Polypropylene material with high strength and high pressure resistance and preparation method thereof

Abstract

The invention relates to the technical field of materials, and discloses a polypropylene material with high strength and strong anti-pressure ability and a preparation method, the polypropylene material is prepared by taking polypropylene as a base material and a linen fiber modified additive and the like as auxiliary materials through mixing and extrusion processes, the linen fiber modified additive is prepared by modifying macromolecular substances with norbornane-erythritol alternate connection structures on the surfaces of linen fibers, and the macromolecular substances can react with anhydride groups of maleic anhydride grafted polypropylene in the subsequent melt extrusion process, so that interlocking can be formed between the linen fibers and a polypropylene matrix; according to the present invention, the macromolecular substance structure contains the high bond energy silicon-oxygen bond and the rigid ring structure, such that the stability of the polypropylene can be improved so as to further enhance the impact resistance and other mechanical properties of the polypropylene.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a high-strength, high-compression-resistance polypropylene material and its preparation method. Background Technology

[0002] Polypropylene (PP) is a semi-crystalline polymer produced by the addition polymerization of propylene monomers. It is colorless, odorless, non-toxic, and translucent, exhibiting characteristics such as lightweight, low cost, excellent processing performance, chemical resistance, and recyclability. It occupies an important position in the field of daily-use plastics. As the application of daily-use plastics becomes more widespread, the requirements for strength are also increasing. Due to the linear structure of polypropylene, its mechanical properties such as impact resistance are relatively poor, which is gradually becoming an important obstacle to its further application in daily-use plastics. Therefore, it is urgent to strengthen and modify polypropylene.

[0003] Currently, there is considerable research on the reinforcement and modification of polypropylene using nanotechnology, such as nano-silica and nano-titanium dioxide. These nano-additives can improve the impact resistance of polypropylene by dispersing stress concentration points. In addition, fiber additives such as glass fiber can improve the mechanical strength of polypropylene by bearing external loads. However, there is a natural interface problem between these inorganic additives and polypropylene, and they cannot form a good dispersion system, inevitably leading to agglomeration. Therefore, it is difficult to achieve efficient performance. Based on this, the present invention provides a polypropylene material with good mechanical strength, which can solve the problems existing in the prior art. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the purpose of this invention is to provide a high-strength, high-compression-resistance polypropylene material and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A high-strength, high-compression-resistance polypropylene material, comprising the following raw materials measured in parts by weight:

[0007]

[0008] The flax fiber modifying additive is prepared by modifying the surface of flax fibers with macromolecular substances having alternating linkage structures.

[0009] As a further embodiment of the present invention, the toughening agent is a polyolefin elastomer; the antioxidant is any one of antioxidant 168, antioxidant 626 or antioxidant 1076; and the lubricant is vinyl bis-stearamide or magnesium stearate.

[0010] As a further aspect of the present invention, the flax fiber modifying additive is prepared by the following method:

[0011] Step 1: Add the alkali-treated flax fiber to anhydrous toluene and disperse it evenly. Then add isocyanate methacrylate and catalyst. After the addition is complete, stir evenly and keep it at a temperature of 60-70℃ for 6-9 hours. Then discharge the material, separate the solid material, and wash and vacuum dry it to obtain organic modified flax fiber.

[0012] Step 2: Add the organically modified flax fiber to ethanol, sonicate until a uniform dispersion is formed, then purge with nitrogen for protection, and continue to add norbornene derivative and photoinitiator. After the addition is complete, irradiate with ultraviolet light for 30-60 minutes, then add dithioerythritol and irradiate for 3-6 hours. After that, separate the product and purify it to obtain the flax fiber modified additive.

[0013] As a further aspect of the present invention, in step one, the alkali treatment method for the flax fiber is as follows:

[0014] Add flax fibers to a 10-30% sodium hydroxide aqueous solution, stir until homogeneous, heat to 60-70℃, stir continuously for 1-2 hours, cool down and discharge, wash until neutral, and vacuum dry.

[0015] As a further aspect of the present invention, in step one, the catalyst is any one of dibutyltin dilaurate, stannous octoate, methyl thiotin, octyl thiotin, or dibutyltin diacetate.

[0016] As a further aspect of the present invention, in step two, the norcamphorane derivative is prepared by the following method:

[0017] 2-norborneol methanol and diallyl dichlorosilane were added to tetrahydrofuran and mechanically stirred until homogeneous. Then, an acid-binding agent was added. After the addition was complete, the temperature was raised to 60-65℃ and stirred continuously for 4-8 hours. The solvent was then evaporated to remove the product, which was collected and purified.

[0018] As a further aspect of the present invention, the molar ratio of 2-norborneol methanol and diallyl dichlorosilane is 1-2:1.

[0019] As a further embodiment of the present invention, the acid-binding agent is triethylamine or triethylenediamine.

