butoxide have three methyl groups, the electronic effect and steric effect that this structure can produce can keep it more basic and active than other alkali metal alkoxides, and it is suitable for synthesizing polyacrylates/ In the process of polyacrylamide polymer, the active species of the polymer is more stable, the occurrence of side reactions is reduced, and the monomer conversion rate of acrylate/acrylamide compounds is further improved; it also makes the polymerization reaction controllable Increased, the syndiotacticity of the synthesized polymer is higher and the molecular weight distribution range is narrower, thus providing an improvement direction for improving production efficiency for the industrialization of the anionic polymerization process of polyacrylate/polyacrylamide polymers.

Preferably, the tetraalkylammonium salt is any one of tetrabutylammonium salt, tetrahexylammonium salt, cetyltrimethylammonium salt and benzyltriethylammonium salt.

Tetrabutylammonium salt, tetrahexylammonium salt, cetyltrimethylammonium salt and benzyltriethylammonium salt are used as the phase transfer regulator in the polymerization process, and potassium tert-butoxide as a co-initiator system, which The constructed ion-pair initiator has a good regulating effect in the polymerization reaction of polyacrylate/polyacrylamide polymers, and accelerates the process of forming high molecular polymers from low molecular reaction monomers through chain growth.

In addition, tetrabutylammonium salts are more preferred, and tetrabutylammonium bromide is most preferred. Because its raw materials are cheap and easy to obtain, it can better promote the progress of the polymerization reaction, thereby further promoting low-cost industrial production.

Preferably, the organic solvent is formed by mixing one or two of toluene, tetrahydrofuran, N,N'-dimethylformamide, n-hexane, and acetonitrile. More preferably, the organic solvent is toluene.

Usually, the solvent does not directly participate in the polymerization reaction. However, the solvent is often not absolutely inert and can induce decomposition of the initiator. Both effects may affect the rate of polymerization and molecular weight. In ionic polymerization, the influence of the solvent is greater, and the polarity of the solvent will have a significant impact on the existence form and activity of active ion pairs, polymerization rate, molecular weight distribution and chain microstructure.

In order to cooperate with the reaction system of alkali metal alkoxide and tetraalkylammonium salt, choose toluene, tetrahydrofuran, N,N'-dimethylformamide, n-hexane, acetonitrile or a mixture of two, alkali metal alkoxide, The activities of tetraalkylammonium salts and acrylate/acrylamide compound monomers are less affected in the above-mentioned organic solvents, which further increases the polymerization reaction rate.

Further selected toluene makes the molecular weight distribution range of the synthetic polyacrylate/polyacrylamide polymer more narrow, and the quality of the synthetic polyacrylate/polyacrylamide polymer is stable, which is more conducive to polyacrylate/polyacrylamide The advancement of the industrialization of the synthesis of polyacrylamide polymers.

Preferably, the polymerization temperature is 25-60°C, further selected as room temperature.

When the polymerization temperature is 60°C, the active groups in the reaction system are more active, which promotes the rapid anionic polymerization toward the direction of synthesizing polyacrylate/polyacrylamide polymers, and further improves the synthesis of polyacrylate/polyacrylamide polymers. The reaction rate of the polyacrylamide polymer improves the industrial production efficiency. Of course, the polymer is prepared at room temperature (25°C±2°C), and polyacrylate/polyacrylamide polymerization with high monomer conversion rate, high syndiotacticity and narrow molecular weight distribution range can be obtained without heating or cooling. It reduces the investment in equipment that needs to be heated or cooled, greatly saves the energy required in industrial production, and can further promote low-cost, large-scale industrial production.

Preferably, the alkali metal alkoxide is first dissolved in an organic solvent to obtain an initiating solution, then the regulator tetraalkylammonium salt is dissolved in acrylate/acrylamide compounds and stirred evenly to obtain a reaction solution, and the reaction solution is added to the initiating solution in the polymerization reaction.

