A bio-based thermoplastic elastomer and its preparation and modification methods based on RAFT polymerization.

Abstract

This invention discloses a bio-based thermoplastic elastomer and its preparation method. The preparation method is as follows: a macromolecular RAFT reagent is dissolved in water and added to a reaction flask, followed by the addition of a first-stage monomer, styrene, and a water-soluble initiator A. The mixture is stirred and kept at a constant temperature for 1-2 hours, then an aqueous sodium hydroxide solution is added, and the reaction continues for 5-10 hours. Next, a second-stage monomer, myrcene or a blend of myrcene and acrylate monomers, and a water-soluble initiator B are added, and the reaction continues for 10-20 hours. Then, a third-stage monomer, styrene, and a water-soluble initiator C are added, and the reaction continues for 5-10 hours to obtain a stable emulsion. The emulsion is then demulsified and flocculated in an aqueous CaCl2 solution to form raw rubber. The raw rubber is washed and vacuum dried to obtain the bio-based thermoplastic elastomer. The bio-based thermoplastic elastomer has a highly controllable molecular structure, a narrow molecular weight distribution, a wide range of applications, and good mechanical properties and self-healing properties.

Description

Technical Field

[0001] This invention relates to thermoplastic elastomer materials, and more particularly to a bio-based thermoplastic elastomer and its preparation and modification methods based on RAFT (Reversible Addition-Fragmentation Chain Transfer Polymerization) polymerization. Background Technology

[0002] ABA-type triblock thermoplastic elastomers (TPEs) are a type of thermoplastic elastomer that exhibits the high elasticity of vulcanized rubber at room temperature while possessing the easy processing properties of thermoplastics at high temperatures. They are polymer materials that combine the performance characteristics of vulcanized rubber with the processing characteristics of thermoplastics. SBS is a representative of this type of elastomer, in which styrene hard segments form physical crosslinking points and are dispersed as a dispersed phase within a soft rubber matrix. By adjusting the proportion of hard segments along the entire molecular chain, different microphase separation structures can be formed, thus regulating the mechanical properties of the thermoplastic elastomer to varying degrees. Because vulcanization is not required and molding is simple, the industrial production process for TPEs is shortened by 1 / 4 compared to traditional vulcanized rubber, saving 25-40% of energy and increasing efficiency by 10-20 times. Furthermore, TPEs can be processed and recycled multiple times, saving petroleum resources needed for synthesizing polymer materials and reducing environmental pollution. The styrene and butadiene used in the synthesis of SBS are derived from petrochemical resources, making the raw material supply unsustainable, and the preparation process generates carbon emissions.

[0003] Myrcene is a commonly used bio-based monomer, belonging to the terpene family. Found in plants, myrcene is widely used in the fragrance and pharmaceutical industries due to its strong odor and bioactivity, and is also used as a food additive and agricultural pesticide. Myrcene's structure is similar to butadiene and isoprene, all possessing two conjugated double bonds, but the difference lies in the fact that myrcene has an additional non-conjugated double bond in its side chain. Therefore, myrcene can serve as a substitute for the petrochemical-based chemicals butadiene and isoprene, and is also a green raw material for the preparation of bio-based polymers.

[0004] The typical synthesis method for SBS involves a three-step feeding process using butyllithium as the initiator, cyclohexane as the solvent, and a small amount of tetrahydrofuran as the activator, sequentially adding styrene, butadiene, and styrene monomers—a typical anionic polymerization process. Anionic polymerization requires relatively harsh reaction conditions and large amounts of organic solvents. Free radical polymerization, on the other hand, has a wide range of monomer applications, suitable for solution polymerization, emulsion polymerization, suspension polymerization, and other polymerization methods. Conventional free radical polymerization struggles to control the sequence structure. With the development of living radical polymerization, methods such as nitrile radical polymerization (NMP), atom transfer radical polymerization (ATRP), and chain fracture transfer radical polymerization (RAFT) have been developed. RAFT polymerization offers a wider range of monomers, particularly suitable for polar monomer polymerization; and its reaction conditions are mild, allowing for use in both solution and emulsion systems. RAFT emulsion polymerization combines the controllable activity of RAFT polymerization with the high polymerization rate and high molecular weight of emulsion polymerization, making it highly advantageous in the synthesis of block copolymers.

[0005] Nikolaos et al. successfully synthesized block copolymers with up to 21 blocks using methacrylate monomers with relatively low chain growth rate constants (kp) via RAFT emulsion polymerization, with each block requiring only 2 hours of reaction time. However, the degree of polymerization of each block was relatively low, only 10, making it difficult to achieve microphase separation (Engelis NG, Anastasaki A, Nurumbetov G, et al. Sequence-controlled methacrylic multiblock copolymers via sulfur-free RAFT emulsion polymerization[J]. Nature chemistry, 2017, 9(2): 171-178). Although the prepared polymers had up to 21 blocks, due to the low degree of polymerization of each block, it was difficult for the same type of chain segments to aggregate and form microphase separation under the same thermodynamic conditions, resulting in no significant modification to the thermodynamic and mechanical properties.

[0006] Thermoplastic elastomers (TPEs) are widely used in daily necessities, medical applications, and other engineering fields. Compared to traditional reinforced vulcanized rubber, TPEs like SBS have lower modulus or tensile strength and poorer resilience. During use, they inevitably experience various types of damage and aging, with performance deterioration and a shortened service life due to internal microcracks and localized damage. Therefore, improving the modulus and repairability of TPEs is of great significance. Self-healing generally falls into two categories: extrinsic and intrinsic. Most extrinsic self-healing materials cannot achieve multiple self-repair cycles. Intrinsic self-healing materials utilize their inherent chemical structure properties, relying on reversible covalent bonds and non-covalent chemical reactions such as hydrogen bonds and ionic bonds to self-repair. However, self-healing achieved through low-bond-energy dynamic covalent bonds (Diels-Alder reactions, transesterification, olefin metathesis, disulfide exchange, imine exchange, etc.) or some non-covalent bonds (such as hydrogen bonds, metal-ligand coordination, ionic interactions, and π–π stacking) results in materials with lower overall strength. However, the properties of self-healing materials offer vast potential for development. Therefore, there is an urgent need to develop thermoplastic elastomer materials with good mechanical properties and self-healing capabilities. Summary of the Invention

[0007] Therefore, this invention proposes a bio-based thermoplastic elastomer with a simple preparation process, controllable product preparation, good mechanical properties, and self-healing ability, as well as its preparation and modification methods based on RAFT polymerization.

[0008] Unlike existing technologies, the above technical solution provides a bio-based thermoplastic elastomer with the molecular formula shown in Formula I.

