阅读说明：本技术 一种含硅氧烷基链端官能化聚合物及其制备方法与应用 (Polysiloxane-containing chain end functionalized polymer and preparation method and application thereof ) 是由 廖明义 王文恒 杨潇寒 常云飞 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种含硅氧烷基链端官能化聚合物及其制备方法与应用,属于端基官能化聚合物制备领域。该方法在烃类溶剂中,极性有机化合物作调节剂、有机锂作引发剂,引发单乙烯基芳烃和/或共轭二烯烃单体进行负离子聚合反应生成活性聚合物,活性聚合物先与环氧类盖帽剂反应,钝化链端活性,然后与含硅氧烷基的封端剂进行封端反应,制备硅烷氧端基的官能化聚合物。本发明采用环氧类化合物作为盖帽剂,具有价格低廉、反应活性高等特点,并且反应条件温和、操作容易、封端效率高。制备的硅氧烷端基官能化橡胶及其复合材料具有与碳黑/白碳黑良好相互作用、低滚动阻力和高抗湿滑等性能,可以应用在轮胎行业。(The invention discloses a siloxane-containing chain end functionalized polymer and a preparation method and application thereof, belonging to the field of preparation of end group functionalized polymers. In a hydrocarbon solvent, a polar organic compound is used as a regulator, organic lithium is used as an initiator, a monovinylarene and/or conjugated diene monomer is initiated to carry out negative ion polymerization reaction to generate an active polymer, the active polymer is firstly reacted with an epoxy capping agent to passivate the activity of a chain end, and then the active polymer is subjected to end capping reaction with an end capping agent containing siloxane groups to prepare a functionalized polymer with a siloxane end group. The invention adopts epoxy compounds as the capping agent, has the characteristics of low price, high reaction activity and the like, and has mild reaction conditions, easy operation and high end-capping efficiency. The prepared siloxane end group functionalized rubber and the composite material thereof have the performances of good interaction with carbon black/white carbon black, low rolling resistance, high wet skid resistance and the like, and can be applied to the tire industry.)

1. A method for preparing a siloxane end-group functionalized polymer by anion technology, characterized in that: the method comprises the following steps:

(1) respectively adding a hydrocarbon solvent, a monovinylarene and/or conjugated diene monomer and a polar organic compound structure regulator into a reactor, uniformly stirring, adding an organic lithium initiator, and carrying out polymerization reaction;

(2) after the polymerization reaction is finished, adding a capping agent for capping reaction; the capping agent is a 1, 2-epoxy compound selected from 1, 2-ethylene oxide, 1, 2-propylene oxide or 1, 2-butylene oxide;

(3) after the cap reaction is finished, adding a capping agent for capping reaction;

(4) and after the end-capping reaction is finished, adding a compound containing protons to terminate the reaction, and coagulating and drying the glue solution to obtain the siloxane end-group functionalized polymer.

2. The method of claim 1, wherein: in the step (1), the monovinyl aromatic hydrocarbon comprises styrene and linear chain or branched chain alkyl substituted styrene with 1-10 carbon atoms; the conjugated diene is various unsaturated olefins with molecular structures containing conjugated double bonds, and comprises conjugated diene with 4-12 carbon atoms.

3. The method of claim 1, wherein: the polar organic compound structure regulator is an oxygen-containing compound selected from R₁OCH₂CH₂OR₂Wherein: r₁、R₂Is an alkyl group having 1 to 6 carbon atoms, R₁、R₂May be the same or different; r₃OCH₂CH₂OCH₂CH₂OR₄Wherein: r₃、R₄Is an alkyl group having 1 to 6 carbon atoms, R₃、R₄May be the same or different; asymmetric ethers, ethylene glycol ethyl tert-butyl ether or ethylene glycol methyl tert-butyl ether; having the general formula:an alkyl tetrahydrofurfuryl ether of formula (I), wherein: r₅Is alkyl with 1-10 carbon atoms; or 2, 2-di (2-tetrahydrofuran) propane, tetrahydrofuran and its derivatives, dioxane, crown ethers.