The initiator is fully dissolved first, so that the active group can be fully exposed, and the regulator is dissolved in the reaction monomer to be fully dispersed. During the polymerization reaction, these active groups can more fully initiate the monomer, further improving the conversion rate, thereby improving the efficiency of preparing polyacrylate/polyacrylamide polymers.

Preferably, the polymerization reaction time is 5-60min.

In the process of industrial production, the control of reaction time is very critical. The reaction time is short, and the initiation of the monomer is not sufficient, so that the conversion rate of the monomer is low, which causes a waste of raw materials. The reaction time is too long, prolonging the production cycle of the product. The monomer conversion rate of acrylate group/acrylamide compound can reach a large level within 5-60min, and the processing time is short, and the obtained polymer has a higher syndiotacticity and a narrower molecular weight The distribution range can obtain polyacrylate/acrylamide polymers with stable quality and uniform quality.

Preferably, an alcoholic solvent containing 0.1-0.3 mol/L of HCl is added to the crude polyacrylate/polyacrylamide polymer to terminate the polymerization to obtain a quenched mixture, and the quenched mixture is added to a volume of Precipitation is formed in alcoholic solvent more than 10 times, and the precipitated part is washed with alcoholic solvent to remove unreacted monomer, filtered, and then dried to constant weight to obtain a fine polyacrylate/polyacrylamide polymer.

The crude product of the polyacrylate/polyacrylamide polymer is post-treated by the above-mentioned method, and the processing steps are simple, and the post-treatment agent used is an alcohol solvent, which is cheap and easy to obtain. Higher purity polyacrylate/polyacrylamide polymer products can be obtained with a low-cost post-treatment process. In addition, the solvent used in post-treatment can be recycled and reused, further reducing the cost of post-treatment, thereby reducing the production cost of polyacrylate/polyacrylamide polymers and saving resources.

In the second aspect, the present application provides a method for preparing polyacrylate/polyacrylamide polymers, which adopts the following technical scheme:

1.6-3.4，间规度大于40％。A polyacrylate/polyacrylamide polymer prepared by the above polymerization process, with a molecular weight between 5000-300000g/mol, and a molecular weight distribution of

1.6-3.4, syndiotacticity greater than 40%.

越小，分子量分布范围越窄，说明聚合物的低分子量聚合物含量较少，得到聚合物的分子量较为集中，其加工性较为接近。另外，窄的分子量分布范围反映了聚合物的质量更为均一。The molecular weight distribution

The smaller the value, the narrower the molecular weight distribution range, indicating that the polymer has less low-molecular-weight polymer content, and the molecular weight of the obtained polymer is more concentrated, and its processability is closer. In addition, the narrow molecular weight distribution range reflects a more uniform quality of the polymer.

The degree of syndiotacticity of the polymer reflects the stability of the crystal form formed by the polymer. High syndiotacticity indicates that the crystal form formed by the polymer is relatively stable and the melting point of the polymer is high. The syndiotacticity of the present application is as high as more than 40%, can form a polyacrylate/polyacrylamide polymer with stable crystal form, and has the advantages of high strength, easy processing, chemical resistance and the like.

It is very important to maintain the stability of the product in the industrial production process. The polyacrylate/polyacrylamide polymer prepared by the above method has uniform quality and good stability, which is more conducive to realizing large-scale industrial production.

In summary, the application has the following beneficial effects:

1. Since this application uses alkali metal alkoxide as the initiator, under the action of tetraalkylammonium salt, it participates in the reaction with acrylate/acrylamide compounds at a specific molar ratio, and has a higher reaction temperature than the existing anionic polymerization Mild, short reaction time, stable quality of polyacrylate/polyacrylamide polymers obtained, high monomer conversion rate, etc., so that low-cost, large-scale industrial preparation of polyacrylate/polyacrylamide polymers can be realized .

