A nucleating agent having alpha nucleation effect on polypropylene and its preparation method and application

Abstract

This invention relates to the field of polymer materials, and discloses a nucleating agent with α-nucleation activity in polypropylene, its preparation method, and its application. The preparation method includes: adding norbornene dicarboxylic acid and mercaptoethylamine to a methanol solution and mixing them evenly; adding a photoinitiator and irradiating with ultraviolet light to generate a norbornene dicarboxylic acid-mercaptoethylamine precipitate; dissolving the precipitate with sodium hydroxide; and drying to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder; dispersing the sodium norbornene dicarboxylic acid-mercaptoethylamine powder and epoxy polypropylene in xylene and reacting at 120-160℃ to generate sodium norbornene dicarboxylic acid-mercaptoethylamine grafted epoxy polypropylene, thus obtaining the nucleating agent. The nucleating agent prepared by this invention can improve mechanical properties by enhancing its dispersibility in PP, and is expected to broaden the application fields of polypropylene. The process of direct blending followed by room temperature polymerization in the modified preparation of polypropylene composites is simple to operate, highly controllable, and easy to scale up for industrial production.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a nucleating agent that has an α-nucleation effect on polypropylene, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP), a thermoplastic polymer with excellent comprehensive properties, is widely used in medical devices, packaging materials, building pipes, and automotive parts due to its good mechanical properties, thermal stability, chemical resistance, low cost, and electrical insulation characteristics. However, PP suffers from insufficient rigidity and a relatively large spherulite size, which makes it difficult to meet the requirements of high-end applications, thus limiting its application in certain high-performance fields.

[0003] Adding α-nucleating agents is an effective technique for improving the mechanical properties of polypropylene (PP). Currently, Milliken's Hyperform® series of high-performance polypropylene nucleating agents, such as HPN-68L, are widely used as α-nucleating agents. They can impart high crystallization temperature and short crystallization cycle to PP, while improving warpage and increasing the rigidity and heat distortion temperature of polypropylene. However, when HPN-68L is blended with PP, it tends to agglomerate to some extent, making uniform dispersion difficult. This results in significant fluctuations in the mechanical properties of PP, with limited improvement in mechanical properties, thus restricting its application in high-end manufacturing.

[0004] Therefore, developing alternative materials for nucleating agents with superior performance remains a pressing problem and challenge in this research field. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the problems of poor dispersibility and easy agglomeration of existing HPN-68L nucleating agents in PP, and to provide a novel nucleating agent with α-nucleation effect on polypropylene, which can improve the dispersibility of nucleating agents in PP, thereby improving the mechanical properties of PP and broadening the application fields of polypropylene.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a nucleating agent that has an α-nucleation effect on polypropylene, comprising the following steps: S1. Add norbornene dicarboxylic acid (NA) and mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly. Add the photoinitiator 2,2-dimethoxy-2-phenylacetophenone. Under ultraviolet light irradiation, a norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate is generated. Then, sodium hydroxide (NaOH) is added to dissolve the precipitate, generating a sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. S2. Sodium norbornene dicarboxylate-mercaptoethylamine powder and epoxy polypropylene (GPP) are dispersed in xylene and reacted at 120~160℃ to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene (NaNA / MEA-g-GPP), which is a nucleating agent with α-nucleation effect on polypropylene.

[0007] As a further preferred embodiment of the present invention, the amount of photoinitiator added is 0.2 to 1.0 wt% of the total mass of norbornene dicarboxylic acid (NA) and mercaptoethylamine (MEA).

[0008] As a further preferred embodiment of the present invention, the mass ratio of norbornene dicarboxylic acid and mercaptoethylamine is 1:0.1~0.5, and even more preferably the mass ratio is 1:0.3~0.4.

[0009] As a further preferred embodiment of the present invention, the mass ratio of epoxy polypropylene to sodium norbornene dicarboxylate-mercaptoethylamine is 0.2~10:1, and more preferably the mass ratio is 1~5:1.

[0010] According to a second aspect of the present invention, the present invention also provides a nucleating agent prepared by the preparation method described in the first aspect.

[0011] According to a third aspect of the invention, the invention also provides the application of the nucleating agent described in the second aspect in modified polypropylene.

[0012] According to a fourth aspect of the present invention, the present invention also provides a method for preparing a polypropylene composite material, wherein the nucleating agent of the second aspect and polypropylene are added as raw materials to a mixing device for melt blending to obtain a polypropylene composite material.

