A compatibilizer for polystyrene polyolefin blends and a method for preparing the same

Abstract

This application discloses a compatibilizer for polystyrene / polyolefin blends and its preparation method, belonging to the field of block copolymers. A block copolymer is disclosed, comprising polystyrene blocks and polyethylene blocks; the block copolymer is crystalline; the aggregated structure of the block copolymer consists of a polystyrene microphase region, a polyethylene crystalline region, and a branched amorphous region—three phases coexisting. This block copolymer exhibits extremely high compatibility with both polystyrene and polyolefin materials, effectively reducing interfacial tension between different materials, significantly improving the impact resistance, mechanical properties, and rheological behavior of polystyrene / polyolefin blends, without damaging other properties of the materials, and without side reactions such as crosslinking or degradation; this block copolymer exhibits plastic processing properties at high temperatures and elastomer properties at room temperature, classifying it as a thermoplastic elastomer; this block copolymer is also more flexible and has better transparency.

Description

Technical Field

[0001] This application relates to a compatibilizer for polystyrene-polyolefin blends and its preparation method, belonging to the field of block copolymers. Background Technology

[0002] Polymer blending is a simple and practical method for integrating material properties. However, blending modification must address the key technical challenge of polymer thermodynamic incompatibility. The aggregated structure of polymer alloys is primarily constrained by the thermodynamic compatibility between its components, and most polymers are thermodynamically incompatible due to significant differences in their solubility parameters. Furthermore, the high surface tension during melt blending makes it difficult to achieve process compatibility during mixing and processing.

[0003] Polystyrene (PS) possesses excellent moldability, transparency, and electrical properties, along with advantages such as high rigidity, ease of dyeing, low moisture absorption, and low cost. It is widely used in packaging, construction, automotive, home appliances, daily necessities, and toys, and has become one of the four major general-purpose plastics. However, its poor toughness, solvent resistance, environmental stress cracking resistance, and relatively low heat distortion temperature (70-98℃) limit its engineering applications. Therefore, improving the impact strength and heat distortion temperature of polystyrene without significantly compromising its modulus, and obtaining polystyrene alloys with excellent comprehensive properties, has become an important research topic over the years. In 1952, Dow Chemical Company in the United States launched high-impact polystyrene (HIPS), which offered low cost and high performance, leading to the emergence of modified polystyrene products such as ABS, AS, and MBS. Among various modification methods, blending modification of PS, with its advantages of low investment, short cycle, and flexible production and processing, has always been a research hotspot for modified polystyrene. Current research has made some progress in improving the impact strength and toughness of PS through blending modification with polyolefin (PO) materials. Compared with PS, commonly used polyolefin materials such as polyethylene (PE) and polypropylene (PP) have good toughness, solvent resistance, heat resistance, and impact resistance, but low rigidity and difficulty in dyeing. In order to obtain materials with excellent comprehensive performance, researchers have conducted modification studies on PS and PO, hoping to obtain a composite material that combines the excellent properties of both PS and PO. In recent years, the novel thermoplastic elastomer material POE has attracted great attention and has been widely used in the impact modification of PP and PS due to its excellent physical and mechanical properties. Compared with traditional toughening agents, POE can maintain good strength and processing fluidity while toughening the material.

[0004] The compatibility between PS and PO has a significant impact on many properties of PS / PO blends, making compatibility a key consideration. These two materials differ considerably in molecular structure, polarity, and molecular weight, making it difficult for PS / PO blends to achieve microscopic homogeneous mixing even under strong mechanical forces.

[0005] Table 1. Solubility parameters of PS and polyolefin materials

[0006] polymer PS PE EPDM PP PVC <![CDATA[δ(10 3 J 1 / 2 m -2 / 3 )]]> 17.5-18.7 16.1-16.6 16.2-16.4 16.0-16.9 19.2-22.1

[0007] Based on the solubility parameters above, PS and polyolefin materials have significantly different solubility parameters, belonging to a typical thermodynamically incompatible system with weak interfacial adhesion. Simple mechanical blending is insufficient to disperse the components, and direct blending will result in severe phase separation, leading to uneven particle size and irregular shape in the dispersed phase of the PS / PO blend, poor interfacial bonding, easy stress cracking, and poor mechanical properties. Therefore, improving the compatibility of PS and PO and enhancing the interfacial adhesion of PS / PO blends are crucial for preparing high-performance PS / PO blends. From a practical point of view, partial compatibility (or process compatibility) between the different components of a PS / PO blend is sufficient. An ideal PS / PO blend should be macroscopically homogeneous, microscopically phase-separated, with high interfacial adhesion between phases. Through the complementary advantages of each component's properties, a polymer alloy with overall performance superior to any single component can be obtained. Therefore, improving the process compatibility between PS and PO is essential to obtaining good PS / PO blends.

