Star-shaped high trans-1,4-structured poly-1,3-pentadiene elastomer, its preparation method and application

Abstract

The application relates to the technical field of high polymer materials, and discloses a star-shaped poly-1,3-pentadiene elastomer with high trans-1,4-structure content and a preparation method and application thereof. The structural expression of the elastomer is (PPD-PB)n-A; PPD is a poly-1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of a multifunctional lithium initiator mLi, n is 3-50, and A is an organic residue of mLi; the trans-1,4-structure content in the elastomer is 65-95 mol%, the cis-1,4-structure content is 0-20 mol%, the 1,2-structure content is 5-20 mol%, and the 3,4-structure content is 0-10 mol%. The star-shaped poly-1,3-pentadiene elastomer with high trans-1,4-structure content prepared has a higher molecular weight than similar linear products.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to a star-shaped poly1,3-pentadiene elastomer with high trans-1,4-structure content, a preparation method and application thereof. BACKGROUND

[0002] Compared with linear polymers, star-shaped polymers have lower diffusion coefficient, melt viscosity and crystallinity at the same molecular weight, and have unique properties such as smaller hydrodynamic volume on the molecular surface and higher functionality. The melt viscosity of star-shaped polymers is independent of the total molecular weight and only depends on the size of the single-arm molecular weight, which is the biggest difference from linear polymers. From the perspective of process production, star-shaped polymers prepared by using a multi-functional initiator of star core type are significantly superior to linear polymers in terms of Mooney viscosity control and gel self-acceleration phenomenon, which is due to the weak intermolecular interaction caused by the spherical symmetric structure and small atomic spatial arrangement size of star-shaped polymers. Because of the chemical bond constraint between the star core and each arm, the number of free ends per unit volume of star-shaped polymers is significantly lower than that of linear polymers, and this feature is also reflected in the chain end effect of vulcanized rubber: when the entire macromolecular chain is in elastic motion, the fewer the ends are bound by the intermolecular network, the more difficult it is to restore the original position, and the energy cannot be completely released, resulting in hysteresis effect; for example, solution-polymerized styrene-butadiene and lithium-based polybutadiene rubber need to be further improved in wet skid resistance and rolling resistance by coupling with silicon-tin coupling agents. The tight structure and high segment density of star-shaped polymers also give themselves higher mechanical strength and modulus.

[0003] Lithium-based synthetic rubber and thermoplastic elastomer can be prepared into star-shaped polymers by (1) coupling method (2) multi-functionality initiator method. Coupling method is simple in process, easy to realize in the synthesis of star-shaped polymers, and the coupling agent itself is also relatively cheap and easy to obtain. The core atom also has reinforcing effect on the performance of the elastomer. For example, after the coupling of butadiene rubber using tin tetrachloride, the tin-carbon bond is easy to break, which can effectively promote the dispersion of fillers such as carbon black, thereby improving the wet skid resistance of the product and reducing the rolling resistance. When star-shaped or linear-star hybrid SBS dry gum prepared by using siloxane is used for asphalt modification, the high-temperature performance is very outstanding. However, the coupling efficiency and coupling degree of the coupling agent in the use process have high requirements on the process. Low coupling efficiency or insufficient coupling degree will increase the low molecular weight linear single-arm polymer in the star-shaped polymer, which will greatly reduce the product performance. The silicon-tin coupling agent will also repel some polar modifiers, making the coupling effect worse. At the same time, the coupling effect is greatly related to the steric hindrance of the active chain end, such as the difference in steric hindrance of the methyl group at the end of polyisoprene chain and the head and tail of polystyrene. A small piece of butadiene cap or randomization reagent is often needed to obtain high coupling efficiency and coupling degree. As a coupling agent, di-vinyl benzene (DVB) has high process difficulty. If the amount of DVB is large, the number of side reactions in the system will increase, and the randomness will increase the cross-linking between the chains and the DVB oligomer microgel core, which will cause the viscosity of the solution to increase sharply. If the amount of DVB is low, the coupling degree is not high, and it is difficult to prepare star-shaped polymers with stable arm number. The multi-lithium initiator method for preparing star-shaped polymers can effectively solve the above problems caused by poor coupling effect, such as residual single-arm linear polymer and low coupling efficiency in the presence of complex polar modifiers. The multi-lithium complex initiator with DVB as the core can effectively solve the solubility of itself after chain extension, and has better compatibility with some μ-type ligand polar modifiers, that is, the high-efficiency structure control of the polymer chain can be realized. CN101899135A uses a multi-lithium complex initiator with DVB as the core to prepare a star-shaped high-impact SBC. The star-shaped structure gives the material high impact and transparency, and optimizes the processing performance of the material.

[0004] In lithium-based polydiene elastomer materials, various polybutadiene products can be prepared into star-shaped polymers with a branching degree of 4 or higher to improve physical properties and solve the cold flow phenomenon of narrow molecular weight linear products. For example, non-flowing low-cis butadiene rubber LCBR and various branched structure vinyl butadiene rubber. US 4482677 uses DVB to initiate the prepolymerization of a multi-functionality initiator with a branching degree less than 6 in the presence of a small amount of Bd monomer for the preparation of high-vinyl polybutadiene, which effectively solves the poor performance of melt viscosity (high shear) and cold flow (low shear) of linear products of the same type.

[0005] High trans 1,4-structure polydiene rubber has excellent low temperature performance of low heat build-up, high fatigue resistance and wear resistance, while effectively balancing the rolling resistance of the tire, and is an ideal rubber for developing high performance energy saving tires. At present, the method for preparing high trans 1,4-structure rubber from unsaturated hydrocarbon monomers is mainly by homopolymerization or copolymerization of butadiene and isoprene monomers, and there is no research report on star structure 1,3-pentadiene. Anionic polymerization can realize the preparation of star high trans-polybutadiene, but the high crystallinity affects the processing performance of the elastomer, especially greatly increases the process cost of the vulcanization process. US4048418, US4148983, US5066754 and CN103709295 respectively relate to the preparation of linear and low branched poly 1,3-pentadiene by iron-based, cobalt-based, vanadium-based and rare earth-based catalysts, some of which cannot effectively realize the precise control of the microstructure of the polymer, and the molecular weight distribution is generally high PDI>2.5. US4482771 prepared linear high propylene content poly 1,3-pentadiene by anionic polymerization, high Tg(Tg>-20℃) limits the application in some fields, and cannot effectively overcome the problem of low molecular weight of the polymer caused by the residual pentacetylene and cyclopentadiene in 1,3-pentadiene monomer. SUMMARY

[0006] The purpose of the present application is to overcome the problem of low number average molecular weight of poly 1,3-pentadiene in the prior art, and the defects of the preparation method of poly 1,3-pentadiene in the prior art, such as wide molecular weight distribution, poor effect of coupling agent method, and unable to effectively control the arm number, to provide a star high trans 1,4-structure content poly 1,3-pentadiene elastomer and its preparation method and application. The preparation method is simple, and the star high trans 1,4-structure content poly 1,3-pentadiene elastomer prepared has a higher molecular weight than similar linear products, which provides technical support for the high performance elastomer materialization of 1,3-pentadiene.