[0013] As a further preferred technical solution of the present invention, the mixing equipment is an internal mixer with a rotation speed of 20~100 rpm, a mixing time of 2~20 min, and a mixing temperature range of 180~210℃.

[0014] As a further preferred embodiment of the present invention, the amount of nucleating agent added is 0.05~1.0 wt% of polypropylene.

[0015] As a further preferred technical solution of the present invention, it also includes a drying step for the raw materials: before melt blending, the polypropylene granules are vacuum dried at 70~80°C for 24~72h, and the nucleating agent powder is vacuum dried at 50~60°C for 24~72h.

[0016] According to a fifth aspect of the present invention, the present invention also provides a polypropylene composite material prepared by the preparation method of the fourth aspect.

[0017] The core mechanism by which the novel α-nucleating agent of this invention can improve the dispersibility of nucleating agents in PP and thus enhance the mechanical properties of PP is as follows: Sodium norbornene dicarboxylate (NaNA) has a similar structure to HPN-68L, but sodium norbornene dicarboxylate has an additional intracyclic double bond, which can react with the thiol group of mercaptoethylamine (MEA). Polypropylene (PP) and epoxy polypropylene (GPP) have good compatibility. After sodium norbornene dicarboxylate-mercaptoethylamine is grafted onto epoxy polypropylene, it will be better dispersed in polypropylene, thereby significantly improving the mechanical properties of polypropylene.

[0018] Compared with the prior art, the present invention can achieve the following beneficial effects: 1) The production process of the material of this invention is green and environmentally friendly, without generating wastewater, waste gas or dust emissions, and with relatively low energy consumption, which meets the requirements of modern industry for sustainable development. 2) This invention adopts a process of direct blending followed by room temperature polymerization, which is simple to operate, highly controllable, and easy to scale up for industrial production. 3) This invention only requires the use of commonly used melt mixing equipment, making industrial preparation simple and conducive to large-scale industrial production; 4) This invention can improve the mechanical properties of polypropylene by providing dispersibility of nucleating agents in polypropylene, and is expected to broaden the application fields of polypropylene. Attached Figure Description

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Figure 1 FT-IR spectra of norbornenedicarboxylic acid (NA), mercaptoethylamine (MEA), norbornenedicarboxylic acid-mercaptoethylamine (NA-MEA), and norbornenedicarboxylic acid sodium-mercaptoethylamine (NaNA-MEA).

[0021] Figure 2 In the middle: (a1) are the XRD patterns of sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA) and HPN-68L, and (a2) are the XRD patterns of samples from Comparative Example 1, Comparative Example 2 and Example 3. The shooting angle 2θ ranges from 10° to 20°.

[0022] Figure 3 The images are TEM images of Comparative Example 2, Example 3 and Comparative Example 3, where (a1) and (a2) represent the internal microstructure of the sample of Comparative Example 2, with TEM magnifications of 5 K and 2 K; (b1) and (b2) represent the internal microstructure of the sample of Example 3, with TEM magnifications of 5 K and 2 K; and (c1) and (c2) represent the internal microstructure of the sample of Comparative Example 3, with TEM magnifications of 5 K and 2 K.

[0023] Figure 4 The following are DSC plots for Comparative Examples 1, 2, and 3, where (a1) represents the first cooling curve of Comparative Examples 1, 2, and 3, and (a2) represents the second heating curve of Comparative Examples 1, 2, and 3. Test conditions: The first heating was performed from 30 °C to 200 °C at a rate of 10 °C / min, followed by a 5-minute heat dissipation period at a constant temperature. The temperature was then rapidly reduced to 30 °C at a rate of 10 °C / min, and the temperature was then increased again from 30 °C to 200 °C at a rate of 10 °C / min.

[0024] Figure 5 The images are SEM images of Comparative Example 3, Comparative Example 2, and Example 3, where (a1) and (a2) represent the internal microstructure of the sample of Comparative Example 3, with SEM magnifications of 5 K and 10 K; (b1) and (b2) represent the internal microstructure of the sample of Comparative Example 2, with SEM magnifications of 5 K and 10 K; and (c1) and (c2) represent the internal microstructure of the sample of Example 3, with SEM magnifications of 5 K and 10 K.

