CN117106141A

CN117106141A - Hydrogenated dendritic random asymmetric long-chain branched polystyrene-conjugated diene block copolymer and preparation method thereof

Info

Publication number: CN117106141A
Application number: CN202210528995.3A
Authority: CN
Inventors: 朱建军; 梁智英; 姚琼; 张建国
Original assignee: Sinopec Baling Petrochemical Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Baling Petrochemical Co ltd; China Petroleum and Chemical Corp
Priority date: 2022-05-16
Filing date: 2022-05-16
Publication date: 2023-11-24

Abstract

The invention discloses a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer and a preparation method thereof. The polymer is obtained by selective hydrogenation of branched styrene-conjugated diene/divinylbenzene-styrene triblock copolymer with asymmetric long chain, the hydrogenated polymer molecules are generally in different dendritic structures, and the polymer has the characteristics of high oil locking, low deformation, high cohesion and high strength under the environment of high oil filling, and has comprehensive physical properties superior to those of the prior polystyrene-conjugated diene block hydride.

Description

Hydrogenated dendritic random asymmetric long-chain branched polystyrene-conjugated diene block copolymer and preparation method thereof

Technical Field

The invention relates to a hydrogenated polystyrene-conjugated diene block copolymer, in particular to a hydrogenated dendritic random asymmetric long-chain branched polystyrene-conjugated diene block copolymer and a preparation method thereof, and belongs to the technical field of functional polymer synthesis.

Background

The existing polystyrene-conjugated diene-styrene block hydrides (SEBS and SEPS) are generally obtained by selective hydrogenation of the corresponding polystyrene-butadiene block copolymers (SBS) and polystyrene-isoprene block copolymers (SIS), which are characterized in that the benzene rings in the molecule are not hydrogenated and the double bonds in the polybutadiene units are completely hydrogenated. For example, products such as YH-501 and YH-503 produced by commercial synthetic rubber factories of China petrochemical and Baling petrochemical companies are hydrogenated by polystyrene-butadiene-styrene triblock linear copolymers, YH-4051, YH-4053, SEPTON-2063, G1765M, G1702M and the like are hydrogenated by polystyrene-isoprene-block linear copolymers, YH-602, YH-603, YH-604 and the like are hydrogenated by polystyrene-butadiene diblock copolymers and silicon tetrachloride coupling into star shapes, the number of coupling symmetrical arms in molecules is between 2.5 and 3.5, and the coupling efficiency is less than 85%. Wherein YH-604 is formed by mixing star-shaped hydrogenated SEBS and linear hydrogenated SEBS. The number average molecular mass Mn of the existing SEBS polymer is 8-25 ten thousand.

In the text of molecular structure design and hydrogenation of star-shaped butadiene polymers, university of great company, chemical engineering, 2021), a living anion polymerization method and a coupling modification technology are adopted, difunctional ether Lewis base is selected as a regulator, divinylbenzene (DVB) is used as a coupling agent, and two star-branched butadiene polymers, namely high 1, 2-structure star-branched polybutadiene (S-g-PB) and a star-branched styrene-butadiene-styrene (S-g-SBS) copolymer with polystyrene as a regular branched chain are synthesized. And (2) hydrogenating unsaturated double bonds in PB chain segments in the two polymerization products by adopting a p-toluenesulfonyl hydrazide (TSH)/tri-n-propylamine (TPA) system to generate corresponding hydrogenation products, wherein the hydrogenation degree can reach more than 98%, and the hydrogenation products have a certain effect in the aspect of modification of finished oil. The PB and SBS are characterized in that DVB is used as a coupling agent, namely, monomers are firstly copolymerized into a polymer of active lithium, then DVB is coupled, polymer molecules are coupled and copolymerized into a 'core' formed by homopolymerization of a plurality of DVBs, and the 'core' contains a plurality of multi-arm star polymers taking polybutadiene or SB/S as branched chains, namely, the molecular fraction of the polymer is unimodal. DVB is easy to form copolymerization in coupling, and if the using amount of DVB is small, a branched chain cannot be formed; if the amount is large, the polymer can form a star-shaped radial molecular conformation, but partial gel is unavoidable, so that the usability and processing performance of the polymer are affected, and the hydrogenated product is used in the modification of the finished oil. However, as a tackifier for the lubricating oil of the finished oil, the product of a plurality of related structures of (polystyrene-butadiene/isoprene) -divinylbenzene coupling synthesized by the method by the synthetic rubber industry department of China petrochemical Baling petrochemical company is used as the tackifier for the lubricating oil, and as a result, the oil obviously contains the defects of swelling polymer gel, poor viscosity temperature performance, poor shear stability and the like, and the polymer is not suitable as a modifier for the oil, and the comprehensive performance is far less than that of polystyrene/isoprene copolymer hydrogenated products such as commercially available SV-260 and ethylene propylene diene monomer, and the synthesis method has been disclosed in a plurality of technologies.