4. The method of claim 1, wherein: the organic lithium initiator is a mono-organic lithium initiator or a di-organic lithium initiator;

the molecular general formula of the mono-organic lithium initiator is as follows: r₆Li, formula (II) wherein R₆Is straight-chain or branched alkyl, cycloalkylOr an aryl group.

The bis-organolithium initiator comprises trimethylene dilithium or tetramethylene dilithium.

5. The method of claim 1, wherein: the end-capping reagent in the step (3) has a structure shown in a formula (I).

R₇-Si(OR₈)₃ (Ⅰ)

Wherein R is₇Is a functional group capable of reacting with a polymer active terminal carbanion, and is selected from vinyl, allyl, 3-chloropropyl and epoxybutyl; r₈Is C₁-C₁₈Or C containing an oxygen atom₁-C₁₈Linear or branched alkoxy groups of (1).

6. The method of claim 1, wherein: the concentration of the monovinylarene and/or conjugated diene monomer in the hydrocarbon solvent is 1-50% by mass percent; the molar ratio of the polar organic compound structure regulator to the organic lithium initiator is 0.5-100: 1; the mol ratio of the capping agent to the organic lithium initiator is 0.5-5: 1; the molar ratio of the end-capping reagent to the organic lithium initiator is 0.5-5: 1; the polymerization reaction temperature is 20-150 ℃, and the polymerization reaction time is 5-200 minutes; the capping reaction temperature is 20-150 ℃, and the capping reaction time is 5-90 minutes; the end capping reaction temperature is 20-150 ℃, and the end capping reaction time is 5-90 minutes.

7. A siloxane end-functionalized polymer prepared by the process of any one of claims 1 to 6, wherein: the siloxane end group functionalized polymer comprises 0-100% of monovinylarene and 100-0% of conjugated diene according to the mass percentage, namely, the monomer comprises monovinylarene or conjugated diene homopolymerization, and the monomer comprises monovinylarene and conjugated diene binary or ternary copolymerization.

8. The siloxane end-functionalized polymer of claim 7, wherein: the siloxane end-functionalized polymer has a number average molecular weight of 2000-400000; the siloxane end-functionalized polymer has an end-capping efficiency of 60 to 100%.

9. A styrene-butadiene rubber composite for a tire prepared using the siloxane end-functionalized polymer of claim 7 or 8.

10. The styrene-butadiene rubber composite material for a tire according to claim 9, characterized in that: the composition comprises the following components in parts by weight: 100 parts of siloxane end group functionalized polymer, 10-150 parts of reinforcing agent and 0-30 parts of silane coupling agent; 0.1-10 parts of vulcanizing agent, 0.1-5 parts of accelerator, 0.5-8 parts of zinc oxide, 0.5-5 parts of stearic acid, 1-5 parts of anti-aging agent and 1-50 parts of process oil.

Technical Field

The present invention is in the field of end-functionalized polymer preparation. The end-group functionalized styrene-butadiene rubber prepared by the method and the rubber composite material for the tire, which has good interaction with carbon black/white carbon black, low rolling resistance and high wet skid resistance, are prepared by adopting the end-group functionalized styrene-butadiene rubber.

Background

Due to the unique structure of the chain end of the living anionic polymer, the polymer can be reacted with a functionalized electrophile (also called a capping agent) to directly prepare the omega-end functionalized polymer, which becomes a simple and effective method for preparing the end-functionalized polymer. By this method, a wide variety of polar functional groups can be introduced at the polymer chain ends, such as amine groups, hydroxyl groups, carboxyl groups, epoxy groups, siloxane groups, and the like. The prepared end group functionalized polymer has polarity, and can obviously enhance the interaction force with various inorganic fillers, such as carbon black, white carbon black, montmorillonite, calcium carbonate, pottery clay, mica and the like. The prepared siloxane end group functionalized rubber draws attention and attention, mainly because a large amount of white carbon black is used as a reinforcing agent in the current green energy-saving tire, the compatibility between rubber macromolecules and the white carbon black is poor, the performances of rubber processing, vulcanization, mechanics and the like are reduced, and siloxane functional groups have chemical properties similar to the white carbon black and are introduced to the tail end of a rubber molecular chain, so that the motion lag of the tail end of the rubber macromolecule chain can be obviously reduced, the compatibility between the siloxane functional groups and the carbon black/white carbon black can be increased, and the energy loss is reduced.