[0009]

[0010] In Formula I, a and d are the number of styrene repeating units St in the first segment and the third segment, respectively, where a is an integer from 200 to 800 and d is an integer from 200 to 800. The molecular weight range of the first and third hard segment polystyrene repeating units is 20800 to 83200. The second repeating unit is myrcene homopolymer or myrcene-acrylate copolymer, where the number of myrcene repeating units My is c and the number of acrylate repeating units EA is m, where c is an integer from 200 to 800 and m is 0 or an integer from 200 to 800. The molecular weight range of the soft segment myrcene repeating unit is 27200 to 108000, and the molecular weight range of the acrylate repeating unit is 25600 to 102400.

[0011] The bio-based thermoplastic elastomer of this invention is a triblock bio-based thermoplastic elastomer with myrcene (or myrcene and acrylate) as the main raw materials. The hard segment of this elastomer is a styrene segment, and the soft segment is a myrcene segment or a copolymer of myrcene and acrylate. The addition of acrylate can effectively increase polymerization efficiency and control the glass transition temperature of the polymer.

[0012] Furthermore, this invention copolymerizes soft segment myrcene with acrylate, and the introduction of acrylate can adjust the modulus of the thermoplastic elastomer. The acrylate can generate carboxyl groups through hydrolysis, which can regulate the hydrophilicity and lipophilicity, and glass transition temperature of the triblock polymer. The hydrogen bond interactions generated by a large number of carboxyl groups can play a role in regulating the mechanical properties of the thermoplastic elastomer.

[0013] Simultaneously, in the presence of carboxyl groups, metal salts or metal oxides can be added to react with the bio-based thermoplastic elastomer of this invention. Introducing ionic bonds or ionic clusters to form new dynamic "physical cross-linking points" enhances and toughens the thermoplastic elastomer. Furthermore, the dynamic hydrogen bonds and ionic bonds reversibly form or disappear with increasing or decreasing temperature, exhibiting self-healing properties at room temperature or high temperature, thus giving the thermoplastic elastomer of this invention self-healing capabilities.

[0014] The present invention also provides a method for preparing the bio-based thermoplastic elastomer based on RAFT polymerization, which includes the following steps:

[0015] Step 1: Dissolve the macromolecular RAFT reagent in water and add it to the reaction flask. Then add the first-stage monomer styrene. Stir and pre-emulsify for 30-60 min at room temperature and under a nitrogen atmosphere. Then heat to 70-80℃ and continue stirring and emulsifying for 30-60 min. Add water-soluble initiator A and keep warm and stir for 1-2 h. Then add sodium hydroxide aqueous solution and continue the reaction for 5-10 h.

[0016] Step 2: Next, add the second monomer myrcene or a blend of myrcene and acrylate monomers to the reaction flask, keep warm and stir for 1-2 hours, then add water-soluble initiator B, and continue the reaction for 10-20 hours to obtain a stable emulsion.

[0017] Step 3: Add the third monomer styrene to the reaction flask, keep warm and stir for 1-2 hours, then add water-soluble initiator C and continue the reaction for 5-10 hours to obtain a stable emulsion; demulsify and flocculate the emulsion obtained in step 3 in a 0.5-2% CaCl2 aqueous solution to form raw gum, wash and vacuum dry the raw gum to obtain the bio-based thermoplastic elastomer;

[0018] The weight proportions of each component added are as follows:

[0019]

[0020] This invention synthesizes triblock bio-based thermoplastic elastomers using a reversible addition-fragmentation chain transfer polymerization (RAFT) emulsion polymerization method. The invention employs an amphiphilic RAFT reagent that functions as both an emulsifier and a chain transfer agent. RAFT polymerization is a living radical polymerization, with a controllable process; molecular weight and chain sequence can be controlled through stepwise addition. This invention uses emulsion polymerization, overcoming the slow polymerization rate problem of conventional living polymerization and significantly accelerating polymerization efficiency. The addition of alkali during polymerization ensures the stability of the emulsion polymerization system. Simultaneously, this invention utilizes a specific structured amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent as both an emulsifier and a chain transfer agent, and the addition of alkali improves emulsion stability. This polymerization process is simple, energy-efficient, has a short reaction time, high conversion rate, eliminates the need for traditional emulsifiers, and achieves molecular weights that meet design values ​​with a molecular weight distribution <2.0, demonstrating excellent industrialization prospects.

[0021] The macromolecular RAFT reagent used is the same as that used in Example 2 of Chinese Invention Patent No. CN 102585123 A, entitled "Poly((meth)acrylic acid-b-styrene-b-butadiene-b-styrene) block copolymer latex and its preparation method".

[0022] This invention copolymerizes soft segment myrcene with acrylate, and the introduction of acrylate can adjust the modulus of the thermoplastic elastomer. The polyacrylate unit can be hydrolyzed to generate carboxyl groups, which regulate the hydrophilicity and lipophilicity, and glass transition temperature of the triblock polymer. The hydrogen bonding interactions generated by the numerous carboxyl groups can also regulate the mechanical properties of the thermoplastic elastomer.

[0023] Furthermore, the acrylate monomers include one of the following: tert-butyl acrylate, n-butyl acrylate, ethyl acrylate, ethyl methacrylate, methyl methacrylate, isopropyl methacrylate, and isobutyl methacrylate.

[0024] Furthermore, the water-soluble initiator A, water-soluble initiator B, and water-soluble initiator C are each one of the following: ammonium persulfate aqueous solution, potassium persulfate aqueous solution, hydrogen peroxide aqueous solution, and an aqueous solution of a hydrogen peroxide derivative. The water-soluble initiator A, water-soluble initiator B, and water-soluble initiator C added during the primary polymerization of bio-based thermoplastic elastomers can be the same compound or different compounds.

[0025] This invention also provides a method for modifying the bio-based thermoplastic elastomer, comprising the following steps:

[0026] The bio-based thermoplastic elastomer prepared above is added to an alkaline solution, wherein the mass of the added bio-based thermoplastic elastomer is 10-20% of the mass of the alkaline solution; the reaction is refluxed at 50-80°C for 24-48 hours, and then 1-2 wt% hydrochloric acid aqueous solution is added to adjust the pH of the reaction solution to 2-6, and the reaction is continued for 30-60 minutes to obtain a latex. The latex is washed and vacuum dried to obtain a carboxyl-modified bio-based thermoplastic elastomer.