Ai Ni, in chinese application (CN 106459424B), discloses a hydrogenated polymer having a radial structure with an aromatic-based core, the radial structure having a core composed of aromatic hydrocarbons, to which core hydrogenated linear polymer segments are attached: hydrogenated homopolymers or copolymers of conjugated dienes are prepared from hydrogenated copolymers of conjugated dienes and monoalkenyl arenes, and mixtures thereof, containing silicon groups in addition to carbon, hydrogen and heteroatoms; the core radiates outwardly an integer in the range between 4 and 16.

Chinese patent (CN 107793542B) discloses a method for synthesizing hydrogenated styrene/isoprene block copolymer, synthesizing diblock copolymer or multiblock copolymer containing styrene block and isoprene block, and hydrogenation, wherein the mixed solvent of nonpolar alkane and toluene can effectively increase the reaction probability of active PS-Li end group and isoprene, so as to reduce or eliminate the small molecular polystyrene content in the hydrogenated styrene/isoprene block copolymer, and improve the drop point of the diblock or multiblock hydrogenated styrene/isoprene block copolymer when applied to optical fiber and optical cable filling ointment.

Chinese patent (CN 112708085A) hydrogenated isoprene/styrene block coupled polymer optical cable ointment gelling agent, preparation method thereof and application thereof in optical cable ointment, and the gelling agent has a structural formula (EIS) _n Coupling polymers of polyhydrogenated polymer arms of M; the hydrogenated polymer arms are two-block polymer arms of a hydrogenated polyisoprene block-polystyrene block, and the polystyrene block is connected to a coupling center (M).

Chinese patent (CN 1662562 a) hydrogenated copolymer and composition containing the same, filed by the chinese chemical company, comprising at least one hydrogenated copolymer block obtained by hydrogenating an unhydrogenated random copolymer block consisting of conjugated diene monomer units and vinyl aromatic monomer units, wherein the hydrogenated copolymer has the following characteristics: the hydrogenated copolymer has a content of vinyl aromatic monomer units of more than 40% by weight to less than 95% by weight; at least one peak of loss tangent (tan delta) is observed in the dynamic viscoelasticity spectrum obtained for the hydrogenated copolymer at-10 ℃ to 80 ℃; substantially no crystallization peaks ascribed to the copolymer blocks (hydrogenated segments of conjugated dienes) are observed in the Differential Scanning Calorimetry (DSC) chart obtained for hydrogenated copolymers at-20℃to 80 ℃.

In the section of the "research on the preparation of eight-arm star-shaped block copolymer by living anion polymerization and its hydrogenation reaction", the journal of Polymer science, 09 in 2020 "), the synthesis of lithium (PS-PI-Li) living chain by living anion polymerization method was studied, and then the coupling reaction with octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) was performed, and a small amount of the low coupling product was removed by fractional precipitation to obtain pure eight-arm star-shaped block copolymer (PS-PI) ₈ POSS; finally, p-toluenesulfonyl hydrazide (TSH) pair (PS-PI) was used ₈ The PI chain segment in POSS is subjected to hydrogenation addition reaction to prepare another novel eight-arm star-shaped block copolymer (PS-PI) containing saturated hydrocarbon chain segments ₈ POSS, and preliminary investigation of the effect of TSH dosing and reaction time on the hydrogenation addition reaction. Gel Permeation Chromatography (GPC) and nuclear magnetic resonance hydrogen spectrum ¹ H-NMR) and Fourier transform Infrared Spectroscopy (FTIR) detailsThe chemical structure, molecular weight and molecular weight distribution of the polymer were characterized and tested (PS-PI) using thermogravimetric analysis (TGA) ₈ Thermal stability of POSS before and after hydrogenation addition reaction.

Chinese patent (CN 102161927 a) lubricating oil composition filed by inflight international limited, the lubricating oil composition comprising: (A) A major amount of an oil of lubricating viscosity comprising a group III base stock; (B) A minor amount of a viscosity index improver as an additive component comprising a linear or star polymer that can be at least partially derived from the polymerization of one or more conjugated diene monomers.

The molecular fraction of the existing polystyrene-conjugated diene hydride is unimodal narrow distribution, part of the commercial products are bimodal narrow distribution mixed by a two-step method, the hydrogenated star-shaped polystyrene-conjugated diene is formed by rehydrogenating a polymer coupled by silicon tetrachloride, divinylbenzene and OVPOSS, 1, 4-addition units in a conjugated diene section in the polystyrene-conjugated diene polymer synthesis increase along with the rising of the polymerization exothermic temperature, so that 1, 2-or 3, 4-side branch addition units of the conjugated diene in the later section in the polymerization are reduced, the ethylene long chain of part of the molecular chain after the hydrogenation of the virgin rubber appears to cause crystallization, and the final hydrogenated polymer has poor oil absorption performance and high oil locking performance of the high-oil-charge product, and the like. But has bimodal narrow distribution, random asymmetric long chain branching and dendritic polystyrene-conjugated diene block hydride which has not been reported up to the present.

