Copolymerization modified solution polymerized styrene-butadiene rubber and preparation method thereof

Abstract

The invention discloses copolymerized modified solution polymerized styrene-butadiene rubber and a preparation method thereof. The preparation method comprises the following steps: adding a solvent, a Lewis base structure regulator, styrene, butadiene and a furyl-substituted olefin monomer into a polymerization kettle under a nitrogen protection condition, mixing, heating to 25-35 DEG C, adding an anionic polymerization initiator, heating to 45-70 DEG C, carrying out a polymerization reaction, adding ethanol to terminate the reaction after the reaction is completed, and cooling to room temperature to obtain the high-molecular polymer. And pouring the obtained glue solution into ethanol to flocculate, precipitating the copolymer, and carrying out vacuum drying to constant weight to obtain the copolymerized modified solution polymerized styrene-butadiene rubber. According to the invention, the furan group is grafted into the solution polymerized styrene-butadiene rubber through a specific copolymerization reaction, so that the interaction between the rubber and the filler is improved.

Description

Technical Field

[0001] This invention relates to the field of rubber technology, specifically to a copolymer-modified solution-polymerized styrene-butadiene rubber and its preparation method. Background Technology

[0002] Solution-polymerized styrene-butadiene rubber (SSBR) is a type of styrene-butadiene rubber produced through solution polymerization. As an important rubber material, it possesses excellent low-temperature flexibility, resilience, and abrasion resistance, and is widely used in tires, rubber products, and other fields. However, as a non-polar rubber, it has poor compatibility with carbon black and silica, resulting in uneven dispersion of carbon black and silica, which is detrimental to improving the rubber's wet skid resistance and reducing rolling resistance. Therefore, modification of SSBR is imperative.

[0003] Introducing monomers containing polar groups during butadiene-styrene copolymerization is one way to reduce hysteresis loss in vulcanized rubber and decrease tire rolling resistance. Patent CN 114716619B uses a dry grafting method to graft maleic anhydride compatibilizer onto styrene-butadiene rubber. However, this method requires the prior preparation of the rubber product, followed by grafting at 125-200°C under the action of an organic peroxide initiator. The preparation process is complex, time-consuming, and prone to generating toxic gases at high temperatures. Furan compounds are polar compounds that can react with functional groups such as amino, mercapto, and nitro groups, and can also undergo a Diels-Alder reaction with maleimide. Furthermore, furan compounds can also serve as structure modifiers in butadiene-styrene polymerization. For example, CN 118878741A describes the preparation of a novel polar furan modifier, developing a tough and impact-resistant styrene-butadiene rubber. However, this method requires the compounding of two structure modifiers.

[0004] Therefore, there is an urgent need to find a simple and rapid copolymerization modification technology for solution-polymerized styrene-butadiene rubber. Summary of the Invention

[0005] The purpose of this invention is to provide a simple and rapid method for preparing copolymerized modified solution-polymerized styrene-butadiene rubber (SBR), aiming to solve the problem of poor compatibility between SBR and carbon black filler. This invention uses butadiene, styrene, and furanyl-substituted olefin monomers for copolymerization modification.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing copolymerized solution-polymerized styrene-butadiene rubber: Under nitrogen protection, solvent, Lewis base structure modifier, styrene, butadiene and furanyl-substituted olefin monomers are added to a polymerization reactor. After mixing, the temperature is raised to 25-35°C, and then an anionic polymerization initiator is added and the temperature is raised to 45-70°C for polymerization reaction. After the reaction is completed, ethanol is added to terminate the reaction. The resulting rubber solution is poured into ethanol for flocculation. After the copolymer precipitates, it is vacuum dried to constant weight to obtain copolymerized solution-polymerized styrene-butadiene rubber. The structure of the furanyl-substituted olefin monomer is shown below: ; Where R 1 Can be , or .

[0007] Furthermore, the solvent is at least one selected from cyclohexane, hexane, octane, benzene, and toluene. Its amount used can be the conventional amount used in the art, and there is no particular limitation thereto.

[0008] Furthermore, the Lewis base structure modifier is at least one of tetrahydrofuran, ethyl tetrahydrofurfuryl ether, and diethyl ether.

[0009] Furthermore, the total monomer concentration of styrene and butadiene is 10%-30%; the mass percentage content of styrene to butadiene is (1~5):(5~9), and the monomer concentration is the mass of monomer / volume of solvent.

[0010] Furthermore, the concentration of the furanyl-substituted olefin monomer is 0.1% to 5%.

[0011] Furthermore, the anionic polymerization initiator is one or more of n-butyllithium, sec-butyllithium, tert-butyllithium, ethyllithium, n-propyllithium, and isopropyllithium, and the amount of anionic polymerization initiator used is 0.2 to 3 mmol per 100 grams of total monomer.

[0012] Furthermore, the copolymerization reaction takes 1 to 5 hours.