[0007] In order to achieve the above purpose, the first aspect of the present application provides a star high trans 1,4-structure content poly 1,3-pentadiene elastomer, wherein the elastomer has a structure expression shown in formula (1):

[0008] (PPD-PB)n-A, formula (1);

[0009] Wherein, PPD is a poly 1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of a multi-functional lithium initiator mLi, n is 3-50, and A is an organic residue of mLi;

[0010] The trans-1,4-structure content in the elastomer is 65-95 mol%, the cis-1,4-structure content is 0-20 mol%, the 1,2-structure content is 5-20 mol%, and the 3,4-structure content is 0-10 mol%.

[0011] The second aspect of the present application provides a preparation method of star-shaped high-trans-1,4-structure poly-1,3-pentadiene, wherein the preparation method comprises:

[0012] (1) mixing and preheating butadiene monomers and a first aprotic solvent in a reactor to obtain a mixed solution;

[0013] (2) contacting the mixed solution with a catalyst for aging treatment; wherein the catalyst comprises a main catalyst and an optional co-catalyst, wherein the main catalyst comprises an organic barium salt or an organic sodium salt, and the co-catalyst is an alkyl aluminum;

[0014] (3) mixing the product after step (2) with a first polarity regulator and a multifunctional organic lithium initiator mLi to initiate a polymerization reaction until the butadiene monomers are completely converted;

[0015] (4) adding 1,3-pentadiene monomers to the system after step (3) to initiate a polymerization reaction and then terminating the reaction to obtain a star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer (PPD-PB)n-A;

[0016] wherein PPD is a poly-1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of the multifunctional lithium initiator mLi, n is 3-50, and A is the organic residue of mLi.

[0017] The third aspect of the present application provides a star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the preparation method described above.

[0018] The fourth aspect of the present application provides an application of the star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer described above as a rubber compound in the tire tread and / or tire side.

[0019] Through the above technical solution, the technical solution of the present application has the following advantages:

[0020] (1) The preparation method of the present application uses easily available raw materials, has a fast reaction rate, and has a high conversion rate.

[0021] (2) The star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the present application has controllable arm number, which can effectively solve the problem of low molecular weight of the polymer caused by ppm-level pentynyl and cyclopentadiene residues in 1,3-pentadiene monomers. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 DSC curve of the star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer prepared in Example 1 of the present application;

[0023] Figure 2 GPC curve of the star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values claimed herein are presented as approximations. Unless otherwise stated, the endpoints of ranges are not to be understood as being presented to the nearest integer, but are to be understood to include fractions of the recited integer as well as ends. Ordinal terms such as first, second, third, etc. are used merely as labels to avoid confusion and do not in fact show sequential or chronological order unless explicitly indicated to do so. Accordingly, a first step, process, object, composition, etc. discussed above could be a second step, process, object, composition, etc. These and other variations, modifications, additions and improvements can be resorted to by those skilled in the art constructing implementations of this application, without departing from the scope thereof, and it is therefore intended that such changes and modifications should be understood as being possible by those skilled in the art, and that this application should be understood only in terms of the scope of the appended claims.

[0025] In a first aspect, the present application provides a star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer, wherein the elastomer has a structural expression shown in formula (1):

[0026] (PPD—PB)n—A, formula (1);

[0027] wherein PPD is a poly-1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of the multifunctional lithium initiator mLi, n is 3-50, and A is the organic residue of mLi.

[0028] wherein the trans-1,4-structure content in the elastomer is 65-95 mol%, the cis-1,4-structure content is 0-20 mol%, the 1,2-structure content is 5-20 mol%, and the 3,4-structure content is 0-10 mol%.

[0029] The inventors of the present application have unexpectedly found that, under the catalysis of a main catalyst (an organic barium salt or an organic sodium salt) and an optional cocatalyst (an alkyl aluminum), the initiation of 1,3-pentadiene anion polymerization by a polar regulator can produce a star-shaped high-trans 1,4-structure-content poly-1,3-pentadiene elastomer instead of a linear poly-1,3-pentadiene, and the multi-functional organic lithium initiator used in the method of the present application is simple to synthesize with raw materials being easy to obtain, and the organic barium salt or the organic sodium salt can be recovered by water vapor condensation. In addition, the present application provides a solution to the problem of low molecular weight of poly-1,3-pentadiene caused by the acetylene and cyclopentadiene residual content in the 1,3-pentadiene monomer on the market being greater than 20 ppm, and the star-shaped high-trans 1,4-structure-content poly-1,3-pentadiene elastomer has a higher molecular weight than the linear product of the same kind, which provides technical support for the high-performance elastomeric materialization of 1,3-pentadiene.

[0030] According to the present application, the number average molecular weight of the elastomer is 5x10 4 g / mol to 1x10 6 g / mol. 4 g / mol to 5x10 5 g / mol.

[0031] According to the present application, the value of the molecular weight distribution PDI (PDI = weight average molecular weight Mw / number average molecular weight Mn) of the elastomer is 1.05-2.5, preferably 1.05-1.8.

[0032] According to the present application, the content of the poly-1,3-pentadiene block is 50-95 mass%, and the content of the polybutadiene block is 2-50 mass% based on the total weight of the elastomer; preferably, the content of the poly-1,3-pentadiene block is 91.5-95 mass%, and the content of the polybutadiene block is 4.2-8.5 mass% based on the total weight of the elastomer.

[0033] According to the present application, the mass ratio of the poly-1,3-pentadiene block to the polybutadiene block is (1-22):1, preferably (10-22):1.

[0034] According to the present application, the content of the trans 1,4-structure in the elastomer is 70-95 mol%, preferably 82-88 mol%.

[0035] According to the present application, preferably, the content of the cis 1,4-structure in the elastomer is 0-5 mol%, the content of the 1,2-structure is 5-15 mol%, and the content of the 3,4-structure is 0-3 mol% of the units.