[0008] In recent years, scholars both domestically and internationally have conducted extensive research on the modification of PS / PO blends using mechanical blending or compatibilization methods. To improve the dispersion effect of PS / PO blends, many scholars have designed novel screw mixing elements and explored methods such as external energy fields. In 1999, Liu YH et al. first introduced chaotic mixing into the polymer blending process. Jana, Foster, and others applied chaotic mixing to single-screw extruders. Kim et al. intermittently inserted barrier-type chaotic mixing screws into ordinary single-screw extruders to improve the blending effect of PS and PO. Isayev et al. applied an external ultrasonic energy field during the extrusion blending process, studying the rheological and mechanical properties of the blended materials by applying orthogonal and parallel oscillating ultrasonic waves to the pressure flow. These studies only attempted to improve the extrusion blending process, enhancing diffusion and penetration between components to some extent, promoting the fragmentation and homogenization of the dispersed phase, and improving and enhancing the material properties. However, because PS and PO are typical thermodynamically incompatible systems, mechanical mixing alone cannot achieve the ideal state of process compatibility. Therefore, in the research on PS / PO blend modification, the addition of suitable compatibilizers to reduce the interfacial tension between the PS and PO phases and significantly improve the microphase separation state of the blend material has increasingly attracted researchers' interest. In PS / PO blends, the lower the interfacial tension between the two phases, the better it promotes the mixing and dispersion of the components, thereby refining and uniformly distributing the dispersed phase particles. After compatibilization, the average particle size of the dispersed phase in thermodynamically incompatible blends can usually reach the submicron level. At the same time, the reduction of interfacial tension can strengthen the adhesion between the two phases, and the stress can be better transferred between different phase regions, making the thermodynamically incompatible polymer blend system a process-compatible polymer alloy. Adding suitable compatibilizers can prevent the coalescence and growth of the dispersed phase, refine and stabilize the final microphase separation state, thereby obtaining ideal "sea-island" phase separation structures, fibrous dispersed phase structures, and layered dispersed phase structures. In summary, compatibilizers are an important component of thermodynamically incompatible blend systems and play a very important role in the research and development of polymer blend modification. For example, SBS improves the compatibility between the PP and PS phases, enhancing the impact and tensile properties of the polymer alloy. SB diblock copolymers affect the phase separation state and dispersed phase particle size in LDPE / PS blends, accelerating particle deformation and breakage, thus improving the mechanical properties of the blend. However, the numerous unsaturated double bonds remaining on the SBS molecular chain are chemically reactive and susceptible to yellowing, aging, and even degradation due to environmental factors such as natural light, ultraviolet radiation, ozone, and high temperatures, significantly limiting the application of PP / PS alloy materials. Studies show that SEBS also has a compatibilizing effect on PS / PE blends, improving the toughness and impact strength of the alloy, but it can negatively impact the mechanical properties (reducing tensile strength and flexural modulus) and processing performance.In 2008, Hu Youliang et al. lithiated ethylene / p-allyltoluene copolymer prepared by coordination polymerization and then initiated styrene anionic polymerization to obtain PE-g-PS graft copolymer, which is a dedicated compatibilizer for PS / PE alloys. This resulted in alloy materials with excellent mechanical properties, impact resistance, and chemical resistance (see patent CN101230119A). However, this compatibilizer has a wide molecular weight distribution, uncontrollable structure, and a complex and cumbersome preparation process, making it unsuitable for industrial application. Xu Wei of Nanjing Institute of Chemical Technology also studied the reactive blending of oxazoline-functionalized polystyrene with maleic anhydride-grafted polyethylene, finding that reactive blending improved the mechanical properties of PS / PE blends. However, the reaction between the functional groups at the polymer chain ends is a diffusion-controlled reaction, requiring high blending temperature and shear mixing efficiency. The grafting efficiency between the aforementioned functionalized polymers is not high. In 1999, Yu Qiang et al. from Jiangsu Institute of Petrochemical Technology studied the reactive extrusion blending of PS / PE. They found that dicumyl peroxide (DCP) induced macromolecular free radical reactions in the PS and PE melts, resulting in the in-situ formation of PS-g-PE graft copolymers at the phase interface of the blend system. While this improved compatibility, it was accompanied by significant side reactions such as crosslinking and degradation, which negatively impacted the material's performance. In 2002, Gao Ying et al. from the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, also used reactive extrusion to study the in-situ compatibilization modification of PS / POE blends under the catalysis of a strong Lewis acid catalyst (anhydrous aluminum trichloride) via the Friedel-Crafts alkylation mechanism. This study indeed improved the phase separation state, mechanical properties, and rheological behavior of the PS / POE blends. However, the crosslinking, degradation, and gelation side reactions accompanying the in-situ grafting reaction severely affected the compatibilization modification effect of the blends. Summary of the Invention

[0009] According to the first aspect of this application, a block copolymer of polystyrene and polyethylene is provided. The aggregated structure of this block copolymer consists of three phases: a polystyrene microphase region, a polyethylene crystalline region, and a branched amorphous region. Therefore, it exhibits extremely high compatibility with both polystyrene and polyolefin materials, effectively reducing interfacial tension between different materials, significantly improving the impact resistance, mechanical properties, and rheological behavior of polystyrene / polyolefin blends, without damaging other properties of the materials, and without side reactions such as crosslinking or degradation. It can serve as a highly efficient compatibilizer for polystyrene / polyolefin blends. In the crystalline block copolymer containing PS blocks, the PS blocks are in a hard plastic state at room temperature, the polyethylene segments are crystalline, and the branched segments containing R1 and R2 are in a viscoelastic state at room temperature. Therefore, it exhibits plastic processing properties at high temperatures and elastomer properties at room temperature, making it a thermoplastic elastomer. Structurally, the R1 and R2 portions are uniformly distributed along the molecular chain, resulting in a more flexible and transparent polymer.

[0010] A block copolymer comprising polystyrene blocks and polyethylene blocks;

[0011] The block copolymer is crystalline;

[0012] The aggregated structure of the block copolymer is a three-phase coexistence of polystyrene microphase region, polyethylene crystalline region, and branched segment amorphous region.

[0013] Optionally, in the block copolymer, the diene block structure comprises ethylene structural units and long side-chain structural units.

[0014] The polystyrene block contains monovinyl aromatic hydrocarbons, mainly including alkyl-substituted styrene such as styrene, α-methylstyrene, p-methylstyrene, and p-ethylstyrene. In this invention, styrene and α-methylstyrene are preferred, and styrene is the most preferred.

[0015] Optionally, the content of the diene block is 40% to 95%.

[0016] Optionally, the content of the diene block is 50% to 85%.

[0017] Optionally, the content of the diene block is 60% to 70%.

[0018] Optionally, the content of the diene block is independently selected from any value of 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any range between both.

[0019] Optionally, the molecular weight of the diene block is 28,500 to 60,000.

[0020] Optionally, the molecular weight of the diene block is 34,000 to 50,000.

[0021] Optionally, the molecular weight of the diene block is 35,000 to 42,000.

