Linear high trans 1,4-structure content poly 1,3-pentadiene elastomer and preparation method and application thereof

Abstract

The present invention relates to the field of functional polymer technology, and discloses a linear high trans 1,4-structure content poly 1,3-pentadiene elastomer and its preparation method and application. The poly 1,3-pentadiene elastomer includes 50-95 mol% of trans 1,4-structure, and in the microscopic sequence distribution of the poly 1,3-pentadiene elastomer, the content linked in a 1,4-4,1 head-to-tail manner is 30-80 mol%. The preparation method of the present invention is simple, and the microstructure can be efficiently regulated; in the prepared poly 1,3-pentadiene elastomer, the proportion of trans 1,4-structure is very high, the sequence of the polymer is highly regular, the polymer linearity is good, and the 1,4-4,1 head-to-tail linking mode is dominant.

Description

Technical Field

[0001] The present invention relates to the technical field of functional polymers, and in particular to a linear poly(1,3-pentadiene) elastomer with a high trans-1,4-structure content, a preparation method thereof, and applications thereof. Background Art

[0002] With the rapid development of the aerospace and automotive industries, the development of new rubbers with specialized applications and energy-saving and environmentally friendly properties has become increasingly important. High-trans 1,4-polydiene rubber offers excellent low-temperature properties, including low heat buildup, high fatigue and wear resistance, while also effectively balancing tire rolling resistance, making it an ideal rubber for the development of high-performance, energy-saving tires.

[0003] Current high-trans polydienes, such as high-trans polybutadiene (HTBD), high-trans polyisoprene (TPI), and high-trans poly(Bd-Ip), are produced using ZN-based catalysts or lithium-based polymerization. Coordination-based catalytic systems produce polymers with a high trans-1,4-structure. Lithium-based systems offer slightly less control over this structure, but they offer greater molecular structure design and a narrower molecular weight distribution, resulting in advantages in Mooney viscosity and cold flow. TPI and HTBD produced using ZN-based catalysts can have up to 99% trans-1,4-structure content. This excessive trans content results in crystalline polymers, making them rigid plastics at room temperature. The sulfur content required for vulcanization and crosslinking is high, or they must be co-vulcanized with other rubbers. The high melt temperature makes processing difficult. Introducing a small amount of Ip using lithium-based copolymerization can effectively reduce the regularity of the chain segments and prevent complete crystallization. However, the pendant propylene structure content of Ip cannot be effectively controlled, resulting in a decrease in polymer elasticity.

[0004] 1,3-Pentadiene is an important conjugated diene derived from the C5 fraction, a byproduct of ethylene cracking. Currently, it has not been industrialized for use in elastomer materials and is commonly used in the production of C5 petroleum resins. 1,3-Pentadiene, purified through extractive distillation, can be used for anionic polymerization. The product routes and process methods of lithium-based elastomer processes are all applicable to the polymerization of 1,3-pentadiene. Different addition modes, resulting in chemical stereoisomers and stereoisomers of asymmetric carbon atoms, exhibit mechanical properties distinct from those of polybutadiene rubber and isoprene rubber. Studies have found that 1,3-pentadiene predominates in the 1,4- and 4,1-addition modes. Under specific catalytic systems, continuous tail-trans 4,1- and head-trans 1,4- structures are readily formed within the chain segments. This results in highly regular polymer chains, and the resulting elastomers can be stretched and crystallized, exhibiting outstanding heat generation, wet-slip resistance, and wear resistance. Currently, few relevant research reports have been published.

[0005] Goodyear has disclosed a method for preparing SIR rubber with a high trans-1,4-structure content using sodium dodecylbenzenesulfonate (SDBS). The St incorporation ranges from 10% to 40%. SDBS not only acts as a modifier of the trans-1,4-structure of Ip but also as a randomizing agent. The resulting copolymer exhibits a broad molecular weight distribution, excellent raw rubber properties and adhesion, and is suitable for use in high-performance pneumatic tire treads. However, this method does not involve 1,3-pentadiene, and the overall trans-1,4-structure content is still insufficient (Adel F. Halasa, Chad Jusinas, Wen-Liang Hsu, et al., Random low vinylstyrene–isoprene copolymers, European Polymer Journal, 2010, 46:2013–2018). US4048418 discloses a method for preparing polypentadiene-1,3 having a 93% cis-1,4 structure using an iron-based catalyst. In this system, the cis-isomer in the pentadiene-1,3 monomer is an inert component and is difficult to initiate polymerization, resulting in a very low total monomer conversion rate.

[0006] CN104557660A discloses a barium dibenzopyrrolyl carboxylate compound, its preparation method, an anionic initiator system, and a method for preparing a copolymer; CN104557855A discloses a barium dibenzothiophene carboxylate compound, its preparation method, an anionic initiator system, and a method for preparing a conjugated diene polymer. These two systems utilize an organolithium / organoaluminum / alkoxybarium catalytic system of barium pyrrolyl carboxylate and barium dibenzothiophene carboxylate, respectively, to prepare a styrene-butadiene-pentadiene terpolymer rubber with a high trans-1,4-structure content, reaching 87% and 88% in the two systems, respectively. Furthermore, the corresponding organic acid formed by this type of barium salt after hydrolysis has a high boiling point and does not azeotrope with cyclohexane, allowing it to be recovered in a coagulation tower. However, the organic acid portion of this barium salt is expensive and requires a large amount, significantly increasing production and equipment maintenance costs.

[0007] CN102351970A discloses a method for preparing poly 1,3-pentadiene, which utilizes an organic amine light rare earth and lanthanum catalyst system to prepare poly 1,3-pentadiene. The polymerization conversion rate can reach 50% in 7 hours at 50°C, but precise control of the microstructure cannot be achieved. The polymer is mainly composed of a cis-1,4-structure (50%), with the remainder being a trans-1,4-structure and cis-trans isomeric 1,2-addition structures.

[0008] CN105585646A discloses a linear poly(1,3-pentadiene) with a low propylene content and narrow molecular weight distribution and a preparation method thereof. The invention involves preparing the linear poly(1,3-pentadiene) with a low pendant propylene content by polymerization in a lithium-based system. The product has a molecular weight distribution (PDI) of less than 1.2, a rapid conversion rate, and an overall content of pendant propylene structures formed by 1,2-addition less than 20%. However, the content of the trans-1,4-structure can only be controlled within the range of 40-70%. The continuous propylene structure reduces the polymer's elasticity and slightly increases its Tg temperature. Therefore, the mechanical strength and low-temperature performance of the rubber used in high-performance tire treads or sidewalls need to be improved.

[0009] Therefore, it is of great significance to study and develop a linear poly(1,3-pentadiene) elastomer with a high trans-1,4-structure content and a preparation method thereof. Summary of the Invention

[0010] The present invention aims to overcome the problem of the inability to precisely control the structure of polypentadiene 1,3 in the prior art, and provides a linear polypentadiene 1,3 elastomer with a high trans-1,4-structure content, a preparation method thereof, and applications thereof. The elastomer has 50-95 mol % of a trans-1,4-structure. In addition, the preparation method is simple, the conversion rate is high, and the microstructure can be efficiently controlled.

[0011] In order to achieve the above-mentioned object, the first aspect of the present invention provides a linear poly(1,3-pentadiene) elastomer with a high trans-1,4-structure content, wherein the poly(1,3-pentadiene) elastomer has a linear structure, and the poly(1,3-pentadiene) elastomer includes 50-95 mol% of a trans-1,4-structure, and in the microscopic sequence distribution of the poly(1,3-pentadiene) elastomer, the content of 1,4-4,1 head-to-tail linkage is 30-80 mol%.

[0012] The second aspect of the present invention provides a method for preparing a linear polypentadiene-1,3-diene elastomer having a high trans-1,4-structure content, wherein the preparation method comprises:

[0013] (1) mixing 1,3-pentadiene monomer and a non-polar hydrocarbon solvent and performing a first preheating to obtain a mixed solution;

[0014] (2) contacting the mixed solution with a catalyst for a second preheating or aging treatment; wherein the catalyst comprises a main catalyst and a co-catalyst, wherein the main catalyst comprises an organic barium salt or an organic sodium salt, and the co-catalyst is an alkyl aluminum;

[0015] (3) contacting the product obtained from step (2) with a polarity regulator and an initiator to initiate a polymerization reaction and then perform a termination reaction to obtain a linear high-trans 1,4-structured poly(1,3-pentadiene) elastomer.