[0025] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0027] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0028] The materials used in the following examples and comparative examples are: norbornene dicarboxylic acid (NA) with a molecular weight of 182.17 and a chemical formula of C9H. 10 O4; the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone with a molecular weight of 256.3 and a molecular formula of C. 16 H 16 O3; Mercaptoethylamine (MEA) has a molecular weight of 77.15 and a molecular formula of C2H7NS; The manufacturer of polypropylene is Sumitomo, Japan, H501; The manufacturer of epoxy polypropylene (GPP) is Jia Yi Rong, SPG-01.

[0029] Comparative Example 1: Prepare polypropylene (PP) without any modifiers.

[0030] Step S1. Vacuum dry the PP granules at 80℃ for 24 hours. Step S2. Add 50 g of PP granules to a mixer and melt-blend at 180°C and 50 rpm for 8 min to obtain polypropylene material PP.

[0031] Comparative Example 2: Prepare polypropylene composite material PP-HPN-68L.

[0032] Step S1. Vacuum dry the PP granules at 80°C for 24 hours, and vacuum dry the HPN-68L powder (purchased from Milliken) at 50°C for 24 hours. Step S2. Add 0.1 g of HPN-68L powder to 50 g of PP granules and mix evenly at room temperature to obtain a mixture; Step S3. Add the mixture to a mixer and melt-blend at 180°C and 50 rpm for 8 minutes to obtain the polypropylene composite material PP-hPN-68L.

[0033] Comparative Example 3: Prepare polypropylene composite material PP-NaNA-MEA.

[0034] Step S1. Add 4 g of norbornene dicarboxylic acid (NA) and 1.34 g of mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly to obtain a homogeneous, stable, and transparent mixed solution; then add 27 mg of photoinitiator 2,2-dimethoxy-2-phenylacetophenone, and generate norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate under ultraviolet light irradiation. Add 1.76 g of sodium hydroxide (NaOH) to dissolve the precipitate to generate sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. Step S2. Vacuum dry the PP granules at 80°C for 24 hours, and vacuum dry the NaNA-MEA powder at 50°C for 24 hours; Step S3. Add 0.1 g of NaNA-MEA powder to 50 g of PP granules and mix evenly at room temperature to obtain a mixture; Step S4. Add the mixture to an internal mixer and melt-blend at 180°C and 50 rpm for 8 minutes to obtain the polypropylene composite material PP-NaNA-MEA.

[0035] Example 1: To prepare the polypropylene composite material PP-NaNA / MEA-g-GPP, the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA) powder to epoxy polypropylene (GPP) was 5:1.

[0036] Step S1. Add 4 g of norbornene dicarboxylic acid (NA) and 1.34 g of mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly to obtain a homogeneous, stable, and transparent mixed solution; then add 27 mg of photoinitiator 2,2-dimethoxy-2-phenylacetophenone, and generate norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate under ultraviolet light irradiation. Add 1.76 g of sodium hydroxide (NaOH) to dissolve the precipitate to generate sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. Step S2. Disperse 5 g of sodium norbornene dicarboxylate-mercaptoethylamine powder and 1 g of epoxy polypropylene (GPP) in xylene and react at 140 °C for 6 h to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene (NaNA / MEA-g-GPP), which is a nucleating agent with excellent dispersibility and mechanical properties in polypropylene.

[0037] Step S3. Vacuum dry the PP granules at 80℃ for 24h, and vacuum dry the NaNA / MEA-g-GPP powder at 50℃ for 24h. Step S4. Add 0.1 g NaNA / MEA-g-GPP powder to 50 g PP granules and mix evenly at room temperature to obtain a mixture; Step S5. Add the mixture to a mixer and melt-blend at 180°C and 50 rpm for 8 min to obtain the polypropylene composite material PP-NaNA / MEA-g-GPP.

[0038] Example 2: To prepare the polypropylene composite material PP-NaNA / MEA-g-GPP, the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA) powder to epoxy polypropylene (GPP) was 1:1.

[0039] Step S1. Add 4 g of norbornene dicarboxylic acid (NA) and 1.34 g of mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly to obtain a homogeneous, stable, and transparent mixed solution; then add 27 mg of photoinitiator 2,2-dimethoxy-2-phenylacetophenone, and generate norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate under ultraviolet light irradiation. Add 1.76 g of sodium hydroxide (NaOH) to dissolve the precipitate to generate sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. Step S2. Disperse 3 g of sodium norbornene dicarboxylate-mercaptoethylamine powder and 3 g of epoxy polypropylene (GPP) in xylene and react at 140 °C for 6 h to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene (NaNA / MEA-g-GPP), which is a nucleating agent with excellent dispersibility and mechanical properties in polypropylene.