Disclosure of Invention

It is known that in the prior art, when a conjugated diene segment is polymerized in the synthesis of hydrogenated polystyrene-conjugated diene block polymer, polymerization of the conjugated diene is a strong exothermic reaction, and even if forced withdrawal of polymerization heat is adopted in a polymerization two-segment, the 1, 4-addition of diene is raised due to a plurality of factors such as local overheating in a polymerization environment or limited mass and heat transfer, and the like, the temperature is raised, and the hydrogenated 1, 4-addition unit has ethylene long chains to generate crystallization, so that the hydrogenated polymer has defects such as poor oil absorption and oil locking performance, large permanent deformation, and the like.

The first object of the present invention is to provide a branched hydrogenated polystyrene-conjugated diene block copolymer having a bimodal narrow distribution and a molecular chain exhibiting random asymmetric long chain branching, wherein the hydrogenated polymer molecules are generally in different dendritic structures, and the hydrogenated polystyrene-conjugated diene block copolymer has the characteristics of high oil locking performance, low deformation, high cohesion and high strength under a high oil-filled environment, and has comprehensive physical properties superior to those of the existing polystyrene-conjugated diene block copolymers.

It is another object of the present invention to provide a simple and low cost process for preparing said hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer.

In order to achieve the above technical object, the present invention provides a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer having the following structural expression:

(S _t -E _o D _p ) _m -E _q D _r /Y _n

wherein E is _q D _r /Y _n A random copolymer backbone of a hydrogenated conjugated diene and divinylbenzene; s is S _t -E _o D _p Is a hydrogenated diblock copolymer branched chain of styrene and a conjugated diene; s is a styrene unit; e is a hydrogenated 1, 4-addition conjugated diene unit; d is a hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit; y is a divinylbenzene unit; t, o, p, q and r are the degrees of polymerization of the styrene unit, the hydrogenated 1, 4-addition conjugated diene unit in the branch, the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit in the branch, the hydrogenated 1, 4-addition conjugated diene unit in the main chain, the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit in the main chain, respectively; n is the number of branching nodes introduced by divinylbenzene units; m is the number of branches. The hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer of the present invention has a structure different depending on the conjugated diene selected. If the conjugated diene is butadiene, the hydrogenated copolymer dry adhesive is dendritic SEBS; if the conjugated diene is selected from single isoprene, the hydrogenated copolymer dry adhesive is dendritic-SEPS; for example, conjugated dienes selected from mixtures of butadiene and isopreneWhen the hydrogenated copolymer gum is "dendritic-SEBPS".

The hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer of the present invention comprises a hydrogenated asymmetric long chain branched conjugated diene polymer having a main chain formed by random copolymerization of conjugated diene monomers and divinylbenzene branching units, wherein the branched chain is mainly of a two-block structure, the terminal graft polystyrene block is a hydrogenated conjugated diene block at the terminal of the main chain. The combined expression can be seen: e (E) _q D _r /Y _n Is a random copolymer backbone of a hydrogenated conjugated diene and divinylbenzene, S _t -E _o D _p Is a hydrogenated diblock copolymer branched chain of styrene and a conjugated diene; e (E) _o Addition of conjugated diene units, D, to hydrogenated 1,4 in the branches _p Conjugated diene units for hydrogenation of 1, 2-addition (e.g.butadiene units) and/or 3, 4-addition (e.g.isoprene units) in the branches, E _q Addition of conjugated diene units to hydrogenation 1,4 in the backbone, D _r For the hydrogenation of the 1, 2-addition and/or 3, 4-addition conjugated diene units in the main chain, Y is homogeneously distributed in the main chain by random copolymerization, constituting the grafts S _t -E _o D _p Branched nodes of (a).

The hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer molecules of the present invention inevitably produce small amounts of coupling and cyclizing products during the polymerization due to the introduction of divinylbenzene as branching unit, these coupling and cyclizing products being mainly composed of 2 to 3 different asymmetric long chain branched linear molecules coupled linear molecules and 2 to 3 different asymmetric long chain branched linear molecules coupled into cyclic molecules, the coupled and cyclized polymers having a number average molecular mass M _n ＝25×10 ⁴ ～50×10 ⁴ The method comprises the steps of carrying out a first treatment on the surface of the Molecular mass distribution index M _w /M _n And.ltoreq.1.16, and these coupled and cyclized polymers generally have a mass fraction of from 27 to 35%.

As a preferable technical scheme, t, o, p, q and r are positive integers more than or equal to 1 and are not equal to each other.

As a preferable technical scheme, m and n are positive integers, m is more than or equal to n, and n is more than or equal to 1 and less than or equal to 2.

As a preferable technical scheme, the mass percentage composition of the styrene unit and the total mass percentage composition of the hydrogenated 1, 4-addition conjugated diene unit and the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit is 25-35 percent, 75-65 percent. It should be noted that isoprene generally does not undergo 1, 2-addition for anionic polymerization of conjugated dienes, its 1, 2-addition unit content is negligible, and its 1, 4-and 3, 4-addition unit contents are >99.5%.

As a preferred embodiment, the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene units account for 38% to 68% of the total mass of the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene units and the hydrogenated 1, 4-addition conjugated diene units. If the proportion of 1,4 addition units in the conjugated diene unit is too high, the resulting ethylene units in the molecular chain are too large, and the hydride has a tendency to crystallize, and this phenomenon can be effectively alleviated by controlling the proportion of 1, 2-addition and/or 3,4 addition conjugated diene units.