[0027] Furthermore, the modification method also includes the following steps:

[0028] The modified bio-based thermoplastic elastomer with carboxyl groups is mixed with metal oxides or metal salts and processing aids during the open milling process to obtain a modified thermoplastic elastomer with ionic clusters; wherein, the modified bio-based thermoplastic elastomer with carboxyl groups comprises 10 parts by weight; the metal oxides or metal salts comprise 1-10 parts by weight; and the processing aids comprise 1-3 parts by weight.

[0029] Furthermore, the metal oxide is one of zinc oxide and magnesium oxide; the metal salt is one of zinc chloride and calcium chloride.

[0030] Furthermore, the solute in the alkaline solution is one of NaOH, Ca(OH)2, and KOH, and the solvent in the alkaline solution is a mixture of ethanol and water in a volume ratio of 4:1.

[0031] Furthermore, the concentration of the alkaline solution is 2-10%.

[0032] Hydrogen bonds obtained through hydrolysis typically contribute little to the modulus of thermoplastic elastomers. Through the modification reaction of the above-mentioned hydrolysis operation, polyacrylate units can generate carboxyl groups through hydrolysis treatment, thereby regulating the hydrophilicity and lipophilicity and glass transition temperature of triblock polymers. The hydrogen bond interactions generated by a large number of carboxyl groups can play a role in regulating the mechanical properties of thermoplastic elastomers.

[0033] Furthermore, hydrolyzed carboxyl-containing thermoplastic elastomers can be mixed with metal oxides or metal salts to introduce ionic bonds or ionic clusters to form new dynamic "physical cross-linking points," thereby enhancing and toughening the thermoplastic elastomer. Moreover, the dynamic hydrogen bonds and ionic bonds can reversibly form or disappear as the temperature rises or falls, exhibiting self-healing properties at suitable temperatures.

[0034] Meanwhile, by introducing dynamic metal ion bonds, the mechanical properties of thermoplastic elastomers can be controlled to a greater extent, since the bond energy of ionic bonds is higher than that of hydrogen bonds.

[0035] The beneficial effects of this invention are as follows:

[0036] 1. This invention uses an emulsion polymerization system combined with reversible addition-fragmentation chain transfer radical polymerization technology to efficiently synthesize multi-block copolymers with highly controllable structures. At the same time, emulsion polymerization has the advantages of low viscosity, high heat transfer efficiency, no need for organic solvents, and less pollution, which facilitates industrialization and continuous production.

[0037] 2. This invention utilizes emulsion polymerization. Because emulsion polymerization has a free radical isolation effect, free radicals in different micelles will not react, reducing the rate of free radical termination. At the same time, it has the characteristics of high polymerization rate and high molecular weight. Therefore, the reaction of this invention can maintain a high polymerization rate even at extremely low initiator concentrations.

[0038] 3. The amphiphilic macromolecular reversible addition-fragmentation chain transfer reagent used in this invention serves as both a chain transfer agent and an emulsifier. This not only allows for good control of the molecular structure and distribution of the final product, but also avoids the cumbersome operation of removing the added emulsifier later.

[0039] 4. The multi-block copolymer prepared by this invention has a highly controllable molecular structure, a narrow molecular weight distribution, and a wide range of applications.

[0040] 5. The present invention modifies thermoplastic elastomers with multiphase structures to give them abundant carboxyl groups, which provides a large space for post-functionalization and allows for the control of the hydrophilicity and lipophilicity and glass transition temperature of triblock polymers. The interaction between the hydrogen bonds generated by the large number of carboxyl groups and the ionic bonds introduced by further modification can play a role in controlling the mechanical properties of thermoplastic elastomers.

[0041] 6. The bio-based thermoplastic elastomer prepared by the present invention can self-heal after modification. After the sample is cut within the gauge length and the cross-section is re-contacted and placed for 24 hours, the tensile strength, elongation at break and toughness of the sample can be restored to a certain extent, and it has good mechanical properties. Detailed Implementation

[0042] To explain in detail the technical content, structural features, objectives, and effects of the technical solution, the following detailed description is provided in conjunction with specific embodiments.

[0043] Example 1: This example synthesizes styrene-b-myrcene-b-styrene (St 200 -b-My 800 -b-St 200 Triblock thermoplastic elastomer.

[0044] 0.5 parts by weight of the macromolecular RAFT reagent AA 20St5 Macro-RAFT was dissolved in 100 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 5.6 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at a stirring rate of 450 rpm for 30 min to remove oxygen. The temperature was then raised to 70 °C, and the mixture was pre-emulsified at a stirring rate of 430 rpm with nitrogen purging for another 30 min. 0.1 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate monomer polymerization. The stirring speed was adjusted to 350 rpm, and the reaction was allowed to proceed for 100 min. Then, 0.5 parts by weight of a 10% sodium hydroxide aqueous solution was added. After reacting for 5 hours, 24.7 parts by weight of the second-stage monomer myrcene were injected using a syringe. The reaction temperature and rotation speed were maintained constant for 2 hours of emulsification. Then, 0.1 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate the polymerization of myrcene. After reacting for 20 hours, 5.6 parts by weight of styrene were added for pre-emulsification with nitrogen to remove oxygen for 1 hour. Finally, 0.1 parts by weight of a 10% ammonium persulfate aqueous solution was added to initiate the reaction for 5 hours to complete the reaction. The monomer polymerization was demulsified and flocculated in a 0.5 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0045] Example 2: This example synthesizes styrene-b-myrcene-b-styrene (St 500 -b-My 500 -b-St 500 Triblock thermoplastic elastomer.

[0046] 0.8 parts by weight of the macromolecular RAFT reagent AA 20 St5 Macro-RAFT was dissolved in 150 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 11.8 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at a stirring rate of 400 rpm for 40 min to remove oxygen. The temperature was then raised to 75°C, and the mixture was pre-emulsified at a stirring rate of 330 rpm with nitrogen purging for 40 min. 0.5 parts by weight of a 10% aqueous solution of per-tert-butyl hydroperoxide was added to initiate monomer polymerization. After reacting at 350 rpm for 100 min, 0.9 parts by weight of a 10% aqueous solution of sodium hydroxide was added. After reacting for 8 hours, 15.45 parts by weight of the second-stage monomer myrcene were injected using a syringe. The reaction temperature and rotation speed were maintained constant for 1.5 hours of emulsification. Then, 0.5 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate the polymerization of myrcene. After reacting for 15 hours, 11.8 parts by weight of styrene were added and pre-emulsified for 1.5 hours with nitrogen purging. Finally, 0.5 parts by weight of a 10% ammonium persulfate aqueous solution was added to initiate the reaction for another 8 hours. The monomer polymerization was demulsified and flocculated in a 1.0 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0047] Example 3: This example synthesizes styrene-b-myrcene-b-styrene (St 800 -b-My 200 -b-St 800 Triblock thermoplastic elastomer.