[0022] Optionally, the molecular weight of the diene block is independently selected from any value or a range between any two of 28,500, 29,000, 29,500, 30,000, 30,500, 31,000, 31,500, 32,000, 32,500, 33,000, 33,500, 34,000, 34,500, 35,000, 35,500, 36,000, 36,500, 37,000, 37,500, 38,000, 38,500, 39,000, 39,500, 40,000, 40,500, 41,000, 41,500, 42,000, 44,000, 46,000, 48,000, 50,000, 52,000, 54,000, 56,000, 58,000, and 60,000.

[0023] The degree of hydrogenation of the diene block must be higher than 95%.

[0024] The degree of hydrogenation of the diene block is 98%.

[0025] The degree of hydrogenation of the diene block is 99%.

[0026] Optionally, the content of polystyrene blocks in the block copolymer is 5% to 60%.

[0027] Optionally, the content of polystyrene blocks is 15% to 50%.

[0028] Optionally, the content of polystyrene blocks is 30-40%.

[0029] Optionally, the content of the diene block is independently selected from any value of 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or any range between both.

[0030] Optionally, the molecular weight of the polystyrene blocks is 1,500 to 90,000.

[0031] Optionally, the molecular weight of the polystyrene blocks is 6,000 to 50,000.

[0032] Optionally, the molecular weight of the polystyrene blocks is 15,000 to 30,000.

[0033] Optionally, the degree of hydrogenation of the polystyrene block is 0% to 5%.

[0034] Optionally, the degree of hydrogenation of the polystyrene block is 2%.

[0035] Optionally, the degree of hydrogenation of the polystyrene block is independently selected from any value of 0%, 1%, 2%, 3%, 4%, 5%, or a range between any two.

[0036] Optionally, the molecular chain of the block copolymer has one of the structures shown in Formula I, Formula II, and Formula III;

[0037]

[0038] Formula I, Formula II, and Formula III represent a linear diblock polymer, a linear triblock polymer, and a star-shaped polymer, respectively.

[0039] Where k is the number of styrene structural units;

[0040] n is the number of ethylene structural units;

[0041] m and p represent the number of different units in the long side chain structure, respectively;

[0042] y represents the number of arms in the star-shaped polymer structure;

[0043] X represents the structure of the coupling agent residues in the star-shaped polymer;

[0044] R1 can be any of the following structural formulas:

[0045]

[0046] R2 can be any of the following structural formulas:

[0047]

[0048] The long side-chain structural units are obtained by hydrogenation after 1,4-addition polymerization of the second monomer (including β-myrcene and β-farnesene) (the quantity is represented by m), and are introduced by hydrogenation after 1,2-addition polymerization of butadiene or 3,4-addition polymerization of the second monomer (the quantity is represented by p).

[0049] The coupling degree of the star-shaped polymer is 2.2 to 4.0.

[0050] The coupling degree of star-shaped polymers is 2.4–3.0.

[0051] The coupling degree of star-shaped polymers is 2.5 to 2.8.

[0052] The coupling efficiency of star-shaped polymers is 50%–92%.

[0053] The coupling efficiency of star-shaped polymers is 60%–88%.

[0054] The coupling efficiency of star-shaped polymers is 80%–85%.

[0055] Optionally, the value of 0.5n / (m+p) is 63 / 37 to 94 / 6.

[0056] Optionally, the value of 0.5n / (m+p) is 77 / 23 to 91 / 9.

[0057] Optionally, the value of 0.5n / (m+p) is 86 / 14 to 90 / 10.

[0058] Optionally, the total molecular weight of the block copolymer is 30,000 to 150,000.

[0059] Optionally, the total molecular weight of the block copolymer is 40,000 to 100,000.

[0060] Optionally, the total molecular weight of the block copolymer is 50,000 to 70,000.

[0061] Optionally, the polydispersity index (PDI) of the block copolymer is 1.05 to 1.10.

[0062] According to a second aspect of this application, a method for preparing a block copolymer is provided, comprising polymerization and hydrogenation reactions. This preparation method exhibits very high hydrogenation activity, efficiency, and reproducibility; the degree of hydrogenation can be stably reached above 98% within 2 hours. The amount of hydrogenation catalyst used is very low, with titanium content less than 35 ppm and aluminum content less than 40 ppm relative to the polymer. Therefore, residual metals in the polymer product are negligible, eliminating the need for deionization, simplifying the production process, and reducing costs.

[0063] The method for preparing the block copolymer described above includes the following steps:

[0064] S1. A mixture containing styrene, an initiator, and a solvent is polymerized to obtain polystyrene-based lithium active chains.

[0065] S2. Add the mixture containing butadiene and the second monomer to S1, and polymerize II to obtain a diblock polymerized active chain;

[0066] S3. Add the terminator to S2 to obtain a non-crystalline linear diblock polymer;

[0067] Alternatively, adding a coupling agent to S2 yields a non-crystalline star-shaped block polymer;

[0068] Alternatively, styrene can be added to S2 to obtain a non-crystalline linear triblock polymer;

[0069] S4. A mixture containing aromatic esters and a hydrogenation catalyst is added to S3 to react and obtain a crystalline block copolymer.

[0070] Optionally, in step S1, the initiator is sec-butyllithium;

[0071] The solvent is cyclohexane.

[0072] Optionally, in step S1, the concentration of styrene is 0.5% to 9%;

[0073] The molar ratio of the initiator to the styrene is 1 / 15 to 1 / 860.

[0074] Optionally, in step S1, the conditions for aggregation I are as follows:

[0075] The temperature is 50℃~60℃;

[0076] The time is 50 to 60 minutes;

[0077] The pressure is 0.1 MPa to 0.5 MPa;

[0078] The reaction atmosphere is an inert atmosphere;

[0079] The inactive atmosphere is selected from at least one of nitrogen, argon, and neon.

[0080] Optionally, in step S2, the second monomer is selected from β-myrcene and β-farnesene.

[0081] Optionally, the concentration of butadiene is 4% to 14%.

[0082] The molar ratio of butadiene to the second monomer is 79 / 21 to 99.5 / 0.5.

[0083] The molar ratio of butadiene to the second monomer is 91 / 9 to 99 / 1.

[0084] The molar ratio of butadiene to the second monomer is 96 / 4 to 98.5 / 1.5.