As a preferred embodiment, the (S _t -E _o D _p ) _m -E _q D _r /Y _n Number average molecular mass M of (2) _n ＝8×10 ⁴ ～20×10 ⁴ 。

As a preferred embodiment, the (S _t -E _o D _p ) _m -E _q D _r /Y _n Molecular mass distribution index M of (2) _w /M _n ＝1.02～1.05。

As a preferred embodiment, the mass of divinylbenzene units is from 0.7/1000 to 1.2/1000 of the total mass of hydrogenated 1, 4-addition conjugated diene units and hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene units. More preferably 0.9 to 1.1/1000. Of further elucidation are worth of: the DVB dosage is too low, the branching degree of the polymer is too low, and the purpose of branching cannot be achieved; if the DVB dosage is too high, the branching degree of the polymer is too high under the condition that the NBL dosage is constant, the molecular mass of the polymer is too high, and the polymer generates gel or a blunt kettle.

As a preferred embodiment, the conjugated diene may be at least one of butadiene and isoprene. The most preferred conjugated diene unit consists of 0 to 90% by mass of butadiene units and 100 to 10% by mass of isoprene units.

As a preferred embodiment, the (S _t -E _o D _p ) _m -E _q D _r /Y _n The degree of hydrogenation of (2) is greater than 98%. The hydrogenation degree of the present invention refers to the hydrogenation degree of alkenyl groups, not the hydrogenation degree of benzene rings.

The invention also provides a preparation method of the hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene segmented copolymer, which comprises the steps of firstly adding part of styrene monomer into an anionic polymerization system for one-stage polymerization, then uniformly and continuously adding divinylbenzene and conjugated diene mixed monomer containing a structure regulator for two-stage polymerization, then adding the rest part of styrene for three-stage polymerization, stopping polymerization after the three-stage polymerization is completed, obtaining a dendritic random asymmetric long chain branched polystyrene-conjugated diene segmented copolymer raw glue solution, carrying out hydrogenation reaction on the glue solution, obtaining hydrogenated glue solution, and sequentially condensing and drying the obtained hydrogenated glue solution.

As a preferable technical scheme, the anionic polymerization system comprises an activator, an initiator and a solvent. For anionic polymerization systems, activators, initiators, and solvents are common in the art.

As a preferred embodiment, the activator is tetrahydrofuran.

As a preferred embodiment, the initiator is an alkyllithium, such as, in particular, n-butyllithium.

As a preferred embodiment, the solvent is cyclohexane and/or hexane. The amount of the solvent is generally such that the mass ratio of the total mass of the styrene monomer and the conjugated diene monomer to the solvent is (8 to 15)/100.

As a preferable technical scheme, the dosage of the activator is 80-160 mg/kg of solvent.

As a preferred technical scheme, the conditions of the one-stage polymerization are as follows: the temperature is 50-60 ℃ and the time is 20-30 min.

As a preferred technical scheme, the conditions of the two-stage polymerization are as follows: the heating rate is controlled within the range of 0.5-1.0 ℃/min, the highest temperature is not higher than 73 ℃, the adding time of the divinylbenzene and conjugated diene mixed monomer containing the structure regulator is not less than 20min, and the reaction is carried out for 15-25 min at the temperature not higher than 73 ℃ after the adding is finished. In the two-stage polymerization process, the most preferred operation is that DVB and a structure regulator are premixed with butadiene monomer and continuously and evenly added into the active polystyrene lithium solution prepared by the first-stage polymerization, the continuous feeding time is not less than 20min, so that the divinylbenzene and conjugated diene monomer are fully and randomly and evenly chain-grown and branched, the aim that the aggregation self-polymerization core cannot be dispersed and branched due to the fact that DVB is added into a polymerization environment at one time is avoided, and after the mixed monomer is added, a certain period of time is reacted, random different asymmetric long-chain branches are formed, and finally different asymmetric long-chain dendritic polymers are formed. Of interest are: when DVB and conjugated diene monomers are copolymerized, although the chemical activity of DVB is much higher than that of butadiene and isoprene, the probability of collision of the conjugated diene monomers with active chain lithium relative to DVB is high due to the low content of DVB in the conjugated diene monomers or polymerization environment, i.e., the probability of chain growth of the conjugated diene and the probability of branching of DVB are competing synchronously, as described in (W.M sortman. "stereo rubber"). DVB is gradually branched along with the increase of the polymerization chain of conjugated diene monomer in an anionic polymerization environment, and after the polymerization of the final monomer is finished, the molecular structure of the polymer forms dendrites, and the branching density or branching factor (g) depends on the use amount of DVB and an initiator in the polymerization environment.

As a preferred technical scheme, the conditions for the three-stage polymerization are: the temperature is 55-75 ℃ and the time is 20-30 min.

As a preferable technical scheme, the structure regulator is at least one of tetrahydrofurfuryl alcohol ethyl ether, ditetrahydrofurfuryl propane, tetrahydrofurfuryl alcohol hexyl ether and tetrahydrofurfuryl amine.

