Block copolymer compatibilizer, preparation method thereof and application of block copolymer compatibilizer in polyurethane / silicone rubber blending system

Abstract

The invention relates to a block copolymer compatibilizer, a preparation method thereof and application of the block copolymer compatibilizer in a polyurethane / silicone rubber blending system. The compatibilizer is obtained by carrying out a plurality of reactions on amino-terminated methyl vinyl silicone oil (PDMS), hydroxyl-terminated polybutadiene (HTPB) and methylene diphenyl diisocyanate (MDI) under the catalysis of an organic tin catalyst, and has a PDMS-PU-PB soft-hard-soft triblock structure. The compatibilizer plays an amphiphilic compatibilization role in a bio-based thermoplastic polyurethane / silicone rubber Bio-TPU / MVQ blending system, a PDMS soft segment is anchored to a non-polar MVQ phase through a hydrophobic effect, a PB soft segment is compatible with a weak-polarity material in Bio-TPU, a PU hard segment stabilizes an interface through hydrogen bonds and microcrystal crosslinking, and the compatibilization effect is good. Finally, the interfacial tension is obviously reduced, the two-phase structure is effectively refined, and the interfacial bonding force and the macroscopic mechanical property of the blended material are improved. The invention provides an efficient solution for the compatibility problem of a Bio-TPU / MVQ system, and is expected to promote the rapid development and large-scale popularization and application of the bio-based thermoplastic polyurethane / silicone rubber blended material.

Description

Technical Field

[0001] This invention relates to the fields of polymer composite materials and biomaterials, specifically to a block copolymer compatibilizer, its preparation method, and its application in bio-based thermoplastic polyurethane / silicone rubber blends. Background Technology

[0002] Thermoplastic polyurethane (TPU) holds an important position in the elastomer field due to its excellent mechanical strength and easy processability, but its insufficient heat resistance, chemical resistance, and weather resistance limit its high-end applications. Introducing silicone rubber (MVQ) into the TPU system and preparing thermoplastic silicone rubber vulcanizate (TPSiV) through dynamic vulcanization technology can effectively combine thermoplastic processing with the excellent physical properties of silicone rubber.

[0003] However, traditional TPSiV systems largely rely on petroleum-based matrices, making it difficult to meet the urgent needs of sustainable development. Therefore, developing green Bio-TPSiV materials based on bio-based thermoplastic polyurethane (Bio-TPU) has become an inevitable trend.

[0004] Bio-TPU and MVQ differ significantly in polarity, chemical structure, and solubility parameters, resulting in poor compatibility during blending. This easily leads to macroscopic phase separation, forming coarse phase domains that severely impair the material's mechanical and processing properties. Although existing compatibilization strategies (such as reactive compatibilization and block / graft copolymer compatibilization) have been extensively studied, efficient and specific solutions for the Bio-TPU / MVQ system are still lacking. This is because traditional compatibilizers have limited or unspecific compatibilizing effects, while reactive compatibilization is not only complex but may also affect the structure or polymerization efficiency of the bio-based component.

[0005] Therefore, there is an urgent need to develop a new and efficient dedicated compatibilizer to fundamentally solve the interfacial compatibility problem of the Bio-TPU / MVQ blend system, thereby promoting the development and application of high-performance Bio-TPSiV materials. Summary of the Invention

[0006] One objective of this invention is to provide a novel, highly efficient compatibilizer specifically designed to improve the interfacial compatibility of bio-based thermoplastic polyurethane (TPU) and silicone rubber blends. This compatibilizer is a polymethyl vinyl silicone oil-polyurethane-polybutadiene (PDMS-PU-PB) triblock copolymer. The polyurethane (PU) segment in its molecular chain is compatible with bio-based TPU, the polymethyl vinyl silicone oil (PDMS) segment is compatible with silicone rubber, and the polybutadiene (PB) segment provides flexible bonding and synergistic effects, thereby achieving precise bridging and reinforcement of the two-phase interface.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned PDMS-PU-PB compatibilizer, comprising: using amino-terminated methyl vinyl silicone oil (PDMS), hydroxyl-terminated polybutadiene (HTPB), and diphenylmethane diisocyanate (MDI) as raw materials, mixing and reacting them to obtain the PDMS-PU-PB compatibilizer.

