Shape memory polyurethane resin, distillation tower filler prepared therefrom, and preparation methods thereof

Abstract

The present invention relates to the technical field of organic polymer materials, specifically a shape memory polyurethane resin and a distillation tower filler prepared therefrom, as well as a preparation method thereof. First, hydroxy-terminated polybutadiene and polytetramethylene ether glycol are used as soft segments and toluene diisocyanate is used as hard segments. A prepolymer is formed under the action of a chain extender 2-ethyl-1,3-hexanediol, and an α-hydroxy, ω-epoxy polycaprolactone oligomer is used for end group termination to obtain a shape memory polyurethane material. The synthesized shape memory polyurethane resin is melt-blended with a polypropylene matrix, maleic anhydride-modified polybutadiene rubber, and a maleic anhydride-grafted polypropylene compatibilizer. The mixture is plasticized, granulated, and injection molded by a twin-screw extruder at high temperature. A distillation tower filler having excellent mechanical strength, corrosion resistance, and adaptive shape recovery characteristics is prepared. This technical solution effectively improves the mechanical properties and operating adaptability of traditional polypropylene fillers through molecular structure design and composite process optimization.

Description

Technical Field

[0001] The invention relates to the technical field of organic polymer materials, in particular to a shape memory polyurethane resin and a distillation tower filler prepared therefrom, and methods for preparing the same. Background Art

[0002] As tower-type gas-liquid mass transfer equipment, distillation towers operate based on the differential volatility of components in a mixture. This principle involves vaporizing low-boiling-point components in the liquid phase and migrating them to the gas phase, while simultaneously condensing high-boiling-point components in the gas phase into the liquid phase, ultimately achieving separation. Generally, based on the contact method, distillation towers can be categorized as continuous contact (packed towers) and step-by-step contact (plate towers). In packed towers, resin packings, such as polypropylene packings, offer significant advantages: low fluid resistance, low unit mass transfer height, and a high flooding threshold. Combined with sufficient gas-liquid contact, these packings are ideal for improving distillation separation efficiency.

[0003] Long-term exposure to high temperature in the distillation tower will cause the polypropylene filler to become brittle or lose strength, resulting in the collapse or breakage of the filler layer, shortening the filler life, reducing distillation efficiency, and increasing maintenance costs. Thermoplastic polyurethane elastomers have both the high elasticity of rubber materials and the processing properties of thermoplastics, and have excellent wear resistance, oil resistance, and corrosion resistance. They can effectively cope with chemical corrosion in the distillation tower. Moreover, because they are thermosensitive shape memory polymer materials, they not only exhibit better mechanical properties at high temperatures, but can also achieve dynamic shape adjustment through temperature stimulation, thereby optimizing the mass transfer efficiency of the filler tower. By blending thermoplastic polyurethane elastomers with shape memory functions with polypropylene to prepare distillation tower fillers, the service life can be extended. However, existing literature shows that due to the poor compatibility between the two, even if a compatibilizer is added during blending, excessive polyurethane dosage will lead to reduced performance of the mixture (Wang Ying, Du Wuqing, Zhong Huiting, et al. Study on mechanical properties and micromorphology of polypropylene / thermoplastic polyurethane composites [J]. Plastics Industry, 2020, 48(10): 134-137+149.). Therefore, new modification methods need to be tried. Summary of the Invention

[0004] The object of the present invention is to provide a shape memory polyurethane resin and a distillation tower filler prepared therefrom, as well as a preparation method of the both, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a shape memory polyurethane resin, comprising the following steps:

[0006] Step 1:

[0007] Using lipase Novozym-435 as a catalyst, ε-caprolactone and glycidol were added to toluene under argon protection, and the reaction was stirred at 60-65°C for 24 hours. After adding chloroform to terminate the reaction, the lipase Novozym-435 was filtered out, and the filtrate was added to n-hexane for precipitation. The precipitate was washed with n-hexane and dried in vacuum at 50-60°C to obtain α-hydroxy, ω-epoxy polycaprolactone oligomers.