As a preferable technical scheme, the dosage of the structure regulator is 120-200 mg/kg of solvent. In order to ensure that the 1,2 addition and/or 3.4 addition units of the conjugated diene in the polymer before hydrogenation account for 38 to 68% of the conjugated diene units, it is necessary to add an appropriate amount of structure regulator to the anionic polymerization system.

As a preferable technical scheme, the hydrogenation catalyst adopted in the hydrogenation reaction is nickel naphthenate/triisobutyl aluminum aging liquid, wherein the Ni/Al molecular ratio is=3-5:1, the addition amount of the hydrogenation catalyst is 0.5-0.8 mmol/100g relative to the glue solution, the hydrogenation catalyst is measured according to the molar amount of nickel naphthenate, and the glue solution is measured according to the dry mass. Since the conventional dicyclopentadiene titanium dichloride catalyst is inactive for polyisoprene hydrogenation, the nickel naphthenate/triisobutylaluminum aging liquid is preferably selected as the catalyst in the present invention.

As a preferable technical scheme, the hydrogenation reaction conditions are as follows: the pressure is 13-18 bar, the temperature is 70-85 ℃ and the time is 120-180 min. By controlling the hydrogenation reaction conditions, the degree of hydrogenation of the hydride can be >98%.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

aiming at the defects that the existing triblock linear and three-four arm coupling star-shaped SBS and SIS hydrogenated SEBS and SEPS molecules have polyethylene long chains to generate crystallization, so that the oil absorption rate is low, the oil locking performance of a high oil-filled product is poor, the oil seepage and flaccidity shrinkage of the product occur, the permanent deformation is large, the use behavior is lost, and the high oil-filled soft product is not suitable to be manufactured. The hydrogenated dendritic random asymmetric long-chain branched polystyrene-conjugated diene segmented copolymer mainly comprises macromolecules which are composed of asymmetric long-chain branched arms and main chains, wherein the conformations of the macromolecules are dendritic, side group hydrogenation units in the macromolecules are uniformly distributed, and short chains containing side groups and random branched chains are mutually entangled with the main chains and encircle to enable the polymers to lose crystallization behavior, and physical crosslinking distribution points in the dendritic molecules are larger than 6, so that the polymers exhibit the behavior of thermoplastic elastomers. Compared with the existing commercial SEBS and SEPS, the hydrogenated dendritic random asymmetric long-chain branched polystyrene-conjugated diene segmented copolymer not only has good comprehensive physical and mechanical properties, but also shows lower deformation, has excellent compatibility and oil locking property for mineral oil white oil, and is an ideal substitute for the existing SEBS and SEPS; the soft product is more suitable for being used as a jelly-shaped soft product with high oil filling, and can be compared with silica gel with meat feeling.

The preparation method of the hydrogenated dendritic random asymmetric long-chain branched polystyrene-conjugated diene block copolymer is simple, low in cost and beneficial to mass production.

Drawings

FIG. 1 is a GPC chromatogram of SIS-Y polymerized virgin rubber.

FIG. 2 is a chart of H1-NMR spectrum of SIS-Y polymerized virgin rubber.

FIG. 3 is H of SEPS-Y ¹ -NMR spectrum.

FIG. 4 is a GPC chart of SIBS-1 #.

FIG. 5 is H of SIBS-1# ¹ -NMR spectrum.

FIG. 6 is a diagram of H of SEBPS-1# ¹ -NMR spectrum.

FIG. 7 is H of D3-SIBS ¹ -NMR spectrum.

Note that: h ¹ The proton of chemical shift 5.573-5.373 in the NMR spectrum is the proton on-ch=ch-, and the proton of chemical shift 4.995-4.956 is-ch=ch ₂ The protons of chemical shifts 5.128-4.978 are those on the isoprene 1, 4-addition unit and the protons of chemical shifts 4.751-4.666 are those on the isoprene 3, 4-addition unit.

Detailed Description

The following examples are intended to further illustrate the present invention in detail and are not to be construed as limiting the scope of the invention as claimed.

The number average molecular mass and the molecular weight distribution index of the polymer were measured by Gel Permeation Chromatography (GPC) in the following examples; quantitatively determining the microstructure of the polymer by adopting an H1-NMR spectrum; the mechanical properties of the tabletting glue are tested according to the GB/T36089-2018 method; the degree of hydrogenation of the polymers was measured according to the method GB/T13892-2020.

Determination of oil permeability of high-oil-filled composite rubber material: the oil-filled composite was hot-pressed at 120 ℃ into 20×60×2mm coupons, placed in a mixed solution consisting of ethanol/n-octane (weight) =7/3, immersed for 72h at room temperature, then the coupons were removed and air-dried at room temperature, and the weight loss was measured. Percent weight loss on soaking = [ (weight before soaking-weight after soaking)/weight before soaking ] ×100.