[0085] The 1,2-polybutadiene content in butadiene is 5% to 20%.

[0086] The 1,2-polybutadiene content in butadiene is 7% to 15%.

[0087] The 1,2-polybutadiene content in butadiene is 8% to 10%.

[0088] The side group content in the second monomer is 2% to 10%.

[0089] The side group content in the second monomer is 4% to 7%.

[0090] The side group content in the second monomer is 5% to 6%.

[0091] During the polymerization process, the different feed rates of butadiene and the second monomer must be controlled and fed synchronously.

[0092] Optionally, in step S2, the conditions for polymerization II are as follows:

[0093] The temperature is 50℃~60℃;

[0094] The time is 50 to 60 minutes;

[0095] The pressure is 0.1 MPa to 0.5 MPa;

[0096] The reaction atmosphere is an inert atmosphere;

[0097] The inactive atmosphere is selected from at least one of nitrogen, argon, and neon.

[0098] Optionally, in step S3, the terminating agent is selected from one of hydrogen, methanol, water, isooctyl alcohol, isooctanoic acid, 2,6-di-tert-butyl-p-cresol, and 2,4,6-tri-tert-butylphenol;

[0099] The amount of the terminator added is 100% to 150% of the initiator;

[0100] The terminator is selected from one of hydrogen, methanol, and 2,4,6-tri-tert-butylphenol.

[0101] The terminating agent is hydrogen gas.

[0102] Optionally, in step S3, the coupling agent is selected from one of methyltrichlorosilane, silicon tetrachloride, tetramethoxysilane, tetraethoxysilane, tris(2,4-di-tert-butyl)phosphite, divinylbenzene, trimethylolpropane triglycidyl ether, and dimethyl phthalate.

[0103] The amount of the coupling agent added is 0.01% to 1% of the total monomers;

[0104] Total monomer content refers to the total amount of styrene and diene in the system.

[0105] The coupling agent is selected from one of tetramethoxysilane, silicon tetrachloride, tris(2,4-di-tert-butyl)phosphite, and divinylbenzene.

[0106] The coupling agent is tetramethoxysilane.

[0107] Optionally, in step S3, the amount of styrene added is the same as that in S1.

[0108] Optionally, in step S4, the aromatic ester is methyl phthalate and dimethyl phthalate in a 1:1 ratio. mol. / mol. A mixture;

[0109] The amount of the aromatic ester added is 1 ppm to 20 ppm.

[0110] The aromatic ester can be added during the preparation of the hydrogenation catalyst solution, or before or after the start of the hydrogenation reaction.

[0111] The amount of the aromatic ester added is 2 ppm to 12 ppm.

[0112] The amount of the aromatic ester added is 4 ppm to 7.5 ppm.

[0113] Optionally, in step S4, the hydrogenation catalyst is composed of a main catalyst, titanium dichlorodicyclopentadiene, and a co-catalyst, triethylaluminum.

[0114] The amount of hydrogenation catalyst added is 0.1% to 0.001% of the polymer.

[0115] The hydrogenation catalyst was prepared in cyclohexane solvent under an anhydrous and oxygen-free inert atmosphere and at room temperature.

[0116] The hydrogenation catalyst is prepared as follows: the amount of titanium dichlorocerocene added relative to the polymer (based on titanium element) is 25ppm to 50ppm, preferably 30ppm to 40ppm, and most preferably 30ppm to 35ppm; triethylaluminum / titanium dichlorocerocene mol. / mol. The concentration of the catalyst solution is 1 / 1 to 3 / 1, preferably 1.2 / 1 to 2.5 / 1, and most preferably 1.5 / 1 to 2.0 / 1; the concentration of the catalyst solution (calculated as titanium) is 0.01 mol / L to 0.5 mol / L, and the stirring time of the catalyst solution is 5 min to 30 min.

[0117] Optionally, in step S4, the reaction conditions are as follows:

[0118] The temperature is 65℃~75℃;

[0119] The time is 1.5h to 2.5h;

[0120] The pressure is 1.5MPa~2.0MPa.

[0121] The preparation process of crystalline block copolymers containing PS blocks is as follows:

[0122]

[0123]

[0124]

[0125] According to a third aspect of this application, an application of a block copolymer is provided.

[0126] Application of the block copolymers described above or the block copolymers obtained by the preparation methods described above in compatibilizers for polystyrene / polyolefin blends.

[0127] The beneficial effects that this application can produce include:

[0128] 1) The block copolymer provided in this application has extremely high compatibility with both polystyrene and polyolefin materials, can effectively reduce the interfacial tension between different materials, significantly improve the impact resistance, mechanical properties and rheological behavior of polystyrene / polyolefin blends, and does not damage other properties of the materials, and does not have side reactions such as crosslinking or degradation; the block copolymer has plastic processing properties at high temperature and elastomer properties at room temperature, and is a thermoplastic elastomer; the block copolymer is more flexible and has better transparency.

[0129] 2) The present application provides a method for preparing a block copolymer, which has very high hydrogenation activity, efficiency and reproducibility, and the degree of hydrogenation can be stably reached above 98% within 2 hours; the preparation method does not require deionization, simplifies the production process and reduces costs. Attached Figure Description

[0130] Figure 1 The above is the 1H NMR spectrum of HSD-1 prepared in Example 1 of this application.

[0131] Figure 2 The DSC cooling curve of HSD-1 prepared in Example 1 of this application.

[0132] Figure 3 The WAXD diffraction pattern of HSD-1 prepared in Example 1 of this application.

[0133] Figure 4 The image shows the HNMR spectrum of the SDS prepared in Example 5 of this application.

[0134] Figure 5 The GPC curve of the SDX prepared in Example 6 of this application is shown. Detailed Implementation

[0135] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0136] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.

[0137] The analysis method in the embodiments of this application is as follows:

[0138] Nuclear magnetic resonance (NMR) analysis was performed using a BRUKER AV-600 model, 600MHz, proton NMR spectrometer.