[0008] Step 2:

[0009] The method comprises the following steps: taking hydroxy-terminated polybutadiene and polytetramethylene glycol, drying and dehydrating them in vacuum, and mixing them to obtain a mixed diol; adding toluene diisocyanate to the mixed diol using dibutyltin dilaurate as a catalyst; reacting the mixture at 65-75°C for 2-3 hours to obtain a prepolymer; adding 2-ethyl-1,3-hexanediol as a chain extender and continuing the reaction for 0.5-1 hour to obtain an isocyanate-terminated polyurethane prepolymer; and adding α-hydroxy, ω-epoxy polycaprolactone oligomer to react to obtain a shape memory polyurethane resin.

[0010] Furthermore, in step 1, the number average molecular weight of the α-hydroxy, ω-epoxy polycaprolactone oligomer is 1500-2000.

[0011] Furthermore, in step 1, the amounts of the components used, by weight, are 0.5-0.7 parts of lipase Novozym-435, 1-2 parts of glycidol, 10-12 parts of ε-caprolactone, and 20-25 parts of toluene.

[0012] Furthermore, in step 2, the weight ratio of the hydroxy-terminated polybutadiene and polytetramethylene ether glycol in the mixed diol is (1-1.5):5.

[0013] Furthermore, in step 2, the mixed diol and toluene diisocyanate are reacted at a molar ratio of hydroxyl group to isocyanate group of (0.8-0.9): (1.5-2).

[0014] Furthermore, in step 2, the molar ratio of 2-ethyl-1,3-hexanediol to toluene diisocyanate is (0.3-0.5): (1.5-2).

[0015] Furthermore, in step 2, the α-hydroxy, ω-epoxy polycaprolactone oligomer reacts with the isocyanate-terminated polyurethane prepolymer at a molar ratio of hydroxyl group to isocyanate group of 1:1.

[0016] A method for preparing a distillation tower filler using a shape memory polyurethane resin comprises the following steps:

[0017] S1: Mix polypropylene, maleic anhydride-modified polybutadiene rubber, and maleic anhydride-grafted polypropylene, heat to 50-60°C and hold for 3-5 minutes, add shape memory polyurethane resin, vulcanizing agent, and accelerator, mix evenly, add to the upstream feed port of a twin-screw extruder, mix, extrude strands, and pelletize to obtain a polypropylene composite material;

[0018] S2: Cooling the polypropylene composite material and vacuum drying it for 4 to 6 hours; injection molding the dried polypropylene composite material and cooling it to obtain a distillation tower filler.

[0019] Furthermore, in S1, the amounts of the components, by weight, are 100 parts of polypropylene, 10-12 parts of maleic anhydride-modified polybutadiene rubber, 5-8 parts of maleic anhydride-grafted polypropylene, 18-23 parts of shape memory polyurethane resin, 0.2-0.3 parts of vulcanizing agent, and 0.05-0.1 parts of accelerator.

[0020] Compared with the existing technology, the present invention achieves the following beneficial effects: first, a shape-memory polyurethane resin is obtained by reacting hydroxyl-terminated polybutadiene, polytetramethylene glycol, and toluene diisocyanate as raw materials, using 2-ethyl-1,3-hexanediol as a chain extender and α-hydroxy, ω-epoxy polycaprolactone oligomer as a capping agent. The shape-memory polyurethane resin is then mixed with polypropylene, maleic anhydride-modified polybutadiene rubber, and maleic anhydride-grafted polypropylene, melt-extruded, and granulated to obtain a polypropylene composite material. The composite material is then injection-molded and cooled to form a distillation tower filler.

[0021] Typically, due to their polarity differences, polyurethane and polypropylene have poor compatibility, making it difficult to obtain a composite material with excellent performance by direct blending. However, in the present invention, maleic anhydride-modified polybutadiene rubber and maleic anhydride-grafted polypropylene are added as compatibilizers to reduce the interfacial tension between polyurethane and polypropylene, thereby solving the problem of incompatibility between the two after blending. On the one hand, both maleic anhydride-modified polybutadiene rubber and the polyurethane resin prepared in the present invention contain polybutadiene molecular segments, and their molecular structures are similar; maleic anhydride-grafted polypropylene and polypropylene also have similar molecular structures. Therefore, during melt blending, the components with similar structures are more compatible with each other and easier to mix; and after mixing with polypropylene, maleic anhydride-grafted polypropylene improves the polarity of the latter, thereby improving the compatibility between polypropylene and polyurethane.