[0040] Step S3. Vacuum dry the PP granules at 80℃ for 24h, and vacuum dry the NaNA / MEA-g-GPP powder at 50℃ for 24h. Step S4. Add 0.1 g NaNA / MEA-g-GPP powder to 50 g PP granules and mix evenly at room temperature to obtain a mixture; Step S5. Add the mixture to a mixer and melt-blend at 180°C and 50 rpm for 8 min to obtain the polypropylene composite material PP-NaNA / MEA-g-GPP.

[0041] Example 3: To prepare the polypropylene composite material PP-NaNA / MEA-g-GPP, the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA) powder to epoxy polypropylene (GPP) was 1:2.

[0042] Step S1. Add 4 g of norbornene dicarboxylic acid (NA) and 1.34 g of mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly to obtain a homogeneous, stable, and transparent mixed solution; then add 27 mg of photoinitiator 2,2-dimethoxy-2-phenylacetophenone, and generate norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate under ultraviolet light irradiation. Add 1.76 g of sodium hydroxide (NaOH) to dissolve the precipitate to generate sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. Step S2. Disperse 2 g of sodium norbornene dicarboxylate-mercaptoethylamine powder and 4 g of epoxy polypropylene (GPP) in xylene and react at 140 °C for 6 h to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene (NaNA / MEA-g-GPP), which is a nucleating agent with excellent dispersibility and mechanical properties in polypropylene.

[0043] Step S3. Vacuum dry the PP granules at 80℃ for 24h, and vacuum dry the NaNA / MEA-g-GPP powder at 50℃ for 24h. Step S4. Add 0.1 g NaNA / MEA-g-GPP powder to 50 g PP granules and mix evenly at room temperature to obtain a mixture; Step S5. Add the mixture to a mixer and melt-blend at 180°C and 50 rpm for 8 min to obtain the polypropylene composite material PP-NaNA / MEA-g-GPP.

[0044] Example 4: To prepare the polypropylene composite material PP-NaNA / MEA-g-GPP, the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA) powder to epoxy polypropylene (GPP) was 1:5.

[0045] Step S1. Add 4 g of norbornene dicarboxylic acid (NA) and 1.34 g of mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly to obtain a homogeneous, stable, and transparent mixed solution; then add 27 mg of photoinitiator 2,2-dimethoxy-2-phenylacetophenone, and generate norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate under ultraviolet light irradiation. Add 1.76 g of sodium hydroxide (NaOH) to dissolve the precipitate to generate sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. Step S2. Disperse 1 g of sodium norbornene dicarboxylate-mercaptoethylamine powder and 5 g of epoxy polypropylene (GPP) in xylene and react at 140 °C for 6 h to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene (NaNA / MEA-g-GPP), which is a nucleating agent with excellent dispersibility and mechanical properties in polypropylene.

[0046] Step S3. Vacuum dry the PP granules at 80℃ for 24h, and vacuum dry the NaNA / MEA-g-GPP powder at 50℃ for 24h. Step S4. Add 0.1 g NaNA / MEA-g-GPP powder to 50 g PP granules and mix evenly at room temperature to obtain a mixture; Step S5. Add the mixture to a mixer and melt-blend at 180°C and 50 rpm for 8 min to obtain the polypropylene composite material PP-NaNA / MEA-g-GPP.

[0047] Example 5: To prepare the polypropylene composite material PP-NaNA / MEA-g-GPP, the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA) powder to epoxy polypropylene (GPP) was 1:10.

[0048] Step S1. Add 4 g of norbornene dicarboxylic acid (NA) and 1.34 g of mercaptoethylamine (MEA) to a methanol (MeOH) solution and mix thoroughly to obtain a homogeneous, stable, and transparent mixed solution; then add 27 mg of photoinitiator 2,2-dimethoxy-2-phenylacetophenone, and generate norbornene dicarboxylic acid-mercaptoethylamine (NA-MEA) precipitate under ultraviolet light irradiation. Add 1.76 g of sodium hydroxide (NaOH) to dissolve the precipitate to generate sodium norbornene dicarboxylic acid-mercaptoethylamine (NaNA-MEA) solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. Step S2. Disperse 1 g of sodium norbornene dicarboxylate-mercaptoethylamine powder and 10 g of epoxy polypropylene (GPP) in xylene and react at 140 °C for 6 h to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene (NaNA / MEA-g-GPP), which is a nucleating agent with excellent dispersibility and mechanical properties in polypropylene.