[0016] The third aspect of the present invention provides a linear polypentadiene 1,3-elastomer having a high trans 1,4-structure content, prepared by the aforementioned preparation method.

[0017] A fourth aspect of the present invention provides a use of the aforementioned linear polypentadiene-1,3 elastomer having a high trans-1,4-structure content as a rubber compound in a tire tread and / or sidewall.

[0018] Through the above technical solution, the technical solution of the present invention has the following advantages:

[0019] (1) The raw materials of each component are easily available, the reaction rate is fast, and the conversion rate is high.

[0020] (2) The molecular weight of the polypentadiene elastomer prepared by the present invention can be designed in a wide range, and the number average molecular weight Mn is within 2×10 4 g / mol to 5×10 5 g / mol, with a narrow molecular weight distribution, which is much lower than that of 1,3-pentadiene prepared by coordination polymerization within a narrow range. The microstructure can be efficiently controlled, with a high proportion of trans 1,4-structure and a very low content of side propylene structure. The sequence of the polymer is highly regular, with 1,4-4,1 head-to-tail linkage being dominant. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the poly 1,3-pentadiene elastomer prepared in Example 1, Example 14 and Comparative Example 1 of the present invention is ( 1 H NMR) spectra;

[0022] Figure 2 The carbon nuclear magnetic resonance spectra of the unsaturated carbon region of the polypentadiene elastomer prepared in Example 1, Example 14 and Comparative Example 1 of the present invention are ( 13 C NMR) spectra;

[0023] Figure 3 The saturated carbon nuclear magnetic resonance spectra of the polypentadiene elastomers prepared in Example 1, Example 14 and Comparative Example 1 of the present invention are ( 13 C NMR) spectra;

[0024] Figure 4 is a gel permeation chromatography (GPC) chart of the polypentadiene-1,3-ene elastomer prepared in Example 1, Example 10, Example 14 and Comparative Example 1 of the present invention;

[0025] Figure 5 3 is a differential scanning calorimetry (DSC) graph of the polypentadiene-1,3 elastomer prepared in Example 1, Example 10, Example 14 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0027] As described above, the first aspect of the present invention provides a linear high trans 1,4-structure content poly 1,3-pentadiene elastomer, wherein the poly 1,3-pentadiene elastomer has a linear structure, and the poly 1,3-pentadiene elastomer includes 50-95 mol% of the trans 1,4-structure, and in the microscopic sequence distribution of the poly 1,3-pentadiene elastomer, the content of 1,4-4,1 head-to-tail linkage is 30-80 mol%.

[0028] The inventors of the present invention have discovered that, using a polarity regulator to regulate alkyl aluminum to initiate 1,3-pentadiene polymerization under the catalysis of an optional organic barium salt or organic sodium salt in combination with alkyl aluminum, the raw materials of each component are readily available, the reaction rate is fast, and the conversion rate is high. In addition, due to the inherent characteristics of anionic polymerization using alkyl lithium as an initiator, the molecular weight of the prepared poly 1,3-pentadiene elastomer is easy to control and the molecular weight distribution is narrow. Because the complex formed by the organic barium salt or organic sodium salt and the alkyl aluminum is more conducive to the conversion of the 1,3-pentadiene monomer from a σ-allyl structure to a six-membered ring transition state during the polymerization process, the microstructure can be efficiently controlled, with a high proportion of trans 1,4-structures and a low content of pendant propylene structures. Because n-butyl lithium and tert-butyl lithium do not cause branching or cyclization side reactions when initiating 1,3-pentadiene polymerization, the polymer sequence is highly regular, and the polymer chain exhibits a linear structure, in which a 1,4-4,1 head-to-tail linkage mode is dominant.

[0029] According to the present invention, the microstructure can be efficiently controlled, the proportion of trans 1,4-structure is very high, and the content of pendant propylene structure is very low; preferably, the poly 1,3-pentadiene elastomer includes 70-95 mol% of trans 1,4-structure; preferably, the poly 1,3-pentadiene elastomer includes 79-91 mol% of trans 1,4-structure; more preferably, the poly 1,3-pentadiene elastomer includes 85-91 mol% of trans 1,4-structure.

[0030] According to the present invention, in the proportion of each structure of the poly1,3-pentadiene elastomer, the poly1,3-pentadiene elastomer further includes 0-30 mol% of cis-1,4-structure, 4-25 mol% of 1,2-structure and 0-10 mol% of 3,4-structure; preferably, the poly1,3-pentadiene elastomer includes 0-15 mol% of cis-1,4-structure, 7-15 mol% of 1,2-structure and 0-3 mol% of 3,4-structure.

[0031] According to the present invention, the sequence of the polypentadiene-1,3-diene elastomer is highly regular, with a 1,4-4,1 head-to-tail linkage being dominant. In the microscopic sequence distribution of the polypentadiene-1,3-diene elastomer:

[0032] The content of 1,4-4,1 head-to-tail linkage is 45-80 mol %, preferably 51-78 mol %, preferably 65-80 mol %, more preferably 71-79 mol %.

[0033] The total content of the head-to-head 1,4-1,4 linkage and the tail-to-tail 4,1-4,1 linkage is 10-40 mol%, preferably 10-33 mol%, more preferably 10-20 mol%; in addition, the ratio of 1,4-1,4 to 4,1-4,1 is 1:(1-5), preferably 1:1;

[0034] The content of 1,4-1,2 linkage is 5-20 mol%, preferably 5-10 mol%.

[0035] The present invention also includes other linking methods with very small contents. Preferably, the content of linking in other methods is 0-20 mol %, preferably 0-12 mol %.

[0036] According to the present invention, the molecular weight of the polypentadiene 1,3-ene elastomer can be designed in a wide range, and the number average molecular weight Mn of the polypentadiene 1,3-ene elastomer is 2×10 4 g / mol to 5×10 5 g / mol.

[0037] According to the present invention, the molecular weight distribution is narrow, and the molecular weight distribution PDI (PDI=weight average molecular weight Mw / number average molecular weight Mn) is 1.05-2.5, preferably 1.1-1.9, and more preferably 1.26-1.88; in the present invention, within the aforementioned PDI range, it is much lower than the poly 1,3-pentadiene elastomer prepared by coordination polymerization, the microstructure can be efficiently controlled, the proportion of trans 1,4-structure is very high, and the content of side propylene structure is very low.

[0038] According to the present invention, the glass transition temperature T of the poly 1,3-pentadiene elastomer is determined by DSC test. g-70°C to -30°C, preferably -70°C to -50°C; melting temperature T m 0-90°C, preferably 70-90°C.

[0039] The second aspect of the present invention provides a method for preparing a linear polypentadiene-1,3-diene elastomer having a high trans-1,4-structure content, wherein the preparation method comprises:

[0040] (1) mixing 1,3-pentadiene monomer and a non-polar hydrocarbon solvent and performing a first preheating to obtain a mixed solution;

[0041] (2) contacting the mixed solution with a catalyst for a second preheating or aging treatment; wherein the catalyst comprises a main catalyst and a 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) contacting the product obtained from step (2) with a polarity regulator and an initiator to initiate a polymerization reaction and then perform a termination reaction to obtain a linear poly(1,3-pentadiene) elastomer having a high trans-1,4-structure content.

[0043] In the present invention, it should be noted that in step (2), when the catalyst is an organic sodium salt, aging treatment is not required.

[0044] According to the present invention, the catalytic-initiation reaction system of the present invention is under anhydrous and oxygen-free conditions, and the catalyst used is composed of a main catalyst and a co-catalyst, and the molar ratio of the co-catalyst to the main catalyst is (0-100):1, preferably (0-4):1.