[0013] A copolymer-modified solution-polymerized styrene-butadiene rubber (SBR) prepared by the method described above. On the one hand, the introduction of polar furan groups can increase the dispersion performance of silica in the rubber; on the other hand, as a furan olefin monomer, it can also act as a structure regulator, playing a certain role in regulating the 1,2-structure of SBR.

[0014] Compared with the prior art, the present invention has the following advantages: (1) The present invention provides a method for preparing copolymerized solution-modified styrene-butadiene rubber. By copolymerizing, styrene-butadiene rubber obtains furan polar groups, which can promote the dispersion effect between rubber and carbon black.

[0015] (2) The present invention uses monomers containing furan groups to copolymerize and modify styrene-butadiene rubber. The furan monomer can be used as a polarity regulator to promote butadiene-styrene polymerization and obtain styrene-butadiene rubber with high vinyl content.

[0016] (3) The preparation method of copolymerized modified solution polystyrene-butadiene rubber provided by the present invention is simple and the conditions are mild. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the synthesis reaction principle of the copolymerized solution-polymerized styrene-butadiene rubber of the present invention.

[0018] Figure 2 The images show the 1H NMR spectra of Example 1 and Comparative Example 1. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1 In a jacketed 5L polymerization reactor, the system was purged three times with nitrogen. 4L of cyclohexane, 150g of styrene, 450g of butadiene, and furanylene were added to the polymerization reactor. (Synthesized according to patent CN 115521404A) 30 g of tetrahydrofuran and 4.3 g of tetrahydrofuran were added. The mixture was heated to 30°C, and 6.0 mmol of n-butyllithium was added. The temperature was then raised to 50°C, and the polymerization reaction was carried out for 2 hours. The reaction was terminated by adding 2 mL of anhydrous ethanol. 50 g of the gel solution was poured into 100 mL of anhydrous ethanol for flocculation and dried in a vacuum oven to constant weight.

[0021] Take 20 mg of the product and dissolve it completely in 0.5 mL of deuterated chloroform containing 0.03% TMS. Transfer 0.5 mL of the sample solution into an NMR tube and use a high-resolution liquid resonance spectrometer (HPLC). 1 H-NMR) test results are shown in […]. Figure 2 .

[0022] Example 2 In a jacketed 5L polymerization reactor, the system was purged three times with nitrogen. 4 L of cyclohexane, 150 g of styrene, 450 g of butadiene, and ethylene furanene were added to the polymerization reactor. (Synthesized according to patent CN 115521404A) 60 g of tetrahydrofuran and 4.3 g of tetrahydrofuran were added. The mixture was heated to 30°C, and 6.0 mmol of n-butyllithium was added. The temperature was then raised to 50°C, and the polymerization reaction was carried out for 2 hours. The reaction was terminated by adding 2 mL of anhydrous ethanol. 50 g of the gel solution was poured into 100 mL of anhydrous ethanol for flocculation and dried in a vacuum oven to constant weight.

[0023] Example 3 In a jacketed 5L polymerization reactor, the system was purged three times with nitrogen. 4L of cyclohexane, 150g of styrene, 450g of butadiene, and 6-furanyl-1-hexene were added to the polymerization reactor. (Synthesized according to the literature "DOI:10.26991 / d.cnki.gdllu.2021.002635") 30 g of tetrahydrofuran and 4.3 g of tetrahydrofuran were added. The mixture was heated to 30℃, and 6.0 mmol of n-butyllithium was added. The temperature was then raised to 50℃, and the polymerization reaction was carried out for 2 h. The reaction was terminated by adding 2 mL of anhydrous ethanol. 50 g of the gel solution was poured into 100 mL of anhydrous ethanol for flocculation and dried in a vacuum oven to constant weight.

[0024] Example 4 In a jacketed 5L polymerization reactor, the system was purged three times with nitrogen. 4L of cyclohexane, 150g of styrene, 450g of butadiene, and furan-substituted styrene were added to the polymerization reactor. (Synthesized according to reference "DOI:10.26991 / d.cnki.gdllu.2021.001541") 30 g of tetrahydrofuran and 4.3 g of tetrahydrofuran were added. The mixture was heated to 30℃, and 6.0 mmol of n-butyllithium was added. The temperature was then raised to 50℃, and the polymerization reaction was carried out for 2 h. The reaction was terminated by adding 2 mL of anhydrous ethanol. 50 g of the gel solution was poured into 100 mL of anhydrous ethanol for flocculation and dried in a vacuum oven to constant weight.

[0025] Comparative Example 1 In a jacketed 5L polymerization reactor, the system was purged three times with nitrogen. 4L of cyclohexane, 150 g of styrene, 450 g of butadiene, and 4.3 g of tetrahydrofuran were added to the reactor. The temperature was raised to 30°C, and 6.0 mmol of n-butyllithium was added. The temperature was raised to 50°C, and the polymerization reaction was carried out for 2 hours. The reaction was terminated by adding 2 mL of anhydrous ethanol. 50 g of the polymer solution was poured into 100 mL of anhydrous ethanol for flocculation and dried in a vacuum oven to constant weight.