[0008] In the above scheme, the preparation method specifically includes: mixing PDMS and HTPB evenly and heating to perform vacuum dehydration, then adding an organic solvent and cooling to the reaction temperature, then adding a catalyst and MDI to perform a reflux reaction, after the reaction is completed, cooling, standing and precipitating the mixture in sequence, and then placing the solid obtained therefrom at the reaction temperature to dry it thoroughly, finally obtaining the PDMS-PU-PB compatibilizer.

[0009] In the above scheme, the mass ratio of PDMS to HTPB during mixing is 1:2 to 2:1, the vacuum dehydration temperature is controlled between 75-95℃, the dehydration time is controlled between 1-3h, and the vacuum degree is controlled between -0.08 MPa and -0.1 MPa.

[0010] In the above scheme, the organic solvent added to the dehydrated blend is selected from at least one of tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, and acetone, preferably tetrahydrofuran.

[0011] In the above scheme, the reflux reaction temperature after adding the catalyst is controlled between 70-90℃. The catalyst is specifically an organotin catalyst, and its addition amount is equivalent to 0.05%-2% of the mass of MDI.

[0012] In the above scheme, the MDI is added dropwise to the reaction solution in the form of an MDI solution, and the amount of MDI added is equivalent to 15%-30% of the mass of HTPB. The organic solvent used to prepare the MDI solution is the same as the organic solvent added to the mixture after vacuum dehydration.

[0013] In the above scheme, the concentration of MDI solution is 0.1-0.5 kg / L, the dropping rate is 1-5 drops / s, and the reaction is continued under reflux for 1.5-4 hours after the dropping is completed.

[0014] In the above scheme, a precipitate is formed by adding a precipitant (e.g., ethanol) to the reaction solution, and the volume ratio of the precipitant to the reaction solution is 5:1 to 10:1.

[0015] A third objective of this invention is to provide the application of the above-mentioned PDMS-PU-PB compatibilizer in the preparation of bio-based thermoplastic polyurethane / silicone rubber (i.e., Bio-TPU / MVQ) composite materials.

[0016] In the above scheme, the Bio-TPU / MVQ composite material includes Bio-TPU / MVQ blends, Bio-TPU / MVQ vulcanizates, etc., in which Bio-TPU is the continuous phase and MVQ is the dispersed phase.

[0017] The specific application method in the above scheme is as follows: Bio-TPU, PDMS-PU-PB compatibilizer, and antioxidant are mixed evenly, and then MVQ is added and mixed again to obtain a Bio-TPU / MVQ blend; or MVQ and processing aids are mixed evenly at room temperature to obtain addition silicone rubber, and then Bio-TPU, PDMS-PU-PB compatibilizer, and antioxidant are mixed evenly, and then the addition silicone rubber is added and mixed, and finally graded hot pressing is performed to obtain Bio-TPU / MVQ vulcanizate.

[0018] In the above scheme, the temperature of the entire mixing process needs to be controlled between 200 and 220°C.

[0019] In the above scheme, the equipment used for mixing is a torque rheometer equipped with a double reverse meshing rotor, and the speed is controlled between 100 and 180 rpm.

[0020] In the above scheme, the formulation by weight parts is as follows during the preparation of the two composite materials: 70-80 parts of Bio-TPU, 1-10 parts of PDMS-PU-PB (preferably 5 parts), 20-30 parts of MVQ, and the amount of antioxidant is equivalent to 0.1%-0.5% of the mass of Bio-TPU.

[0021] In the above scheme, the antioxidant is selected from at least one of antioxidants 1010, 168, 245, 425, and 1790, and is preferably a mixture of antioxidant 1010 and antioxidant 168 in equal mass ratio.