[0020] As a further aspect of the present invention, in step two, the photoinitiator is any one of Irgacure 184, Irgacure 2959, or Irgacure 907.

[0021] It should be noted that in the above technical solution, flax fibers are first treated with alkali to expose a large number of active hydroxyl groups on their surface. Then, under the action of a catalyst, ethyl isocyanate methacrylate is used to perform alkenyl functionalization modification on the alkali-treated flax fibers to obtain flax fibers with unsaturated alkenyl substituents on their surface, i.e., organically modified flax fibers. Next, using the unsaturated alkenyl substituents of the organically modified flax fibers as active initiation sites, using norcamphene derivatives as crosslinking agents, and using dithioerythritol as chain extenders, under photoinitiator and light irradiation conditions, the unsaturated alkenyl substituents and thiol substituents in each other's structures undergo continuous click-addition reactions, thereby modifying the surface of the flax fibers with a macromolecular substance with an alternating nocamphene-erythritol linkage structure to obtain a flax fiber modified additive.

[0022] The norbornene derivatives are prepared by reacting the active hydroxyl substituents in the structures of 2-norborneol methanol and diallyl dichlorosilane with Si-Cl.

[0023] A method for preparing a high-strength, high-compression-resistance polypropylene material includes the following steps:

[0024] Step 1: Weigh each raw material according to the specified weight proportions to complete the material preparation;

[0025] The second step is to add all the raw materials into a high-speed mixer and mechanically stir and mix them evenly at a speed of 300-500 r / min to obtain the mixed raw materials.

[0026] The third step is to feed the mixed raw materials into the twin-screw extruder through the feed port, control the extrusion temperature to 190-220℃, and then perform melt extrusion granulation.

[0027] The beneficial effects of this invention are:

[0028] This invention prepares a flax fiber modifying additive by modifying the surface of flax fibers with a macromolecular substance featuring an alternating linking structure of norbornene and erythritol. On one hand, the hydroxyl groups of erythritol in the macromolecular substance can interact with the anhydride groups of maleic anhydride-grafted polypropylene during subsequent melt extrusion, thereby promoting a three-dimensional cross-linking structure between the macromolecular substance and the polypropylene molecular chains. This allows for interlocking between the flax fiber and the polypropylene matrix, creating a "mortise and tenon" effect, fully utilizing the properties of the flax fiber and improving the mechanical strength of the polypropylene. Simultaneously, the cross-linking network can alter the direction of force transmission, preventing stress concentration. Furthermore, the presence of high-bond-energy silicon-oxygen bonds and rigid cyclic structures in the macromolecular substance structure improves the stability of the polypropylene, further enhancing its impact resistance and other mechanical properties.

[0029] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is an infrared analysis test image of norcamphene derivatives. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Preparation Example

[0034] Preparation of flax fiber modifying additives:

[0035] Step A: Add 2.5g of flax fiber to 100mL of 20% sodium hydroxide aqueous solution, stir evenly, heat to 65℃, stir continuously for 1 hour, cool down and discharge, wash until neutral, and vacuum dry.

[0036] Step B: Add 1.8g of alkali-treated flax fiber to anhydrous toluene and disperse it evenly. Then add 0.4g of isocyanate methacrylate and 0.01g of dibutyltin dilaurate. After the addition is complete, stir evenly and keep it at 70℃ for 8 hours. Then discharge the material, separate the solid material, wash and vacuum dry it to obtain organic modified flax fiber.

[0037] Step C: Add 1.5g of organically modified flax fiber to ethanol, sonicate until a uniform dispersion is formed, then purge with nitrogen for protection, and continue to add 0.8g of norbornene derivative and 0.1g of photoinitiator Irgacure2959. After the addition is complete, irradiate with a 365nm ultraviolet lamp for 40min, then add 0.3g of dithioerythritol, and irradiate for 4h. Separate the product, and after purification, obtain the flax fiber modified additive.

[0038] The norbornene derivatives were prepared using the following method:

[0039] 0.69 g of 2-norborneol methanol and 0.5 g of diallyl dichlorosilane were added to tetrahydrofuran and mechanically stirred until homogeneous. Then, 0.1 g of triethylamine was added. After the addition was complete, the temperature was raised to 65 °C and stirred continuously for 6 h. The solvent was then evaporated to remove the product, which was collected and purified.

[0040] Figure 1 The image shows the infrared analysis results of norbornene derivatives, with 3061 cm⁻¹ as an example. -1 The characteristic absorption peak appearing at 2930 cm⁻¹ is attributed to the characteristic absorption peak of CH in unsaturated carbon-carbon double bonds. -1 and 2868cm -1 The characteristic absorption peak appearing at 1076 cm⁻¹ is attributed to the CH characteristic absorption peaks of the methylene and methine groups. -1 The characteristic absorption peak appearing at this point is attributed to the characteristic absorption peak of Si-O.