At present, the main problems of the preparation of end-functionalized polymers by the anion polymerization method are that side reactions are easy to generate, by-products such as dimers and polymers are generated, the end-capping efficiency of end-functionalization is reduced, and the modification effect of the polymers is influenced, and the following methods (1) reaction at ultralow temperature (-78 ℃) are reported in documents for eliminating the side reactions. (2) And (3) a terminal group protection method. (3) A high volume capping agent capping process, such as capping agent Diphenylethylene (DPE), is used. The methods still have some defects, and the reaction conditions are harsh at ultralow temperature (-78 ℃); the preparation process of the end group protection method is complex; the large volume capping agent is expensive and has low reactivity, so the development of efficient and simple terminal-functionalized polymer preparation technology is still an important research topic.

Disclosure of Invention

The invention provides a method for preparing a terminal group functionalized polymer by using an epoxy compound with low price and high reactivity as a capping agent, capping an anion active chain end to passivate the activity of the chain end, and then reacting with a capping agent to prepare the terminal group functionalized polymer, which can eliminate side reactions and has the characteristics of mild reaction conditions, easy operation, low price and the like. The prepared siloxane end group functionalized polymer can be applied to the fields of low rolling resistance tires, shock absorption, noise reduction and the like.

The invention aims to provide a method for preparing a terminal-functionalized polymer by using siloxane as an end-capping agent and adopting an anion technology, siloxane terminal-functionalized styrene-butadiene rubber prepared by the method and a rubber composite material for a tire, which has the properties of good interaction with carbon black/white carbon black, low rolling resistance, high wet skid resistance and the like, prepared by adopting the siloxane terminal-functionalized styrene-butadiene rubber.

The present invention provides a method for preparing end-functionalized polymers using siloxanes as endcapping agents. Firstly, in a hydrocarbon solvent, a polar organic compound is used as a structure regulator, organic lithium is used as an initiator, monovinylarene and/or conjugated diene are initiated to carry out negative ion polymerization reaction to generate an active polymer, a capping agent is added to passivate chain end activity, and then an end capping agent is added to react to prepare the end group functionalized polymer. The prepared end-group functionalized styrene-butadiene rubber is mixed with compounding agents such as a reinforcing agent, a vulcanizing agent, an accelerator and the like to prepare styrene-butadiene rubber compound, and the styrene-butadiene rubber compound is vulcanized to obtain the rubber composite material with good mechanical property, low rolling resistance and high wet skid resistance. The method is realized by the following technical scheme:

a method of preparing a siloxane end-group functionalized polymer by anion technology, the method comprising the steps of:

(1) respectively adding a hydrocarbon solvent, a monovinylarene and/or conjugated diene monomer and a polar organic compound structure regulator into a reactor, uniformly stirring, adding an organic lithium initiator, and carrying out polymerization reaction;

(2) after the polymerization reaction is finished, adding a capping agent for capping reaction;

(3) after the cap reaction is finished, adding a capping agent for capping reaction;

(4) and after the end-capping reaction is finished, adding a compound containing protons to terminate the reaction, and coagulating and drying the glue solution to obtain the siloxane end-group functionalized polymer.

The hydrocarbon solvent is selected from one, two or more of aliphatic hydrocarbon solvents and aromatic hydrocarbon solvents, and is generally selected from one, two or more of cyclohexane, n-hexane, n-pentane, n-heptane, n-octane, benzene, toluene, ethylbenzene, xylene, mixed xylene and raffinate oil. Preferably cyclohexane, n-hexane or a mixture of both.

Further, in the step (1), the monovinyl aromatic hydrocarbon is generally selected from styrene, linear or branched alkyl substituted styrene with 1-10 carbon atoms, preferably one or two or more selected from styrene, vinyl toluene, alpha-methyl styrene, 4-tert-butyl styrene and 4-methyl styrene; the conjugated diene is various unsaturated olefins with molecular structures containing conjugated double bonds. It is generally selected from conjugated diolefins having 4 to 12 carbon atoms, and preferably one or two or more selected from 1, 3-butadiene, isoprene, 1, 3-pentadiene, 1, 3-hexadiene, 2, 3-dimethyl-1, 3-butadiene and 2-phenyl-1, 3-butadiene. Particularly preferably from styrene and 1, 3-butadiene.