[0026] Comparative Example 2 In a jacketed 5L polymerization reactor, the system was purged three times with nitrogen. 4L of cyclohexane, 150 g of styrene, 450 g of butadiene, and 8.6 g of tetrahydrofuran were added to the reactor. The temperature was raised to 30°C, and 6.0 mmol of n-butyllithium was added. The temperature was raised to 50°C, and the polymerization reaction was carried out for 2 hours. The reaction was terminated by adding 2 mL of anhydrous ethanol. 50 g of the polymer solution was poured into 100 mL of anhydrous ethanol for flocculation and dried in a vacuum oven to constant weight.

[0027] The physical and mechanical properties of the SSBR rubber obtained in the examples and comparative examples are shown in Table 1: Table 1 Physical and mechanical properties of SSBR rubber

[0028] Note: The rubber composite material processing involves preparing carbon black-reinforced rubber via mechanical blending. The vulcanization conditions are as follows: 100 parts solution-polymerized styrene-butadiene rubber, 50 parts carbon black, 4 parts zinc oxide, 1.5 parts stearic acid, 1.2 parts DM (dibenzothiazole disulfide) accelerator, 1 part D (diphenylguanidine) accelerator, 1 part antioxidant RD, and 1.8 parts sulfur. In the examples, the 1,2-structure refers to the content of the 1,2-unit segment of polybutadiene, which was determined using NMR spectroscopy.

[0029] from Figure 2 The 1H NMR spectrum shows that, compared to Comparative Example 1, Example 1 exhibited two peaks in the 5.5-6.0 ppm range, indicating that furanyl ethylene (… It successfully reacted with butadiene and styrene to obtain a new polymer.

[0030] Compared to Comparative Example 1, the solution-polymerized styrene-butadiene rubbers with added furan substituents in the examples all achieved a vinyl structure content of over 40%. This indicates that the furan olefin monomer and the tetrahydrofuran modifier have a synergistic effect on regulating the 1,2-structure content. Compared to Comparative Example 1, the tensile strength of each example is significantly increased. tanδ (0℃) characterizes the rubber's wet skid resistance; a higher value indicates better wet skid resistance. tanδ (60℃) characterizes the rubber's rolling resistance; a lower value indicates lower rolling resistance. The results in the table above show that the wet skid resistance of the examples is significantly improved compared to the comparative example, and the rolling resistance is reduced. Furthermore, although the 1,2-structure content of Example 1 and Comparative Example 2 is similar, Example 1 has a significantly better wet skid resistance than Comparative Example 2, and its rolling resistance is also lower. This indicates that the solution-polymerized styrene-butadiene rubber with furan groups in the synthetic chain, due to its increased polarity, can increase the dispersibility of carbon black, thereby improving the rubber strength and resulting in superior dynamic mechanical properties.

[0031] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing copolymerized solution-modified styrene-butadiene rubber, characterized in that: Under nitrogen protection, solvent, Lewis base structure modifier, styrene, butadiene and furanyl-substituted olefin monomers are added to the polymerization reactor. After mixing, the temperature is raised to 25-35°C, and then an anionic polymerization initiator is added and the temperature is raised to 45-70°C to carry out the polymerization reaction. After the reaction is completed, anhydrous ethanol is added to terminate the reaction. The resulting adhesive solution is then poured into anhydrous ethanol for flocculation. After the copolymer precipitates, it is dried under vacuum to constant weight to obtain copolymerized solution-polymerized styrene-butadiene rubber. The structure of the furanyl-substituted olefin monomer is shown below: ； Where R 1 for , or .

2. The preparation method according to claim 1, characterized in that: The solvent is at least one selected from cyclohexane, hexane, octane, benzene, and toluene.

3. The preparation method according to claim 1, characterized in that: The Lewis base structure modifier is at least one of tetrahydrofuran, ethyl tetrahydrofurfuryl ether, and diethyl ether.

4. The preparation method according to claim 1, characterized in that: The total monomer concentration of styrene and butadiene is 10%-30%; the mass ratio of styrene to butadiene is (1~5):(5~9).

5. The preparation method according to claim 1, characterized in that: The concentration of the furanyl-substituted olefin monomer is 0.1% to 5%.

6. The preparation method according to claim 1, characterized in that: The anionic polymerization initiator is one or more of n-butyllithium, sec-butyllithium, tert-butyllithium, ethyllithium, n-propyllithium, and isopropyllithium, and the amount of anionic polymerization initiator used is 0.2 to 3 mmol per 100 grams of total monomer.

7. The preparation method according to claim 1, characterized in that: The copolymerization reaction takes 1 to 5 hours.

8. A copolymer-modified solution-polymerized styrene-butadiene rubber prepared by the preparation method according to any one of claims 1 to 7.

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