[0022] Furthermore, in the present invention, the polyurethane resin has epoxy end groups, allowing it to chemically react with maleic anhydride. Physical crosslinking and chemical bonding between the components form an interlaced, interpenetrating three-dimensional network structure. Compared to single polypropylene, the composite material prepared by the present invention exhibits superior mechanical properties and shape memory, overcoming the shortcomings of polypropylene, such as poor toughness and high-temperature deformation. Its use as a filler in distillation towers in the chemical distillation stage can effectively extend service life, reduce maintenance costs during industrial production operations, and improve economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 This is a cross-sectional SEM scanning electron microscope image of the distillation tower packing in Example 1 of the present invention (magnification is 2000 times). DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0026] Materials used in the present invention and their sources: polypropylene is from Beijing Yanshan Petrochemical Co., Ltd., model M2600R; maleic anhydride-modified polybutadiene rubber is from Evonik, Germany, model MA-75; maleic anhydride-grafted polypropylene is from Exxon, USA, model PO 1020; the vulcanizing agent is diisopropylbenzene peroxide, and the accelerator is dibenzothiazole disulfide, both from Hebi Yuanhao New Materials Group Co., Ltd.; hydroxyl-terminated polybutadiene is from Shandong Zero New Materials Co., Ltd., model LBH 2000; polytetramethylene ether glycol is from Jining Liduo Chemical Co., Ltd., with an average molecular weight of 2000.

[0027] Example 1: A method for preparing a distillation tower packing prepared from a shape memory polyurethane resin, comprising the following steps:

[0028] Step 1: 100 kg of polypropylene, 12 kg of maleic anhydride modified polybutadiene rubber, and 6 kg of maleic anhydride grafted polypropylene were mixed and heated to 50 ° C for 3 minutes. 21 kg of shape memory polyurethane resin, 0.27 kg of vulcanizing agent, and 0.08 kg of accelerator were added and mixed evenly. The mixture was added to the upstream feeding port of the twin-screw extruder for mixing, and the strands were extruded and granulated to obtain a polypropylene composite material.

[0029] The method for preparing the shape memory polyurethane resin comprises the following steps:

[0030] S1: Using lipase Novozym-435 as a catalyst, ε-caprolactone and glycidol were added to toluene under argon protection, and the reaction was stirred at 60°C for 24 hours. After adding chloroform to terminate the reaction, the lipase Novozym-435 was filtered out, and the filtrate was added to n-hexane for precipitation. The precipitate was washed with n-hexane and dried in vacuo at 50°C to obtain α-hydroxy, ω-epoxy polycaprolactone oligomer with a number average molecular weight of 1500. The amount of each component used was: 0.5 kg lipase Novozym-435, 1 kg glycidol, 12 kg ε-caprolactone, and 25 kg toluene.

[0031] S2: hydroxy-terminated polybutadiene and polytetramethylene glycol are vacuum dried and dehydrated, and then mixed to obtain a mixed diol. Toluene diisocyanate is added to the mixed diol using dibutyltin dilaurate as a catalyst, and the mixture is reacted at 65°C for 2 hours to obtain a prepolymer. 2-ethyl-1,3-hexanediol is added as a chain extender and the reaction is continued for 0.5 hours to obtain an isocyanate-terminated polyurethane prepolymer. α-hydroxy, ω-epoxy polycaprolactone oligomer is added to the mixture to react to obtain a shape memory polyurethane resin.

[0032] Among them, in the mixed diol, the weight ratio of terminal hydroxyl polybutadiene and polytetramethylene ether diol is 1:5; the mixed diol; the mixed diol and toluene diisocyanate are reacted at a molar ratio of hydroxyl group to isocyanate group of 0.8:1.6; the molar ratio of 2-ethyl-1,3-hexanediol and toluene diisocyanate is 0.4:1.6; the α-hydroxy, ω-epoxy polycaprolactone oligomer and the isocyanate-terminated polyurethane prepolymer are reacted at a molar ratio of hydroxyl group to isocyanate group of 1:1.