Further, the concentration of the monovinylarene and/or the conjugated diene in the hydrocarbon solvent is 1-50 percent by mass percent, and preferably 10-20 percent by mass percent.

Further, theThe polar organic compound structure regulator is an oxygen-containing compound selected from R₁OCH₂CH₂OR₂Wherein: r₁、R₂Is an alkyl group having 1 to 6 carbon atoms, R₁、R₂May be the same or different, with R₁、R₂The difference is preferably as follows: ethylene glycol dimethyl ether, ethylene glycol diethyl ether; r₃OCH₂CH₂OCH₂CH₂OR₄Wherein: r₃、R₄Is an alkyl group having 1 to 6 carbon atoms, R₃、R₄May be the same or different, with R₃、R₄Preferably different, such as symmetrical ethers, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether; asymmetric ethers, ethylene glycol ethyl tert-butyl ether, ethylene glycol methyl tert-butyl ether; having the general formula:an alkyl tetrahydrofurfuryl ether of formula (I), wherein: r₅Is alkyl with 1-10 carbon atoms, such as Ethyl Tetrahydrofurfuryl Ether (ETE) and propyl tetrahydrofurfuryl ether, and the oxygen-containing compound also comprises 2, 2-di (2-tetrahydrofuran) propane (DTHFP), Tetrahydrofuran (THF) and derivatives thereof, dioxane and crown ether. Preferably THF, ETE, DTHFP, the molar ratio of the polar organic compound structure regulator to the organolithium initiator being 0.5-100:1, preferably 1-50: 1.

Further, the organic lithium initiator is various existing lithium-containing initiators capable of initiating the polymerization of the monovinylarene and the conjugated diene. Selected from mono-organolithium initiators or bis-organolithium initiators. The molecular general formula of the mono-organic lithium initiator is as follows: r₆Li, formula (II) wherein R₆Is a linear or branched alkyl, cycloalkyl or aryl group. One, two or more selected from methyllithium, ethyllithium, propyllithium, isopropyllithium, n-butyllithium (n-BuLi), sec-butyllithium, tert-butyllithium, 4-phenylbutyllithium, pentyllithium, hexyllithium, cyclohexyllithium, tert-octyllithium, phenyllithium, 4-methylphenyllithium, 4-butylphenyllithium, diphenylhexyllithium and 2-naphthyllithium. The bis-organolithium initiator comprises trimethylenedilithiumOr tetramethylene dilithium. Preferably an alkyl lithium such as n-butyl lithium, and the amount of the organolithium initiator can be selected appropriately according to the designed molecular weight. When preparing the polymer with larger molecular weight, the lower dosage of the organic lithium initiator is adopted; when preparing the polymer with smaller molecular weight, the use amount of the organic lithium initiator is higher.

Further, the polymerization reaction temperature is 20-150 ℃, preferably 50-70 ℃; the polymerization time is 5 to 200 minutes, preferably 30 to 120 minutes.

Further, the capping agent is a 1, 2-epoxy compound selected from 1, 2-Ethylene Oxide (EO), 1, 2-propylene oxide or 1, 2-butylene oxide, preferably 1, 2-ethylene oxide. The electronegativity of oxygen atoms is larger than that of carbon atoms, and the stability of the tail end of oxygen lithium formed by ring opening is higher than that of the tail end of carbon lithium, so that the activity of the tail end of a chain is reduced, and the aims of passivating the active chain end, eliminating side reactions and improving the end-capping efficiency are fulfilled.

Further, the mol ratio of the capping agent to the organic lithium initiator is 0.5-5:1, preferably 1-1.5: 1.

Furthermore, the reaction temperature of the cap is close to the polymerization reaction temperature, and the shorter the reaction time, the better the reaction time. The reaction temperature of the cap is 20-150 ℃, and preferably 50-70 ℃; the capping reaction time is 5 to 90 minutes, preferably 10 to 60 minutes.

Further, the end-capping reagent has a structure shown in formula (I).