2. In this application, toluene is preferred as the solvent. The activity of alkali metal alkoxides, tetraalkylammonium salts, and acrylate/acrylamide compound monomers has less influence in toluene, which further improves the polymerization rate and makes the synthesis The molecular mass distribution range of the polyacrylate/polyacrylamide polymer is narrower, and the molecular weight of the synthesized polyacrylate/polyacrylamide polymer is stable, which is more conducive to the polymerization of polyacrylate/polyacrylamide The advancement of industrialization.

3. In the method of the present application, by fully dissolving the compounds participating in the reaction first, the acrylate/acrylamide compound can be fully reacted at a milder temperature, which improves the rate of the polymerization reaction and reduces the required reaction time. energy, thereby saving industrial production costs and improving production efficiency.

Detailed ways

The present application will be described in further detail below in conjunction with the examples.

In order to facilitate the understanding of the existing anionic polymerization process of acrylate/acrylamide compounds, the initiators, reaction temperature and property parameters used in the preparation of polyacrylate/polyacrylamide polymers are listed in Table 1.

Sequence numbers 1-38 are for preparing polyacrylate polymers: Sequence numbers 1-37, 38, and 39 are MMA, furfuryl methacrylate initiators, reaction temperature and property parameters of polymers.

Serial numbers 39-40 are for the preparation of polyacrylic acid amide polymers: N,N'-dimethylacrylamide, N,N'-dimethylmethacrylamide initiators, reaction temperature and polymer properties .

Among them, broad represents a broad peak, and bm represents multiple broad peaks.

Table 1 Anionic polymerization of acrylate/acrylamide compounds under different conditions

According to the table above, scientists have tried various types of initiators, solvents and anionic polymerization of polyacrylates/polyacrylamides in experimental environments. But no matter which method is used, anionic polymerization is carried out at low temperature (mostly at -78°C). Although a few experiments were carried out at 0°C, none of the experiments were very ideal, with low monomer conversion and wide molecular weight distribution, and what's more, the ideal anionic polymerization should have no single-peak distribution. Therefore, the anionic polymerization for preparing polyacrylates/polyacrylamides can only be carried out under laboratory conditions at present, and it is difficult to realize low-cost and industrial production.

Based on this, the present application studies an anionic polymerization process of polyacrylates/polyacrylamides that can realize low-cost and industrialized production.

Example

laboratory research stage

The room temperature in the examples refers to the reaction under the environment of 25±2°C, without heating or cooling the reaction body.

Examples 1-5 are used to demonstrate the influence of the selection of alkali metal alkoxide and tetraalkylammonium salt on the polymerization reaction.

Example 1

The present embodiment discloses a kind of polymerization technique of PMMA, comprises the following steps:

A flame-dried 25 ml Schlenk bottle in the glove box was charged with the initiator sodium ethoxide (0.048 mmol, 3.3 mg), the regulator tetrahexyl ammonium bisulfate (0.096 mmol, 43.4 mg, 4 equivalents) and 4 mL of the dry organic solvent toluene , stirred at room temperature for 5 min. Then, MMA (19.2 mmol, 2 mL, 800 equivalents) was added into the Schlenk bottle at one time, and the Schlenk bottle was stirred at room temperature for 5 min to obtain a PMMA mixture.

A methanol solution containing 0.1 mol/L HCl was added to the PMMA mixture to terminate the polymerization to obtain a quenched mixture. The quenched mixture was then precipitated into a 10-fold excess of methanol, filtered, washed with methanol to remove unreacted monomers, and dried to constant weight in a vacuum oven at 40 °C to obtain PMMA.

In the above reaction, the molar ratio of MMA: tetrahexyl ammonium bisulfate: sodium ethoxide is 100:0.5:0.25.

Example 2

This embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 1 is:

The regulator was cetyltrimethylammonium hydroxide (0.004mmol, 1.14mg), and sodium tert-butoxide was used to replace sodium ethoxide in equimolar amounts, MMA (96.0mmol, 10mL, 4000 equivalents), and 20mL of dry toluene.

In the above reaction, the molar ratio of MMA: cetyltrimethylammonium hydroxide: sodium tert-butoxide is 500:0.02:0.25.