[0033] Step 2: Cool the polypropylene composite material and vacuum dry it for 4 hours; perform injection molding and cooling molding on the dried polypropylene composite material to obtain a distillation tower filler.

[0034] Example 2: A method for preparing a distillation tower packing prepared from a shape memory polyurethane resin, comprising the following steps:

[0035] Step 1: 100 kg of polypropylene, 10 kg of maleic anhydride-modified polybutadiene rubber, and 5 kg of maleic anhydride-grafted polypropylene were mixed and heated to 55°C for 4 minutes. 18 kg of shape memory polyurethane resin, 0.2 kg of vulcanizing agent, and 0.05 kg of accelerator were added and mixed evenly. The mixture was added to the upstream feeding port of a twin-screw extruder for mixing. The strands were extruded and pelletized to obtain a polypropylene composite material.

[0036] The method for preparing the shape memory polyurethane resin comprises the following steps:

[0037] S1: Using lipase Novozym-435 as a catalyst, ε-caprolactone and glycidol were added to toluene under argon protection, and the reaction was stirred at 63°C for 24 hours. After adding chloroform to terminate the reaction, the lipase Novozym-435 was filtered out, and the filtrate was added to n-hexane for precipitation. The precipitate was washed with n-hexane and then dried in vacuo at 55°C to obtain α-hydroxy, ω-epoxy polycaprolactone oligomer with a number average molecular weight of 1800. The amount of each component used was: 0.6 kg lipase Novozym-435, 1.4 kg glycidol, 10 kg ε-caprolactone, and 20 kg toluene.

[0038] S2: hydroxy-terminated polybutadiene and polytetramethylene glycol are vacuum dried and dehydrated, and then mixed to obtain a mixed diol. Toluene diisocyanate is added to the mixed diol using dibutyltin dilaurate as a catalyst, and the mixture is reacted at 70°C for 2.5 hours to obtain a prepolymer. 2-ethyl-1,3-hexanediol is added as a chain extender and the reaction is continued for 0.5 hours to obtain an isocyanate-terminated polyurethane prepolymer. α-hydroxy, ω-epoxy polycaprolactone oligomer is added to the mixture for reaction to obtain a shape memory polyurethane resin.

[0039] Among them, in the mixed diol, the weight ratio of terminal hydroxyl polybutadiene and polytetramethylene ether diol is 1.2:5; the mixed diol; the mixed diol and toluene diisocyanate are reacted at a molar ratio of hydroxyl group to isocyanate group of 0.8:1.5; the molar ratio of 2-ethyl-1,3-hexanediol and toluene diisocyanate is 0.3:1.5; the α-hydroxy, ω-epoxy polycaprolactone oligomer and the isocyanate-terminated polyurethane prepolymer are reacted at a molar ratio of hydroxyl group to isocyanate group of 1:1.

[0040] Step 2: Cool the polypropylene composite material and vacuum dry it for 5 hours; perform injection molding and cooling molding on the dried polypropylene composite material to obtain a distillation tower filler.

[0041] Example 3: A method for preparing a distillation tower packing prepared from a shape memory polyurethane resin, comprising the following steps:

[0042] Step 1: 100 kg of polypropylene, 11 kg of maleic anhydride-modified polybutadiene rubber, and 8 kg of maleic anhydride-grafted polypropylene were mixed and heated to 60°C for 4 minutes. 23 kg of shape memory polyurethane resin, 0.3 kg of vulcanizing agent, and 0.1 kg of accelerator were added and mixed evenly. The mixture was added to the upstream feeding port of a twin-screw extruder for mixing. The strands were extruded and pelletized to obtain a polypropylene composite material.