R₇-Si(OR₈)₃(Ⅰ)

Wherein R is₇Is a functional group capable of reacting with a polymer terminal carbanion, and is selected from vinyl, allyl, 3-chloropropyl and epoxybutyl; r₈Is C₁-C₁₈Or C containing an oxygen atom₁-C₁₈Linear or branched alkyl. Preferably selected from C₁-C₅Straight chain alkyl group of (2) or C containing an oxygen atom₁-C₅Straight-chain alkyl radicals of, e.g. -CH₂CH₃、-CH₂CH₂OCH₂CH₃、-CH₂CH₂OCH₂CH₂OCH₃. Specific examples are: vinyltrimethoxysilane (TIVS), allyltrimethoxysilane (TIOS), allyltriethoxysilane, allyltrimethoxyethoxyethoxyethoxysilane, 3-chloropropyltrimethoxysilane and epoxybutyltrimethoxysilane. Preferably selected from vinyltrimethoxysilane and allyltrimethoxysilane.

Further, the mol ratio of the end-capping reagent to the organic lithium initiator is 0.5-5:1, preferably 1-2: 1.

Further, the end-capping reaction temperature is preferably close to the polymerization reaction temperature, and the shorter the reaction time, the better the reaction time. The end-capping reaction temperature is 20-150 ℃, preferably 50-70 ℃; the capping reaction time is 5 to 90 minutes, preferably 10 to 60 minutes.

The invention also provides a siloxane end group functionalized polymer prepared by the method, wherein the monomer composition proportion of the siloxane end group functionalized polymer is 0-100% of monovinylarene and 100-0% of conjugated diene by mass percent, namely, the siloxane end group functionalized polymer comprises monovinylarene or conjugated diene homopolymerization, and monovinylarene and conjugated diene binary or ternary copolymerization.

Further, the number average molecular weight of the siloxane end-functionalized polymer is 2000-. The number average molecular weight is measured by a Gel Permeation Chromatograph (GPC), THF is used as a mobile phase, narrow-distribution polystyrene is used as a standard sample, the measuring temperature is 30 ℃, and the operation is carried out for 25 min.

Further, the siloxane end-functionalized polymer has an end-capping efficiency of 60 to 100%.

In the present invention, the "blocking efficiency" refers to the ratio of the number of moles of molecular chains whose terminal groups contain the structural unit of the blocking agent to the total number of moles of molecular chains of the polymer. The capping efficiency can be measured using nuclear magnetic spectroscopy (NMR) and Gel Permeation Chromatography (GPC).

The end-functionalized polymer is prepared by end-capping an end-capping agent with the structure of formula (I), such as siloxane end-functionalized Polystyrene (PS), siloxane end-functionalized butadiene rubber (PB), siloxane end-functionalized solution-polymerized styrene-butadiene rubber (SSBR), siloxane end-functionalized styrene-butadiene triblock copolymer and siloxane end-functionalized butadiene-styrene triblock copolymer, and thermoplastic elastomer (SBS).

As known to those skilled in the art, the anionic polymerization system has no significant termination reaction and transfer reaction, and therefore, after the termination reaction is completed, a terminator should be added to terminate the reaction. The terminator can be various proton-containing compounds capable of inactivating the negative ion active center, such as one or more of water, methanol, ethanol and isopropanol, preferably isopropanol.

After the reaction is terminated, the end-functionalized polymer is obtained by coagulation, filtration, isolation and drying, all of which are well known to those skilled in the art.

The invention also provides the siloxane end group functionalized styrene-butadiene rubber prepared by the method and a styrene-butadiene rubber composite material for the tire prepared by adopting the styrene-butadiene rubber. The styrene-butadiene rubber composite material comprises 100 parts of the siloxane end group functionalized polymer, 10-150 parts of a reinforcing agent and 0-30 parts of a silane coupling agent in parts by weight; 0.1-10 parts of vulcanizing agent, 0.1-5 parts of accelerator, 0.5-8 parts of zinc oxide, 0.5-5 parts of stearic acid, 1-5 parts of anti-aging agent and 1-50 parts of process oil.