[0036] According to the present application, the glass transition temperature Tg of the elastomer is in the range of -70°C to -20°C, preferably in the range of -70°C to -40°C; the melting temperature Tm is in the range of 0-90°C, preferably in the range of 70-90°C. g m

[0037] According to the present application, the number of arms of the elastomer is determined by the functionality n of the multifunctional lithium initiator mLi, n being in the range of 3-50, preferably in the range of 3-10. In the present application, the "number of arms" refers to the number of PPD-PB block copolymers connected to each organic residue A of mLi.

[0038] According to the present application, the star-shaped high molecular weight poly-1,3-pentadiene copolymer with high trans-1,4-structure content is prepared by using a solution polymerization method and a multi-lithium initiator.

[0039] As previously described, the second aspect of the present application provides a preparation method of a star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer, wherein the preparation method comprises:

[0040] (1) mixing and preheating butadiene monomers with a first aprotic solvent in a reactor to obtain a mixed solution;

[0041] (2) contacting the mixed solution with a catalyst for aging treatment; wherein the catalyst comprises a main catalyst and an optional co-catalyst, wherein the main catalyst comprises an organic barium salt or an organic sodium salt, and the co-catalyst is an alkyl aluminum;

[0042] (3) mixing the product after step (2) with a first polarity regulator and a multifunctional organic lithium initiator mLi to perform an initiation polymerization reaction until the butadiene monomers are completely converted;

[0043] (4) adding 1,3-pentadiene monomers to the system after step (3) to perform a mixed initiation polymerization reaction and then terminate the reaction to obtain a star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer (PPD-PB)n-A;

[0044] wherein PPD is a poly-1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of the multifunctional lithium initiator mLi, n being in the range of 3-50, and A is the organic residue of mLi.

[0045] According to the present application, the amount of the multifunctional lithium initiator mLi is determined by the single-arm poly-1,3-pentadiene / polybutadiene block copolymer PPD-PB, and the design value of the number average molecular weight of the single arm is in the range of 1×10 4 g / mol to 5×10 4 g / mol.

[0046] ​​According to the application, the preparation method of the multi-function organic lithium initiator mLi comprises the following steps: mixing divinylbenzene, unsaturated hydrocarbon and polar modifier in proportion with aprotic solvent, and then adding alkyl lithium to carry out addition reaction to obtain the multi-function organic lithium initiator mLi.

[0047] The molar ratio of the amounts of the divinylbenzene, the unsaturated hydrocarbon, the second polar modifier and the alkyl lithium is (0.1-10):(1-100):(1-100):1.

[0048] The addition reaction conditions of the alkyl lithium include that the temperature is -20-60℃ and the time is 0.5-12h.

[0049] According to the application, the unsaturated hydrocarbon is selected from one or more of butadiene, styrene, 4-tert-butylstyrene, 1,1-diphenyl ethylene, isoprene and 1,3-pentadiene; the butadiene, isoprene and 1,3-pentadiene belong to conjugated dienes, and the styrene derivative is actually a large π bond and a double bond for π and double conjugation.

[0050] According to the application, the alkyl lithium is selected from one or more of methyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium and phenyllithium.

[0051] According to a preferred embodiment of the application, the synthesis method of the multi-function organic lithium initiator mLi used in the application is as follows: in a glove box in a high-purity argon atmosphere, 100g of cyclohexane, 4g of butadiene, 1.4g of triethylamine and 1.8g of divinylbenzene are added to a polymerization bottle baked at high temperature according to the proportion, and then 9.3ml of n-butyllithium cyclohexane solution with a concentration of 1.6mol / L is gradually added, and the mixture is uniformly mixed; the reaction is carried out at 50℃ for 2h, and then the concentration is determined by Gilman double titration for standby use; the multi-lithium initiator prepared by the method is purple red.

[0052] When the catalyst is prepared, the organic barium salt BAD and BHT can be purchased from the market or prepared according to the common synthesis route disclosed in the prior art, and toluene is used as a solvent to configure a solution. The n-butyllithium and tert-butyllithium are provided by Balin Petrochemical Company.

[0053] According to the application, the catalytic-initiating reaction system of the application is used under anhydrous and anaerobic conditions, and the catalyst used in the system is composed of a main catalyst and an optional cocatalyst, and the molar ratio of the amounts of the cocatalyst and the main catalyst is (0-100):1, preferably (0-4):1.

[0054] According to the present application, the main catalyst is an organic barium salt or an organic sodium salt which can be used in lithium-based preparation of trans-polyunsaturated hydrocarbons; wherein the organic barium salt is selected from one or more of alkoxy barium salt, cycloalkoxy barium salt, alcohol ether barium salt, alcohol amine barium salt, phenol barium salt and carboxylic acid barium salt; preferably, the organic barium salt is selected from one or more of barium mentholate, barium thymol (BHT), barium diethylene glycol monoethyl ether (BAD), barium morpholine ethanol, barium dodecyl benzene sulfonate, barium tetrahydrofurfuryl acid and barium tetrahydrofurfuryl alcohol; more preferably, the organic barium salt is barium thymol and / or barium diethylene glycol monoethyl ether.

[0055] According to the present application, the organic sodium salt is an alkoxy sodium salt and / or a sulfonic acid sodium salt; preferably, the organic sodium salt is selected from one or more of sodium dodecyl sulfate (SDS), sodium p-toluenesulfonate, sodium dodecyl benzene sulfonate (SDBS), sodium tetrahydrofurfuryl alcohol and sodium tert-pentanol, preferably sodium dodecyl benzene sulfonate and sodium dodecyl sulfate.

[0056] According to the present application, the co-catalyst is an alkyl aluminum, wherein the alkyl aluminum is selected from one or more of trimethyl aluminum (TMA), triethyl aluminum (TEA), tripropyl aluminum, triisobutyl aluminum (TIBA), triisopropyl aluminum, trioctyl aluminum and methylaluminoxane, preferably trimethyl aluminum, triethyl aluminum and triisobutyl aluminum.

[0057] According to the present application, the aprotic solvent is selected from one or more of cyclohexane, n-hexane, n-pentane, n-heptane, benzene, hydrogenated oil and extracted oil, preferably cyclohexane; wherein the benzene includes toluene, ethylbenzene and xylene.

[0058] According to the present application, the polarity regulator is selected from one or more of tetrahydrofuran (THF), dioxane, triethylamine, bis-tetrahydrofurfuryl propane, N,N-dimethyl tetrahydrofurfuryl amine, tetrahydrofurfuryl alcohol ethyl ether, tetrahydrofurfuryl alcohol butyl ether, pentamethyl diethyl triamine, dipiperidyl ethane, triphenyl phosphine and carbon disulfide, preferably one or more of tetrahydrofuran, tetrahydrofurfuryl alcohol ethyl ether and carbon disulfide.