[0022] In the above scheme, the processing aids include silicone oil, Pt catalyst, inhibitors, etc.

[0023] In the above scheme, the amount of silicone oil added is equivalent to 5%-10% of the mass of MVQ.

[0024] In the above scheme, the amount of Pt catalyst added is equivalent to 0.1%-5% of the mass of MVQ.

[0025] In the above scheme, the inhibitor is selected from at least one of alkynols or their derivatives (e.g., alkoxysilanized alkynols) and nitrogen / phosphorus compounds, and the amount added is equivalent to 0.1%-3% of the mass of MVQ.

[0026] In the above scheme, the graded hot pressing molding is specifically a three-stage molding process, wherein the pressure of the first stage is 0 MPa, the pressure of the second stage is 4-6 MPa, and the pressure of the third stage is 10-12 MPa. The molding time for each stage may be the same or different, preferably the same. The molding temperature for each stage is the same, all controlled between 210-220℃.

[0027] In the above scheme, after the graded hot pressing is completed, it is first cooled and shaped, and then left to stand at room temperature for a long time to eliminate the internal stress of processing.

[0028] This invention uses MDI as a bridging unit to alternately bond HTPB and PDMS, constructing a "soft-hard-soft" triblock structure PDMS-PU-PB compatibilizer. Under the catalysis of dibutyltin dilaurate, the isocyanate groups (-NCO) preferentially undergo nucleophilic addition reactions with the terminal hydroxyl groups of hydroxyl-terminated polybutadiene (HTPB) to form urethane bonds and constitute the PU hard segment. Simultaneously, it reacts with the amino groups of hydroxyl-terminated methyl vinyl silicone oil (PDMS) to form urea bonds. The PU hard segment, due to its strong polarity and hydrogen bonding, forms microcrystalline regions that impart mechanical strength to the material. The PDMS chains provide heat resistance and flexibility, while the HTPB chains achieve hydrophobic interactions through double bonds. This multiblock structure can exert an amphiphilic compatibilizing effect in blend systems: the PDMS chains bind nonpolar polymers through hydrophobic interactions, the HTPB chains are compatible with weakly polar materials through π-π stacking, and the PU hard segment stabilizes the interface through hydrogen bonding and microcrystalline crosslinking, ultimately effectively reducing the interfacial tension of the composite material and improving its mechanical properties.

[0029] Compared with existing similar products or technologies, the beneficial effects of the present invention are mainly reflected in the following aspects: (1) A novel multiblock copolymer that can be used as a compatibilizer was prepared, which achieved interfacial compatibilization between Bio-TPU and MVQ, significantly reduced the interfacial tension between the two, and improved the interfacial bonding strength.

[0030] (2) The introduction of PDMS-PU-PB compatibilizer refines the phase morphology, significantly reduces the size of the dispersed phase in Bio-TPU / MVQ blend and makes the distribution more uniform, while greatly improving the mechanical properties of the composite material, such as tensile strength and elongation at break.

[0031] (3) The synthesis method of the PDMS-PU-PB compatibilizer is relatively mature and controllable. The application process is compatible with conventional polymer processing technology. All process parameters are clearly specified, so the process control is simple, which effectively reduces the development cost and production difficulty, and is very conducive to large-scale promotion and application. Attached Figure Description

[0032] Figure 1 The infrared spectrum of the block copolymer compatibilizer PDMS-PU-PB prepared in Example 2 is shown.

[0033] Figure 2 The brittle fracture cross-sectional morphology and particle size distribution of the Bio-TPU / MVQ blends prepared by Application Examples 4-6 and Comparative Example 1 are shown.