[0045] According to the present invention, the main catalyst is an organic barium salt or an organic sodium salt that can be used for lithium-based preparation of trans-polyconjugated olefins; in the present invention, the organic barium salt is selected from one or more of alkoxy barium salts, cycloalkoxy barium salts, alcohol ether barium salts, alcoholamine barium salts, phenol barium salts and carboxylic acid barium salts; preferably, the organic barium salt is selected from one or more of menthol barium, thymol barium (BHT), diethylene glycol monoethyl ether barium (BAD), morpholine ethanol barium, dodecylbenzenesulfonate barium, tetrahydrofuroate barium and tetrahydrofurfuryl alcohol barium; more preferably, the organic barium salt is thymol barium and / or diethylene glycol monoethyl ether barium.

[0046] According to the present invention, 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 dodecylbenzenesulfonate (SDBS), sodium tetrahydrofurfuryl alcohol and sodium tert-amyl alcohol, preferably sodium dodecylbenzenesulfonate and sodium dodecyl sulfate.

[0047] According to the present invention, 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, trioctylaluminum and methylaluminoxane, preferably trimethyl aluminum, triethyl aluminum and triisobutyl aluminum.

[0048] According to the present invention, the non-polar hydrocarbon solvent is selected from one or more of cyclohexane, n-hexane, n-pentane, n-heptane, benzene, hydrogenated oil and extracted oil, preferably cyclohexane; wherein benzene includes toluene, ethylbenzene and xylene.

[0049] According to the present invention, the polarity regulator is selected from one or more of tetrahydrofuran (THF), dioxane, triethylamine, ditetrahydrofurfuryl propane, N,N-dimethyltetrahydrofurfurylamine, tetrahydrofurfuryl alcohol ethyl ether, tetrahydrofurfuryl alcohol butyl ether, pentamethyldiethyltriamine, dipyridineethane, triphenylphosphine and carbon disulfide, preferably one or more of tetrahydrofuran, tetrahydrofurfuryl alcohol ethyl ether and carbon disulfide.

[0050] According to the present invention, the initiator is an organic lithium initiator; preferably, the initiator is selected from one or more of alkyl lithium, aryl lithium, amide lithium, organic lithium chloride and macromolecular active lithium; wherein the alkyl lithium is n-butyl lithium (n-BuLi), sec-butyl lithium, tert-butyl lithium (t-BuLi), or methyl lithium; the aryl lithium is phenyl lithium or benzyl lithium; the amide lithium is dimethyl amide lithium, diethyl amide lithium or diisopropyl amide lithium; the organic lithium chloride is n-butyl lithium chloride or isobutyl lithium chloride; the macromolecular active lithium is polystyrene-based active lithium, polybutadiene-based active lithium, polyisoprene-based active lithium or poly-1,3-hexadiene-based active lithium. Preferably, it is n-butyl lithium, sec-butyl lithium, tert-butyl lithium, polystyrene-based active lithium or polybutadiene-based active lithium.

[0051] In the present invention, the synthesis method of polystyrene-based active lithium initiator PSLi is as follows:

[0052] Under anhydrous and oxygen-free conditions, 25 mL of a 5% mass fraction styrene-cyclohexane solution was added to a dry, nitrogen-filled, vacuum-treated polymerization bottle, followed by 1.3 mL of n-butyl lithium initiator (0.4 mol / L, cyclohexane solution, the designed molecular weight Mn of the polystyrene base segment is 2,000 g / mol) and reacted at 60°C for 2 h. After the reaction, the bottle was sealed and stored under an inert gas atmosphere. GPC results were used to determine the [Li + ] concentration.

[0053] In the present invention, the synthesis method of polybutadiene-based active lithium initiator PBLi is as follows:

[0054] Under anhydrous and oxygen-free conditions, 25 mL of a 3% mass fraction of butadiene in cyclohexane solution was added to a dry, nitrogen-filled, vacuum-treated polymerization bottle, followed by 0.75 mL of n-butyllithium initiator (0.4 mol / L, cyclohexane solution, the designed molecular weight Mn of the polybutadiene olefinic segment is 2,000 g / mol) at 70°C for 2 h. After the reaction, the bottle was sealed and stored under an inert gas atmosphere. GPC results were used to determine the [Li + ] concentration.

[0055] According to the present invention, the 1,3-pentadiene monomer used is selected from cis-1,3-pentadiene (Zp), trans-1,3-pentadiene (Ep), mixed isomeric 1,3-pentadiene (Pd) in any proportion, 2-methyl-1,3-pentadiene (Mpd), and 2,3-dimethyl-1,3-pentadiene (Dmpd); preferably, cis-1,3-pentadiene (Zp), trans-1,3-pentadiene (Ep), and mixed isomeric 1,3-pentadiene (Pd, E / Z=65 / 35) in a specific proportion.

[0056] According to the present invention, the molar ratio of the total amount of the co-catalyst and the main catalyst to the amount of the initiator is (0.01-100):1, preferably (0.2-1.53):1.

[0057] According to the present invention, the molar ratio of the polarity regulator to the initiator is (0.1-100):1, preferably (10-20):1.

[0058] According to the present invention, the molar ratio of 1,3-pentadiene monomer to the initiator is (200-1000):1, preferably (294-735):1, and more preferably (588-735):1. The ratio of monomer to initiator is generally determined by limiting the design molecular weight. For example, if the design molecular weight is 50,000 g / mol, the actual molar ratio (monomer:initiator) is 735:1; if the design molecular weight is 20,000 g / mol, the actual molar ratio (monomer:initiator) is 588:1.

[0059] According to the present invention, in step (1), the concentration of 1,3-pentadiene monomer in the mixed solution of 1,3-pentadiene and a non-polar hydrocarbon solvent is 5-20% by weight, preferably 8-15% by weight.

[0060] According to the present invention, the first preheating conditions include: temperature of 25-80° C. and time of 0.5-3 h.

[0061] According to the present invention, the second preheating conditions include: a temperature of 50-60° C. and a time of 4-5 hours.

[0062] According to the present invention, the aging treatment conditions include: a temperature of 25-60° C. and a time of 10-300 min.

[0063] According to the present invention, the polymerization reaction conditions include: temperature of 0-100° C. and time of 1-24 h.

[0064] According to the present invention, after the polymerization is completed, 0.5-3 mL of an aqueous solution or alcohol solution containing an anti-aging agent and an antioxidant is added to terminate the reaction, and excess methanol is precipitated and then vacuum dried at 40-60° C. for 24-72 hours.

[0065] In the present invention, the antioxidant is selected from antioxidant 264 and / or antioxidant 2264.

[0066] In the present invention, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 168 and antioxidant 1076.

[0067] According to the present invention, the terminator used in the termination reaction is generally selected from any one of water, methanol, ethanol and isopropanol, preferably isopropanol.

[0068] According to a preferred embodiment of the present invention, a method for preparing a linear polypentadiene-1,3-diene elastomer having a high trans-1,4-structure content comprises:

[0069] (1) A mixed solution of polymerization-grade 1,3-pentadiene monomer and a non-polar hydrocarbon solvent is prepared and added to a polymerization bottle that has been baked, nitrogen-filled, and deoxygenated; the polymerization bottle is preheated at 25-80°C for 0.5-3h;

[0070] (2) adding a catalyst to the mixed solution, preheating at 50-60° C. for 4-5 hours, and aging at 25-60° C. for 10-300 minutes; wherein the catalyst comprises a co-catalyst and a main catalyst in a molar ratio of (0-4):1, the main catalyst being an alkoxy barium salt, a cycloalkoxy barium salt, an alcohol ether barium salt, an alcoholamine barium salt, a phenol barium salt, a carboxylic acid barium salt, an alkoxy sodium salt, or a sulfonic acid sodium salt; and the co-catalyst being an alkyl aluminum;

[0071] (3) After aging and impurity removal, a polarity regulator and an organic lithium initiator are added to initiate polymerization, the polymerization temperature is 0-100° C., and the polymerization time is 1-24 hours; the molar ratio of the total amount of the co-catalyst and the main catalyst to the organic lithium initiator is (0.2-1.53):1; the molar ratio of the polarity regulator to the organic lithium initiator is (10-20):1;

[0072] (4) After the polymerization is completed, 0.5-3 mL of an alcohol solution containing an anti-aging agent and an antioxidant is added to terminate the reaction. After precipitation with excess methanol, the mixture is vacuum dried at 40-60° C. for 24-72 hours to obtain a poly(1,3-pentadiene) elastomer containing a high trans-1,4-structure content.