[0059] According to the present application, the molar ratio of the catalyst to the amount of the multi-functional organic lithium initiator mLi is (0.01-100):1, preferably (0.5-1.25):1.

[0060] According to the present application, the molar ratio of the first polarity regulator to the amount of the multi-functional organic lithium initiator mLi is (0-100):1, preferably (0-20):1.

[0061] According to the present application, the mass ratio of butadiene, 1,3-pentadiene monomer to the amount of the first aprotic solvent is (1-50):(50-100):1000.

[0062] According to the present application, the mixing preheating condition includes: temperature of 25-80℃, time of 0.5-3h;

[0063] According to the present application, the aging treatment condition includes: temperature of 25-60℃, time of 10min-5h;

[0064] According to the present application, the polymerization condition includes: temperature of 0-100℃, time of 1-24h.

[0065] According to the present application, after the polymerization, 0.5-3mL of water solution or alcohol solution containing anti-aging agent and antioxidant is added to terminate the reaction, and the excess methanol is precipitated and vacuum dried at 40-60℃ for 24-72h.

[0066] In the present application, the anti-aging agent is selected from anti-aging agent 264 and / or anti-aging agent 2264.

[0067] In the present application, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168 and antioxidant 1076.

[0068] According to the present application, the terminating agent used in the termination reaction is generally selected from any one of water, methanol, ethanol and isopropanol, and preferably isopropanol.

[0069] According to the present application, the 1,3-pentadiene monomer used is selected from cis-1,3-pentadiene (Zp), trans-1,3-pentadiene (Ep), mixed isomer 1,3-pentadiene (Pd) in any proportion, 2-methyl-1,3-pentadiene (Mpd), 2,3-dimethyl-1,3-pentadiene (Dmpd); preferably cis-1,3-pentadiene (Zp), trans-1,3-pentadiene (Ep) and mixed isomer 1,3-pentadiene (Pd, E / Z=65 / 35) in a specific proportion.

[0070] According to a preferred embodiment of the present application, a preparation method of a star-shaped high-trans-1,4-structure content poly-1,3-pentadiene elastomer includes:

[0071] (1) The butadiene monomer is configured into a mixed solution with the first aprotic solvent, and is added into a polymerization bottle subjected to baking, nitrogen flushing and oxygen removal treatment; the polymerization bottle is preheated at 25-80℃ for 0.5-3h;

[0072] (2) After preheating, the catalyst is added and aged for 10-300min;

[0073] (3) After aging, the first polar modifier and the multifunctional organic lithium initiator mLi are added to initiate the first-stage polybutadiene polymerization, the polymerization temperature is 0-100℃, and the polymerization time is 1-24h;

[0074] (4) after the polymerization is completed, 1,3-pentadiene monomer is added, the polymerization temperature is 0-100 DEG C, the polymerization time is 1-24 hours; after the reaction is completed, 0.5-3 mL of alcohol solution containing anti-aging agent and antioxidant is added into the final obtained polymerization mother liquor to terminate the reaction, after excessive methanol is precipitated, vacuum drying is carried out at 40 DEG C for 24 hours, and the star-shaped poly-1,3-pentadiene elastomer containing high trans-1,4-structure content is obtained;

[0075] The catalyst is composed of two components of a main catalyst and a cocatalyst in a molar ratio of (0-100):1, the main catalyst is an organic barium salt compound, the cocatalyst is alkyl aluminum, the multi-functional organic lithium initiator mLi is a multi-chelated organic lithium initiator obtained by reacting divinylbenzene DVB and alkyl lithium, R is a hydrocarbon group with 10-100 carbon atoms, the functionality n ranges from 3 to 50, the molar ratio of the catalyst to the multi-functional organic lithium initiator mLi is (0.01-100):1, the molar ratio of the first polarity regulator to the multi-functional organic lithium initiator mLi is (0-100):1, and the mass ratio of butadiene, 1,3-pentadiene monomer to the amount of the first aprotic solvent is (1-50):(50-100):1000.

[0076] The third aspect of the application provides a star-shaped poly-1,3-pentadiene elastomer with high trans-1,4-structure content, which is prepared by the preparation method.

[0077] The fourth aspect of the application provides application of the star-shaped poly-1,3-pentadiene elastomer with high trans-1,4-structure content as a rubber compound in tire tread and / or tire side.

[0078] The application will be described in detail below through examples.

[0079] The microstructure of the synthesized polymer is determined by a nuclear magnetic instrument produced by the American Varian company, model INOVA-400, frequency 400 MHz, tetramethylsilane (TMS) as an internal standard, and deuterated chloroform as a solvent.

[0080] The infrared analysis is determined by an infrared instrument produced by Shimadzu company, model IRAffinity-1, with CS2 as a solvent, and a resolution of 2 cm -1 , and transmittance T% is between 30-50%.

[0081] The molecular weight and molecular weight distribution are determined by a gel permeation chromatograph produced by the British PL company, model GPC-220, THF as a washing liquid, a flow rate of 1.0 mL / min, and a test temperature of 40 DEG C.

[0082] The glass transition temperature is measured by using DSC200F3 differential scanning calorimeter produced by Germany NETZSCH Instruments Trading Ltd. The first temperature rising is 25℃-100℃, 10℃ / min, holding for 10 min; the temperature falling is 100℃-(-100)℃, 5℃ / min; the second temperature rising is (-100)-150℃, 5℃ / min; the purging gas is nitrogen, 50 mL / min; the protective gas is nitrogen, 50 mL / min.

[0083] The 1,3-pentadiene monomer, styrene, butadiene, divinylbenzene and polarity regulator used in the polymerization reaction in the present application are all subjected to strict water and oxygen removal operation, and the water and oxygen content reaches the anionic polymerization requirement.