[0048] 1.0 part by weight of the macromolecular RAFT reagent AA 20 St5 Macro-RAFT was dissolved in 250 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 18.9 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at 300 rpm for 60 min to remove oxygen. The temperature was then raised to 80 °C, and the mixture was pre-emulsified at 300 rpm with nitrogen purging for another 60 min. 1.0 part by weight of a 10% potassium persulfate aqueous initiator was added to initiate monomer polymerization. After reacting at 300 rpm for 100 min, 2.0 parts by weight of a 10% sodium hydroxide aqueous solution was added. After reacting for 10 hours, 7.4 parts by weight of the second-stage monomer myrcene were injected using a syringe. The reaction temperature and rotation speed were maintained constant for 1 hour of emulsification. Then, 1.0 part by weight of a 10% potassium persulfate aqueous solution was added to initiate the polymerization of myrcene. After reacting for 10 hours, 18.9 parts by weight of styrene were added and pre-emulsified for 2 hours with nitrogen to remove oxygen. Finally, 1.0 part by weight of a 10% potassium persulfate aqueous solution was added to initiate the reaction for another 10 hours. The monomer polymerization was demulsified and flocculated in a 2.0 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0049] Example 4. This example synthesizes styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene (St 500 -b-(My 500 -co-tBA 200 )-b-St 500 A triblock thermoplastic elastomer containing 7.2 parts by weight of tert-butyl acrylate.

[0050] 0.8 parts by weight of the macromolecular RAFT reagent AA 20St5 Macro-RAFT was dissolved in 150 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 11.8 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at 330 rpm for 40 min. The temperature was then raised to 75°C, and the mixture was pre-emulsified with nitrogen purging at 210 rpm for 40 min. 0.5 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate monomer polymerization. After stirring at 210 rpm for 60 min, 0.9 parts by weight of a 10% sodium hydroxide aqueous solution was added. After reacting for 8 hours, 15.45 parts by weight of the second-stage monomer myrcene and 7.2 parts by weight of tert-butyl acrylate were injected using a syringe. The reaction temperature and rotation speed were maintained constant for emulsification for 1.0 hour. Then, 0.5 parts by weight of 10% potassium persulfate initiator was added to initiate the polymerization reaction of myrcene and tert-butyl acrylate for 10 hours. Finally, 11.8 parts by weight of styrene were added for pre-emulsification with nitrogen to remove oxygen for 1.5 hours, followed by 8 hours of initiation with 0.5 parts by weight of 10% potassium persulfate initiator. The monomer polymerization was demulsified and flocculated in a 0.5 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0051] Example 5. This example synthesizes styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene (St 500 -b-(My 500 -co-tBA 400 )-b-St 500 A triblock thermoplastic elastomer containing 14.54 parts by weight of tert-butyl acrylate.

[0052] 0.8 parts by weight of the macromolecular RAFT reagent AA 20St5 Macro-RAFT was dissolved in 150 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 11.8 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at 200 rpm for 40 min to remove oxygen. The temperature was then raised to 75°C, and the mixture was pre-emulsified at 200 rpm with nitrogen purging for another 40 min. 0.5 parts by weight of a 10% potassium persulfate aqueous initiator was added to initiate monomer polymerization. After reacting for 100 min, 0.9 parts by weight of a 10% sodium hydroxide aqueous solution was added. After reacting for 8 hours, 15.45 parts by weight of the second-stage monomer myrcene and 14.54 parts by weight of tert-butyl acrylate were injected using a syringe. The reaction temperature and rotation speed were maintained constant for emulsification for 1.5 hours. Then, 0.8 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate the polymerization of myrcene and tert-butyl acrylate. The reaction was continued for 15 hours. Finally, 11.8 parts by weight of styrene were added for pre-emulsification with nitrogen to remove oxygen, followed by 1.5 hours of pre-emulsification. Then, 0.5 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate the reaction for another 8 hours. The monomer polymerization was demulsified and flocculated in a 0.5 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0053] Example 6: This example synthesizes styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene (St 500 -b-(My 500 -co-tBA 800 )-b-St 500 A triblock thermoplastic elastomer containing 27.9 parts by weight of tert-butyl acrylate.

[0054] 0.5 parts by weight of the macromolecular RAFT reagent AA 20St5 Macro-RAFT was dissolved in 150 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 11.8 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at a stirring rate of 250 rpm for 40 min to remove oxygen. The temperature was then raised to 75°C, and the mixture was pre-emulsified at a stirring rate of 330 rpm with nitrogen purging for another 40 min. 0.5 parts by weight of a 10% potassium persulfate aqueous initiator was added to initiate monomer polymerization. After reacting at 250 rpm for 120 min, 0.9 parts by weight of a 10% sodium hydroxide aqueous solution was added. After reacting for 8 hours, 15.45 parts by weight of the second-stage monomer myrcene and 27.9 parts by weight of tert-butyl acrylate were injected using a syringe. The reaction temperature and rotation speed were maintained constant for emulsification for 2 hours. Then, 1.0 part by weight of a 10% potassium persulfate aqueous initiator was added to initiate the polymerization of myrcene and tert-butyl acrylate, and the reaction was allowed to proceed for 20 hours. Finally, 11.8 parts by weight of styrene were added for pre-emulsification with nitrogen to remove oxygen for 1.5 hours, followed by the addition of 0.5 parts by weight of a 10% potassium persulfate aqueous initiator to initiate the reaction for another 8 hours. The monomer polymerization was demulsified and flocculated in a 0.5 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0055] Example 7. This example synthesizes styrene-b-(myrcene-co-butyl acrylate)-b-styrene (St 500 -b-(My 500 -co-BA 400 )-b-St 500 A triblock thermoplastic elastomer containing 14.54 parts by weight of tert-butyl acrylate.