The reinforcing agent is carbon black, white carbon black or a mixture of carbon black and white carbon black. The carbon black is specified by the national standard 'GB 3778-2011 carbon black for rubber'. The white carbon black is white carbon black prepared by a wet process or white carbon black prepared by a dry process. The addition amount of the reinforcing agent is 10-150 parts, preferably 30-100 parts.

The vulcanizing agent is sulfur and a sulfur-containing compound. The amount added is 0.1-10 parts, preferably 0.5-5 parts.

The accelerator is sulfenamide, such as N-cyclohexyl-2-benzothiazole sulfenamide (CZ), N-dicyclohexyl-2-benzothiazole sulfenamide (DZ) and N-tertiary butyl-2-benzothiazole sulfenamide (TBBS); thiazoles, such as 2- (4-morpholinothiol) benzothiazole (NOBS), N-tert-butyl-2-benzothiazolesulfenamide (NS), 2-mercaptobenzothiazole (M), dibenzothiazyl Disulfide (DM); thiurams, such as tetramethylthiuram monosulfide (TMTM), tetrabutylthiuram monosulfide (TBTS), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetramethylthiuram tetrasulfide (TMTT), and the like, are added in an amount of 0.1 to 5.0phr, preferably 0.5 to 3.0 phr, of the vulcanization accelerator.

Other compounding agents in the rubber composite material are conventional choices in the field of rubber processing industry, such as zinc oxide, stearic acid, paraffin, an anti-aging agent and process oil.

In the rubber composite, a silane coupling agent is generally added when white carbon black is used, and the silane coupling agent is expensive. Because the siloxane end group functionalized rubber has higher compatibility with the white carbon black, the use amount of a silane coupling agent can be reduced, or the silane coupling agent is not added, and the prepared rubber composite material still has higher performance. The adding amount of the silane coupling agent is 1-30 wt% of the adding amount of the white carbon black.

The rubber composite material is plasticated and mixed by using a double-roll open mill or an internal mixer to obtain mixed rubber, and then vulcanized on a flat vulcanizing machine to obtain vulcanized rubber.

The vulcanized rubber was subjected to various property tests such as mechanical properties, tan δ representing rolling resistance and wet skid resistance.

The invention has the beneficial effects that the anion polymerization technology is adopted, firstly, an epoxy compound with low price and high reaction activity is adopted as a capping agent, the active organic lithium end group is capped to passivate the activity of a chain end and eliminate side reaction, then, a capping agent containing siloxane groups is adopted to prepare the siloxane end group functionalized polymer by in-situ capping, so that the movement activity of the rubber molecular chain end can be passivated, and the binding force between the rubber molecular chain and carbon black/white carbon black can be increased, thereby reducing the hysteresis energy loss, and the prepared rubber composite material has good mechanical property, low rolling resistance, high wet skid resistance and the like, and can be applied to the tread of an automobile tire. The prepared siloxy end group functionalized polymer has the advantages of no side reaction, simple process, low cost, high end capping efficiency and easy industrialization.

Drawings

FIG. 1 is a GPC chart of PS (a) and PS-TIVS (b).

FIG. 2 is a GPC chart of PB (a), PB-TIVS (b), PB-DPE-TIVS (c) and PB-EO-TIVS (d).

FIG. 3 is a GPC chart of SBR (a), SBR-TIVS (b) and SBR-EO-TIVS (c).

FIG. 4 is a GPC chart of PS (a) and PS-TIOS (b).

FIG. 5 is a GPC chart of PB (a), PB-TIOS (b), and PB-EO-TIOS (c).

FIG. 6 is a GPC chart of SBR (a), SBR-TIOS (b), and SBR-EO-TIOS (c).

FIG. 7 is a graph of the dynamic mechanical properties of the sample vulcanizates prepared in comparative example 1, example 3 and example 5.

Detailed Description

The following further description of the technical solutions of the present invention with reference to specific examples will help understanding the present invention. However, the present invention is not limited to the following examples, and the scope of the present invention is defined by the claims.