[0084] Example 1

[0085] The present example is to illustrate the star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0086] (1) In a glove box under high-purity argon atmosphere, 2.9 g of cyclohexane and 0.085 g of butadiene are added to a polymerization bottle after high-temperature baking, and preheated at 50℃ for 1 hour;

[0087] (2) After preheating, 0.21 mmol of butylated hydroxytoluene (BHT) in toluene solution (BHT concentration is 0.55 mol / L) and 0.42 mmol of trimethylaluminum (TMA) in hexane solution (TMA concentration is 0.1 mol / L) are added, and then aged at 50℃ for 30 min;

[0088] (3) Then 3.4 mmol of tetrahydrofuran is added, the mixed solution is subjected to impurity removal treatment, and then 0.85 mmol of multi-lithium initiator with a concentration of 0.1 mol / L is added, and the reaction is carried out at 80℃ for 2 hours until the butadiene is completely converted;

[0089] (4) A mixed solution prepared from 15.6 g of cyclohexane and 1.7 g of polymerization grade 1,3-pentadiene is added, the single-arm molecular weight design value of the poly-1,3-pentadiene is 20,000 g / mol, the second section continues to react at 80℃ for 4 hours, after the monomer is completely converted, 2 mL of isopropyl alcohol-toluene solution containing 1% of antioxidant 264 and 1% of antioxidant 1010 is added to terminate the reaction, after excess methanol is precipitated, the product is repeatedly chromatographed 4-5 times with methanol, and then vacuum dried at 40℃ for 24 hours to obtain the star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer; the microstructure content, the actual number average molecular weight Mn and the distribution PDI of the product are shown in Table 1 as No. 1.

[0090] The DSC curve and the GPC curve of the polymer are shown in Figs. 1 and 2 respectively. Figure 1 Figure 2 The DSC curve and the GPC curve of the polymer are shown in Figs. 1 and 2 respectively. Figure 1 ​It can be seen that the amorphous region of the frozen macromolecular chain queue began to "thaw" after slowly warming to -54℃, and can move freely after the temperature reached -49℃, that is, the glass state is converted to the high elastic state; but due to the trans-1,4-structure content of the polymer being greater than 80%, the polymer chain is relatively regular, and the relatively regular part of the molecular chain existing in the high elastic state is arranged in a direction to form a partial crystalline region, and with the further increase of the temperature, the melting of the crystalline region appears, and because the crystal structures are different, there are multiple crystal forms, and a relatively wide melting peak appears at 58℃. It can also be seen from the figure that the glass transition temperature of the polymer is -51℃, and the melting temperature of the crystal is 74℃;

[0091] From Figure 2 It can be seen that the star-shaped poly-1,3-pentadiene elastomer is a single-peak normal distribution, and no obvious shoulder peak and double peak appear, and the arm number of the polymer prepared by the mLi used in the application is controllable.

[0092] The total monomer conversion rate of butadiene and 1,3-pentadiene is 99% by weight, 13 C NMR and 1 The quantitative analysis of the H NMR result shows that the polybutadiene content in the polymer accounts for 5.0% of the total polymer, and the content of the poly-1,3-pentadiene block is 95% by mass; the average arm number is 4.5, which is calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0093] Example 2

[0094] This embodiment is to illustrate the star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the application.

[0095] The poly-1,3-pentadiene elastomer is prepared according to the same method as in Example 1, except that only "mixed isomer 1,3-pentadiene (Pd, E / Z=65 / 35)" is used to replace "cis-1,3-pentadiene monomer" to prepare the star-shaped high-trans-1,4-structure content poly-1,3-pentadiene elastomer; the polymerization process, the microstructure content of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 2.

[0096] The total monomer conversion rate of butadiene and 1,3-pentadiene is 97% by weight, the glass transition temperature of the product is -47℃, and the melting temperature of the crystal is 70℃. 13 C NMR and 1 The quantitative analysis of the H NMR result shows that the polybutadiene content in the polymer accounts for 5.2% of the total polymer, and the content of the poly-1,3-pentadiene block is 94.8% by mass; the average arm number is 4.1, which is calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0097] Example 3

[0098] This example is to illustrate the star-shaped high trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0099] The poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that only "trans-1,3-pentadiene monomer (Ep)" was used to replace "cis-1,3-pentadiene monomer (Zp)" for the preparation of the star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer, and the ratio of the organic barium salt to TMA was not changed. The polymerization process, the microstructure content of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 3.

[0100] The total monomer conversion of butadiene and 1,3-pentadiene was 94% by gravimetric method, and the glass transition temperature of the product was -42°C, and no melting peak of the polymer was observed. 13 C NMR and 1 The quantitative analysis of the H NMR results showed that the polybutadiene content in the polymer accounted for 5.3% by mass of the total polymer, and the content of poly-1,3-pentadiene block was 94.7% by mass; the average arm number was 4.4 calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0101] Example 4

[0102] This example is to illustrate the star-shaped high trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0103] The poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that only "diethylene glycol monoethyl ether barium (BAD)" was used to replace "barium thymol (BHT)" for the preparation of the star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer, and the ratio of the organic barium salt to TMA was not changed. The polymerization process, the microstructure content of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 4.

[0104] The total monomer conversion of butadiene and 1,3-pentadiene was 92% by gravimetric method, and the glass transition temperature of the product was -49°C, and the melting temperature of the crystallization was 71°C. 13 C NMR and 1 The quantitative analysis of the H NMR results showed that the polybutadiene content in the polymer accounted for 5.3% by mass of the total polymer, and the content of poly-1,3-pentadiene block was 94.7% by mass; the average arm number was 4.4 calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0105] Example 5

[0106] The embodiment is to illustrate the star-shaped high-trans 1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the application.

[0107] The poly-1,3-pentadiene elastomer is prepared by the same method as in the embodiment 1, except that only "triethyl aluminum (TEA)" is used to replace "trimethyl aluminum (TMA)" for the preparation of the star-shaped high-trans 1,4-structure poly-1,3-pentadiene, and the ratio of BHT to TEA is not changed, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 5.

[0108] The total monomer conversion rate of butadiene and 1,3-pentadiene is 95% by the gravimetric method, the glass transition temperature of the product is -51℃, and the melting temperature of the crystal is 72℃. 13 C NMR and 1 The quantitative analysis of the H NMR result shows that the content of the polybutadiene in the polymer accounts for 5.3% of the total polymer, and the content of the poly-1,3-pentadiene block accounts for 94.7% of the total polymer; and the average arm number is 4.4, which is calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0109] Embodiment 6

[0110] The embodiment is to illustrate the star-shaped high-trans 1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the application.

[0111] The poly-1,3-pentadiene elastomer is prepared by the same method as in the embodiment 1, except that only the ratio of TMA is changed, specifically:

[0112] The "hexane solution containing 0.42 mmol of trimethyl aluminum (TMA) (the TMA concentration is 0.1 mol / L)" is replaced by "hexane solution containing 0.85 mmol of trimethyl aluminum (TMA) (the TMA concentration is 0.1 mol / L)";

[0113] The star-shaped high-trans 1,4-structure poly-1,3-pentadiene is prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 6.