[0049] Step S3. Vacuum dry the PP granules at 80℃ for 24h, and vacuum dry the NaNA / MEA-g-GPP powder at 50℃ for 24h. Step S4. Add 0.1 g NaNA / MEA-g-GPP powder to 50 g PP granules and mix evenly at room temperature to obtain a mixture; Step S5. Add the mixture to a mixer and melt-blend at 180°C and 50 rpm for 8 min to obtain the polypropylene composite material PP-NaNA / MEA-g-GPP.

[0050] Performance testing: The polypropylene composite material samples prepared in the above comparative examples and embodiments were subjected to notched impact, tensile and bending tests to characterize the mechanical properties of the samples. The results are summarized in Table 1.

[0051] Impact testing was performed using a micro-injection molding machine to prepare impact specimens measuring 80 mm in length, 10 mm in width, and 4 mm in thickness, with a V-notch depth of 2 mm. The specimens were then left at room temperature for 12–24 hours. Impact tests were then conducted on the specimens using an impact testing machine according to GB / T 16420-1997 standard, with a pendulum energy of 2 J.

[0052] For tensile testing, dumbbell-shaped tensile specimens (20 mm long × 4 mm wide × 2 mm thick) were prepared using a micro-injection molding machine and allowed to stand at room temperature for 12–24 hours. Tensile tests were then performed on the specimens using a universal testing machine at a tensile rate of 10 mm / min.

[0053] Table 1

[0054] The present invention will be further analyzed below with reference to Table 1 and specific embodiments.

[0055] As shown in Table 1, the pure PP in Comparative Example 1 exhibited poor mechanical properties, with a tensile strength of only 37.6 ± 0.20 MPa. Comparative Examples 2 and 3, with the addition of commercially available HPN-68L nucleating agent and ungrafted NaNA-MEA, showed a certain improvement in overall mechanical properties, although the fluctuations in related properties were also significant. This invention utilizes the synergistic effect of sodium norbornene dicarboxylate-mercaptoethylamine and epoxy polypropylene in polypropylene composites to jointly improve the overall performance of the material. Sodium norbornene dicarboxylate-mercaptoethylamine acts as the core nucleating agent, effectively inducing polypropylene crystallization; while epoxy polypropylene plays the role of a dispersant, greatly improving the uniformity of the nucleating agent's dispersion in the polypropylene matrix, thus enhancing both mechanical properties and stability. Extensive experimental testing revealed that the optimal synergistic effect is achieved only when the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine to epoxy polypropylene reaches a certain range. In Examples 1-5 above, as the mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine to epoxy polypropylene decreased from 5:1 to 1:10, the dispersibility of the nucleating agent in polypropylene continuously improved, while the content of sodium norbornene dicarboxylate-mercaptoethylamine continuously decreased. This resulted in the mechanical properties of the polypropylene composite material exhibiting a trend of first increasing and then decreasing. Among them, the sample in Example 3 with a mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine to epoxy polypropylene of 1:2 showed the best mechanical properties, with a tensile strength reaching 43.9 ± 0.3 MPa. Comparing Example 3 and Comparative Example 2, the mechanical properties of PP were improved after the addition of both nucleating agents. However, the NaNA / MEA-g-GPP of the present invention has a greater potential for improving the strength and modulus of PP, and the performance fluctuation is smaller, making it more widely applicable.

[0056] Figure 1 It can be observed in the FT-IR image that, compared to norbornene dicarboxylic acid (NA), the introduction of mercaptoethylamine (MEA) results in a change at 1705 cm⁻¹. -1 The carbonyl peak disappears at 1603 cm⁻¹, while the peak at 1603 cm⁻¹ disappears at 1603 cm⁻¹. -1 COO appears at [location] - The peaks indicate the formation of norbornenedicarboxylic acid-mercaptoethylamine (NA-MEA) and norbornenedicarboxylic acid sodium-mercaptoethylamine (NaNA-MEA).

[0057] Figure 2It can be observed that in sodium norbornene dicarboxylate-mercaptoethylamine (NaNA-MEA), calculated using the formula d=λ / 2sinθ (λ=0.15406 nm), the NaNA-MEA crystal itself has a 2θ=13.2° angle and a crystal interplanar spacing of 0.670 nm, which is close to the α-iPP a-axis length (0.665 nm); while in HPN-68L, the HPN-68L crystal itself has a 2θ=13.5° angle and a crystal interplanar spacing of 0.655 nm, which is close to the α-iPP c-axis length (0.650 nm). Therefore, both NaNA-MEA and HPN-68L have α-nucleation effects. NaNA-MEA mainly induces the α crystal form, and its induction effect on the β crystal form is extremely weak (no obvious peak at β(300) in the figure), making it a highly efficient α-nucleating agent.