[0139] Differential scanning calorimetry (DSC) analysis was performed using the STARe system of the Swiss company METTLER-TOLEDO.

[0140] Comparative analysis of blends was conducted using the POE8480 from DOW Corporation, USA.

[0141] Diffraction analysis was performed using ultimaIV.

[0142] GPC analysis was performed using a Waters 515-2410 model.

[0143] Preparation of hydrogenation catalyst solution

[0144] A clean 500ml three-necked glass flask was placed in a glove box. The air in the glove box was then replaced with high-purity nitrogen to maintain an inert atmosphere. 1.5g of titanium dichlorodecene was added to the flask, followed by 21ml of a 0.5M triethylaluminum cyclohexane solution injected into the flask using a glass syringe. The flask was then heated and stirred at 30°C for 10 minutes in an electric heating mantle equipped with a magnetic stirrer. The red titanium dichlorodecene crystals completely dissolved, forming a sky-blue homogeneous solution. Finally, 280ml of cyclohexane was added to dilute the solution, resulting in a 0.02M titanium hydrogenation catalyst solution.

[0145] Example 1

[0146] Preparation of SD-1

[0147] The polymerization reaction was carried out in a 10-liter polymerization reactor equipped with a stirrer, electric heating, and 10°C circulating water temperature control. Before polymerization, the reactor was ensured to be anhydrous and oxygen-free. Then, 5 liters of cyclohexane solvent and 159 grams of styrene monomer (monomer concentration controlled at 12%) were added. Simultaneously, stirring was started to ensure uniform mixing, and the temperature was preheated. Once the temperature reached 50°C, 7.9 mmol of sec-butyllithium was added to initiate polymerization. After reacting for 60 minutes, 344 grams of butadiene and 27 grams of myrcene were added, and the reaction continued for another 60 minutes. Then, the mixture was transferred to a hydrogenation reactor, and hydrogen gas was introduced to terminate the polymerization. A small amount of the polymer solution was then taken and anhydrous ethanol was added to precipitate the polymer; this sample was designated SD-1. After drying in a vacuum oven at 60℃ for 1 hour, the molecular weight of the polymer was analyzed by gel permeation chromatography (GPC) using a Waters 515-2410 instrument. The analytical conditions were as follows: mobile phase: THF; test temperature: 30℃; injection volume: 50 μL; test flow rate: 1 mL / min; test concentration: 2–2.5 mg / mL; standard sample: polystyrene. The molecular weight information of the polymer is shown in Table 2. In addition, a Bruner AV-600 600 MHz 1H NMR spectrometer was used to analyze the microstructure of the polymer using deuterated chloroform as the test solvent. The microstructure data of the polymer are shown in Table 2.

[0148] Preparation of HSD-1

[0149] After the hydrogenation of the base adhesive was terminated, the temperature of the hydrogenation reactor was raised to 70°C. 51.3 mL of an aromatic ester mixture (1 / 1:1 ratio of methyl phthalate to dimethyl phthalate) was added. mol. / mol. The mixture (diluted with cyclohexane to a 0.5 g / L solution before use) was then added to 18.6 mL of the above catalyst solution. Hydrogen gas was immediately introduced to maintain the pressure at 1.8 MPa, and the reaction was continuously stirred for 2 h. A small amount of the hydrogenated gel was taken and the polymer was precipitated with anhydrous ethanol, then filtered and vacuum dried for 24 h. The sample was designated HSD-1. Approximately 60 mg of the hydrogenated sample was weighed, placed in an iodine flask, and 25 mL of n-heptane was added. The mixture was heated to 80 °C until completely dissolved, then 10 mL of iodine chloride solution (C = 0.1 mol / L) was added. The solution was sealed with KI solution and stored in the dark for 1 hour. 80 mL of deionized water and 15 mL of potassium iodide solution (C = 20%) were added, and the mixture was shaken well. Titration with 0.1 mol / L Na₂S₂O₃ standard solution was performed until a pale yellow color was reached. Starch indicator was then added, and titration continued until the solution turned deep blue and the blue color disappeared. The volume V of Na₂S₂O₃ consumed was recorded at this point. Simultaneously perform a blank test and record the volume V0 of Na2S2O3 consumed. The iodine value is calculated using the following formula: A = (V0 - V) × C × 126.9 × 100 ÷ (W × 1000), where A represents the iodine value; V0 represents the volume (ml) of Na2S2O3 standard solution consumed in the blank test; V represents the volume (ml) of Na2S2O3 standard solution consumed in the titration of the hydrogenated sample; C is the concentration (mol / L) of the Na2S2O3 standard solution; and W is the mass (g) of the hydrogenated sample. The theoretical iodine value is calculated using the following formula:

[0150] X represents the mass fraction of butadiene in the hydrogenated sample; Y represents the mass fraction of myrcene in the hydrogenated sample. The formula for calculating the degree of hydrogenation is as follows: The iodine value and degree of hydrogenation of HSD-1 are shown in Table 3, and the 1H NMR spectrum is shown in [Table 3]. Figure 1 This invention also employed differential scanning calorimetry (DSC) to analyze the crystallization properties of the hydrogenation product HSD-1. The test conditions were: temperature change rate 10 K / min; inert atmosphere; temperature range -60℃ to 120℃; holding time 5 min. The crystallization peak temperatures are listed in Table 3, and the cooling curves are shown in [Figure number missing]. Figure 2 The melt index test conditions were: 230℃; 2.16 kg. Melt index and mechanical property data are shown in Table 3. This invention also performed wide-angle X-ray diffraction (WAXD) analysis on HSD-1 within the diffraction angle range of 5°-60°, as shown in Table 3. Figure 3 .

[0151] Example 2

[0152] Preparation of SD-2

[0153] The polymerization process was largely the same as in Example 1, except that the amounts of styrene, butadiene, and myrcene were changed to 212 g, 295 g, and 23 g, respectively. The molecular weight and microstructure data of SD-2 are shown in Table 2.

[0154] Preparation of HSD-2

[0155] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-2, and the analytical data are listed in Table 3.