[0056] 0.8 parts by weight of the macromolecular RAFT reagent AA 20St5 Macro-RAFT was dissolved in 150 parts by weight of deionized water. After complete dissolution, the solution was poured into a 250 ml three-necked flask, and 11.8 parts by weight of the first-stage monomer styrene was added. The mixture was pre-emulsified at room temperature with nitrogen purging at 200 rpm for 40 min to remove oxygen. The temperature was then raised to 75°C, and the mixture was pre-emulsified at 200 rpm with nitrogen purging for another 40 min. 0.5 parts by weight of a 10% potassium persulfate aqueous initiator was added to initiate monomer polymerization. After reacting for 100 min, 0.9 parts by weight of a 10% sodium hydroxide aqueous solution was added. After reacting for 8 hours, 15.45 parts by weight of the second-stage monomer myrcene and 14.54 parts by weight of n-butyl acrylate were injected using a syringe. The reaction temperature and rotation speed were maintained constant for emulsification for 1.5 hours. Then, 0.8 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate the polymerization of myrcene and tert-butyl acrylate. The reaction was continued for 15 hours. Finally, 11.8 parts by weight of styrene were added for pre-emulsification with nitrogen to remove oxygen, followed by 1.5 hours of pre-emulsification. Then, 0.5 parts by weight of a 10% potassium persulfate aqueous solution was added to initiate the reaction for another 8 hours. The monomer polymerization was demulsified and flocculated in a 0.5 wt% CaCl2 solution to form a raw gel. The raw gel was washed 2-3 times with ethanol and deionized water, and then dried in a vacuum oven at 45°C for 24 hours.

[0057] Example 8. This example describes the hydrolysis of styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene (St 500 -b-(My 500 -co-tBA 400 )-b-St 500 Triblock thermoplastic elastomer for 24 hours.

[0058] 180 ml of anhydrous ethanol and 45 ml of deionized water were mixed to obtain a mixture. 3.8 g of NaOH was dissolved in the mixture to obtain a 2% alkaline solution. Then, 19.8 g of the adhesive (St) prepared in Example 5 was added. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Add the mixture to an alkaline solution and reflux at 50°C for 24 hours. Add 1 wt% hydrochloric acid solution to adjust the pH of the reaction solution to 2 and continue the reaction for 30 minutes to obtain the hydrolyzed latex. Finally, wash the latex 2-3 times with ethanol and deionized water, and dry it in a vacuum oven at 45°C for 24 hours.

[0059] Example 9. This example describes the hydrolysis of styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Triblock thermoplastic elastomer 36h.

[0060] 180 ml of anhydrous ethanol and 45 ml of deionized water were mixed to obtain a mixture. 7.8 g of KOH was dissolved in the mixture to obtain a 4% alkaline solution. Then, 36 g of the adhesive (St) prepared in Example 5 was added. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Add to an alkaline solution and reflux at 70°C for 36 hours. Add 1.5wt% hydrochloric acid solution to adjust the pH of the reaction solution to 4.5 and continue the reaction for 45 minutes to obtain hydrolyzed latex. Finally, wash with ethanol and deionized water 2-3 times each and dry the latex in a vacuum oven at 45°C for 24 hours.

[0061] Example 10. This example describes the hydrolysis of styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Triblock thermoplastic elastomer 48h.

[0062] 180 ml of anhydrous ethanol and 45 ml of deionized water were mixed to obtain a mixture. 7.8 g of NaOH was dissolved in the mixture to obtain a 4% alkaline solution. Then, 39 g of the adhesive (St) prepared in Example 5 was added. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Add to an alkaline solution and reflux at 80°C for 48 hours. Adjust the pH of the reaction solution to 6 with a 2wt% hydrochloric acid solution and continue the reaction for 60 minutes to obtain hydrolyzed latex. Finally, wash with ethanol and deionized water 2-3 times each and dry the latex in a vacuum oven at 45°C for 24 hours.

[0063] Examples 8-10 above respectively modified the thermoplastic elastomers prepared in Example 5 by hydrolysis treatment in different batches.

[0064] Example 11. This example describes the hydrolysis of styrene-b-(myrcene-co-butyl acrylate)-b-styrene. 500 -b-(My 500 -co-BA 400 )-b-St 500 Triblock thermoplastic elastomer 48h.

[0065] Anhydrous ethanol and deionized water were mixed in a volume ratio of 4:1 to obtain 225g of the mixture. 20.8g of NaOH was dissolved in the mixture to obtain a 10% alkaline solution. Then, 41.6 parts by weight of the adhesive (St) prepared in Example 7 were... 500 -b-(My 500 -co-BA 400 )-b-St 500 Add to an alkaline solution and reflux at 80°C for 48 hours. Adjust the pH of the reaction solution to 6 with a 2wt% hydrochloric acid solution and continue the reaction for 60 minutes to obtain hydrolyzed latex. Finally, wash with ethanol and deionized water 2-3 times each and dry the latex in a vacuum oven at 45°C for 24 hours.

[0066] Example 12. In this example, St after hydrolysis for 48 hours in Example 9 was... 500 -b-(My 500 -co-tBA 400 )-b-St 500 Triblock thermoplastic elastomer modified with 1 part by weight of zinc oxide.

[0067] Ten parts by weight of St after hydrolysis for 48 hours in Example 9 were used. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Add 1 part by weight of zinc oxide and 2 parts by weight of stearic acid during the two-roll mill process. Mill 5 to 6 times until the mixture is homogeneous.

[0068] Example 13. In this example, St after hydrolysis for 48 hours in Example 9 was... 500 -b-(My 500 -co-tBA 400 )-b-St 500 Triblock thermoplastic elastomer modified with 5 parts by weight of zinc oxide.

[0069] Ten parts by weight of St after hydrolysis for 48 hours in Example 9 were used. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Add 5 parts by weight of zinc oxide and 3 parts by weight of stearic acid during the two-roll mill process. Mill 5 to 6 times until the mixture is homogeneous.

[0070] Example 14. In this example, St after hydrolysis for 48 hours in Example 9 was... 500 -b-(My 500 -co-tBA 400 )-b-St 500 Triblock thermoplastic elastomer modified with 10 parts by weight of zinc oxide.

[0071] Ten parts by weight of St after hydrolysis for 48 hours in Example 9 were used. 500 -b-(My 500 -co-tBA 400 )-b-St 500 Add 10 parts by weight of zinc oxide and 1 part by weight of stearic acid during the two-roll mill process. Mill 5 to 6 times until the mixture is homogeneous.

[0072] Example 15. In this example, St after hydrolysis for 48 hours in Example 7 was... 500 -b-(My 500 -co-BA 400 )-b-St 500 Triblock thermoplastic elastomer modified with 10 parts by weight of zinc chloride.

[0073] Ten parts by weight of St after hydrolysis for 48 hours in Example 7 were used. 500 -b-(My 500 -co-BA 400 )-b-St 500 Add 10 parts by weight of zinc chloride and 1 part of stearic acid during the two-roll mill process. Mill 5 to 6 times until the mixture is homogeneous.