Example 3

This embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 1 is:

The regulator was equimolar tetrabutylammonium chloride (0.096mmol, 26.7mg, 4 equiv), and the initiator was potassium tert-butoxide (0.024mmol, 2.7mg).

In the above reaction, the molar ratio of MMA:tetrabutylammonium chloride:potassium tert-butoxide is 100:0.5:0.125.

Example 4

The present embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 3 is:

The modifier was equimolar tetrabutylammonium bromide (0.096 mmol, 30.9 mg, 4 equiv).

In the above reaction, the molar ratio of MMA:tetrabutylammonium bromide:potassium tert-butoxide is 100:0.5:0.125.

The polymerization reaction formula of Example 4 is as follows, n=100-3000.

Example 5

The present embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 3 is:

The regulator was equimolar benzyltriethylammonium chloride (0.096 mmol, 21.8 mg, 4 equiv).

In the above reaction, the molar ratio of MMA: benzyltriethylammonium chloride: potassium tert-butoxide is 100:0.5:0.125.

Examples 6-9 are used to compare the influence of process parameters in the processing process on the preparation of PMMA.

Example 6

This embodiment discloses a PMMA polymerization process, the difference from embodiment 4 is that the polymerization reaction temperature is 40°C.

Example 7

This embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 4 is: first put potassium tert-butoxide, tetrabutylammonium bromide and dry toluene in the Schlenk bottle, then add MMA to the Schlenk bottle at one time , the polymerization temperature was 0°C, and the reaction was 60 minutes.

Example 8

This embodiment discloses a kind of polymerization technique of PMMA, and the difference with embodiment 7 is:

Put tetrabutylammonium bromide and 3ml of dry toluene into the Schlenk bottle first, dissolve and add MMA and stir evenly, then dissolve potassium tert-butoxide in 1ml of dry toluene and add it to the Schlenk bottle at one time, the polymerization temperature is 60°C , The reaction time is 5min.

Example 9

This embodiment discloses a kind of polymerization technique of PMMA, and the difference with embodiment 7 is:

First put potassium tert-butoxide and dry toluene in the Schlenk bottle, after the potassium tert-butoxide dissolves, dissolve tetrabutylammonium bromide in MMA and stir evenly, then add dropwise in the Schlenk bottle, the polymerization temperature is room temperature, React for 5 minutes.

Examples 10-12 are used to reflect the influence of the molar ratio of monomer, initiator and regulator on the preparation of PMMA.

Example 10

This embodiment discloses a PMMA polymerization process.

Potassium tert-butoxide (0.024 mmol, 2.7 mg) and 4 ml of dry toluene were charged into a flame-dried 25 ml Schlenk bottle in the glove box, and tetrabutylammonium bromide (0.096 mmol, 26.7 mg, 4 equivalents) was dissolved in MMA (38.4mmol, 4mL, 1600 equivalents) was stirred evenly and then added to a Schlenk bottle at one time, and the Schlenk bottle was stirred at room temperature for 5min to obtain a PMMA mixture.

Add 0.5 mL of methanol solution containing 0.3 mol/L HCl to the PMMA mixture to terminate the polymerization to obtain a quenched mixture, which is then precipitated into a 15-fold excess of methanol, filtered, and washed with methanol to remove unreacted monomers , and then dried in a vacuum oven at 50°C to constant weight to obtain PMMA.

In the above reaction, the molar ratio of MMA:tetrabutylammonium bromide:potassium tert-butoxide is 100:0.25:0.0625.

Example 11

This embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 10 is:

In the above reaction, MMA: tetrabutylammonium bromide: the molar ratio of potassium tert-butoxide is 100:0.063:0.125, namely MMA (19.2mmol, 2mL, 800 equivalents), tetrabutylammonium bromide (0.048mmol, 15.5 mg, 2 equivalents), potassium tert-butoxide (0.024mmol, 2.7mg).