[0114] The total monomer conversion rate of butadiene and 1,3-pentadiene is 92% by the gravimetric method, the glass transition temperature of the product is -54℃, and the melting temperature of the crystal is 79℃. 13 C NMR and 1 The quantitative analysis of the H NMR result shows that the content of the polybutadiene in the polymer accounts for 5.4% of the total polymer, and the content of the poly-1,3-pentadiene block accounts for 94.6% of the total polymer; and the average arm number is 4.8, which is calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0115] Example 7

[0116] This example is to illustrate the star-shaped high-trans 1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0117] The poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that only the ratio of BHT to TMA and multi-lithium initiator was changed, specifically:

[0118] The "toluene solution containing 0.21 mmol of BHT (BHT concentration of 0.55 mol / L)" was replaced by "toluene solution containing 0.15 mmol of BHT (BHT concentration of 0.55 mol / L)";

[0119] The "hexane solution containing 0.42 mmol of trimethylaluminum (TMA) (TMA concentration of 0.1 mol / L)" was replaced by "hexane solution containing 0.30 mmol of trimethylaluminum (TMA) (TMA concentration of 0.1 mol / L)";

[0120] The star-shaped high-trans 1,4-structure poly-1,3-pentadiene was prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 7.

[0121] The total monomer conversion rate of butadiene and 1,3-pentadiene was 98% by gravimetric method, the glass transition temperature of the product was -48°C, and the melting temperature of the crystallization was 63°C. 13 C NMR and 1 The quantitative analysis by H NMR results showed that the polybutadiene content in the polymer accounted for 5.1% by mass of the total polymer, and the content of poly-1,3-pentadiene block was 94.9% by mass; the average arm number was 4.1, which was calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0122] Example 8

[0123] This example is to illustrate the star-shaped high-trans 1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0124] The poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that no TMA was added;

[0125] The star-shaped high-trans 1,4-structure poly-1,3-pentadiene was prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1, No. 8.

[0126] The total monomer conversion of butadiene and 1,3-pentadiene was 95% by gravimetric method, the glass transition temperature of the product was -51°C, and the melting temperature of the crystal was 71°C. 13 C NMR and 1 The quantitative analysis of the H NMR results showed that the polybutadiene content in the polymer was 5.3% by mass of the total polymer, and the poly-1,3-pentadiene block content was 94.7% by mass; the average arm number was 4.5, which was calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0127] Example 9

[0128] This example is to illustrate the star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0129] The poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that only the amount of butadiene in the first stage reaction was changed, specifically:

[0130] "0.085g of butadiene" in "step (1)" was replaced by "0.177g of butadiene";

[0131] The star-shaped high-trans-1,4-structure poly-1,3-pentadiene was prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1 No. 9.

[0132] The total monomer conversion of butadiene and 1,3-pentadiene was 99% by gravimetric method, the glass transition temperature of the product was -55°C, and the melting temperature of the crystal was 70°C. 13 C NMR and 1 The quantitative analysis of the H NMR results showed that the polybutadiene content in the polymer was 9.3% by mass of the total polymer, and the poly-1,3-pentadiene block content was 90.7% by mass; the average arm number was 3.7, which was calculated from the measured relative molecular mass and the design value of the single-arm molecular weight.

[0133] Example 10

[0134] This example is to illustrate the star-shaped high-trans-1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the present application.

[0135] The poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that only the amount of BHT, TMA and multi-lithium initiator was changed, specifically:

[0136] "Step (2), toluene solution containing 0.21 mmol of BHT (BHT concentration 0.55 mol / L)" is replaced by "toluene solution containing 0.10 mmol of BHT (BHT concentration 0.55 mol / L)";

[0137] "Step (2), hexane solution containing 0.42 mmol of trimethylaluminum (TMA) (TMA concentration 0.1 mol / L)" is replaced by "hexane solution containing 0.21 mmol of trimethylaluminum (TMA) (TMA concentration 0.1 mol / L)";

[0138] "Step (3), poly-lithium initiator mLi with concentration 0.1 mol / L, 0.85 mmol" is replaced by "poly-lithium initiator mLi with concentration 0.1 mol / L, 0.43 mmol";

[0139] Star-shaped high-trans 1,4-structure poly-1,3-pentadiene is prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in No. 10 in Table 1.

[0140] The total monomer conversion rate of butadiene and 1,3-pentadiene is 97% by gravimetric method, the glass transition temperature of the product is -52°C, and the melting temperature of the crystal is 72°C. 13 C NMR and 1 The quantitative analysis of H NMR results shows that the content of polybutadiene in the polymer accounts for 5.2% by mass of the total polymer, and the content of poly-1,3-pentadiene block is 94.8% by mass; the average arm number is 3.1, which is calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0141] Example 11

[0142] This example is to illustrate the star-shaped high-trans 1,4-structure poly-1,3-pentadiene elastomer prepared by the method of the application.

[0143] The poly-1,3-pentadiene elastomer is prepared according to the same method as in Example 1, except that only the type of catalyst and the amount of polar modifier are changed, specifically:

[0144] "Step (2), toluene solution containing 0.21 mmol of BHT (BHT concentration 0.55 mol / L), hexane solution containing 0.42 mmol of trimethylaluminum (TMA) (TMA concentration 0.1 mol / L)" is replaced by "toluene solution containing 0.17 mmol of sodium dodecylbenzenesulfonate (SDBS) 1.7 mL (SDBS concentration 0.1 mol / L)", and no trimethylaluminum (TMA) is added;

[0145] "3.4 mmol THF is added in step (3)" is replaced by "17 mmol THF is added";

[0146] Star-shaped high trans-1,4-structure poly(1,3-pentadiene) is prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1 No. 11.

[0147] The total monomer conversion rate of butadiene and 1,3-pentadiene is 98% by gravimetric method, the glass transition temperature of the product is -47℃, and no melting peak of the polymer is observed. 13 C NMR and 1 The quantitative analysis of H NMR results shows that the content of polybutadiene in the polymer accounts for 5.1% of the total polymer, and the content of poly(1,3-pentadiene) block is 94.9% by mass; the average arm number is 4.4 calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0148] Example 12

[0149] This example is to illustrate the star-shaped high trans-1,4-structure poly(1,3-pentadiene) elastomer prepared by the method of the application.

[0150] The poly(1,3-pentadiene) elastomer is prepared according to the same method as in Example 1, except that only the amount of polar modifier THF is changed, specifically,

[0151] "3.4 mmol THF is added in step (3)" is replaced by "0.17 mmol THF is added";

[0152] Star-shaped high trans-1,4-structure poly(1,3-pentadiene) is prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight Mn and the distribution PDI are shown in Table 1 No. 12.