[0043] The method for preparing the shape memory polyurethane resin comprises the following steps:

[0044] S1: Using Novozym-435 lipase as a catalyst, ε-caprolactone and glycidol were added to toluene under argon protection, and the reaction was stirred at 65°C for 24 hours. After adding chloroform to terminate the reaction, the Novozym-435 lipase was filtered out, and the filtrate was added to n-hexane for precipitation. The precipitate was washed with n-hexane and dried in vacuo at 60°C to obtain α-hydroxy, ω-epoxy polycaprolactone oligomer with a number average molecular weight of 2000. The amount of each component used was: 0.7 kg of Novozym-435 lipase, 2 kg of glycidol, 11 kg of ε-caprolactone, and 23 kg of toluene.

[0045] S2: hydroxy-terminated polybutadiene and polytetramethylene glycol are vacuum dried and dehydrated, and then mixed to obtain a mixed diol. Toluene diisocyanate is added to the mixed diol using dibutyltin dilaurate as a catalyst, and the mixture is reacted at 75°C for 3 hours to obtain a prepolymer. 2-ethyl-1,3-hexanediol is added as a chain extender and the reaction is continued for 0.5-1 hour to obtain an isocyanate-terminated polyurethane prepolymer; α-hydroxy, ω-epoxy polycaprolactone oligomer is added to react to obtain a shape memory polyurethane resin;

[0046] Among them, in the mixed diol, the weight ratio of terminal hydroxyl polybutadiene and polytetramethylene ether diol is 1.5:5; the mixed diol; the mixed diol and toluene diisocyanate are reacted at a molar ratio of hydroxyl group to isocyanate group of 0.9:2; the molar ratio of 2-ethyl-1,3-hexanediol and toluene diisocyanate is 0.5:2; the α-hydroxy, ω-epoxy polycaprolactone oligomer and the isocyanate-terminated polyurethane prepolymer are reacted at a molar ratio of hydroxyl group to isocyanate group of 1:1.

[0047] Step 2: Cool the polypropylene composite material and vacuum dry it for 6 hours; perform injection molding and cooling molding on the dried polypropylene composite material to obtain a distillation tower filler.

[0048] Comparative Example 1: Conventional thermoplastic polyurethane resin (polyether type 1180A, BASF (China) Co., Ltd., Germany) was used as a raw material to prepare a distillation tower packing, and the other parameters were the same as those in Example 1.

[0049] Step 1: 100 kg of polypropylene, 12 kg of maleic anhydride modified polybutadiene rubber, and 6 kg of maleic anhydride grafted polypropylene were mixed and heated to 50 ° C for 3 minutes. 21 kg of shape memory polyurethane resin, 0.27 kg of vulcanizing agent, and 0.08 kg of accelerator were added and mixed evenly. The mixture was added to the upstream feeding port of the twin-screw extruder for mixing, and the strands were extruded and granulated to obtain a polypropylene composite material.

[0050] Step 2: Cool the polypropylene composite material and vacuum dry it for 4 hours; perform injection molding and cooling molding on the dried polypropylene composite material to obtain a distillation tower filler.

[0051] Comparative Example 2: No maleic anhydride-modified polybutadiene rubber was added, and the remaining parameters were the same as those in Example 2.

[0052] Step 1: Mix 100 kg of polypropylene and 5 kg of maleic anhydride grafted polypropylene, heat to 55 ° C for 4 minutes, add 18 kg of shape memory polyurethane resin, 0.2 kg of vulcanizing agent, and 0.05 kg of accelerator, mix evenly, add to the upstream feeding port of the twin-screw extruder for mixing, extrude the strands, and granulate to obtain a polypropylene composite material;

[0053] The method for preparing the shape memory polyurethane resin comprises the following steps:

[0054] S1: Using lipase Novozym-435 as a catalyst, ε-caprolactone and glycidol were added to toluene under argon protection, and the reaction was stirred at 63°C for 24 hours. After adding chloroform to terminate the reaction, the lipase Novozym-435 was filtered out, and the filtrate was added to n-hexane for precipitation. The precipitate was washed with n-hexane and then dried in vacuo at 55°C to obtain α-hydroxy, ω-epoxy polycaprolactone oligomer with a number average molecular weight of 1800. The amount of each component used was: 0.6 kg lipase Novozym-435, 1.4 kg glycidol, 10 kg ε-caprolactone, and 20 kg toluene.