Example 12

This embodiment discloses a kind of polymerization process of PMMA, and the difference with embodiment 10 is:

In the above reaction, MMA: tetrabutylammonium bromide: the molar ratio of potassium tert-butoxide is 100:0.125:0.25, namely MMA (9.6mmol, 1mL, 400 equivalents), tetrabutylammonium bromide (0.012mmol, 3.8 mg, 0.5 equivalent), potassium tert-butoxide (0.024mmol, 2.7mg).

Examples 13-15 are used to compare the influence of different organic solvents on the synthesis of PMMA.

Example 13

This example discloses a PMMA polymerization process, and the difference from Example 11 is that an equal volume of tetrahydrofuran is used instead of dry toluene.

Example 14

This embodiment discloses a PMMA polymerization process, the only difference from Example 11 is that an equal volume of N,N'-dimethylformamide is used instead of dry toluene.

Example 15

This example discloses a PMMA polymerization process, the only difference from Example 11 is that an equal volume of a 1:1 mixture of n-hexane and acetonitrile is used instead of dry toluene.

Example 16

This embodiment discloses a polyfurfuryl methacrylate polymerization process, and the difference from Example 9 is that the monomer is furfuryl methacrylate, and the molar ratio to tetrabutylammonium bromide and potassium tert-butoxide is 100 : 0.125: 0.25, that is, the monomer is furfuryl methacrylate (19.2mmol, 4mL, 800 equivalents), tetrabutylammonium bromide (0.012mmol, 3.8mg, 0.5 equivalents), potassium tert-butoxide (0.024mmol, 2.7 mg).

The polymerization reaction formula of Example 16 is as follows, n=100-3000.

Example 17

This embodiment discloses a polymerization process of poly N,N'-dimethylacrylamide.

The difference from Example 16 is that the monomer is N,N'-dimethylacrylamide (19.2mmol, 4mL, 800 equivalents).

The polymerization reaction formula of Example 17 is as follows, n=100-3000.

Scale-up polymerization experiment

Example 18

This example discloses the preparation of 500 g of PMMA.

Under nitrogen, in a 5L polymerization reactor, add dry toluene (1500mL), potassium tert-butoxide (421.9mg), and tetrabutylammonium bromide (4.172g) successively, and start stirring at a stirring speed of 100r/min. While stirring, MMA monomer (625 mL) was added dropwise into the above reaction solution, and stirred at room temperature for 30 min to obtain a PMMA mixture.

Add 1000 mL of methanol solution containing 0.3 mol/L HCl to terminate and precipitate the polymer. Filter, wash with methanol to remove unreacted monomers, and then dry to constant weight in a vacuum oven at 50° C. to obtain 500 g of PMMA.

comparative example

Comparative example 1

Existing polymerization process using Flourenylithium (fluorenyl lithium) as an initiator.

In a flame-dried 500 mL three-neck flask equipped with a mechanical stirrer, a thermometer, and a Y-shaped gas channel, add 260 mL of dry toluene through a syringe. Subsequently, 11 mL of diethyl ether and 19 mL of Flourenylithium (0.158 equivalents) were added to form a mixed solution. The mixed solution was cooled to -70° C. in an acetone-dry ice bath, and 10 mL (0.94 mol) of MMA monomer was quickly injected. The reaction solution was kept at -70°C and stirred for 1 h to obtain a PMMA mixture. Then 5 mL of methanol was added to terminate the reaction. The reaction solution was poured into 10 times the volume of industrial n-hexane under vigorous stirring, and the polymer was separated and vacuum-dried to obtain PMMA.

performance test

test 1

Detection of number average molecular weight and molecular weight distribution of polymers

统一用GPC进行分析计算，获得聚合物的数均分子量、分子量分布。Method: for the number average molecular weight Mn and the molecular weight distribution of the polymer obtained in the above-mentioned Examples 1-18 and Comparative Example 1

GPC is used for analysis and calculation in a unified way to obtain the number average molecular weight and molecular weight distribution of the polymer.