Example 1

3500mL of cyclohexane solution, 0.30mL of THF and 54mL of styrene are added into a 5L polymerization kettle under the protection of nitrogen, stirring is started, the temperature of the materials is raised to 55 ℃, and simultaneously 0.5mol/L of NBL 9.0mL (containing active lithium consumed by impurity breaking and dehumidification) is added for initiation and polymerization for 25min; then uniformly and continuously adding a mixed monomer consisting of 0.14g of DVB, 0.50mL of tetrahydrofurfuryl alcohol ethyl ether and 290mL of isoprene into a polymerization kettle within 23min, controlling the polymerization heating rate to be 0.7 ℃/min, keeping the highest polymerization temperature to be not higher than 73 ℃, continuously stirring and reacting for 20min after the monomer is added, adding 54mL of styrene into the polymerization kettle, polymerizing for 25min at 68 ℃ to obtain a primary emulsion of SIS (marked as SIS-Y) with a random branching arm and a branched molecular chain, sampling and measuring the polymer GPC as shown in figure 1 and H ¹ The NMR spectrum is shown in FIG. 2.

The gum solution was pressed into a 5L hydrogenation kettle with nitrogen, the gum solution was heated to 73 ℃ and 7.0mL of n-hexane aging liquid of nickel naphthenate/triisobutylaluminum (wherein, the Ni concentration is 0.22mol/L, ni/Al molecular ratio=3.4) was added, and the hydrogenation was carried out at a hydrogenation pressure of 14bar and a temperature of 80 ℃ for 165min with stirring, and the hydrogenation degree of the polymer was measured by sampling to be 98.27%. Discharging the hydrogenated liquid, adding 130g of 9.5% (weight) citric acid water solution into the hydrogenated liquid, stirring for 30min, centrifuging the glue solution to obtain water phase, condensing the colorless oil phase with water vapor, and drying to obtain colorless transparent hydride (marked as SEPS-Y) with hydrogenated glue H ¹ The NMR spectrum is shown in FIG. 3. The molecular mass and pendant alkenyl unit content of the hydrogenated virgin rubber are shown in Table 1 respectively.

Example 2

The polymerization and hydrogenation process conditions in example 1 were maintained except that tetrahydrofurfuryl alcohol ethyl ether was added during the polymerization in an amount of 0.25mL, butadiene in an amount of 170mL, and isoprene in an amount of 150mL.

GPC spectra of the resulting polymer virgin rubber (labeled SIBS-1) are shown in FIG. 4, H ¹ -NMRThe spectrum is shown in figure 5; the hydrogenated rubber is marked as SEBPS-1, the hydrogenation degree is 98.23 percent, and H ¹ The NMR spectrum is shown in FIG. 6. The molecular mass and the content of the pendant alkenyl units of the hydrogenated SIBS-1 are shown in Table 1 respectively.

Example 3

The polymerization and hydrogenation conditions in example 2 were maintained except that NBL was 8.0mL, DVB was 0.15mL, ditetrahydrofurfuryl propane was 0.35mL, butadiene was 40mL, and isoprene was 250mL.

The hydrogenated gum prepared as a result was designated SEBPS-2, the hydrogenation degree was 98.35%, and the molecular mass and the pendant alkenyl unit content of the hydrogenated gum (designated SIBS-2) were shown in Table 1, respectively.

Example 4

The polymerization and hydrogenation conditions in example 2 were maintained except that 10mL of NBL was added during the polymerization, 56mL of styrene was added in the first and third stages, 0.16mL of DVB, 0.46mL of ditetrahydrofurfuryl propane, 100mL of butadiene, and 195mL of isoprene were added to the mixed monomers. 10mL of n-hexane aging liquid of nickel naphthenate/triisobutyl aluminum for hydrogenation (wherein Ni concentration is 0.24mol/L, ni/Al molecular ratio=4.3), hydrogenation pressure is 16bar, temperature is 80-85 ℃ and hydrogenation time is 150min.

The hydrogenated gum prepared as a result was designated SEBPS-3, the hydrogenation degree was 99.12%, and the molecular mass and the pendant alkenyl unit content of the hydrogenated gum (designated SIBS-3) were shown in Table 1, respectively.

Example 5

The relevant polymerization and hydrogenation process conditions in example 4 were maintained except that the NBL added during the polymerization was 12mL, the styrene added in the first and third stages was 58mL, the DVB in the mixed monomer was 0.17mL, tetrahydrofurfuryl alcohol ethyl ether was 0.57mL, butadiene was 200mL, and isoprene was 110mL. 12mL of n-hexane aging liquid of nickel naphthenate/triisobutyl aluminum for hydrogenation, the hydrogenation pressure is 18bar, and the hydrogenation time is 170min.

The hydrogenated gum prepared as a result was designated SEBPS-4, the hydrogenation degree was 99.68%, and the molecular mass and the pendant alkenyl unit content of the hydrogenated gum (designated SIBS-4) were shown in Table 1, respectively.

Example 6

The relevant polymerization and hydrogenation process conditions in example 4 were kept unchanged except that the NBL added during the polymerization was 14mL, the styrene added in the first and third stages was 60mL, the DVB in the mixed monomer was 0.18mL, tetrahydrofurfuryl alcohol ethyl ether was 0.65mL, butadiene was 250mL, and isoprene was 60mL.