[0153] The total monomer conversion rate of butadiene and 1,3-pentadiene is 99% by gravimetric method, the glass transition temperature of the product is -55℃, and the melting temperature of the crystal is 67℃. 13 C NMR and 1 The quantitative analysis of H NMR results shows that the content of polybutadiene in the polymer accounts for 5.0% of the total polymer, and the content of poly(1,3-pentadiene) block is 95% by mass; the average arm number is 4.7 calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0154] Comparative Example 1

[0155] The poly(1,3-pentadiene) elastomer is prepared according to the same method as in Example 1, except that "multi-lithium initiator in step (3)" is replaced by "n-butyl lithium";

[0156] A linear poly(1,3-pentadiene) elastomer was prepared, and its polymerization process, microstructure content, measured number average molecular weight and distribution of the polymer are shown in Table 1 as No. P1.

[0157] The total monomer conversion of butadiene and 1,3-pentadiene was 99% by gravimetric method, and the glass transition temperature of the product was -39°C, and no melting peak of the polymer was observed. 13 C NMR and 1 The quantitative analysis of the H NMR results showed that the polybutadiene content in the polymer accounted for 5.0% by mass of the total polymer, and the content of poly(1,3-pentadiene) block was 95% by mass; the polymer was linear poly(1,3-pentadiene).

[0158] Comparative Example 2

[0159] The poly(1,3-pentadiene) elastomer was prepared according to the same method as in Example 1, except that "BHT and TMA in Step (2)" was replaced with "0.17 mmol of sodium tert-butoxide (t-BuONa)";

[0160] A poly(1,3-pentadiene) elastomer was prepared, and its polymerization process, microstructure content, measured number average molecular weight and distribution of the polymer are shown in Table 1 as No. P2.

[0161] The total monomer conversion of butadiene and 1,3-pentadiene was 57% by gravimetric method, and the glass transition temperature of the product was -44°C, and no melting peak of the polymer was observed. 13 C NMR and 1 The quantitative analysis of the H NMR results showed that the polybutadiene content in the polymer accounted for 8.7% by mass of the total polymer, and the content of poly(1,3-pentadiene) block was 91.3% by mass; the average arm number was 3.5, calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0162] Comparative Example 3

[0163] The poly(1,3-pentadiene) elastomer was prepared according to the same method as in Example 1, except that:

[0164] "0.1 mol / L of multi-lithium initiator mLi0.85 mmol was added in Step (3)" was replaced with "0.14 mol / L of multi-lithium initiator mLi-cons0.85 mmol was added";

[0165] In addition, the preparation method of the multi-functional lithium initiator mLi-cons used in the comparative example comprises:

[0166] In a glove box under high purity argon atmosphere, 100 g of cyclohexane, 4 g of butadiene, 0.13 g of triethylamine, 1.8 g of divinylbenzene were added into a high-temperature baked polymerization bottle according to the ratio, and then 9.3 mL of n-butyllithium cyclohexane solution with a concentration of 1.6 mol / L was gradually added. After reaction at 50°C for 2 hours, the solution was prepared by double titration for concentration. The amount of mLi second polarity regulator was reduced in the preparation of the second polarity regulator. The multi-function lithium initiator obtained under the ratio is named as mLi-cons, and the concentration is 0.14 mol / L.

[0167] A poly-1,3-pentadiene elastomer was prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight and distribution are shown in Table 1 as No. P3.

[0168] The total monomer conversion rate of butadiene and 1,3-pentadiene was 99% by gravimetric method, and the glass transition temperature of the product was -41°C. No melting peak of the polymer was observed. 13 C NMR and 1 The quantitative analysis of H NMR results showed that the polybutadiene content in the polymer accounted for 12.4% of the total polymer, and the content of poly-1,3-pentadiene block was 87.6% by mass; the polymer showed obvious crosslinking, and the part of the polymer soluble in DMF was characterized by GPC. The average arm number was 2.4 calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0169] Comparative Example 4

[0170] A poly-1,3-pentadiene elastomer was prepared according to the same method as in Example 1, except that “in step (2), the toluene solution containing 0.21 mmol of butylated hydroxytoluene (BHT) (BHT concentration of 0.55 mol / L), and the hexane solution containing 0.42 mmol of trimethylaluminum (TMA) (TMA concentration of 0.1 mol / L)” was replaced by “the toluene solution containing 0.21 mmol of butylated hydroxytoluene (BHT) (BHT concentration of 0.55 mol / L), and the toluene solution containing 0.11 mmol of diethylaluminum chloride (Et2AlCl) (Et2AlCl concentration of 0.4 mol / L)”;

[0171] A linear poly-1,3-pentadiene elastomer was prepared, and the polymerization process, the content of each microstructure of the polymer, the measured number average molecular weight and distribution are shown in Table 1 as No. P4.

[0172] The total monomer conversion rate of butadiene and 1,3-pentadiene was 67% by gravimetric method, and the glass transition temperature of the product was -43°C. No melting peak of the polymer was observed. 13 C NMR and 1The quantitative analysis of H NMR results shows that the content of polybutadiene in the polymer is 7.7% by mass of the total polymer, and the content of poly-1,3-pentadiene block is 92.3% by mass; the average arm number is 3.1, which is calculated from the measured relative molecular mass and the design value of single-arm molecular weight.

[0173] Table 1

[0174]

[0175] Note: 1,2-% includes the content of trans-1,2- and cis-1,2- structure in poly-1,3-pentadiene structural units.

[0176] In the present application, the multi-functional organic lithium initiator mLi is used, and a star-shaped poly-1,3-pentadiene can be obtained.

[0177] The poly-1,3-pentadiene prepared by using n-butyllithium in Comparative Example 1 is linear, and only linear polymers can be obtained; it is explained that if other alkyl lithium is not used, star-shaped polymers cannot be obtained.

[0178] In Comparative Example 2, sodium tert-butoxide (t-BuONa) is used as a catalyst to replace the organic barium and alkyl aluminum, and since the catalyst defined in the present application is not used, t-BuONa cannot provide the steric hindrance effect of the barium-aluminum double complex formed by BHT and TMA, nor can it form a new active center like SDBS and the polarity modifier, so that the proportion of trans-1,4-structure in the star-shaped polymer is greatly reduced, and the 1,3-pentadiene monomer cannot be completely converted.

[0179] In Comparative Example 3, the amount of the second polarity modifier triethylamine used in the preparation of mLi is reduced, n-BuLi preferentially attacks the double bond on DVB, and butadiene cannot play the role of solubilizing and chain extending, so that the arm number of mLi-cons cannot be accurately controlled, and the product obtained is crosslinked, the number average molecular weight of the polymer part soluble in DMF is low, and is similar to linear polymer, and the content of trans-1,4-structure in the elastomer is also significantly lower than that in Examples 1-12.