[0058] Figure 3 As can be observed in the TEM images of Comparative Examples 2 and 3, HPN-68L and NaNA-MEA exhibit significant aggregation in PP, with Comparative Example 2 showing the most pronounced aggregation, followed by Comparative Example 3. In contrast, due to the good compatibility between GPP and PP, NaNA / MEA-g-GPP in Example 3 shows good dispersibility in PP without aggregation. A comparison between Comparative Examples 2 and 3 reveals that NaNA / MEA-g-GPP exhibits stronger dispersibility in PP than HPN-68L.

[0059] Figure 4 It can be observed in the DSC chart that the crystallization temperatures of Comparative Example 1, Comparative Example 2, and Example 3 are 118℃, 131℃, and 125℃, respectively. This is in contrast to PP and PP-NaNA / MEA-g-GPP. 1:2 PP-NaNA / MEA-g-GPP 1:2 The crystallization temperature was increased by 7℃, resulting in a significant improvement in crystallization performance and an α-nucleation effect.

[0060] Figure 5 As can be observed in the SEM images of Comparative Examples 2 and 3, HPN-68L and NaNA-MEA exhibit significant aggregation in PP. However, in Example 3, due to the good compatibility between GPP and PP, NaNA / MEA-g-GPP shows good dispersibility in PP without aggregation. A comparison between Comparative Examples 2 and 3 reveals that NaNA / MEA-g-GPP exhibits stronger dispersibility in PP than HPN-68L.

[0061] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a nucleating agent with α-nucleation activity on polypropylene, characterized in that, Includes the following steps: S1. Add norbornene dicarboxylic acid and mercaptoethylamine to a methanol solution and mix well. Add the photoinitiator 2,2-dimethoxy-2-phenylacetophenone. Under ultraviolet light irradiation, a norbornene dicarboxylic acid-mercaptoethylamine precipitate is generated. Then, sodium hydroxide is added to dissolve the precipitate to generate a sodium norbornene dicarboxylic acid-mercaptoethylamine solution. Dry the methanol to obtain sodium norbornene dicarboxylic acid-mercaptoethylamine powder. S2. Sodium norbornene dicarboxylate-mercaptoethylamine powder and epoxy polypropylene are dispersed in xylene at a mass ratio of 1:0.2~10 and reacted at 120~160℃ to generate sodium norbornene dicarboxylate-mercaptoethylamine grafted epoxy polypropylene, which is a nucleating agent with α-nucleation effect on polypropylene.

2. The method for preparing the nucleating agent with α-nucleation effect on polypropylene according to claim 1, characterized in that, The amount of photoinitiator added is 0.2 to 1.0 wt% of the total mass of norbornene dicarboxylic acid and mercaptoethylamine.

3. The method for preparing the nucleating agent with α-nucleation effect on polypropylene according to claim 1, characterized in that, The mass ratio of sodium norbornene dicarboxylate-mercaptoethylamine to epoxy polypropylene is 1:5~1.

4. A nucleating agent, characterized in that, It is prepared by the preparation method according to any one of claims 1-3.

5. The application of the nucleating agent according to claim 4 in modified polypropylene.

6. A method for preparing a polypropylene composite material, characterized in that, The nucleating agent described in claim 4 and polypropylene are added to a mixing equipment for melt blending to obtain a polypropylene composite material.

7. The method for preparing the polypropylene composite material according to claim 6, characterized in that, The mixing equipment is an internal mixer with a rotation speed of 20~100 rpm, a mixing time of 2~20 min, and a mixing temperature range of 180~210℃.

8. The method for preparing the polypropylene composite material according to claim 6, characterized in that, The nucleating agent is added at a rate of 0.05 to 1.0 wt% of polypropylene.

9. The method for preparing the polypropylene composite material according to claim 6, characterized in that, It also includes a drying step for the raw materials: before melt blending, the polypropylene granules are vacuum dried at 70~80℃ for 24~72h, and the nucleating agent powder is vacuum dried at 50~60℃ for 24~72h.

10. A polypropylene composite material, characterized in that, It is prepared by the preparation method according to any one of claims 6-9.

Images