[0156] Example 3

[0157] Preparation of SD-3

[0158] The polymerization process was largely the same as in Example 1, except that the amounts of butadiene and myrcene were changed to 356.4 g and 14.6 g, respectively. The molecular weight and microstructure data of SD-3 are shown in Table 2.

[0159] Preparation of HSD-3

[0160] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-2, and the analytical data are listed in Table 3.

[0161] Example 4

[0162] Preparation of SD-4

[0163] The polymerization process was largely the same as in Example 1, except that the amount of sec-butyllithium was changed to 10.6 mmol. The molecular weight and microstructure data of SD-4 are shown in Table 2.

[0164] Preparation of HSD-4

[0165] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-4, and the analytical data are listed in Table 3.

[0166] Example 5

[0167] Preparation of SDS

[0168] The polymerization reaction was carried out in a 10-liter polymerization reactor equipped with a stirrer, electric heating, and 10°C circulating water temperature control. Before polymerization, the reactor was ensured to be anhydrous and oxygen-free. Then, 5 liters of cyclohexane solvent and 79.5 g of styrene monomer were added, with the monomer concentration controlled at approximately 12%. Simultaneously, stirring was started to ensure uniform mixing, and the temperature was preheated. Once the temperature reached 50°C, 7.9 mmol of sec-butyllithium was added to initiate polymerization. After reacting for 60 min, 344 g of butadiene and 27 g of myrcene were added, and the reaction continued for another 60 min. Then, 79.5 g of styrene was added again, and the reaction continued for another 60 min. Finally, the polymerization was terminated by introducing hydrogen gas into a hydrogenation reactor. The molecular weight information and microstructure data of the SDS are shown in Table 2.

[0169] Preparation of HSDS

[0170] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt index test conditions were all performed according to Example 1. Sample numbers were assigned as HSDS, and the analytical data are listed in Table 3.

[0171] Example 6

[0172] SDX preparation

[0173] The polymerization reaction was carried out in a 10-liter polymerization reactor equipped with a stirrer, electric heating, and 10°C circulating water temperature control. Before polymerization, the reactor was ensured to be anhydrous and oxygen-free. Then, 5 liters of cyclohexane solvent and 159 grams of styrene monomer were added, with the monomer concentration controlled at approximately 12%. Simultaneously, stirring was started to ensure uniform mixing, and the temperature was preheated. Once the temperature reached 50°C, 21.5 mmol of sec-butyllithium was added to initiate polymerization. After reacting for 60 minutes, 344 grams of butadiene and 27 grams of myrcene were added, and the reaction continued for another 60 minutes. Then, 6.52 mmol of tetramethoxysilane was added, and the reaction continued for another 30 minutes. Finally, the polymerization was terminated by introducing hydrogen gas into a hydrogenation reactor. The molecular weight information and microstructure data of SDX are shown in Table 2 and [Table data would be inserted here]. Figure 5 .

[0174] Preparation of HSDX

[0175] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt index test conditions were all performed according to Example 1. The sample number was HSDX, and the analytical data are listed in Table 3.

[0176] Example 7

[0177] Preparation of SD-5

[0178] The polymerization process was largely the same as in Example 1, except that myrcene was replaced with farnesene, and the amounts of butadiene and farnesene were 332 g and 39 g, respectively. The molecular weight and microstructure data of SD-5 are shown in Table 2.

[0179] Preparation of HSD-5

[0180] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-5, and the analytical data are listed in Table 3.

[0181] Comparative Example 1

[0182] Preparation of SD-6

[0183] The polymerization process was roughly the same as in Example 2, except that the amounts of butadiene and myrcene were changed to 235.6 g and 82.4 g, respectively. The molecular weight and microstructure data of SD-6 are shown in Table 2.

[0184] Preparation of HSD-6

[0185] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-6, and the analytical data are listed in Table 3.

[0186] Comparative Example 2

[0187] Preparation of SD-7

[0188] The polymerization process was largely the same as in Example 1, except that the amounts of styrene, butadiene, and myrcene were changed to 79.5 g, 418 g, and 32.5 g, respectively. The molecular weight and microstructure data of SD-7 are shown in Table 2.

[0189] Preparation of HSD-7

[0190] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-7, and the analytical data are listed in Table 3.

[0191] Comparative Example 3

[0192] Preparation of SD-8

[0193] The polymerization process was largely the same as in Example 1, except that the amounts of styrene, butadiene, and myrcene were changed to 265 g, 245.8 g, and 19.2 g, respectively. The molecular weight and microstructure data of SD-8 are shown in Table 2.

[0194] Preparation of HSD-8

[0195] The hydrogenation process, iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-8, and the analytical data are listed in Table 3.

[0196] Comparative Example 4

[0197] Preparation of SD-9

[0198] The polymerization process was roughly the same as in Example 1. The molecular weight and microstructure data of SD-9 are shown in Table 2.

[0199] Preparation of HSD-9

[0200] The hydrogenation process was largely the same as in Example 1, but without the addition of aromatic esters. Iodine value analysis, DSC analysis, mechanical testing, and melt index testing conditions were all performed according to Example 1. The sample number was HSD-9, and the analytical data are listed in Table 3.

[0201] Comparative Example 5

[0202] Preparation of SD-10

[0203] The polymerization process was roughly the same as in Example 1. The molecular weight and microstructure data of SD-10 are shown in Table 2.

[0204] Preparation of HSD-10

[0205] The hydrogenation process was largely the same as in Example 1, but without the addition of triethylaluminum. Iodine value analysis, DSC analysis, mechanical testing, and melt indexing experimental conditions were all performed according to Example 1. The sample number was HSD-10, and the analytical data are listed in Table 3.