Comparative example 1

1500g of cyclohexane/n-hexane mixed solvent is weighed according to the volume ratio of 10:1 by adopting a 5-liter stainless steel reaction kettle, 150g of monomer styrene is introduced, and a solution with the monomer mass percentage concentration of 10% is prepared. Then, the molar ratio of DTHFP: DTHFP (2, 2-bis (2-tetrahydrofuryl) propane) was added to n-BuLi ═ 1.2. Adding an initiator n-BuLi in a constant temperature water bath at 50 ℃ to initiate polymerization. After 1 hour of polymerization, the mixture was heated at 50 ℃ in a molar ratio of TIVS: adding a blocking agent TIVS (vinyl trimethoxy silane) into n-BuLi ═ 1.5, after 30 minutes of blocking reaction, adding isopropanol to stop the reaction, condensing the glue solution, and drying on an open mill to obtain the TIVS-blocked polystyrene (PS-TIVS). The GPC spectra of PS before and after capping are shown in FIG. 1. As can be seen from FIG. 1, both curves (a) and (b) show a unimodal distribution, indicating that no coupling side reactions have occurred with the TIVS-terminated PS.

Comparative example 2

Following the synthesis of comparative example 1, except that the monomer was butadiene, a TIVS-terminated polybutadiene (PB-TIVS) was obtained. The GPC spectra of PB before and after capping are shown in FIG. 2. As can be seen from FIG. 2, curve (a) shows a monomodal distribution, while curve (b) corresponds to a bimodal distribution of PB-TIVS indicating that coupling side reactions have occurred, and nearly twice the Mn indicating dimer formation with a coupling rate of up to 71.61%.

Comparative example 3

According to the synthesis method of comparative example 1, the difference is that the monomers are styrene and butadiene, and the mass ratio of styrene: butadiene 30: 70, weighing the monomers to obtain the TIVS-terminated SSBR (SSBR-TIVS). The GPC spectra of SSBR-TIVS before and after capping are shown in FIG. 3. As can be seen from FIG. 3, curve (a) shows a monomodal distribution, while curve (b) corresponds to a bimodal distribution of SSBR-TIVS indicating that coupling side reactions have occurred, with nearly two-fold Mn indicating dimer formation and a coupling rate of greater than 50%.

Comparative example 4

The synthesis of comparative example 1 was followed except that TIOS (allyltrimethoxysilane) was used as the capping agent. And (3) according to molar ratio TIOS: n-BuLi ═ 2 was added to the blocking agent TIOS to give TIOS-blocked polystyrene (PS-TIOS). The GPC spectra of PS before and after capping are shown in FIG. 4. As can be seen from FIG. 4, both curves (a) and (b) show a unimodal distribution, indicating that no coupling side reaction occurred with the TIOS-terminated PS (the small peak on the left of curve (a) is the oxygen coupling peak generated by oxygen entrained in the air).

Comparative example 5

The synthesis of comparative example 2 was followed except that the capping agent was TIOS. And (3) according to molar ratio TIOS: n-BuLi ═ 2 was added to the end-capping agent TIOS to give TIOS-capped polybutadiene (PB-TIOS). The GPC spectra of PB before and after capping are shown in FIG. 5. As can be seen from FIG. 5, curve (a) shows a monomodal distribution, while curve (b) corresponds to a bimodal distribution of PB-TIOS, indicating the occurrence of coupling side reactions, with nearly twice the Mn, indicating the formation of dimers with a coupling rate higher than 50%.

Comparative example 6

The synthesis of comparative example 3 was followed except that the capping agent was TIOS. And (3) according to molar ratio TIOS: n-BuLi 2 was added to the mixture to obtain a TIOS-terminated SSBR (SSBR-TIOS). The GPC spectra of SSBR-TIOS before and after capping are shown in FIG. 6. As can be seen from FIG. 6, curve (a) shows a monomodal distribution, while curve (b) corresponds to a bimodal distribution of SSBR-TIOS, indicating the occurrence of coupling side reactions, with nearly double Mn, indicating the formation of dimers with a coupling rate of more than 50%.

Comparative example 7

The synthesis of comparative example 3 was followed except that no capping agent was added to prepare a non-end-functionalized SSBR for comparison as a blank.