[0034] Figure 3 The loss factor-temperature curves are shown for the Bio-TPU / MVQ blends prepared in Application Example 6 and Comparative Example 1. Detailed Implementation

[0035] To enable those skilled in the art to fully understand the technical solution and beneficial effects of the present invention, the present invention will be described in detail below with reference to specific embodiments. It should be clarified that the following embodiments are for illustrative purposes only, used to demonstrate feasible implementation schemes of the present invention, and are not intended to constitute any limitation on the technical solution or scope of protection of the present invention. Any non-substantial changes made to the embodiments or simple substitutions using equivalent technical means that can be implemented by those skilled in the art without creative effort based on reading and understanding the disclosure of the present invention fall within the scope of protection claimed in the claims of the present invention.

[0036] Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are all commercially available products with AR-grade purity.

[0037] Example 1 PDMS and HTPB were added to the reactor and mixed at a mass ratio of 1:1. The resulting mixture was heated to 90°C and vacuum dehydrated for 1-2 hours.

[0038] The mixture was then transferred to a reflux condenser, and an appropriate amount of tetrahydrofuran was added and stirred until homogeneous. The temperature of the mixture was adjusted to 80°C, and after the system reached a constant temperature, an organotin catalyst equivalent to 2% of the mass of MDI was added. Next, MDI equivalent to 21% of the mass of HTPB was dissolved in tetrahydrofuran at a standard concentration of 5 g / 30 mL. The resulting MDI-tetrahydrofuran solution was then added dropwise to the reaction system at a rate of 0.5–3 drops / s.

[0039] After the addition was complete, the reaction was continued at 80℃ for 2 hours. After the reaction was completed, it was cooled to room temperature and allowed to stand for 8-12 hours. Then, 50% ethanol precipitant was added to the reaction system at a volume ratio of 1:10. After the polymer was fully separated, it was filtered, and the filter residue was thoroughly dried under vacuum at 80℃ to obtain the final product—the block copolymer compatibilizer, denoted as PDMS-PU-PB.

[0040] Example 2 The Fourier Transform Infrared (FTIR) spectrum of the block copolymer compatibilizer PDMS-PU-PB prepared in Example 2 is shown below. Figure 1 As shown. 3320cm in the spectrum.-1 The broad peak of the NH stretching vibration of carbamate at 1710 / 1736 cm⁻¹ -1 The absorption peaks of the C=O stretching vibration at [location missing] jointly confirm the successful polycondensation reaction between the terminal amino groups of MDI and PDI and the terminal hydroxyl groups of HTPB, marking the formation of polyurethane (PU) segments. The strong and broad stretching vibration peaks of Si-O-Si (1019 / 1088 cm⁻¹) further confirm this. -1 Symmetrical stretching vibration (798cm) -1 ) and the stretching and bending vibrations of Si-CH3 (2962 / 1260cm) -1 This indicates that the PDMS chain segment structure is intact. At 1640 cm⁻¹ -1 Stretching vibrations of C=C in the butadiene chain were detected, confirming that no significant side reactions occurred in the HTPB component.

[0041] Furthermore, the completeness of the reaction was verified by the following phenomenon: no characteristic absorption peak of the isocyanate group (2270 cm⁻¹) was detected. -1 (and in the range of 3600-3650cm) -1 and 3300-3500cm -1 No characteristic absorption signals of free hydroxyl or free amino groups were observed in any of the intervals, confirming that the reaction was complete.

[0042] By from Figure 1 The series of characteristic absorption peaks observed in the sample confirm that Example 2 successfully synthesized the target product with the expected structural characteristics.

[0043] Example 3 This embodiment is basically the same as Example 1, except that the raw material HTPB is changed from type IV (hydroxyl value 0.71-0.80 mmol / g) to type II (hydroxyl value 0.54-0.64 mmol / g).