Instrument: GPC, PL-GPC50, PD2000, Agilent Technologies (gel permeation chromatography, Agilent Technologies Co., Ltd.).

test 2

Detection of syndiotactic rr% of polymer

Method: The polymers obtained in Examples 1-18 and Comparative Example 1 were measured and analyzed by the ¹ H-NMR characteristic peak of Bruker AvanceIII 400MHz nuclear magnetic resonance Popper instrument, and the percentage of syndiotactic polymer was obtained.

Test 3

The monomer conversion of the polymer was detected.

Take 0.2mL aliquots from the PMMA mixture in Examples 1-18 and Comparative Example 1, dilute with _0.4mLCDCl , and then inject into Agilent GC7890 gas chromatograph to obtain monomer conversion through gas chromatographic analysis and image data processing Rate.

The specific detection data of experiments 1-3 are shown in Table 2.

Table 2

According to the comparison of the data of Comparative Example 1 and Examples 1-5, the present application uses cheap and easy-to-obtain alkali metal alkoxides and tetrabutylammonium salts and at room temperature can obtain syndiotacticity of more than 40%. PMMA with high volume conversion and narrow molecular weight distribution. Compared with Comparative Example 1, PMMA with similar properties can be prepared only by using expensive and rare fluorenyllithium catalyst at an extremely low temperature of -70°C. It can be seen that the polymerization process of the present application can complete the reaction without cooling equipment, the cost of input equipment is low, and the raw materials are cheap and easy to obtain, so that the synthesis of polyacrylate/polyacrylamide polymers can realize large-scale and low-cost industrialization Production. It solves the technical problem of low polymerization reaction temperature which has been wanted to be solved in this field, which has far-reaching significance to the processing industry of polyacrylate/polyacrylamide polymers.

为1.76的PMMA。According to the data comparison of Examples 6-9 and Example 4, it can be obtained that the feeding method, reaction temperature and reaction time all have an impact on the polymerization process. In industrial production, both the high monomer conversion rate and the preparation of Factors such as process convenience and reaction environment, earlier in embodiment 9, potassium tert-butoxide and dry toluene are loaded into Schlenk bottle, after potassium tert-butoxide dissolves, tetrabutylammonium bromide is dissolved in MMA, After stirring evenly, add it dropwise to the above mixture. The polymerization temperature is room temperature. After 5 minutes of reaction, the monomer conversion rate is 96%, the syndiotacticity is 55 and the molecular weight distribution is obtained.

PMMA of 1.76.

According to the data comparison of Examples 3 and 4 and Examples 10-12, it can be obtained that compared with Examples 3 and 4, the monomer conversion rate of Examples 10-12 is significantly improved, indicating that when acrylates/acrylamides When the molar ratio of compound, tetraalkylammonium salt and alkali metal alkoxide is 100:(0.06-0.25):(0.06-0.25), the polymerization reaction is more sufficient, which improves the industrialization of polyacrylate/polyacrylamide polymers Production efficiency and reduced production costs.

According to the comparison of the data in Example 11 and Examples 13-15, the organic solvent used in Example 11 is dry toluene, and the examples 13-15 used tetrahydrofuran and N, N'-dimethylformamide respectively. As well as the 1:1 mixture of n-hexane and acetonitrile, the monomer conversion rate of Example 11 reached 98%, while that of Examples 13-15 was only 92%. There is a rapid reaction stage and a stable stage in the polymerization reaction. When the monomer conversion rate is stable at a certain value, it is difficult to make a further breakthrough. In order to cooperate with the reaction system of alkali metal alkoxide and tetraalkylammonium salt, the dry toluene further increases the polymerization reaction rate, which is more conducive to the advancement of the industrialization of polyacrylate/polyacrylamide polymer synthesis.

According to the data comparison of Examples 16-17 and Example 9, the polymer prepared in Example 16 is polyfurfuryl methacrylate, and the polymer prepared in Example 17 is poly N, N'-dimethylacrylamide , under the same polymerization conditions as in Example 9, the monomer conversion rate is relatively high, the molecular weight distribution range is narrow and the intermolecular regularity is high, indicating that the anionic polymerization process of the present application can be used to prepare polyacrylates/polymers Acrylamide polymers are widely used and have made outstanding contributions to the technical improvement of this industry.