The hydrogenated gum prepared as a result was designated SEBPS-5, the hydrogenation degree was 99.47%, and the molecular mass and the pendant alkenyl unit content of the hydrogenated gum (designated SIBS-5) were shown in Table 1, respectively.

Comparative example 1

The polymerization and hydrogenation conditions in example 2 were kept unchanged, the mixed monomers in the second stage were added to the polymerization vessel at one time, the reaction heat was removed by forced cooling, and the polymerization temperature was increased from 55℃to the maximum temperature of 78 ℃.

The hydrogenated gum prepared as a result was designated as D-SEBPS-1, and the hydrogenation degree was 98.67%. The molecular mass and the pendant alkenyl unit content of hydrogenated virgin rubber (designated as D-SIBS-1) are shown in Table 1, respectively.

Comparative example 2

The polymerization and hydrogenation process conditions in example 2 were maintained except that tetrahydrofurfuryl alcohol ethyl ether was added in the second polymerization stage at 0.15mL.

The hydrogenated gum prepared as a result was designated as D-SEBPS-2, and the hydrogenation degree was 98.67%. The molecular mass and the pendant alkenyl unit content of hydrogenated virgin rubber (marked as D-SIBS-2) are shown in the table 1, and H of D-SIBS-1 respectively ¹ The NMR spectrum is shown in FIG. 7.

Comparative example 3

The polymerization and hydrogenation process conditions in example 2 were kept unchanged except that no regulator was used in the polymerization stage two.

As a result, polymerized virgin rubber (designated as D3-SIBS) was prepared having a vinyl unit content in the polybutadiene block and a 3, 4-addition unit content in the isoprene block of 10.63% and 6.92%, respectively, and H ¹ The NMR spectrum is shown in FIG. 7. The polymer has low content of the pendant alkenyl units, no hydrogenation value and the hydrogenated polymer shows the behavior of plastics.

Comparative example 4

The polymerization and hydrogenation conditions in example 2 were kept unchanged except that the addition time of the mixed monomer to the polymerizer was 17min during the polymerization in the second stage of the polymerization, and the polymerization temperature-rising rate was 1.23℃per minute

The maximum polymerization temperature is 76 ℃.

The hydrogenated gum prepared as a result was designated as D-SEBPS-3, and the hydrogenation degree was 99.37%. The molecular mass and the pendant alkenyl unit content of hydrogenated virgin rubber (designated as D-SIBS-3) are shown in Table 1, respectively.

Comparative example 5

The polymerization and hydrogenation process conditions in example 4 were maintained constant except that 38mL of styrene was added in both the first and third stages.

The hydrogenated gum prepared as a result was designated as D-SEBPS-4 and the hydrogenation degree was 99.43%. The molecular mass and the pendant alkenyl unit content of hydrogenated virgin rubber (designated as D-SIBS-4) are shown in Table 1, respectively.

Comparative example 6

The polymerization and hydrogenation process conditions in example 2 were maintained constant except that 5mL of aging liquid was added to the hydrogenation unit.

As a result, the degree of hydrogenation of the polymer was 87.34%.

Comparative example 7

The polymerization process conditions in example 4 were kept unchanged except that the DVB added in the second stage of the polymerization reaction was 0.26mL.

As a result, the polymerized glue solution was found to have a gel and poor fluidity.

Table 1 molecular mass and pendant alkenyl group distribution of the polymer in examples

Note that: the 3.4-unit and vinyl unit contents are the mass fractions in the isoprene stage and in the polybutadiene stage, respectively.

Example 7

Hydrogenated gums corresponding to the raw materials in Table 1, YH-4051 (SEPS-4051) and YH-604 produced by the existing commercial synthetic rubber factory of Baling petrochemical company were vulcanized and tabletted at 190 ℃ respectively, and the physical and mechanical properties of each hydrogenated gum were measured and compared to the behavior of each hydrogenated gum are shown in Table 2.

Table 2 physical properties of the tabletted gums

Note that: YH-604 is mixed by star-shaped and linear SEBS, mn=18-22×104.

As can be seen from Table 2, the hydrogenated dendrites of the present invention exhibit lower permanent set, high elongation at break and strength, while the overall physical properties of the comparative samples are inferior to those of the hydrogenated dendrites of the present invention. The reason for this is that, except for the fact that D-SEBPS-4 has lower bound styrene, the content of side group units in other comparative sample molecules is lower than 38%, and the side group units are unevenly distributed, and ethylene long chains are generated in the molecular chain to generate crystallization, so that weak plasticity is generated.

Example 8

The behavior of each of the tabletted gums calibrated in table 2 was determined by dry filling white oil KN4006 at an oil/gum=3.0/1 (weight) ratio, and mixing and tableting at 130 ℃.

TABLE 3 physical Properties of tableting gums

As can be seen from Table 3, the soaking weight loss is the dissolution of the oil exuded from the hydrogenated gum-filled oil product in ethanol/octane solvent. Compared with the traditional SEBS and SEPS, the hydrogenated polymer provided by the invention has excellent oil locking performance, higher strength and lower deformation.