[0044] Application Example 1 The PDMS-PU-PB compatibilizer used in the above embodiments to compatibilize the Bio-TPU / MVQ blend is described in the following specific process: Weigh out 70 parts of pre-dried Bio-TPU, 30 parts of MVQ, and 1 part of the PDMS-PU-PB compatibilizer prepared in Example 1. Antioxidant 1010 and antioxidant 168 are added precisely at 0.2% of the Bio-TPU mass. The rotor speed of the torque rheometer (equipped with a double-reverse meshing rotor) is set to 150 rpm, and the mixing temperature is set to 210℃. After reaching the set conditions, the weighed Bio-TPU, PDMS-PU-PB compatibilizer, and antioxidant are added to the torque rheometer for blending. After the torque stabilizes, MVQ is added, and molding is performed after the torque reaches secondary equilibrium. The molding process uses a staged hot pressing method. The blended material is heated to 220℃ for three-stage molding, pressed at 0MPa, 5MPa, and 10MPa for 4 minutes, 4 minutes, and 4 minutes respectively, and then pressed at 30℃ and 10MPa for 4 minutes to complete cooling and shaping. All samples were placed in a standard laboratory environment for 24 hours after molding to eliminate processing stress.

[0045] Application Example 2 This application example is basically the same as application example 1, except that the amount of PDMS-PU-PB compatibilizer is changed from 1 part to 3 parts.

[0046] Application Example 3 This application example is basically the same as application example 1, except that the amount of PDMS-PU-PB compatibilizer is changed from 1 part to 5 parts.

[0047] Application Example 4 This application example is basically the same as application example 1, except that the PDMS-PU-PB compatibilizer prepared in example 2 is used instead, and the amount of it is 1 part.

[0048] Application Example 5 This application example is basically the same as application example 1, except that the PDMS-PU-PB compatibilizer prepared in example 2 is used instead, and the amount of it is 3 parts.

[0049] Application Example 6 This application example is basically the same as application example 1, except that the PDMS-PU-PB compatibilizer prepared in example 2 is used instead, and the amount of it is 5 parts.

[0050] Application Example 7 This application example is basically the same as application example 1, except that the PDMS-PU-PB compatibilizer prepared in example 3 is used instead, and the amount of it is 1 part.

[0051] Application Example 8 This application example is basically the same as application example 1, except that the PDMS-PU-PB compatibilizer prepared in example 3 is used instead, and the amount of it is 3 parts.

[0052] Application Example 9 This application example is basically the same as application example 1, except that the PDMS-PU-PB compatibilizer prepared in example 3 is used instead, and the amount of it is 5 parts.

[0053] Application Example 10 The Bio-TPU / MVQ blend was compatibilized using the PDMS-PU-PB compatibilizer prepared in Example 2 above. The specific process is as follows: 70 parts of pre-dried Bio-TPU, 30 parts of MVQ, and 5 parts of the PDMS-PU-PB compatibilizer prepared in Example 2 were weighed out. Antioxidant 1010 and antioxidant 168 were added precisely at 0.2% of the Bio-TPU mass. Furthermore, in the hydrosilylation vulcanization system, the amounts of hydrogenated silicone oil, platinum (Pt) catalyst, and inhibitor were calculated and controlled based on the mass of MVQ. Before the reaction, 30 parts of MVQ, silicone oil (7%), Pt catalyst (0.2%), and inhibitor (1%) were mixed evenly at room temperature to obtain the added silicone rubber. Then, the rotor speed of the torque rheometer (equipped with a double anti-meshing rotor) was set to 150 rpm, and the mixing temperature was set to 210°C. After reaching the set conditions, the weighed Bio-TPU, PDMS-PU-PB compatibilizer, and antioxidant were added to the torque rheometer for blending. After the torque stabilizes, the pre-prepared addition silicone rubber is added, and molding is carried out after the torque reaches secondary equilibrium. The molding process adopts a staged hot pressing method. The mixed material is heated to 220℃ and subjected to three-stage molding, which is pressed at 0MPa, 5MPa and 10MPa for 4 minutes, 4 minutes and 4 minutes respectively, and then pressed at 30℃ and 10MPa for 4 minutes to complete the cooling and shaping. After molding, all samples are placed in a standard laboratory environment for 24 hours to eliminate processing stress.