[0206] Blending Experiment 1

[0207] Weigh 200g of general-purpose polystyrene (GPPS) granules (weight average molecular weight 127,000, number average molecular weight 58,000, polydispersity index (PDI) 2.20) and 300g of POE8480 granules from Dow Chemical Company (melt index 1.9 at 230℃ and 2.16kg). Mechanically stir for 20 minutes to achieve a coarse mixture. Vacuum dry at 80℃ for 4 hours, then melt extrude and granulate using a co-rotating twin-screw extruder. The extruder barrel temperature was set to 190-210℃, the material residence time in the barrel was 5-10 minutes, and the screw speed was set to 80-120 rpm. The tensile properties of the uncompressed PS / POE blend can be tested according to Example 1; mechanical property data are shown in Table 4.

[0208] Blending Experiment 2

[0209] The blending process can be roughly referred to as blending experiment 1. Only 5 grams of HSD-1 were added as a compatibilizer during the blending process to prepare HSD-1 compatibilized PS / POE blends. The tensile properties test can be referred to Example 1. The mechanical property data are shown in Table 4.

[0210] Blending Experiment 3

[0211] The blending process can be roughly referred to as blending experiment 1, except that 5 grams of HSD-2 is added as a compatibilizer during the blending process to prepare HSD-2 compatibilized PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0212] Blending Experiment 4

[0213] The blending process can be roughly referred to as blending experiment 1, except that 5 grams of HSD-3 is added as a compatibilizer during the blending process to prepare HSD-3 compatibilized PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0214] Blending Experiment 5

[0215] The blending process can be roughly referred to as blending experiment 1, except that 5 grams of HSD-4 is added as a compatibilizer during the blending process to prepare HSD-4 compatibilized PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0216] Blending Experiment 6

[0217] The blending process can be roughly referred to as blending experiment 1, except that 5 grams of HSDS is added as a compatibilizer during the blending process to prepare HSDS compatibilized PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0218] Blending Experiment 7

[0219] The blending process can be roughly referred to as blending experiment 1, except that 5 grams of HSDX is added as a compatibilizer during the blending process to prepare HSDX-compensated PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0220] Blending Experiment 8

[0221] The blending process can be roughly referred to as blending experiment 1, except that 5 grams of HSD-7 is added as a compatibilizer during the blending process to prepare HSD-7 compatibilized PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0222] Blending Experiment 9

[0223] The blending process can be roughly referred to as blending experiment 1, except that 25 grams of HSD-1 is added as a compatibilizer during the blending process to prepare HSD-1 compatibilized PS / POE blends. The tensile properties test can be referred to Example 1, and the mechanical property data are shown in Table 4.

[0224] Table 2 Structural Design of Base Adhesive

[0225]

[0226]

[0227] Note: The second monomer content refers to the mole fraction of the second monomer structural unit in all diene monomers;

[0228] 3,4-Second monomer % refers to the mole fraction of 3,4-addition structural units in the second monomer;

[0229] The second monomer of SD-5 is farnesene, and the other polymers are all myrcene;

[0230] 1,2-PB% refers to the mole fraction of 1,2-PB structural units in butadiene;

[0231] Table 3 Thermal and mechanical properties of hydrogenated gums

[0232]

[0233] Table 4 Properties of Blends

[0234]

[0235] Note: >100 indicates that the material's hardness is too high, exceeding the range of the Shore A hardness tester;

[0236] The chemical shift of 4.70–4.90 ppm is known to represent the characteristic absorption peaks of the two unsaturated protons of 3,4-polymyrcene, corresponding to… Figure 4 The 11th hydrogen atom; chemical shifts of 5.10-5.20 ppm represent an unsaturated proton peak in the 1,4-polymyrcene backbone and an unsaturated proton peak on the double bond of the 1,4 / 3,4-polymyrcene side chain, corresponding to hydrogens 2, 2', 6, 6', and 14; chemical shifts of 4.90-5.10 ppm represent a methylene characteristic peak in the vinyl side chain of 1,2-polybutadiene, corresponding to hydrogen 21; chemical shifts of 5.30-5.70 ppm represent a methine characteristic peak in the vinyl side chain of 1,2-polybutadiene and two proton peaks on the double bond of the 1,4-polybutadiene backbone, corresponding to hydrogens 17, 18, and 21. (Observation) Figure 1 The discovery that the unsaturated peak of HSD-1 almost completely disappeared in the 4-6 ppm region indicates that the degree of hydrogenation of the polymer of the present invention is very high, and that semi-crystalline blocks with high crystallinity and microstructure highly similar to POE are formed in the molecular chain.

[0237] observe Figure 3 Four different crystal structures with varying interplanar spacings were found in HSD-1 at 2θ = 21.4°, 23.5°, 36.1°, and 19.8°. These structures exhibited similar WAXD diffraction patterns to POE with approximately 5% octene content, indicating that the crystallization behavior of HSD-1 is identical to that of POE. Figure 2Table 3 shows that the crystallization temperature of HSD-1 is very close to that of POE, proving that the PS-POE semi-crystalline block copolymer of the present invention has a very close crystallization temperature and crystallization behavior to POE.

[0238] Observation of Table 3 reveals that, except for HSD-6 and HSD-8, the strength, hardness, and 100% tensile strength of the PS-containing crystalline block copolymers of the present invention are very close to those of POE, but their elongation at break and crystallization peak temperature are slightly lower than those of POE. However, their overall mechanical and thermal properties are very close to those of POE, indicating that the polymers of the present invention are suitable as compatibilizers for polystyrene / polyolefin blends without impairing the inherent properties of the materials. Excessive content of the second monomer or styrene will impair the strength or 100% tensile strength of the material itself. Compared to linear diblock copolymers, HSDS and HSDX exhibit the best mechanical properties, being closest to POE. The hydrogenation degrees of HSD-9 and HSD-10 are both below 96%. These hydrogenation experiment results demonstrate that aromatic ester mixtures and triethylaluminum can significantly improve the efficiency of titanium-based hydrogenation (hydrogenation degree greater than 98% in 2 hours) and significantly reduce the catalyst dosage.