[0074] The molecular weight and molecular weight distribution of the thermoplastic elastomers synthesized in Examples 1-7 were determined. The detection equipment was a gel permeation chromatography (GPC) system, model PL-GPC 220, manufactured by Agilent Technologies, Inc. Prior to testing, the chromatographic column was calibrated with PS, the elution solvent was chromatographic grade tetrahydrofuran, the solvent flow rate was 1 mL / min, and the concentration of SMS was 0.5 g / mL. The molecular weight and molecular weight distribution were then measured. The results are shown in Table 1.

[0075] Table 1. Molecular weight and molecular weight distribution coefficient of polymers in Examples 1-7

[0076] Mn(g / mol) PDI Example 1 140400 1.2 Example 2 182000 1.4 Example 3 199600 1.7 Example 4 284400 1.6 Example 5 283200 1.7 Example 6 207600 1.5 Example 7 208000 1.6

[0077] According to the test results in Table 1, the molecular weights of the triblock copolymers prepared in Examples 1-7 range from 140,400 to 284,400. Because this invention uses an amphiphilic RAFT reagent for soap-free emulsion polymerization, the polymerization conditions are mild, requiring no organic solvents or subsequent recycling, making it environmentally friendly and pollution-free. The molecular weight of the product can be controlled within an ideal range, and the molecular weight distribution is relatively narrow. It exhibits high reactivity, with molecular weights reaching 200,000 and above, resulting in excellent strength or toughness for plastics or rubber. Simultaneously, it can form an ordered multi-block structure with strong designability, indicating that even with stepwise addition of monomers, the reaction system still maintains good polymerization activity, demonstrating high activity and strong controllability. Specific monomers can be introduced to continue the copolymerization reaction according to the performance requirements of the product; for example, introducing fluorinated acrylate monomers to form perfluorinated blocks imparts hydrophobic, oleophobic, and corrosion-resistant properties to the copolymer.

[0078] The glass transition temperatures of the triblock copolymers in Examples 1-15 were tested. A DSC-Q2000 differential scanning calorimeter, manufactured by TA Instruments, USA, was used. The testing procedure was as follows: the temperature was first raised from room temperature to 150°C and held for 3 minutes; then the temperature was lowered to -80°C at a rate of 10°C / min and held for 3 minutes (this was the first cycle); then the temperature was raised from -80°C to 150°C at a rate of 10°C / min and held for 3 minutes (this was the second cycle). The test atmosphere was nitrogen. The test results are shown in Table 2.

[0079] Table 2 Glass transition temperatures of polymers in each example

[0080] <![CDATA[T g1 / ℃]]> <![CDATA[T g2 / ℃]]> Example 1 <![CDATA[St 200 -b-My 800 -b-St 200 ]]> 90 -60 Example 2 <![CDATA[St 500 -b-My 500 -b-St 500 ]]> 89 -58 Example 3 <![CDATA[St 800 -b-My 200 -b-St 800 ]]> 95 -58 Example 4 <![CDATA[St 500 -b-(My 500 -co-tBA 200 )-b-St 500 ]]> 86 -42 Example 5 <![CDATA[St 500 -b-(My 500 -co-tBA 400 )-b-St 500 ]]> 90 -35 Example 6 <![CDATA[St 500 -b-(My 500 -co-tBA 800 )-b-St 500 ]]> 92 -29 Example 7 <![CDATA[St 500 -b-(My 500 -co-BA 400 )-b-St 500 ]]> 91 -57 Example 8 <![CDATA[St 500 -b-(We 500 -co-tBA 297 -co-AA 103 )-b-St 500 ]]> 89 -21 Example 9 <![CDATA[St 500 -b-(We 500 -co-tBA 195 -co-AA 205 )-b-St 500 ]]> 91 -10 Example 10 <![CDATA[St 500 -b-(We 500 -co-tBA 97 -co-AA 303 )-b-St 500 ]]> 90 -5 Example 11 <![CDATA[St 500 -b-(My 500 -co-BA 98 -co-AA 302 )-b-St 500 ]]> 90 -8 Example 12 <![CDATA[St 500 -b-(We 500 -co-tBA 97 -co-AA 303 -g-Zn1)-b-St 500 ]]> 88 -3 Example 13 <![CDATA[St 500 -b-(My 500 -co-tBA 97 -co-AA 303 -g-Zn5)-b-St 500 ]]> 91 2 Example 14 <![CDATA[St 500 -b-(We 500 -co-tBA 97 -co-AA 303 -g-Zn10)-b-St 500 ]]> 90 4 Example 15 <![CDATA[St 500 -b-(We 500 -co-tBA 97 -co-AA 303 -g-Zn10)-b-St 500 ]]> 89 3

[0081] According to the data from Examples 1-3 in Table 2, when styrene monomer and myrcene monomer are added during the polymerization process, the glass transition temperature (T) of the hard segment polystyrene obtained by polymerization is... g1 The glass transition temperature (T) of soft segment polymyrrhene is between 90 and 100°C. g2 It is between -58 and -60℃.

[0082] In Examples 4-6, the glass transition temperature of the intermediate soft segment increased from -58°C to -29°C after introducing different proportions of tert-butyl acrylate into the soft segment. This is because the glass transition temperature of the polyacrylate unit is around 40°C. According to the thermodynamic derivation of the FOX formula, the glass transition temperature of the intermediate soft segment copolymer lies between that of polymyrrhene and polyacrylate, and the experimental results are basically consistent with the theoretical prediction. By adding different proportions of acrylate monomers to the intermediate soft segment, the glass transition temperature of the intermediate soft segment copolymer can be flexibly adjusted. That is, by adjusting the amount of myrcene and acrylate monomers added, thermoplastic elastomers with glass transition temperatures between 40°C and -58°C can be obtained. The amount of myrcene and acrylate monomers added can be adjusted according to the specific application performance requirements to give the product different thermodynamic properties. Example 7 uses a copolymer of n-butyl acrylate and myrcene as the soft segment of a thermoplastic elastomer. The glass transition temperature (GTH) of n-butyl acrylate is -55°C, very close to that of myrcene (-58°C). Its addition did not increase the GTH of the soft segment as it did with tert-butyl acrylate; instead, it effectively lengthened the soft segment. The GTH of the copolymer segment was -57°C. The test results are similar to those derived from the FOX formula.