[0054] Comparative Example 1 The preparation process of the uncompensated Bio-TPU / MVQ blend is as follows: Weigh out 70 parts of pre-dried Bio-TPU and 30 parts of MVQ. Antioxidant 1010 and Antioxidant 168 are added precisely at 0.2% of the Bio-TPU mass. Set the rotor speed of the torque rheometer (equipped with a double-reverse meshing rotor) to 150 rpm and the mixing temperature to 210℃. After reaching the set conditions, add the weighed Bio-TPU and antioxidants to the torque rheometer for blending. After the torque stabilizes, add MVQ until the torque reaches secondary equilibrium, then proceed with molding. The molding process uses a staged hot pressing method. The blended material is heated to 220℃ for three-stage molding, pressing at 0MPa, 5MPa, and 10MPa for 4 minutes, 4 minutes, and 4 minutes respectively, then pressing at 30℃ and 10MPa for 4 minutes, followed by cooling and setting. All molded samples are placed in a standard laboratory environment for 24 hours to eliminate processing stress.

[0055] To evaluate the Bio-TPU / MVQ blends prepared in the above application examples and comparative examples, their mechanical properties and hardness were tested. Mechanical property testing was performed using a DXLL-5000 micro-controlled electronic tensile testing machine. Samples were prepared as dumbbell-shaped specimens (20mm × 4mm × 1.5mm), and the specimen thickness was accurately measured using a thickness gauge. The tensile rate was set to 50mm / min, and each sample was tested at least three times to ensure data reliability. Hardness testing was performed using a Shore hardness tester. Specimens were clean, defect-free, flat sheets, stacked in no more than three layers to ensure support rigidity. The test results are shown in Table 1 below.

[0056] Table 1 Comparison of Mechanical Property Test Results for Different Samples

[0057] As can be seen from Table 1, the PDMS-PU-PB block copolymer compatibilizer prepared in this invention has a significant effect on the application of Bio-TPU / MVQ blend system, but its compatibilization mechanism and dosage have a complex non-monotonic dependence.

[0058] As shown in Application Examples 1, 4, and 7, when the compatibilizer dosage is 1 part, the blend exhibits higher tensile strength and elongation at break. However, because the compatibilizer is insufficient to completely cover the two-phase interface, the system is in a thermodynamically unstable state, thus the precipitation of the MVQ phase is observed. It is noteworthy that in Comparative Example 1, which did not contain any compatibilizer, due to the extremely poor compatibility of the two-phase interface, MVQ silicone rubber precipitated severely. The mechanical property test results actually mainly reflected the performance of the Bio-TPU matrix. Therefore, Comparative Example 1 even outperformed the blend system using compatibilizer in some mechanical properties such as tensile strength. This is mainly because phase separation caused the test object to change from a blend phase to a single phase, and its data could not reflect the synergistic effect of the two phases.

[0059] As the dosage increased to 3 parts, although the precipitation problem was slightly improved, all mechanical properties parameters showed an abnormal decline (Application Examples 2, 5, and 8). The system was in an unstable "semi-compatible" state with insufficient interfacial bonding, forming a fragile phase structure that was prone to stress concentration.

[0060] By further increasing the amount of compatibilizer to 5 parts (corresponding to Application Examples 3, 6, and 9), the system achieved optimal interfacial compatibility. At this dosage, the sample surface was smooth without any phase precipitation, indicating that the compatibilizer was fully saturated and stabilized the interface. Among them, the blend of Application Example 6 achieved excellent comprehensive mechanical properties, with tensile strength recovering to 9.9 MPa and elongation at break of 330%. More importantly, its 300% elongation stress significantly increased to 9 MPa, strongly demonstrating that the PU hard segments in the compatibilizer formed an efficient physical cross-linking network at the interface, thereby significantly enhancing the material's resistance to permanent deformation under large deformation.