Example 1

The synthesis procedure of comparative example 2 was followed, with the difference that the molar ratio DPE: n-BuLi 1.2, adding a capping agent DPE (diphenylethylene), reacting for 30 minutes, and then adding a capping agent TIVS for capping reaction. The DPE capped and TIVS terminated PB (PB-DPE-TIVS) was obtained, and the GPC spectra of the capped PB and then terminated PB are shown in FIG. 2 as curve (c). As can be seen from FIG. 2, the curve (c) still shows a bimodal distribution, and although the coupling ratio is reduced, the side reactions are still not completely eliminated.

Example 2

The synthesis procedure of comparative example 2 was followed, except that the molar ratio EO: n-BuLi is 1.2, EO (1, 2-ethylene oxide) as a capping agent is added, the reaction is carried out for 30 minutes, and then TIVS as a capping agent is added to carry out the capping reaction. EO capped and TIVS capped PB (PB-EO-TIVS) was obtained, and the GPC spectra of the capped PB was shown in FIG. 2 as curve (d). As can be seen from FIG. 2, curve (d) is unimodal, indicating that no coupling side reactions have occurred.

In comparison with comparative example 2, for PB, capping with TIVS after DPE capping did not completely eliminate the coupling side reaction, while capping with EO capping completely eliminated the coupling side reaction.

Example 3

Synthesized according to the procedure of comparative example 3, except that the molar ratio EO: n-BuLi is 1.2, adding a capping agent EO, reacting for 30 minutes, and then adding a capping agent TIVS for capping reaction. The EO capped TIVS capped SSBR (SSBR-EO-TIVS) was obtained and the GPC spectrum of the capped SSBR is shown in FIG. 3, curve (c). As can be seen from FIG. 3, curve (c) is unimodal, indicating that no coupling side reactions have taken place.

In comparison to comparative example 3, for SSBR, coupling side reactions were completely eliminated by capping with TIVS after EO capping.

Example 4

Synthesized according to the procedure of comparative example 5, except that the molar ratio EO: n-BuLi 1.2, EO as a capping agent was added, the reaction was carried out for 30 minutes, and TIOS as a capping agent was added to carry out the capping reaction. An EO-capped TIOS-capped PB (PB-EO-TIOS) was obtained, and the GPC spectrum of the capped PB was shown by curve (c) in FIG. 5. As can be seen from FIG. 5, curve (b) is unimodal, indicating that no coupling side reactions have occurred.

In comparison with comparative example 5, for PB, capping with TIOS after EO capping completely eliminated coupling side reactions.

Example 5

Synthesized according to the procedure of comparative example 6, except that the molar ratio EO: n-BuLi 1.2, EO as a capping agent was added, the reaction was carried out for 30 minutes, and TIOS as a capping agent was added to carry out the capping reaction. The EO capped TIOS capped SSBR (SSBR-EO-TIOS) was obtained and the GPC spectrum of the capped SSBR is shown in FIG. 6, curve (c). As can be seen from FIG. 6, curve (c) is unimodal, indicating that no coupling side reactions have occurred.

In comparison to comparative example 6, for SSBR, capping with TIOS using an EO cap can completely eliminate coupling side reactions.

Application example 1

The SSBR samples prepared in comparative example 7, example 3 and example 5 were mixed with the various auxiliaries according to the formulation given in Table 1 in an internal mixer to prepare rubber mixtures.

TABLE 1

Application example 2

According to the formulation of application example 1, the rubber mixtures prepared in comparative example 7, example 3 and example 5 were vulcanized on a flat plate vulcanizing machine, and the mechanical properties of the vulcanized rubber were tested, and the results are shown in Table 2.

TABLE 2

As can be seen from Table 2, the mechanical properties of examples 3 and 5 are significantly improved compared with those of comparative example 7, indicating that the mechanical properties of SSBR are improved after the end capping of siloxane.

Application example 3

The samples of the comparative example 7, example 3 and example 5 vulcanizates prepared according to application example 2 were further subjected to dynamic mechanical property tests, and the results are shown in fig. 7 and table 3.

TABLE 3

As can be seen from FIG. 7 and Table 3, the loss factors tan. delta. (0 ℃ C.) of examples 3 and 5 are significantly higher than those of comparative example 7, and tan. delta. (60 ℃ C.) is close, which fully demonstrates that the siloxane end-capped modified SSBR is effective in improving the wet skid resistance and reducing the rolling resistance of the rubber.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.