[0055] S2: hydroxy-terminated polybutadiene and polytetramethylene glycol are vacuum dried and dehydrated, and then mixed to obtain a mixed diol. Toluene diisocyanate is added to the mixed diol using dibutyltin dilaurate as a catalyst, and the mixture is reacted at 70°C for 2.5 hours to obtain a prepolymer. 2-ethyl-1,3-hexanediol is added as a chain extender and the reaction is continued for 0.5 hours to obtain an isocyanate-terminated polyurethane prepolymer. α-hydroxy, ω-epoxy polycaprolactone oligomer is added to the mixture for reaction to obtain a shape memory polyurethane resin.

[0056] Among them, in the mixed diol, the weight ratio of terminal hydroxyl polybutadiene and polytetramethylene ether diol is 1.2:5; the mixed diol; the mixed diol and toluene diisocyanate are reacted at a molar ratio of hydroxyl group to isocyanate group of 0.8:1.5; the molar ratio of 2-ethyl-1,3-hexanediol and toluene diisocyanate is 0.3:1.5; the α-hydroxy, ω-epoxy polycaprolactone oligomer and the isocyanate-terminated polyurethane prepolymer are reacted at a molar ratio of hydroxyl group to isocyanate group of 1:1.

[0057] Step 2: Cool the polypropylene composite material and vacuum dry it for 5 hours; perform injection molding and cooling molding on the dried polypropylene composite material to obtain a distillation tower filler.

[0058] Comparative Example 3: No shape memory polyurethane resin was added, and other parameters were the same as those in Example 3.

[0059] Step 1: 100 kg of polypropylene, 11 kg of maleic anhydride modified polybutadiene rubber, and 8 kg of maleic anhydride grafted polypropylene were mixed, heated to 60 ° C for 4 minutes, 0.3 kg of vulcanizing agent and 0.1 kg of accelerator were added and mixed evenly, and the mixture was added to the upstream feeding port of the twin-screw extruder for mixing, and the strands were extruded and granulated to obtain a polypropylene composite material;

[0060] Step 2: Cool the polypropylene composite material and vacuum dry it for 6 hours; perform injection molding and cooling molding on the dried polypropylene composite material to obtain a distillation tower filler.

[0061] Experiment: Referring to the preparation methods in Examples 1 to 3 and Comparative Examples 1 to 3, polypropylene composite materials were prepared into samples for performance test. The experimental method is as follows:

[0062] Impact performance: A pendulum impact tester was used to prepare a V-notch using a notch prototype machine. Five specimens were tested in each group, with the average value calculated according to GB / T1043.1-2018 standard.

[0063] Tensile properties: an electronic universal testing machine was used, referring to GB / T 1040.2-2006 standard, with a tensile speed of 35 mm / min, 5 test specimens per group, and the average value was calculated.

[0064] Heat resistance: Take 10 samples from each group and place them in a vacuum oven at 180℃ for 300 hours. After taking them out, place them in a vacuum dry environment at 25℃ to cool naturally. Test and observe whether the samples show any collapse, deformation, or cracking.

[0065] Deformation recovery rate: Select a standard specimen and take 50mm on the sample as the initial gauge length L0. Heat it to 165℃ in the hot box of the testing machine and maintain it for 5 minutes. Perform a tensile shaping test on the specimen at a rate of 20mm / min and a stretching ratio of 80%. After shaping, cool it at 25℃ for 24 hours. The gauge length is measured and recorded as L1. Finally, place the specimen in a 170℃ oven for deformation recovery for 3 minutes. Take it out and measure its gauge length and record it as L2. Calculate the deformation recovery rate R = (L1-L2) / (L1-L0).

[0066] The experimental results are shown in the following table:

[0067] Table 1. Test results of various performances of samples in each group

[0068]

[0069] The cross-sectional morphology of the distillation tower packing in Example 1 was analyzed using a SEM electron microscope.