[0061] Therefore, based on a comprehensive consideration of phase morphology and mechanical properties, this invention determines that 5 parts of PDMS-PU-PB compatibilizer are the optimal dosage in the Bio-TPU / MVQ blend system. This result not only completely eliminates phase separation and ensures the thermodynamic stability of the blend, but also enables the material to obtain true, stable, and optimal comprehensive mechanical properties, fully verifying the success of this block copolymer molecular structure design as an efficient interfacial compatibilization strategy.

[0062] By further optimizing the preparation process and formulation, a Bio-TPU / MVQ TPSIV material with superior overall performance was successfully obtained (Application Example 10). This material achieved significant breakthroughs in mechanical properties, with a tensile strength of 15.2 MPa, an elongation at break of 516%, a 100% constant elongation stress of 5 MPa, and a 300% constant elongation stress of 9 MPa. The use of compatibilizers optimized the interface and strengthened the physical cross-linking network, effectively solving the compatibility problem of the blend system and yielding a novel thermoplastic vulcanizate material with ultra-high toughness and excellent mechanical strength. This provides a reliable performance foundation for its practical applications in high-end healthcare, advanced sports equipment, and other fields.

[0063] The brittle fracture cross-sectional morphology (SEM) and particle size distribution of the products obtained by Application Examples 4-6 and Comparative Example 1 are shown in the following figures. Figure 2As shown in the figure, P / H(0 / 0), P / H(0.75 / 1)-1%, P / H(0.75 / 1)-3%, and P / H(0.75 / 1)-5% represent Comparative Example 1, Application Example 4, Application Example 5, and Application Example 6, respectively. The figure shows that all tested blend samples exhibited an island-like structure with plastic as the continuous phase. Without compatibilizer (i.e., Comparative Example 1), the MVQ dispersed phase had a wider particle size distribution (0–6 μm) and an average particle size of 1.57 ± 1.06 μm, indicating poor compatibility. After adding the PDMS-PU-PB compatibilizer prepared in Example 2 (i.e., Application Examples 4-6), the particle size of the dispersed phase decreased significantly with increasing dosage. The average particle sizes corresponding to 1%, 3% and 5% addition of the compatibilizer decreased to 1.18 ± 0.37 μm, 0.83 ± 0.41 μm and 0.79 ± 0.37 μm, respectively. At the same time, the particle size distribution became significantly narrower, indicating that the compatibilizer effectively suppressed phase coarsening through polarity matching and interface anchoring.

[0064] Figure 3 The loss factor-temperature curves are shown for the Bio-TPU / MVQ blends prepared in Application Example 6 and Comparative Example 1. The relevant data were obtained using a dynamic mechanical analyzer (TA Q850, USA). The tests were conducted in single cantilever mode, with dumbbell-shaped samples (20 mm × 4 mm × 1.5 mm) heated from -150 °C to 80 °C at a rate of 10 °C / min in a nitrogen atmosphere. The test frequency was 1 Hz and the amplitude was 10 μm.

[0065] As can be seen from the figure, both the uncompensated blend (i.e., Comparative Example 1) and the compatibilized blend (i.e., Application Example 6) show two relaxation peaks, indicating that the blend system exhibits a phase-separated structure, corresponding to the Bio-TPU phase (around 0°C) and the MVQ phase (at low temperature), respectively. g In the uncompensated blend, the two phases T g The temperatures were -7.72℃ and -120.90℃, respectively, a difference of 113.18℃; after adding PDMS-PU-PB compatibilizer, the T of the Bio-TPU phase... g Moved to -17.92℃, the T of the MVQ phase g The temperature was raised to -115.83℃, and the difference between the two phases decreased to 97.91℃. This result can be attributed to the addition of the PDMS-PU-PB compatibilizer, which enhanced the interfacial adhesion between the two phases, thereby effectively suppressing phase separation. This effect reduced the glass transition temperature (Tg) of the two phases. g The close proximity of the components further confirms that the compatibilizer can effectively regulate the microstructure of the blend and significantly improve its compatibility.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art can make improvements or optimizations based on the technical content disclosed in this invention to form substantially equivalent embodiments. It should be understood that, for the sake of brevity, different features are summarized in several embodiments in the foregoing, but this should not be construed as meaning that the claimed technical solution must possess more technical features than explicitly listed. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the content of the technical solution of this invention, or based on the technical essence of this invention, still fall within the protection scope of the technical solution of this invention.