[0073] The third aspect of the present invention provides a linear polypentadiene 1,3-elastomer having a high trans 1,4-structure content, prepared by the aforementioned preparation method.

[0074] In the present invention, the polypentadiene-1,3-ene elastomer is a homopolymer.

[0075] A fourth aspect of the present invention provides a use of the aforementioned linear polypentadiene-1,3 elastomer having a high trans-1,4-structure content as a rubber compound in a tire tread and / or sidewall.

[0076] The present invention will be described in detail below through examples.

[0077] The microstructure of the synthesized polymer was measured using an INOVA-400 nuclear magnetic resonance spectrometer produced by Varian Corporation of the United States at a frequency of 400 MHz, with tetramethylsilane (TMS) as the internal standard and deuterated chloroform as the solvent.

[0078] The molecular weight and molecular weight distribution were determined using a gel permeation chromatograph (GPC-220) produced by PL Company, UK. The eluent was THF, the flow rate was 1.0 mL / min, and the test temperature was 40°C.

[0079] Glass transition temperature was measured using a DSC200F3 differential calorimeter manufactured by NETZSCH Instruments GmbH, Germany. The primary heating cycle was 25-100°C at 10°C / min, followed by a 10-min hold. The temperature was then lowered from 100°C to -100°C at 5°C / min. The secondary heating cycle was from -100°C to 150°C at 5°C / min. Purge gas: nitrogen at 50 mL / min; protective gas: nitrogen at 50 mL / min.

[0080] The 1,3-pentadiene monomer, solvent and terminator used in the polymerization reaction of the present invention are all subjected to a strict water and oxygen removal operation, and the water and oxygen content meets the requirements for anionic polymerization.

[0081] In preparing the catalyst and reaction system, the organic sodium salts SDBS and SDS and the organic barium salts BAD and BHT were purchased commercially or prepared according to publicly available common synthetic routes. n-Butyl lithium, tert-Butyl lithium, sec-Butyl lithium, antioxidant 1010, and anti-aging agent 264 were all provided by Baling Petrochemical Company.

[0082] In the present invention, the formula and molar ratio of the main catalyst, co-catalyst, polarity regulator or organic lithium initiator in the catalysis-initiation reaction system ah in the comparative examples and embodiments are as follows:

[0083] Organic barium catalyst:

[0084] System a: n(BHT):n(TEA):n(THF):n(t-BuLi)=0.25:0.25:10:1

[0085] System b: n(BHT):n(TEA):n(t-BuLi)=0.25:0.75:1

[0086] System c: n(BHT):n(TMA):n(t-BuLi)=0.33:1.2:1

[0087] System d: n(BHT):n(TIBA):n(t-BuLi)=0.16:0.32:1

[0088] System e: n(BAD):n(TEA):n(t-BuLi)=0.25:0.50:1

[0089] Organic sodium catalyst:

[0090] System f: n(SDBS):n(THF):n(n-BuLi)=0.2:20:1

[0091] System g: n(SDS):n(THF):n(n-BuLi)=0.2:10:1

[0092] Monopolar regulator system:

[0093] System h: n(THF):n(t-BuLi)=20:1

[0094] Example 1

[0095] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0096] (1) Under anhydrous and oxygen-free conditions, 250 mL of cyclohexane and 21.75 g (0.33 mol) of cis-1,3-pentadiene (Zp) were added sequentially into a dry, nitrogen-filled, vacuum-treated pressure-resistant polymerization bottle; preheated at 50°C for 30 minutes;

[0097] (2) After preheating, the main catalyst of system a, barium thymol BHT 0.67 mL (0.32 mol / L, 0.216 mmol, toluene solution) and triethylaluminum TEA 2.2 mL (0.1 mol / L, 0.216 mmol, toluene solution) were added, mixed thoroughly, and then allowed to stand at 50°C for 1 h.

[0098] (3) After aging, 0.7 mL (8.65 mmol) of THF was added, and then tert-butyl lithium t-BuLi was used to break the impurities until the solution showed color. Then, 1.3 mL of tert-butyl lithium t-BuLi (0.33 mol / L, cyclohexane solution, 0.865 mmol, the designed molecular weight Mn of poly 1,3-pentadiene elastomer is 50,000 g / mol) was added to initiate polymerization, and the reaction was carried out at 80°C for 4 h.

[0099] (4) After the reaction was completed, the mixture was cooled to room temperature and terminated by adding an isopropyl alcohol-toluene solution containing 1% anti-aging agent 264 and 1% antioxidant 1010. The mixture was precipitated with excess methanol and washed repeatedly 3-4 times. The polymer was then vacuum-dried at 40°C for 24 hours to obtain a polymer product. The monomer conversion rate was determined by gravimetric analysis to be 95%.

[0100] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure (Trans-1,4-structure) content of 88% and a 1,2-structure content of 12%, and is substantially free of 3,4-structure and cis-1,4-structure (Cis cis-1,4-structure).

[0101] The obtained polymer had a molecular weight distribution PDI of 1.45, a glass transition temperature Tg of -54°C, a distinct melting peak, an onset temperature of 47°C, and a midpoint temperature Tm of 76°C.

[0102] The sequence composition of the polymer is shown in Table 1.

[0103] Example 2

[0104] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0105] Polypentadiene-1,3-diene elastomer was prepared using the same organobarium catalyst and alkyllithium polymerization conditions as in Example 1, except that trans-pentadiene-1,3-diene (Ep) was used in place of cis-pentadiene-1,3-diene (Zp) for anionic polymerization of pentadiene-1,3-diene. The resulting polymer was dried after solvent removal, and the monomer conversion rate, as determined by gravimetric analysis, was 91%.

[0106] 1H NMR analysis results show that the polypentadiene 1,3-diene elastomer has a trans-1,4-structure content of 79%, a 1,2-structure content of 15.7%, a cis-1,4-structure content of 6.4%, and substantially no 3,4-structure.

[0107] The molecular weight distribution PDI of the obtained polymer was 1.77, and its glass transition temperature Tg was -46°C. No cold crystallization peak or obvious melting peak appeared.

[0108] The sequence composition of the polymer is shown in Table 1.

[0109] Example 3

[0110] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0111] A polypentadiene-1,3-diene elastomer was prepared using the same organobarium catalyst and alkyllithium polymerization conditions as in Example 1, except that the monomer type was changed: mixed isomeric pentadiene-1,3-diene (Pd, E / Z = 65 / 35) was substituted for cis-pentadiene-1,3-diene (Zp) in Example 1 for anionic polymerization of pentadiene-1,3-diene. The resulting polymer was dried after solvent removal, and the monomer conversion rate, as determined by gravimetric analysis, was 94%.

[0112] 1 H NMR analysis results show that the polypentadiene 1,3-diene elastomer has a trans-1,4-structure content of 82%, a 1,2-structure content of 16.2%, a cis-1,4-structure content of 1.8%, and substantially no 3,4-structure.

[0113] The molecular weight distribution PDI of the obtained polymer was 1.62, and its glass transition temperature Tg was -48°C. A cold crystallization peak appeared at -4°C, and no obvious melting peak appeared.

[0114] The sequence composition of the polymer is shown in Table 1.

[0115] Example 4

[0116] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0117] Polypentadiene-1,3-diene elastomer was prepared using the same organic barium catalyst and alkyl lithium polymerization conditions as in Example 1, except that the type of organic lithium was changed: n-butyllithium n-BuLi (0.40 mol / L, cyclohexane solution, designed molecular weight Mn of polypentadiene-1,3-diene elastomer was 50,000 g / mol) was used in place of tert-butyllithium t-BuLi in Example 1. The resulting polymer was dried after solvent removal, and the monomer conversion rate, as determined by gravimetric analysis, was 93%.

[0118] 1 H NMR results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 85% and a 1,2-structure content of 14.9%, and substantially contains no 3,4-structure or cis-1,4-structure.

[0119] The obtained polymer had a molecular weight distribution PDI of 1.42, a glass transition temperature Tg of -49°C, a distinct melting peak, an onset temperature of 42°C, and a midpoint temperature Tm of 69°C.