[0070] Conclusion: The data of Examples 1 to 3 show that the shape memory polyurethane resin prepared by the present invention can effectively improve the performance of polypropylene, and the filler made of the modified polypropylene composite material can be used in a distillation tower. The data of Example 1 and Comparative Example 1 show that compared with conventional thermoplastic polyurethane resins, the shape memory polyurethane resin prepared by the present invention has better compatibility with polypropylene, and the obtained polypropylene composite material has higher impact strength, tensile strength, heat resistance, and better shape memory effect. The data of Example 2 and Comparative Example 2 show that maleic anhydride modified polybutadiene rubber can effectively reduce the interfacial tension between polypropylene and shape memory polyurethane resin, increase the compatibility between the two, and improve the performance of polypropylene composite materials. The data of Example 3 and Comparative Example 3 show that the polypropylene material prepared without adding shape memory polyurethane resin has poor performance in all aspects.

[0071] Figure 1 There is no obvious phase separation in the electron microscopy image. Combined with other data, it can be seen that the improvement of compatibility improves the performance of polypropylene composites.

[0072] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing distillation tower fillers using shape memory polyurethane resin, characterized in that: The following steps are involved: S1: Mix polypropylene, maleic anhydride-modified polybutadiene rubber, and maleic anhydride-grafted polypropylene, heat to 50-60°C and hold for 3-5 minutes, add shape memory polyurethane resin, vulcanizing agent, and accelerator, mix evenly, add to the upstream feed port of a twin-screw extruder, mix, extrude strands, and pelletize to obtain a polypropylene composite material; S2: cooling the polypropylene composite material and vacuum drying it for 4 to 6 hours; injection molding the dried polypropylene composite material and cooling it to obtain a distillation tower filler; In S1, the amounts of the components, by weight, are: 100 parts of polypropylene, 10-12 parts of maleic anhydride-modified polybutadiene rubber, 5-8 parts of maleic anhydride-grafted polypropylene, 18-23 parts of shape memory polyurethane resin, 0.2-0.3 parts of vulcanizing agent, and 0.05-0.1 parts of accelerator; The preparation method of the shape memory polyurethane resin comprises the following steps: Step 1: Using lipase Novozym-435 as a catalyst, ε-caprolactone and glycidol were added to toluene under argon protection, and the reaction was stirred at 60-65°C for 24 hours. After adding chloroform to terminate the reaction, the lipase Novozym-435 was filtered out, and the filtrate was added to n-hexane for precipitation. The precipitate was washed with n-hexane and then dried in vacuum at 50-60°C to obtain α-hydroxy, ω-epoxy polycaprolactone oligomer; Wherein, by weight, 0.5-0.7 parts of lipase Novozym-435, 1-2 parts of glycidol, 10-12 parts of ε-caprolactone, 20-25 parts of toluene; Step 2: hydroxy-terminated polybutadiene and polytetramethylene glycol are vacuum dried and dehydrated, and then mixed to obtain a mixed diol; toluene diisocyanate is added to the mixed diol using dibutyltin dilaurate as a catalyst, and the mixture is reacted at 65-75° C. for 2-3 hours to obtain a prepolymer; 2-ethyl-1,3-hexanediol is added as a chain extender and the reaction is continued for 0.5-1 hour to obtain an isocyanate-terminated polyurethane prepolymer; and α-hydroxy, ω-epoxy polycaprolactone oligomer is added to react to obtain a shape memory polyurethane resin; Among them, in the mixed diol, the weight ratio of terminal hydroxyl polybutadiene and polytetramethylene ether diol is (1~1.5):5; the mixed diol and toluene diisocyanate are reacted according to the molar ratio of hydroxyl group to isocyanate group of (0.8~0.9):(1.5~2); the molar ratio of 2-ethyl-1,3-hexanediol and toluene diisocyanate is (0.3~0.5):(1.5~2); α-hydroxy, ω-epoxy polycaprolactone oligomer and isocyanate-terminated polyurethane prepolymer are reacted according to the molar ratio of hydroxyl group to isocyanate group of 1:

1.

2. The method for preparing a distillation tower packing from a shape memory polyurethane resin according to claim 1, characterized in that: In step 1, the number average molecular weight of the α-hydroxy, ω-epoxy polycaprolactone oligomer is 1500-2000.

3. A distillation tower filler prepared by the preparation method according to any one of claims 1 to 2.

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