According to the data comparison of Example 18 and Example 10, it can be obtained that Example 18 is an experiment after increasing the scale of the polymerization experiment, and PMMA with a monomer conversion rate of 99%, a molecular weight distribution range of 1.76 and a syndiotacticity of up to 55% was prepared. . It can be seen that the anionic polymerization process of the present application is stable, and the product quality is stable after scale-up, which is conducive to further advancement in industrial production.

This specific embodiment is only an explanation of this application, and it is not a limitation of this application. Those skilled in the art can make modifications to this embodiment without creative contribution according to needs after reading this specification, but as long as the rights of this application All claims are protected by patent law.

Claims (10)

1. A polymerization process of a polyacrylate/polyacrylamide polymer is characterized in that in an organic solvent, an acrylate/acrylamide compound is used as a monomer raw material, an alkali metal alkoxide is used as an initiator, a regulator tetraalkylammonium salt is added, and the reaction is carried out for more than 5min at the polymerization temperature of 0-60 ℃ to obtain a crude polyacrylate/polyacrylamide polymer, wherein the concentration of the acrylate/acrylamide compound in the organic solvent is 0.3-16mol/L, and the molar ratio of the acrylate/acrylamide compound to the tetraalkylammonium salt to the alkali metal alkoxide is (100-500): (0.02-0.5): (0.01-0.25).

2. The polymerization process of polyacrylate/polyacrylamide polymer according to claim 1, wherein: the molar ratio of the acrylic ester/acrylamide compound to the tetraalkylammonium salt to the alkali metal alkoxide is 100: (0.06-0.25): (0.06-0.25).

3. The polymerization process of the polyacrylate/polyacrylamide polymer according to claim 1, wherein: the alkali metal alkoxide is potassium tert-butoxide or sodium tert-butoxide.

4. The polymerization process of the polyacrylate/polyacrylamide polymer according to claim 1, wherein: the tetraalkylammonium salt is any one of tetrabutylammonium salt, tetrahexylammonium salt, hexadecyltrimethylammonium salt, and benzyltriethylammonium salt.

5. The polymerization process of the polyacrylate/polyacrylamide polymer according to any one of claims 1-4, wherein: the organic solvent is one or two of toluene, tetrahydrofuran, N' -dimethylformamide, N-hexane and acetonitrile.

6. The polymerization process of the polyacrylate/polyacrylamide polymer according to claim 5, wherein: the polymerization temperature is 25-60 ℃.

7. The polymerization process of polyacrylate/polyacrylamide polymer according to any of claims 1-6, wherein: firstly, alkali metal alkoxide is dissolved in organic solvent to obtain initiation solution, then tetraalkylammonium salt is dissolved in MMA and uniformly stirred to obtain reaction solution, and the reaction solution is added into the initiation solution to carry out polymerization reaction.

8. The polymerization process of polyacrylate/polyacrylamide polymer according to claim 5, wherein: the polymerization reaction time is 5-60min.

9. The polymerization process of polyacrylate/polyacrylamide polymer according to claim 8, wherein: adding an alcohol solvent with the molar concentration of 0.1-0.3mol/L HCl into the crude polyacrylate/polyacrylamide polymer product, terminating polymerization to obtain a quenched mixture, adding the quenched mixture into the alcohol solvent with the volume more than 10 times that of the quenched mixture to form a precipitate, washing, filtering, and drying to constant weight to obtain a refined polyacrylate/polyacrylamide polymer product.

10. A polyacrylate/polyacrylamide polymer characterized in that: prepared by the polymerization process of any one of claims 1-9, having a molecular weight between 5000 and 300000g/mol, a molecular weight distribution of 2721.6 to 3.4, and a degree of syndiotacticity of greater than 40%.