[0120] The sequence composition of the polymer is shown in Table 1.

[0121] Example 5

[0122] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0123] Polypentadiene-1,3-diene elastomer was prepared using the same organic barium catalyst and alkyl lithium polymerization conditions as in Example 1, except that the type of organic lithium was changed: sec-butyllithium s-BuLi (0.29 mol / L, n-hexane solution, designed molecular weight Mn of polypentadiene-1,3-diene elastomer was 50,000 g / mol) was used in place of tert-butyllithium t-BuLi in Example 1. The resulting polymer was dried after solvent removal, and the monomer conversion rate, as determined by gravimetric analysis, was 92%.

[0124] 1 H NMR analysis results show that the polypentadiene 1,3-diene elastomer has a trans-1,4-structure content of 84%, a cis-1,4-structure content of 0.7%, and a 1,2-structure content of 15.3%, and substantially no 3,4-structure.

[0125] The obtained polymer had a molecular weight distribution PDI of 1.73, a glass transition temperature Tg of -51°C, a distinct melting peak, an onset temperature of 39°C, and a midpoint temperature Tm of 68°C.

[0126] The sequence composition of the polymer is shown in Table 1.

[0127] Example 6

[0128] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0129] Polypentadiene-1,3-diene elastomer was prepared using the same organic barium catalyst and alkyl lithium polymerization conditions as in Example 1, except that the type of organic lithium was changed: tert-butyllithium (t-BuLi) was replaced with "macromolecular active lithium polystyrene-based active lithium (PSLi in cyclohexane, with a design molecular weight Mn of 2,000 g / mol for polystyrene and 50,000 g / mol for polypentadiene-1,3-diene elastomer)" for the polymerization of pentadiene-1,3-diene. After solvent removal and drying, the resulting polymer had a monomer conversion rate of 95% as determined by gravimetric analysis.

[0130] 1 H NMR analysis results show that the trans-1,4-structure content of the poly(1,3-pentadiene) elastomer segment in the polymer is 89%, the 1,2-structure content is 10.9%, and the 3,4-structure and cis-1,4-structure are substantially absent.

[0131] The obtained polymer had a molecular weight distribution PDI of 1.81, a glass transition temperature Tg of -52°C, a distinct melting peak, an onset temperature of 45°C, and a midpoint temperature Tm of 78°C.

[0132] The sequence composition of the polymer is shown in Table 1.

[0133] Example 7

[0134] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0135] Polypentadiene-1,3-diene elastomer was prepared using the same organic barium catalyst and alkyl lithium polymerization conditions as in Example 1, except that the organic lithium was changed to replace the tert-butyl lithium (t-BuLi) in Example 1 with a macromolecular active lithium polybutadienyl active lithium (PBLi in cyclohexane, with a design molecular weight Mn of 2,000 g / mol for polybutadiene and 50,000 g / mol for polypentadiene-1,3-diene elastomer). The resulting polymer was dried after solvent removal, and the monomer conversion, as determined by gravimetric analysis, was 96%.

[0136] 1 H NMR analysis results show that the trans-1,4-structure content of the polypentadiene 1,3-elastomer segment in the polymer is 88%, the 1,2-structure content is 12%, and the 3,4-structure and cis-1,4-structure are substantially absent.

[0137] The obtained polymer had a molecular weight distribution PDI of 1.73, a glass transition temperature Tg of -46°C, a distinct melting peak, an onset temperature of 48°C, and a midpoint temperature Tm of 81°C.

[0138] The sequence composition of the polymer is shown in Table 1.

[0139] Example 8

[0140] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0141] Polypentadiene-1,3-diene elastomer was prepared under the same polymerization conditions of the organobarium catalyst and alkyllithium as in Example 1, except that only the ratio of cis-pentadiene-1,3-diene monomer to initiator was changed. Specifically:

[0142] In step (2), “barium thymol BHT 0.67 mL (0.32 mol / L, 0.216 mmol, toluene solution)” was modified to “barium thymol BHT 1.68 mL (0.32 mol / L, 0.54 mmol, toluene solution)”; “triethylaluminum TEA 2.2 mL (0.1 mol / L, 0.216 mmol, toluene solution)” was modified to “triethylaluminum TEA 5.5 mL (0.1 mol / L, 0.54 mmol, toluene solution)”;

[0143] In step (3), “tert-butyllithium t-BuLi 1.3 mL (0.33 mol / L, cyclohexane solution, 0.865 mmol)” was modified to “tert-butyllithium t-BuLi 3.2 mL (0.33 mol / L, cyclohexane solution, 2.16 mmol”);

[0144] Specifically, the designed molecular weight Mn of the polypentadiene-1,3-diene elastomer was changed to 20,000 g / mol and anionic polymerization of pentadiene-1,3-diene was performed. After solvent removal and drying, the resulting polymer had a monomer conversion rate of 97% as determined by gravimetric analysis.

[0145] 1 H NMR analysis results show that the polypentadiene 1,3-diene elastomer has a trans-1,4-structure content of 86%, a cis-1,4-structure content of 0.7%, and a 1,2-structure content of 13.3%, and substantially no 3,4-structure.

[0146] The molecular weight distribution PDI of the obtained polymer was 1.51, and its glass transition temperature Tg was -49°C. A cold crystallization peak appeared at -8°C, and no obvious melting peak appeared.

[0147] The sequence composition of the polymer is shown in Table 1.

[0148] Example 9

[0149] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0150] Polypentadiene-1,3-diene elastomer was prepared using the same polymerization conditions as in Example 1, using an organobarium catalyst and alkyllithium. The only difference was that the polarity modifier was changed: tetrahydrofurfuryl alcohol ethyl ether (1.2 mL, 8.65 mmol) was used instead of THF. Anionic polymerization of pentadiene-1,3-diene was performed. After solvent removal and drying, the resulting polymer had a monomer conversion rate of 91% as determined by gravimetric analysis.

[0151] 1 The results of H NMR analysis showed that the trans 1,4-structure content of the polypentadiene 1,3-ene elastomer was 91%, the 1,2-structure content was 7%, and there was basically no cis 1,4-structure, but a small amount of 3,4-structure. 13 C NMR quantitative analysis showed that its content was about 2.0%.

[0152] The obtained polymer had a molecular weight distribution PDI of 1.49, a glass transition temperature Tg of -55°C, a distinct melting peak, an onset temperature of 59°C, and a midpoint temperature Tm of 84°C.

[0153] The sequence composition of the polymer is shown in Table 1.

[0154] Example 10

[0155] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0156] Polypentadiene-1,3-diene elastomer was prepared using the same organic barium catalyst and alkyl lithium polymerization conditions as in Example 1, except that only the initiator type was changed, and anionic polymerization of pentadiene-1,3-diene was carried out using the catalyst system of "System B." After solvent removal and drying, the resulting polymer had a monomer conversion rate of 93% as determined by gravimetric analysis. Its DSC curve is shown in Figure 1. Figure 2 shown.

[0157] 1 H NMR analysis results showed that the polypentadiene-1,3-diene elastomer had a trans-1,4-structure content of 86%, a cis-1,4-structure content of 0.9%, and a 1,2-structure content of 13%, with essentially no 3,4-structure. The sequence composition of the polymer is shown in Table 1.

[0158] The obtained polymer had a molecular weight distribution PDI of 1.66, a glass transition temperature Tg of -51°C, a distinct melting peak, an onset temperature of 42°C, and a midpoint temperature Tm of 71°C.

[0159] The sequence composition of the polymer is shown in Table 1.

[0160] Example 11

[0161] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0162] Polypentadiene-1,3-diene elastomer was prepared using the same polymerization conditions as in Example 1, using an organobarium catalyst and alkyllithium. The only difference was that the initiator type was changed, and anionic polymerization of pentadiene-1,3-diene was performed using the catalyst system of "System C." After solvent removal and drying, the resulting polymer had a monomer conversion rate of 90% as determined by gravimetric analysis.

[0163] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 83%, a cis-1,4-structure content of 6%, and a 1,2-structure content of 11%, and substantially no 3,4-structure.