[0083] Examples 8-10 show that after hydrolyzing the thermoplastic elastomer prepared in Example 5 at different time gradients, the glass transition temperature increased from -35°C to -5°C. This is because the partial hydrolysis of acrylate to acrylic acid introduces carboxyl groups into the side chains. Due to intermolecular interactions, these carboxyl groups aggregate and form hydrogen-bonded clusters. The original flexibility of the molecular chains decreases due to the presence of hydrogen bonds, hindering molecular chain movement and thus increasing the glass transition temperature. Example 11 shows that the thermoplastic elastomer prepared in Example 7 was hydrolyzed for 48 hours. Compared to Example 10, only tert-butyl acrylate was changed to n-butyl acrylate. The hydrolyzed portion also became acrylic acid, but the unhydrolyzed n-butyl acrylate chain had higher flexibility than tert-butyl acrylate. Therefore, the glass transition temperature of the intermediate copolymer segment in Example 11 was -8°C, lower than -5°C in Example 10.

[0084] In Examples 12-14, the thermoplastic elastomers hydrolyzed in Example 10 were modified with different concentrations of metal ions, resulting in an increase in the glass transition temperature of the soft segment from -5°C to 4°C. This is because replacing the hydrogen on the carboxyl group with zinc ions transformed the original hydrogen bonds into ionic clusters. Since the bond energy of ionic bonds is greater than that of hydrogen bonds, the clusters formed by the aggregation of metal ions can act as a reinforcing agent similar to fillers, increasing the rigidity of the soft segment chains, raising the glass transition temperature of the soft segment, and enhancing the mechanical properties of the modified thermoplastic elastomer. In Example 15, 10 parts of zinc chloride were added to the thermoplastic elastomer hydrolyzed in Example 10. Due to the introduction of zinc ions, the trend of the glass transition temperature was basically similar to that of Example 14.

[0085] The mechanical properties of the styrene-b-myrcene-b-styrene triblock copolymers synthesized in Examples 1-3, the styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene synthesized in Examples 4-6, the styrene-b-(myrcene-co-n-butyl acrylate)-b-styrene synthesized in Example 7, the hydrolyzed styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene modified in Examples 8-10, and the hydrolyzed styrene-b-(myrcene-co-n-butyl acrylate)-b-styrene modified in Example 11 were tested. The triblock copolymers of hydrolyzed styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene modified by compounding with different concentrations of metal ions in Examples 12-15 were also tested. The tensile mechanical property testing instrument was an Instron 68TM-10 high and low temperature material testing machine (USA). Each test sample consisted of 3 pieces, and the tensile test was performed at a tensile rate of 10 mm / min. The test results are shown in Table 3.

[0086] Table 3 Mechanical property tests of each polymer in Examples 1-15

[0087]

[0088] According to Table 3, the tensile strength of the thermoplastic elastomers prepared in Examples 1-3 is 3.0-10.5 MPa, and the elongation at break is 120-410%.

[0089] Examples 4-6, based on Example 2, showed that by introducing different proportions of tert-butyl acrylate into the soft segment, the tensile strength gradually increased while the elongation at break gradually decreased. Specifically, the tensile strength of the thermoplastic elastomer gradually increased from 7.2 MPa to 10.2 MPa, while the elongation at break decreased from 235% to 201%. This is because the soft segment in Example 2 was polymyrcene, with a glass transition temperature of only -58°C and relatively flexible molecular chains. Introducing different proportions of tert-butyl acrylate into the soft segment disrupted the regularity of the molecular chain segments, hindering molecular chain movement and increasing chain rigidity, thus improving tensile strength. Simultaneously, because the plasticity of the thermoplastic elastomer decreased after the strength increased, the elongation at break decreased. Example 7, based on Example 2, introduces n-butyl acrylate with a degree of polymerization of 400. Compared to Example 5, which introduces tert-butyl acrylate with a degree of polymerization of 400 in the soft segment of Example 2, n-butyl acrylate has a glass transition temperature of -55°C, while tert-butyl acrylate has a glass transition temperature of 110°C, and its chain rigidity is much higher than that of n-butyl acrylate. Therefore, Example 7 exhibits a higher elongation at break and lower tensile strength compared to Example 5, demonstrating a softer yet tougher effect.

[0090] Based on Example 5, after partially hydrolyzing the acrylate to carboxyl groups, the tensile strength of the thermoplastic elastomer increased from 9.1 MPa to 12.2 MPa, and the elongation at break increased from 219% to 316%. The glass transition temperature of polyacrylic acid was 110°C. This is because the hydrolysis treatment introduces the functional carboxyl group, causing hydrogen bonds in the carboxylic acid to aggregate and form clusters, further disrupting the regularity of the intermediate molecular chain structure. During slow stretching, the hydrogen bond clusters slide while continuously undergoing breakage and recombination, resulting in both strengthening and toughening effects. Simultaneously, the elongation at break of the thermoplastic elastomer does not decrease. The longer the hydrolysis time, the greater the proportion of acrylate hydrolyzed to carboxyl groups, resulting in more acrylic acid. Furthermore, with the increase in hydrogen bond clusters, more dynamic bonds are formed, improving both strength and elongation at break. This invention can control the introduction of different proportions of carboxyl groups by varying the hydrolysis time, thereby controlling the mechanical properties within a preset range.

[0091] In Examples 12-15, the thermoplastic elastomers modified by hydrolysis in Example 9 were modified by adding different concentrations of metal ions. The tensile strength increased from 12.2 MPa to 16.2 MPa, and the elongation at break increased from 316% to over 327%. This was due to the addition of metal ions, which formed metal ion clusters. The tensile strength and elongation at break were improved due to the effect of the zinc ion clusters.

[0092] The self-healing properties of the triblock copolymers of styrene-b-(myrcene-co-tert-butyl acrylate)-b-styrene from Examples 12-15, modified with different concentrations of metal ions, were tested. Dumbbell-shaped samples were cut, immediately butted together, and hot-pressed at 80°C for 10, 30, and 50 minutes. The tensile mechanical properties of the repaired samples were then tested using a universal tensile testing machine. The repair performance was evaluated by the repair rate based on tensile strength and elongation at break. The tensile mechanical property testing instrument was an Instron 68TM-10 high and low temperature testing machine (USA). Each test group consisted of three samples, and tensile tests were conducted at a tensile rate of 10 mm / min. The test results are shown in Tables 4, 5, and 6.

[0093] The tensile strength recovery value is calculated by dividing the repaired tensile strength value by the original tensile strength value. Similarly, the elongation at break recovery value is calculated by dividing the repaired elongation at break by the original elongation at break value.

[0094] Table 4. Elongation at break, tensile strength, and recovery of the polymer in Example 12.

[0095]

[0096] Table 5. Elongation at break, tensile strength, and recovery of the polymer in Example 13.

[0097]

[0098] Table 6. Elongation at break, tensile strength, and recovery of the polymer in Example 14.

[0099]

[0100]

[0101] Table 7. Elongation at break, tensile strength, and recovery of the polymer in Example 15.