Claims

1. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer characterized by: has the following structural expression:

(S _t -E _o D _p ) _m -E _q D _r /Y _n

wherein,

E _q D _r /Y _n a random copolymer backbone of a hydrogenated conjugated diene and divinylbenzene;

S _t -E _o D _p is a hydrogenated diblock copolymer branched chain of styrene and a conjugated diene;

s is a styrene unit;

e is a hydrogenated 1, 4-addition conjugated diene unit;

d is a hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit;

y is a divinylbenzene unit;

t, o, p, q and r are the degrees of polymerization of the styrene unit, the hydrogenated 1, 4-addition conjugated diene unit in the branch, the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit in the branch, the hydrogenated 1, 4-addition conjugated diene unit in the main chain, the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit in the main chain, respectively;

n is the number of branching nodes introduced by divinylbenzene units;

m is the number of branches.

2. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1, characterized in that:

t, o, p, q and r are positive integers more than or equal to 1 and are mutually unequal;

m and n are positive integers, m is more than or equal to n, and n is more than or equal to 1 and less than or equal to 2.

3. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1, characterized in that: the mass percentage composition of the styrene unit and the total mass percentage composition of the hydrogenated 1, 4-addition conjugated diene unit and the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene unit is 25-35%: 75-65%.

4. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1 or 3, characterized in that: the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene units account for 38% to 68% of the total mass of the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene units and the hydrogenated 1, 4-addition conjugated diene units.

5. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1, characterized in that:

said (S) _t -E _o D _p ) _m -E _q D _r /Y _n Number average molecular mass M of (2) _n ＝8×10 ⁴ ～20×10 ⁴ ；

Said (S) _t -E _o D _p ) _m -E _q D _r /Y _n Molecular mass distribution index M of (2) _w /M _n ＝1.02～1.05。

6. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1, characterized in that:

the mass of the divinylbenzene unit is from 0.7/1000 to 1.2/1000 of the total mass of the hydrogenated 1, 4-addition conjugated diene units and the hydrogenated 1, 2-addition and/or 3, 4-addition conjugated diene units.

7. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1, 3 or 6, characterized in that: the conjugated diene unit consists of 0-90% of butadiene units and 100-10% of isoprene units by mass percent.

8. A hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 1 or 5, characterized in that: said (S) _t -E _o D _p ) _m -E _q D _r /Y _n The degree of hydrogenation of (2) is greater than 98%.

9. A process for the preparation of a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to any one of claims 1 to 8, characterized in that: in an anion polymerization system, firstly adding part of styrene monomer to carry out first-stage polymerization, then uniformly and continuously adding divinylbenzene and conjugated diene mixed monomer containing a structure regulator to carry out second-stage polymerization, then adding the rest part of styrene to carry out third-stage polymerization, stopping polymerization after the third-stage polymerization is finished to obtain dendritic random asymmetric long-chain branched polystyrene-conjugated diene block copolymer protogum solution, carrying out hydrogenation reaction on the gum solution to obtain hydrogenated gum solution, and sequentially condensing and drying the obtained hydrogenated gum solution to obtain the modified polystyrene-conjugated diene block copolymer.

10. The method for producing a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 9, wherein: the anionic polymerization system comprises an activator, an initiator and a solvent.

11. The method for preparing a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 10, wherein:

the activator is tetrahydrofuran;

the initiator is n-butyllithium;

the solvent is cyclohexane and/or hexane.

12. The process for preparing a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 10 or 11, characterized in that:

the dosage of the activator is 80-160 mg/kg of solvent.

13. The method for producing a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 9, wherein:

the conditions for the first polymerization stage are: the temperature is 50-60 ℃ and the time is 20-30 min;

the conditions for the two-stage polymerization are: the heating rate is controlled within the range of 0.5-1.0 ℃/min, the highest temperature is not higher than 73 ℃, the adding time of the divinylbenzene and conjugated diene mixed monomer containing the structure regulator is not less than 20min, and the reaction is carried out for 15-25 min at the temperature not higher than 73 ℃ after the adding is finished;

the conditions for the three-stage polymerization are: the temperature is 55-75 ℃ and the time is 20-30 min.

14. A process for the preparation of a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 9 or 13, characterized in that:

the structure regulator is at least one of tetrahydrofurfuryl alcohol ethyl ether, ditetrahydrofurfuryl propane, tetrahydrofurfuryl alcohol hexyl ether and tetrahydrofurfuryl amine;

the dosage of the structure regulator is 120-200 mg/kg of solvent.

15. The method for producing a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 9, wherein: the hydrogenation catalyst adopted in the hydrogenation reaction is nickel naphthenate/triisobutyl aluminum ageing liquid, wherein the Ni/Al molecular ratio=3-5:1, the addition amount of the hydrogenation catalyst is 0.5-0.8 mmol/100g relative to the glue solution, the hydrogenation catalyst is measured according to the molar amount of nickel naphthenate, and the glue solution is measured according to the dry mass.

16. The method for producing a hydrogenated dendritic random asymmetric long chain branched polystyrene-conjugated diene block copolymer according to claim 9, wherein: the hydrogenation reaction conditions are as follows: the pressure is 13-18 bar, the temperature is 70-85 ℃ and the time is 120-180 min.