[0164] The molecular weight distribution PDI of the obtained polymer was 1.58, and its glass transition temperature Tg was -48°C. A cold crystallization peak appeared at -6°C, and no obvious melting peak appeared.

[0165] The sequence composition of the polymer is shown in Table 1.

[0166] Example 12

[0167] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0168] Polypentadiene-1,3-diene elastomer was prepared using the same polymerization conditions as in Example 1, using an organobarium catalyst and alkyllithium. The only difference was that the initiator type was changed, and anionic polymerization of pentadiene-1,3-diene was performed using the catalyst system of "System d." After solvent removal and drying, the resulting polymer had a monomer conversion rate of 93% as determined by gravimetric analysis.

[0169] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 89%, a cis-1,4-structure content of 0.5%, and a 1,2-structure content of 11%, and substantially no 3,4-structure.

[0170] The obtained polymer had a molecular weight distribution PDI of 1.54, a glass transition temperature Tg of -54°C, a distinct melting peak, an onset temperature of 55°C, and a midpoint temperature Tm of 79°C.

[0171] The sequence composition of the polymer is shown in Table 1.

[0172] Example 13

[0173] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic barium catalyst system in the method of the present invention.

[0174] Polypentadiene-1,3-diene elastomer was prepared using the same polymerization conditions as in Example 1, using an organobarium catalyst and alkyllithium. The only difference was that the initiator type was changed, and anionic polymerization of pentadiene-1,3-diene was performed using the catalyst system of "System e." After solvent removal and drying, the resulting polymer had a monomer conversion rate of 97% as determined by gravimetric analysis.

[0175] 1 H NMR analysis results show that the trans-1,4-structure content of the polypentadiene-1,3-ene elastomer is 83%, the cis-1,4-structure content is 2.2%, the 1,2-structure content is 13.1%, and a small amount of 3,4-structure is contained.

[0176] The molecular weight distribution PDI of the obtained polymer was 1.75, the glass transition temperature Tg was -47°C, a cold crystallization peak appeared at 5°C, and no obvious melting peak appeared.

[0177] The sequence composition of the polymer is shown in Table 1.

[0178] Example 14

[0179] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic sodium catalyst system in the method of the present invention.

[0180] (1) Under anhydrous and oxygen-free conditions, 100 mL of cyclohexane and 8.7 g (0.13 mol) of cis-1,3-pentadiene (Zp) were added sequentially into a dry, nitrogen-filled, vacuum-treated polymerization bottle and preheated at 50°C for 30 minutes.

[0181] (2) After preheating, system f was added, including 0.012 g (0.0346 mmol) of SDBS, 0.22 mL (3.46 mmol) of THF, and 0.48 mL (0.173 mmol) of a 0.40 mol / L n-BuLi cyclohexane solution, with a designed molecular weight Mn of 50,000 g / mol), and the reaction was carried out at 75°C for 4 h.

[0182] (3) After the reaction is completed, the mixture is cooled to room temperature and an isopropyl alcohol-toluene solution containing 1% anti-aging agent 264 and 1% antioxidant 1010 is added to terminate the reaction. The mixture is precipitated with excess methanol and washed repeatedly 3-4 times. The mixture is vacuum dried at 40° C. for 24 hours to obtain a polymer product, poly1,3-pentadiene elastomer. The monomer conversion rate is 99% as determined by weight method.

[0183] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 81%, a cis-1,4-structure content of 6.6%, a 1,2-structure content of 12.5%, and essentially no 3,4-structure.

[0184] The molecular weight distribution PDI of the obtained polymer was 1.37, the glass transition temperature Tg was -52°C, a cold crystallization peak appeared at -7°C, and no obvious melting peak appeared.

[0185] The sequence composition of the polymer is shown in Table 1.

[0186] Example 15

[0187] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic sodium catalyst system in the method of the present invention.

[0188] A polypentadiene-1,3-diene elastomer was prepared using the same organic sodium catalyst and alkyl lithium polymerization conditions as in Example 14, except that the monomer type was changed: trans-pentadiene-1,3-diene (Ep) was substituted for cis-pentadiene-1,3-diene (Zp) in Example 14. The resulting polymer was dried after solvent removal, and the monomer conversion rate, as determined by gravimetric analysis, was 97%.

[0189] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 77%, a cis-1,4-structure content of 10.2%, and a 1,2-structure content of 12.9%, and substantially no 3,4-structure.

[0190] The molecular weight distribution PDI of the obtained polymer was 1.46, and its glass transition temperature Tg was -39°C. No cold crystallization peak or obvious melting peak appeared.

[0191] The sequence composition of the polymer is shown in Table 1.

[0192] Example 16

[0193] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic sodium catalyst system in the method of the present invention.

[0194] Polypentadiene-1,3-diene elastomer was prepared using the same organic sodium catalyst and alkyl lithium polymerization conditions as in Example 14, except that the monomer type was changed: mixed isomeric pentadiene-1,3-diene (Pd, E / Z = 65 / 35) was substituted for cis-pentadiene-1,3-diene (Zp) for anionic polymerization of pentadiene-1,3-diene. The resulting polymer was dried after solvent removal, and the monomer conversion rate, as determined by gravimetric analysis, was 98%.

[0195] 1 H NMR analysis results show that the polypentadiene 1,3-diene elastomer has a trans-1,4-structure content of 79%, a cis-1,4-structure content of 9.7%, and a 1,2-structure content of 10.3%, and substantially no 3,4-structure.

[0196] The molecular weight distribution PDI of the obtained polymer was 1.39, and its glass transition temperature Tg was -45°C. No cold crystallization peak appeared, and no obvious melting peak appeared.

[0197] The sequence composition of the polymer is shown in Table 1.

[0198] Example 17

[0199] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic sodium catalyst system in the method of the present invention.

[0200] Polypentadiene-1,3-diene elastomer was prepared using the same organic sodium catalyst and alkyl lithium polymerization conditions as in Example 14, except that only the ratio of SDBS to THF was changed: 0.025 g (0.0865 mmol) of SDBS and 0.11 mL (1.73 mmol) of THF were used for anionic polymerization of pentadiene-1,3-diene. The resulting polymer was dried after solvent removal, and the monomer conversion, as determined by gravimetric analysis, was 95%.

[0201] 1 The results of H NMR analysis showed that the trans 1,4-structure content of the polypentadiene 1,3-ene elastomer was 80%, the cis 1,4-structure content was 14.5%, the 1,2-structure content was 4.2%, and a small amount of 3,4-structure was contained. 13 C NMR quantitative analysis showed that its content was about 1.3%. The molecular weight distribution of the obtained polymer was PDI = 1.26,

[0202] Its glass transition temperature Tg = -52°C, a cold crystallization peak appears at 0°C, and no obvious melting peak appears.

[0203] The sequence composition of the polymer is shown in Table 1.

[0204] Example 18

[0205] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic sodium catalyst system in the method of the present invention.

[0206] Polypentadiene-1,3-diene elastomer was prepared using the same organic sodium catalyst and alkyl lithium polymerization conditions as in Example 14, except that the polarity modifier was changed to carbon disulfide instead of THF. 1,3-pentadiene was anionically polymerized using 0.025 g (0.0865 mmol) of SDBS and 0.21 mL (3.46 mmol) of CS2. The resulting polymer was dried after solvent removal, and the monomer conversion, as determined by gravimetric analysis, was 93%.

[0207] 1 H NMR analysis results show that the polypentadiene 1,3-diene elastomer has a trans-1,4-structure content of 82%, a cis-1,4-structure content of 12.1%, and a 1,2-structure content of 5.9%, and substantially no 3,4-structure.

[0208] The molecular weight distribution PDI of the obtained polymer was 1.51, the glass transition temperature Tg was -50°C, a cold crystallization peak appeared at 3°C, and no obvious melting peak appeared.

[0209] The sequence composition of the polymer is shown in Table 1.

[0210] Example 19

[0211] This example is intended to illustrate the preparation of polypentadiene 1,3-diene elastomer using the organic sodium catalyst system in the method of the present invention.