Claims

1. A block copolymer compatibilizer, characterized in that: The compatibilizer has a soft-hard-soft triblock structure, in which the hard segment is a polyurethane (PU) segment, and the soft segments are a polymethyl vinyl silicone oil (PDMS) segment and a polybutadiene (PB) segment.

2. The method for preparing the block copolymer compatibilizer according to claim 1, characterized in that... The method includes: mixing and reacting amino-terminated methyl vinyl silicone oil (PDMS), hydroxyl-terminated polybutadiene (HTPB), and diphenylmethane diisocyanate (MDI) to obtain the target compatibilizer.

3. The method as described in claim 2, characterized in that... The method specifically includes: mixing PDMS, HTPB, and an organic solvent, heating to the reaction temperature, then adding a catalyst and MDI for reflux reaction. After the reaction is completed, a precipitate is formed, and the target compatibilizer is obtained after drying.

4. The method as described in claim 3, characterized in that: The required mass ratio of PDMS to HTPB for the reaction is 1:2 to 2:1, and the amount of MDI added is equivalent to 15%-30% of the mass of HTPB. The catalyst is specifically an organotin catalyst, and its amount added is equivalent to 0.05%-2% of the mass of MDI.

5. The method as described in claim 3, characterized in that: Before mixing, PDMS and HTPB need to be vacuum dehydrated in an environment of 75-95℃ and -0.08 MPa to -0.1 MPa. The reflux reaction temperature is 70-90℃. After the reaction is complete, a precipitant is added to the reaction solution to precipitate the precipitate. The volume ratio of the precipitant to the reaction solution is 5:1 to 10:

1.

6. The method as described in claim 3, characterized in that: MDI was added dropwise to the mixture in the form of an MDI solution. The organic solvent used to prepare the MDI solution was the same as the organic solvent used to disperse PDMS and HTPB.

7. The application of the block copolymer compatibilizer of claim 1 in the preparation of bio-based thermoplastic polyurethane / silicone rubber Bio-TPU / MVQ composite material.

8. The application as described in claim 7, characterized in that... The specific applications include: uniformly mixing bio-based thermoplastic polyurethane Bio-TPU, block copolymer compatibilizer, and antioxidant, then adding silicone rubber MVQ and continuing to mix to obtain a Bio-TPU / MVQ blend; or uniformly mixing silicone rubber MVQ and processing aids at room temperature to obtain addition silicone rubber, then uniformly mixing bio-based thermoplastic polyurethane Bio-TPU, block copolymer compatibilizer, and antioxidant, then adding the addition silicone rubber and mixing, and finally performing graded hot pressing molding to obtain Bio-TPU / MVQ vulcanizate.

9. The application as described in claim 8, characterized in that: The temperature of the entire mixing process is controlled between 200 and 220°C. The equipment used for mixing is a torque rheometer equipped with a double reverse meshing rotor, and its speed is controlled between 100 and 180 rpm. The graded hot pressing molding includes three-stage molding, where the pressure of the first stage is 0 MPa, and the pressure of the second and third stages increases sequentially. The molding time of each stage is the same or different, and the molding temperature of each stage is controlled between 210 and 220°C. After the graded hot pressing molding, it is first cooled and shaped, and then allowed to stand at room temperature for a long time.

10. The application as described in claim 8, characterized in that: The amounts of each raw material by weight are as follows: 70-80 parts Bio-TPU, no more than 10 parts of the compatibilizer, 20-30 parts of MVQ, the amount of antioxidant is equivalent to 0.1%-0.5% of the mass of Bio-TPU, and the amount of processing aid is equivalent to 5.2%-18% of the mass of MVQ.

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