[0180] In Comparative Example 4, diethyl aluminum chloride (Et2AlCl) is used as a cocatalyst to replace alkyl aluminum, and the addition of diethyl aluminum chloride (Et2AlCl) will cause obvious chain transfer and chain termination reaction of 1,3-pentadiene monomer during polymerization, and the content of 3,4-structure in the polymer will increase significantly, and the molecular weight distribution will also become wider.

[0181] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A star-shaped poly-1,3-pentadiene elastomer with a high content of trans-1,4- structure, characterized in that, The elastomer has a structural expression shown in formula (1): (PPD-PB)n-A, formula (1); Wherein, PPD is a poly-1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of the multifunctional organolithium initiator mLi, n is 3-50, A is the organic residue of mLi; Wherein, the content of trans-1,4-structure in the elastomer is 65-95 mol%, the content of cis-1,4-structure is 0-20 mol%, the content of 1,2-structure is 5-20 mol%, and the content of 3,4-structure is 0-10 mol%; wherein the elastomer has a number average molecular weight of 5 x 10 4 g / mol to 1 x 10 6 g / mol; Wherein, the content of the poly-1,3-pentadiene block is 50-95 mass% and the content of the polybutadiene block is 2-50 mass% based on the total weight of the elastomer. Wherein, the preparation method of the multifunctional organolithium initiator mLi comprises: mixing divinylbenzene, butadiene, a second polarity regulator with a second aprotic solvent in a certain proportion, and then adding alkyl lithium to carry out addition reaction to obtain. Wherein, the second polarity regulator is selected from one or more of tetrahydrofuran, dioxane, triethylamine, ditetrahydrofurfuryl propane, N,N-dimethyl tetrahydrofurfuryl amine, tetrahydrofurfuryl alcohol ethyl ether, tetrahydrofurfuryl alcohol butyl ether, pentamethyl diethyl triamine, dipiperidyl ethane, triphenyl phosphine and carbon disulfide.

2. The elastomer of claim 1, wherein, The molar ratio of the use amount of divinylbenzene, butadiene, the second polarity regulator and alkyl lithium is (0.1-10):(1-100):(1-100):

1. And / or, the conditions of alkyl lithium addition reaction include: temperature is-20-60℃, time is 0.5-12h.

3. The elastomer of claim 1, wherein, The number average molecular weight of the elastomer is from 5 x 10 4 g / mol to 5 x 10 5 g / mol.

4. The elastomer of claim 1, wherein, The content of the poly-1,3-pentadiene block is 91.5-95 mass% and the content of the polybutadiene block is 4.2-8.5 mass% based on the total weight of the elastomer.

5. The elastomer of claim 1, wherein, The content of trans-1,4-structure in the elastomer is 70-95 mol%, the content of cis-1,4-structure is 0-5 mol%, the content of 1,2-structure is 5-15 mol%, and the content of 3,4-structure is 0-3 mol%.

6. The elastomer of any one of claims 1-5, wherein, The glass transition temperature T g is -70°C to -20°C, the melting temperature T m is 0-90°C.

7. The elastomer of claim 6, wherein, The glass transition temperature T g is from -70°C to -40°C, the melting temperature T m is from 70 to 90°C.

8. A process for the preparation of a star-shaped high trans- 1,4-structured poly- 1,3-pentadiene elastomer according to any one of claims 1 to 7, characterized in that, The preparation method comprises: (1) mixing butadiene monomer and a first aprotic solvent in a reactor to preheat and obtain a mixed solution; (2) contacting the mixed solution with a catalyst to carry out aging treatment; wherein the catalyst comprises a main catalyst and an optional co-catalyst, wherein the main catalyst comprises an organic barium salt or an organic sodium salt, and the co-catalyst is an alkyl aluminum; (3) mixing the product after step (2) with a first polarity regulator and a multifunctional organolithium initiator mLi to carry out initiation polymerization reaction until the butadiene monomer is completely converted; (4) adding 1,3-pentadiene monomer into the system after step (3) to carry out mixed initiation polymerization reaction and then terminate the reaction to obtain a star-shaped high-trans-1,4-structure-content poly-1,3-pentadiene elastomer (PPD-PB)n-A; Wherein, PPD is a poly-1,3-pentadiene block, PB is a polybutadiene block, n is the functionality of the multifunctional organolithium initiator mLi, n is 3-50, A is the organic residue of mLi.

9. The production method according to claim 8, wherein The organic barium salt is selected from one or more of alkoxy barium salt, cycloalkoxy barium salt, alcohol ether barium salt, alcohol amine barium salt, phenol barium salt and carboxylic acid barium salt; And / or, the organic sodium salt is alkoxy sodium salt and / or sulfonic acid sodium salt; And / or, the alkyl aluminum is selected from one or more of trimethyl aluminum, triethyl aluminum, tripropyl aluminum, triisobutyl aluminum, triisopropyl aluminum and trioctyl aluminum; And / or, the first aprotic solvent and the second aprotic solvent are the same or different, each being selected from one or more of cyclohexane, n-hexane, n-pentane, n-heptane, benzene, hydrogenated oil and extracted oil; And / or, the first polarity regulator is selected from one or more of tetrahydrofuran, dioxane, triethylamine, bis-tetrahydrofurfuryl propane, N,N-dimethyl tetrahydrofurfuryl amine, tetrahydrofurfuryl alcohol ethyl ether, tetrahydrofurfuryl alcohol butyl ether, pentamethyl diethyl triamine, dipiperidyl ethane, triphenyl phosphine and carbon disulfide.

10. The production method according to claim 8, wherein The molar ratio of the catalyst to the amount of the polyfunctional organic lithium initiator mLi is (0.01-100):1; And / or, the molar ratio of the first polarity regulator to the amount of the polyfunctional organic lithium initiator mLi is (20-100):1; And / or, the mass ratio of the amount of butadiene, 1,3-pentadiene monomer to the first aprotic solvent is (1-50):(50-100):1000.

11. The production method according to claim 8, wherein The preheating conditions of the mixing include: temperature of 25-80℃, time of 0.5-3h; And / or, the aging treatment conditions include: temperature of 25-60℃, time of 10min-5h; And / or, the polymerization reaction conditions include: temperature of 0-100℃, time of 1-24h.

12. Use of the star-shaped high trans-1,4-structure content poly-1,3-pentadiene elastomer of any one of claims 1-7 as a rubber compound in tire tread and / or tire side.

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