[0212] Polypentadiene-1,3-diene elastomer was prepared using the same organic sodium catalyst and alkyl lithium polymerization conditions as in Example 14, except that only the initiator type was changed, using "System g" for anionic polymerization of pentadiene-1,3-diene: 0.025 g (0.0865 mmol) of SDBS and 0.21 mL (3.46 mmol) of CS2. The resulting polymer was dried after solvent removal, and the monomer conversion, as determined by gravimetric analysis, was 99%.

[0213] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 71%, a cis-1,4-structure content of 18.9%, and a 1,2-structure content of 10.2%, and substantially no 3,4-structure.

[0214] The molecular weight distribution PDI of the obtained polymer was 1.88, and its glass transition temperature Tg was -44°C. No cold crystallization peak or obvious melting peak appeared.

[0215] The sequence composition of the polymer is shown in Table 1.

[0216] Comparative Example 1

[0217] Under anhydrous and oxygen-free conditions, 100 mL of cyclohexane and 8.7 g (0.13 mol) of mixed isomeric 1,3-pentadiene (Pd, E / Z = 65 / 35) were added sequentially to a dry, nitrogen-filled, vacuum-treated polymerization flask. After preheating the flask at 50°C for 30 minutes, system h, consisting of 0.22 mL (3.46 mmol) of THF and 0.48 mL (0.173 mmol) of n-BuLi (designed molecular weight Mn of 50,000 g / mol), was added and reacted at 75°C for 4 hours. After cooling to room temperature, the reaction was terminated by adding an isopropanol-toluene solution containing 1% antioxidant 264 and 1% antioxidant 1010. The product was precipitated with excess methanol and washed repeatedly 3-4 times. The product was then vacuum-dried at 40°C for 24 hours to yield a polymer. The monomer conversion, as determined by gravimetric analysis, was 95%.

[0218] 1 The results of H NMR analysis showed that the trans 1,4-structure content of the polypentadiene 1,3-ene elastomer was 46%, the cis 1,4-structure content was 17%, the 1,2-structure content was 30%, and a small amount of 3,4-structure was contained. 13 C NMR quantitative analysis showed that the 3,4-content was about 7.0%.

[0219] The molecular weight distribution PDI of the obtained polymer was 1.19, and its glass transition temperature Tg was -44°C. No cold crystallization peak appeared, and no obvious melting peak appeared.

[0220] The sequence composition of the polymer is shown in Table 1.

[0221] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the poly 1,3-pentadiene elastomer prepared in Example 1, Example 14 and Comparative Example 1 of the present invention is ( 1 H NMR) spectrum, from Figure 1 It can be seen that: the characteristic peak of saturated H in the cis-1,4-structure corresponding to δ2 (2.5 ppm), the characteristic peaks of saturated H in the 1,2-structure and cis-1,4-structure corresponding to δ4 (1.6 ppm) and δ5 (1.3 ppm), and the characteristic peak of methyl H in the 1,4-structure content corresponding to δ6 (1.0 ppm) indicate that the δ2 signals of Examples 1 and 14 are extremely low, and δ4 and δ5 are also very low relative to Comparative Example 1, and these two characteristic peaks of Example 1 are the lowest, indicating that the polypentadiene-1,3-ene elastomer obtained by the methods of Examples 1 and 14 is mainly composed of trans-1,4-structure, and the trans-1,4-structure in Example 1 is relatively higher.

[0222] Figure 2The carbon nuclear magnetic resonance spectra of the unsaturated carbon region of the polypentadiene elastomer prepared in Example 1, Example 14 and Comparative Example 1 of the present invention are ( 13 C NMR) spectrum, from Figure 2 It can be seen that the unsaturated carbon regions of Example 1 and Example 14 are mainly composed of two unsaturated carbon C2* and C3* displacements of trans 1,4-structures at δ=127ppm and δ=137ppm, and the two units in the chain structure are mostly TT and TV (trans 1,4-structure and 1,2-structure). In Comparative Example 1, more TV and CV peak signals appear, and an obvious characteristic signal peak δ=116ppm that only exists in 3,4-structure appears.

[0223] Figure 3 The saturated carbon nuclear magnetic resonance spectra of the polypentadiene elastomers prepared in Example 1, Example 14 and Comparative Example 1 of the present invention are ( 13 C NMR) diagram, from Figure 3 It can be seen that the carbon displacement of the saturated carbon region of Example 1 and Example 14 shows that in the polymer chain structure of Example 1 and Example 14, the 1,4-4,1 (head-to-tail) content of TT and the 1,4-1,4 (head-to-head) and 4,1-4,1 (tail-to-tail) content of TT are the majority, among which the TT di-linking mode of Example 1 is the highest with 1,4-4,1 (δ=41ppm, δ=37ppm, δ=20ppm), and the 1,4-1,4 and 4,1-4,1 content ratios of TT are maintained at 1,4-1,4 and 4,1-4,1 respectively. The curves for Example 1 are flat, and Example 1 essentially contains no carbon shifts corresponding to 1,4-1,2 and 1,2-1,2, resulting in a clear polymer chain. However, Example 14, due to the presence of a small amount of 1,2- and cis-1,4-structures, exhibits corresponding carbon atom shifts for CV, TV, and VV diads at δ = 33 ppm and δ = 35 ppm, respectively. The curve for Comparative Example 1 also exhibits shifts at δ = 15 ppm and δ = 21.5 ppm, which are typically associated with high levels of VV diads and 3,4-3,4 diads. Furthermore, no special carbon shifts due to side reactions such as branching and cyclization were observed in Examples 1, 14, and Comparative Example 1, indicating that the polymers obtained by this method are highly linear.

[0224] Figure 4 is a differential scanning calorimetry (DSC) graph of the polypentadiene elastomer prepared in Example 1, Example 7, Example 15 and Comparative Example 1 of the present invention, from Figure 4 It can be seen that: with the increase of the content of trans 1,4-structure, the glass transition temperature Tg continues to decrease, and a cold crystallization peak appears, and as the content increases, it transforms into a melting peak of a semi-crystalline polymer.

[0225] Figure 5is a gel permeation chromatography (GPC) diagram of the poly1,3-pentadiene elastomer prepared in Example 1, Example 7 and Comparative Example 1 of the present invention, from Figure 5 It can be seen that the molecular weight of the poly(1,3-pentadiene) elastomer presents a normal unimodal distribution. The molecular weight distribution of Comparative Example 1 without the addition of organic barium salt or organic sodium salt is narrower. After the addition of organic barium salt and organic sodium salt, the molecular weight is slightly broadened, but still within the controllable range of the unimodal distribution. Compared with the molecular weight distribution (>2.0) of the high trans-structure conjugated diene rubber prepared by vanadium, titanium and transition (Co) catalytic systems, it is narrower.

[0226] Comparative Example 2

[0227] A polypentadiene-1,3-diene elastomer was prepared using the same polymerization conditions as in Example 1, using an organobarium catalyst and alkyllithium, except that the barium thymol (BHT) catalyst in Example 1 was replaced with sodium tert-butoxide (t-BuONa). Anionic polymerization of pentadiene-1,3-diene was carried out using the same proportions as in System 1. After solvent removal and drying, the resulting polymer had a monomer conversion rate of 45%, as determined by gravimetric analysis.

[0228] 1 The results of H NMR analysis showed that the trans-1,4-structure content of the polypentadiene 1,3-ene elastomer was 46%, the cis-1,4-structure content was 14%, the 1,2-structure content was 31%, and a small amount of 3,4-structure was contained. 13 C NMR quantitative analysis showed that its content was about 8.0%.

[0229] The molecular weight distribution PDI of the obtained polymer was 1.96, and its glass transition temperature Tg was -39°C. No cold crystallization peak or obvious melting peak appeared.

[0230] The sequence composition of the polymer is shown in Table 1.

[0231] Comparative Example 3

[0232] A poly(1,3-pentadiene) elastomer was prepared using the same organic sodium catalyst and alkyl lithium polymerization conditions as in Example 14, except that the anionic polymerization of 1,3-pentadiene was performed by modifying the system f from "n(SDBS):n(THF):n(n-BuLi)=0.2:20:1" to "0.2:0.1:1." The resulting polymer was dried to remove the solvent, and the monomer conversion, as determined by gravimetric analysis, was 91%.