[0239] Observation of Table 4 reveals that blending experiment 1, a direct blend of PS / POE, exhibits the lowest strength, hardness, and 100% tensile strength. Blending experiments 2, 3, 4, 5, 8, and 9 all added 1% of a linear diblock copolymer, resulting in significant improvements in hardness, strength, and 100% tensile strength compared to blending experiment 1. However, the linear diblock copolymer in blending experiment 8, with a styrene content below 30%, showed slightly less improvement. Blending experiment 9, with a styrene content of 30% in the linear diblock copolymer, showed the best results. When the addition was increased to 5%, the strength and 100% tensile strength were further improved compared to blending experiment 1, but the elongation at break in the above blending experiments was significantly lower than that in blending experiment 1. In blending experiments 6 and 7, 1% of linear triblock copolymer and star polymer were added as solubilizers for the blending system, respectively. The 100% tensile strength, tensile strength, hardness and elongation at break were significantly improved compared to blending experiment 1. The compatibilization modification effect was the most obvious and significantly better than that of linear diblock copolymer.

[0240] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A block copolymer, characterized in that, The block copolymer includes polystyrene blocks and polyethylene blocks; The block copolymer is crystalline; The aggregated structure of the block copolymer is a coexistence of three phases: polystyrene microphase region, polyethylene crystalline region, and branched segment amorphous region. The molecular chain of the block copolymer has one of the structures shown in Formula I, Formula II, and Formula III; Formula I Formula II Formula III Formula I, Formula II, and Formula III represent a linear diblock polymer, a linear triblock polymer, and a star-shaped polymer, respectively. Where k is the number of styrene structural units; n is the number of ethylene structural units; m and p represent the number of different units in the long side chain structure, respectively; y represents the number of arms in the star-shaped polymer structure; X represents the structure of the coupling agent residues in the star-shaped polymer; R1 can be any of the following structural formulas: ； R2 can be any of the following structural formulas: And it satisfies the ratio 0.5n / (m+p) = 86 / 14~90 / 10; The second monomer is selected from β-myrcene and β-farnesene; The degree of hydrogenation of the diene block is higher than 95%; In the block copolymer, the diene block structure includes ethylene structural units and long side chain structural units; The content of polystyrene blocks in the block copolymer is 5% to 60%. The molecular weight of polystyrene blocks ranges from 1,500 to 90,000. The degree of hydrogenation of polystyrene blocks is 0% to 5%.

2. The block copolymer according to claim 1, characterized in that, The total molecular weight of the block copolymer is 30,000 to 150,000; The polydispersity index (PDI) of the block copolymer is 1.05 to 1.

10.

3. The method for preparing the block copolymer according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1. A mixture containing styrene, an initiator, and a solvent is polymerized to obtain polystyrene-based lithium active chains. S2. Add the mixture containing butadiene and the second monomer to S1, and polymerize II to obtain a diblock polymerized active chain; S3. Add the terminator to S2 to obtain a non-crystalline linear diblock polymer; Alternatively, adding a coupling agent to S2 yields a non-crystalline star-shaped block polymer; Alternatively, styrene can be added to S2 to obtain a non-crystalline linear triblock polymer; S4. A mixture containing aromatic esters and a hydrogenation catalyst is added to S3, and the reaction yields a crystalline block copolymer. In step S2, the second monomer is selected from β-myrcene and β-farnesene.

4. The preparation method according to claim 3, characterized in that, In step S1, the initiator is sec-butyllithium; The solvent is cyclohexane.

5. The preparation method according to claim 3, characterized in that, In step S1, the concentration of styrene is 0.5% to 9%; The molar ratio of the initiator to the styrene is 1 / 15 to 1 / 860.

6. The preparation method according to claim 3, characterized in that, In step S1, the conditions for polymerization I are as follows: The temperature is 50℃ ~ 60℃; The time is 50 min ~ 60 min; The pressure is 0.1 MPa ~ 0.5 MPa; The reaction atmosphere is an inert atmosphere; The inactive atmosphere is selected from at least one of nitrogen, argon, and neon.

7. The preparation method according to claim 3, characterized in that, In step S2, the concentration of butadiene is 4% to 14%.

8. The preparation method according to claim 3, characterized in that, In step S2, the conditions for polymerization II are as follows: The temperature is 50℃ ~ 60℃; The time is 50 min ~ 60 min; The pressure is 0.1 MPa ~ 0.5 MPa; The reaction atmosphere is an inert atmosphere; The inactive atmosphere is selected from at least one of nitrogen, argon, and neon.

9. The preparation method according to claim 3, characterized in that, In step S3, the terminating agent is selected from one of hydrogen, methanol, water, isooctyl alcohol, isooctanoic acid, 2,6-di-tert-butyl-p-cresol, and 2,4,6-tri-tert-butylphenol. The amount of the terminator added is 100% to 150% of the initiator.

10. The preparation method according to claim 3, characterized in that, In step S3, the coupling agent is selected from one of methyltrichlorosilane, silicon tetrachloride, tetramethoxysilane, tetraethoxysilane, tris(2,4-di-tert-butyl)phosphite, divinylbenzene, trimethylolpropane triglycidyl ether, and dimethyl phthalate. The amount of the coupling agent added is 0.01% to 1% of the total monomer.

11. The preparation method according to claim 3, characterized in that, In step S3, the amount of styrene added is the same as that in S1.

12. The preparation method according to claim 3, characterized in that, In step S4, the aromatic ester is methyl phthalate and dimethyl phthalate in a 1:1 ratio. mol. / mol. A mixture; The amount of the aromatic ester added is 1 ppm to 20 ppm.

13. The preparation method according to claim 3, characterized in that, In step S4, the hydrogenation catalyst is composed of the main catalyst, titanium dichlorodicyclopentadiene, and the co-catalyst, triethylaluminum. The amount of hydrogenation catalyst added is 0.1% to 0.001% of the polymer.

14. The preparation method according to claim 3, characterized in that, In step S4, the reaction conditions are as follows: The temperature is 65℃ ~ 75℃; The time is 1.5 h to 2.5 h; The pressure is 1.5 MPa ~ 2.0 MPa.

15. The use of the block copolymer according to any one of claims 1 to 2 or the block copolymer obtained by the preparation method according to any one of claims 3 to 14 in the compatibilizer of polystyrene / polyolefin blends.

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