[0102]

[0103] As shown in Tables 4, 5, 6, and 7, the thermoplastic elastomers modified with metal ions exhibit self-healing properties. Furthermore, it can be observed that the higher the concentration of introduced metal ions, the higher the self-healing efficiency. Due to the dissociation and association of ionic crosslinking, the longer the repair time at room temperature or above, the greater the self-healing efficiency.

[0104] When a sample is cut into two pieces, the chains in the thermoplastic elastomer break and the ion clusters dissociate. However, after the two fracture surfaces come into slight contact, the molecular chains can diffuse through the fracture surface and adjust their conformation. This allows smaller, dissociated ion clusters to recombine into larger clusters, thus achieving ion cross-linking and reconnecting the elastomer network. High temperatures enhance molecular chain migration, therefore, it is preferable to repair at temperatures above room temperature (e.g., 50-90°C) for a certain period to achieve excellent self-healing effects.

[0105] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Unless otherwise specified, an element defined by the phrase "comprising..." or "including..." does not exclude the presence of additional elements in the process, method, article, or terminal device that includes said element. Additionally, in this document, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number.

[0106] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection for this invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of this invention, or any equivalent structural or procedural transformations made using the content of this specification, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of patent protection for this invention.

Claims

1. A modified bio-based thermoplastic elastomer with ionic clusters, characterized in that: which is obtained by the process of adding a bio-based thermoplastic elastomer, the molecular formula of which is shown in formula I, (St) a -[(EA) m -co-(My) c ]-(St) d Formula I; In formula I, a and d are the number of the first section of styrene repeating units St and the number of the third section of styrene repeating units St respectively, a is an integer of 200-800, d is an integer of 200-800, the molecular weight range of the first section of hard segment polystyrene repeating units and the third section of hard segment polystyrene repeating units is 20800-83200; the second section of repeating units is a myrcene and acrylate copolymer, the number of myrcene repeating units is c, the number of acrylate repeating units is m, c is an integer of 200-800, and m is an integer of 200-800, the acrylate monomer corresponding to the acrylate repeating unit is one of the following: tert-butyl acrylate, n-butyl acrylate, ethyl acrylate; the molecular weight range of the myrcene repeating unit is 27200-108000, and the molecular weight range of the acrylate repeating unit is 25600-102400; The mass of the added bio-based thermoplastic elastomer is 10-20% of the mass of the alkaline solution; refluxing at 50-80℃ for 24-48 hours, then adding 1-2wt% hydrochloric acid aqueous solution to adjust the pH of the reaction solution to 2-6, continuing to react for 30-60min to obtain a latex, and washing and vacuum drying the latex to obtain a carboxyl-modified bio-based thermoplastic elastomer; The solute in the alkaline solution is one of NaOH, Ca(OH)2, and KOH, and the solvent in the alkaline solution is a mixture of ethanol and water with a volume ratio of 4:1; The carboxyl-modified bio-based thermoplastic elastomer is mixed with metal oxide or metal salt and processing aid in an open mill during the open milling process to obtain a modified bio-based thermoplastic elastomer with ion clusters; wherein the carboxyl-modified bio-based thermoplastic elastomer is 10 parts by weight; the metal oxide or metal salt is 1-10 parts by weight; The processing aid is 1-3 parts by weight; The metal oxide is one of zinc oxide and magnesium oxide; the metal salt is one of zinc chloride and calcium chloride.

2. The modified bio-based thermoplastic elastomer with ionic clusters based on RAFT polymerization modification process according to claim 1, characterized in that, It comprises the following steps: Step 1: Dissolve the macromolecular RAFT agent in water and add it to the reaction bottle, then add the first section of monomer styrene, stir and pre-emulsify at room temperature and under a nitrogen atmosphere for 30-60min, then heat to 70-80℃ and continue to stir and emulsify for 30-60min, then add water-soluble initiator A, and stir and react for 1-2h, then add sodium hydroxide aqueous solution, and continue to react for 5-10h; Step 2: Then add a blend of the second section of myrcene and acrylate monomers to the reaction bottle, stir and react for 1-2h, then add water-soluble initiator B, and continue to react for 10-20h to obtain a stable emulsion; Step 3: Then add the third section of monomer styrene to the reaction bottle, stir and react for 1-2h, then add water-soluble initiator C, and continue to react for 5-10h to obtain a stable emulsion; break the emulsion of the emulsion in this step in a 0.5-2% CaCl2 aqueous solution to flocculate the raw rubber, and wash and vacuum dry the raw rubber to obtain the bio-based thermoplastic elastomer; The weight parts of each component added are as follows: Macromolecular RAFT agent 0.5-1.0 parts; First-stage monomer styrene 5.6-18.9 parts; Water-soluble initiator A 0.1-1.0 parts, concentration 10%; Sodium hydroxide aqueous solution 0.5-2.0 parts, concentration 10%; Myrcene 7.4-24.7 parts; Acrylate monomer 7.2-27.9 parts; Water-soluble initiator B 0.1-1.0 parts, concentration 10%; Third-stage monomer styrene 5.6-18.9 parts; Water-soluble initiator C 0.1-1.0 parts, concentration 10%; The prepared bio-based thermoplastic elastomer is added to an alkaline solution, the mass of the added bio-based thermoplastic elastomer being 10-20% of the mass of the alkaline solution; reflux reaction is carried out at 50-80°C for 24-48 hours, 1-2wt% hydrochloric acid aqueous solution is then added to adjust the pH of the reaction solution to 2-6, and the reaction is continued for 30-60min to obtain a latex, which is washed and vacuum dried to obtain a carboxyl-modified bio-based thermoplastic elastomer; The carboxyl-modified bio-based thermoplastic elastomer is mixed with a metal oxide or metal salt and a processing aid in a two-roll mill to obtain an ion cluster-modified bio-based thermoplastic elastomer; wherein the carboxyl-modified bio-based thermoplastic elastomer is 10 parts by weight; the metal oxide or metal salt is 1-10 parts by weight; and the processing aid is 1-3 parts by weight.

3. The modified bio-based thermoplastic elastomer with ionic clusters based on RAFT polymerization modification process according to claim 2, characterized in that: The water-soluble initiator A, the water-soluble initiator B, and the water-soluble initiator C are each one of the following: ammonium persulfate aqueous solution, potassium persulfate aqueous solution, hydrogen peroxide aqueous solution, and hydrogen peroxide derivative aqueous solution.

4. The method of modifying a modified bio-based thermoplastic elastomer with ionic clusters of claim 2, wherein: The concentration of the alkaline solution is 2-10%.

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