[0233] 1 H NMR analysis results show that the polypentadiene-1,3-diene elastomer has a trans-1,4-structure content of 69%, a cis-1,4-structure content of 12%, and a 1,2-structure content of 19%, and substantially no 3,4-structure.

[0234] The molecular weight distribution PDI of the obtained polymer was 1.32, and its glass transition temperature Tg was -42°C. No cold crystallization peak appeared, and no obvious melting peak appeared.

[0235] The sequence composition of the polymer is shown in Table 1.

[0236] Table 1

[0237]

[0238] Note 1: When the Trans-1,4 structure content is greater than 80%, the sequence composition is not completely corresponding to the 1,2-structure content because the 1,4-4,1-methyl carbon shift peaks of the triple-chain structure TVT overlap with those of the di-TT, and the characteristic peaks of the saturated carbon region are not obvious due to the low 1,2-1,2 content.

[0239] Note 2: This includes various linking methods of 1,2-1,2, as well as head-to-head, head-to-tail and tail-to-tail of Cis-1,4 and linking content of 1,4-3,4.

[0240] Note: "%" refers to "mol %".

[0241] From the examples, comparative examples and the results in Table 1, it can be seen that:

[0242] (1) The preparation method of the present invention is easy to obtain, the reaction rate is fast, and the conversion rate is high.

[0243] (2) The molecular weight of the poly 1,3-pentadiene elastomer prepared by the present invention is easy to control, and the number average molecular weight Mn is within 4×10 4 g / mol to 5×10 5 The molecular weight distribution is between 1.26-1.88, which is much lower than that of 1,3-pentadiene prepared by coordination polymerization. The microstructure can be efficiently controlled, the proportion of trans 1,4-structure is very high, and the content of side propylene structure is very low. The sequence of the polymer is highly regular, the polymer chain presents a linear structure, and the 1,4-4,1 head-to-tail linking mode is dominant.

[0244] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A linear polypentadiene 1,3-diene elastomer having a high trans 1,4-structure content, characterized in that: The polypentadiene-1,3-diene elastomer has a linear structure, and the polypentadiene-1,3-diene elastomer includes 70-95 mol% of a trans-1,4-structure, and in the microscopic sequence distribution of the polypentadiene-1,3-diene elastomer, the content of 1,4-4,1 head-to-tail linkage is 51-78 mol%; The number average molecular weight of the polypentadiene 1,3-diene elastomer is 2×10 4 g / mol to 5×10 5 g / mol; The molecular weight distribution PDI of the polypentadiene 1,3 elastomer is 1.05-2.

5.

2. The elastic body according to claim 1, wherein The polypentadiene-1,3-ene elastomer includes 79-91 mol % of a trans-1,4-structure.

3. The elastic body according to claim 1, wherein The polypentadiene-1,3-diene elastomer further comprises 0-30 mol% of a cis-1,4-structure, 4-25 mol% of a 1,2-structure and 0-10 mol% of a 3,4-structure.

4. The elastic body according to claim 3, wherein The polypentadiene-1,3-ene elastomer includes 0-15 mol % of a cis-1,4-structure, 7-15 mol % of a 1,2-structure and 0-3 mol % of a 3,4-structure.

5. The elastic body according to claim 1, wherein In the microscopic sequence distribution of the polypentadiene 1,3-diene elastomer: The total content of the linkages in the manner of head-to-head 1,4-1,4 and tail-to-tail 4,1-4,1 is 10-40 mol%; and / or, the ratio of head-head 1,4-1,4 and tail-tail 4,1-4,1 contents is 1:(1-5); And / or, the content of 1,4-1,2 linkage is 5-20 mol%.

6. The elastic body according to claim 5, wherein In the microscopic sequence distribution of the polypentadiene 1,3-diene elastomer: The total content of the linkages in the head-to-head 1,4-1,4 and tail-to-tail 4,1-4,1 manner is 10-33 mol%; And / or, the content of 1,4-1,2 linkage is 5-10 mol%.

7. The elastomer according to any one of claims 1 to 6, wherein: The glass transition temperature T of the poly 1,3-pentadiene elastomer g -70℃ to -30℃; and / or the melting temperature T of the polypentadiene 1,3-diene elastomer m 0-90℃.

8. The elastic body according to claim 7, wherein The molecular weight distribution PDI of the polypentadiene-1,3-ene elastomer is 1.1-1.9; And / or, the glass transition temperature T g -70℃ to -50℃; and / or the melting temperature T of the polypentadiene 1,3-diene elastomer m It is 70-90℃.

9. A method for preparing the linear polypentadiene-1,3-diene elastomer having a high trans-1,4-structure content according to any one of claims 1 to 8, characterized in that: The preparation method comprises: (1) mixing 1,3-pentadiene monomer and a non-polar hydrocarbon solvent and performing a first preheating to obtain a mixed solution; (2) contacting the mixed solution with a catalyst for a second preheating or aging treatment; wherein the catalyst comprises a main catalyst and a co-catalyst, wherein the main catalyst comprises an organic barium salt or an organic sodium salt, and the co-catalyst is an alkyl aluminum; wherein the organic barium salt is selected from one or more of alkoxy barium salts, cycloalkoxy barium salts, alcohol ether barium salts, alcohol amine barium salts, phenol barium salts, and carboxylic acid barium salts; Wherein, the organic sodium salt is an alkoxy sodium salt and / or a sulfonic acid sodium salt; wherein the alkyl aluminum is selected from one or more of trimethyl aluminum, triethyl aluminum, tripropyl aluminum, triisobutyl aluminum, triisopropyl aluminum, trioctylaluminum and methylaluminoxane; (3) contacting the product obtained from step (2) with a polarity regulator and an initiator to initiate a polymerization reaction and then perform a termination reaction to obtain a linear poly(1,3-pentadiene) elastomer having a high trans-1,4-structure content; Wherein, the molar ratio of the total amount of the main catalyst and the co-catalyst to the amount of the initiator is (0.01-100):1; And / or, the molar ratio of the polarity regulator to the initiator is (0.1-100):1; and / or, the molar ratio of the 1,3-pentadiene monomer to the initiator is (200-1000):1; and / or, the molar ratio of the co-catalyst to the main catalyst is (0-100):1; and / or, in step (1), in the mixed solution, the concentration of 1,3-pentadiene monomer is 5-20% by weight; The first preheating conditions include: temperature of 25-80°C and time of 0.5-3h; And / or, the second preheating conditions include: temperature of 50-75°C and time of 4-5h; And / or, the polymerization reaction conditions include: temperature of 0-100° C. and time of 1-24 h.

10. The preparation method according to claim 9, wherein The molar ratio of the co-catalyst to the main catalyst is (0-4):

1.

11. The preparation method according to claim 9, wherein The 1,3-pentadiene monomer is selected from one or more of cis-1,3-pentadiene, trans-1,3-pentadiene, mixed isomeric 1,3-pentadiene, 2-methyl-1,3-pentadiene and 2,3-dimethyl-1,3-pentadiene; and / or, the non-polar hydrocarbon solvent is selected from one or more of cyclohexane, n-hexane, n-pentane, n-heptane, benzene, hydrogenated oil and extracted oil; and / or, the polarity regulator is selected from one or more of tetrahydrofuran, dioxane, triethylamine, ditetrahydrofurfuryl propane, N,N-dimethyltetrahydrofurfurylamine, tetrahydrofurfuryl alcohol ethyl ether, tetrahydrofurfuryl alcohol butyl ether, pentamethyldiethyltriamine, dipyridineethane, triphenylphosphine and carbon disulfide; And / or, the initiator is an organic lithium initiator.

12. The preparation method according to claim 11, wherein The initiator is selected from one or more of alkyl lithium, aryl lithium, amide lithium, organic lithium chloride and macromolecular active lithium.

13. A linear polypentadiene 1,3-elastomer having a high trans 1,4-structure content prepared by the preparation method according to any one of claims 9 to 12.

14. Use of the linear polypentadiene-1,3 elastomer with a high trans 1,4-structure content according to any one of claims 1 to 8 and 13 as a rubber compound in a tire tread and / or sidewall.

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