[0041] Example 1

[0042] A high-strength, high-compression-resistance polypropylene material, comprising the following raw materials measured in parts by weight:

[0043]

[0044] The preparation method of the polypropylene material includes the following steps:

[0045] Step 1: Weigh each raw material according to the specified weight proportions to complete the material preparation;

[0046] The second step is to add all the raw materials into a high-speed mixer and mechanically stir and mix them evenly at a speed of 400 r / min to obtain the mixed raw materials.

[0047] The third step is to feed the mixed raw materials into the twin-screw extruder through the feed port, control the extrusion temperature to 200℃, and then perform melt extrusion granulation.

[0048] The preparation method of the flax fiber modified additive is shown in the preparation example, and the same applies to the following.

[0049] Example 2

[0050] A high-strength, high-compression-resistance polypropylene material, comprising the following raw materials measured in parts by weight:

[0051]

[0052]

[0053] The preparation method of the polypropylene material includes the following steps:

[0054] Step 1: Weigh each raw material according to the specified weight proportions to complete the material preparation;

[0055] The second step is to add all the raw materials into a high-speed mixer and mechanically stir and mix them evenly at a speed of 400 r / min to obtain the mixed raw materials.

[0056] The third step is to feed the mixed raw materials into the twin-screw extruder through the feed port, control the extrusion temperature to 200℃, and then perform melt extrusion granulation.

[0057] Example 3

[0058] A high-strength, high-compression-resistance polypropylene material, comprising the following raw materials measured in parts by weight:

[0059]

[0060] The preparation method of the polypropylene material includes the following steps:

[0061] Step 1: Weigh each raw material according to the specified weight proportions to complete the material preparation;

[0062] The second step is to add all the raw materials into a high-speed mixer and mechanically stir and mix them evenly at a speed of 500 r / min to obtain the mixed raw materials.

[0063] The third step involves feeding the mixed raw materials into a twin-screw extruder through the feed port, controlling the extrusion temperature at 200℃, and then performing a melt extrusion granulation process.

[0064] Comparative Example 1

[0065] A polypropylene material, which differs from Example 2 in that the flax fiber modifying additive is replaced with flax fiber, otherwise the same.

[0066] Comparative Example 2

[0067] A polypropylene material, which differs from Example 2 in that the flax fiber modifying additive is removed, but otherwise it is the same.

[0068] Test case

[0069] The polypropylene materials used in the examples and comparative examples were prepared into various test specimens that met specifications, and various performance tests were conducted:

[0070] Tensile strength tests were conducted according to standard GB / T 1040.1-2025, with the tensile rate controlled at 10 mm / min.

[0071] According to standard GB / T 1843-2008, notched impact strength test was conducted, type A notch, at a test temperature of 23℃;

[0072] The test results are recorded in the table below:

[0073] Table 1 - Test Results

[0074] Tensile strength (MPa) <![CDATA[Notch impact strength (kJ / m 2 )]]> Example 1 33.6 13.1 Example 2 33.9 13.5 Example 3 33.8 13.3 Comparative Example 1 30.5 11.0 Comparative Example 2 26.4 9.4

[0075] Analysis of the test results shows that the polypropylene material prepared in the embodiments of the present invention exhibits good tensile strength and impact resistance. However, after replacing the flax fiber modifier with flax fiber, an interfacial problem exists between the flax fiber and the polypropylene matrix, preventing it from fully exerting its reinforcing effect and utilizing the properties of macromolecules, resulting in a significant decline in the various properties of the polypropylene material.

[0076] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength, high-compression-resistance polypropylene material, characterized in that, Including the following raw materials measured in parts by weight: The flax fiber modifying additive is prepared by modifying the surface of flax fibers with macromolecular substances having alternating linkage structures.

2. The high-strength, high-compression-resistance polypropylene material according to claim 1, characterized in that, The toughening agent is a polyolefin elastomer; the antioxidant is any one of antioxidant 168, antioxidant 626, or antioxidant 1076; and the lubricant is vinyl bis-stearamide or magnesium stearate.

3. The high-strength, high-compression-resistance polypropylene material according to claim 1, characterized in that, The flax fiber modifying additive is prepared using the following method: Step 1: Add the alkali-treated flax fiber to anhydrous toluene and disperse it evenly. Then add isocyanate methacrylate and catalyst. After the addition is complete, stir evenly and keep it at a temperature of 60-70℃ for 6-9 hours. Then discharge the material, separate the solid material, and wash and vacuum dry it to obtain organic modified flax fiber. Step 2: Add the organically modified flax fiber to ethanol, sonicate until a uniform dispersion is formed, then purge with nitrogen for protection, and continue to add norbornene derivative and photoinitiator. After the addition is complete, irradiate with ultraviolet light for 30-60 minutes, then add dithioerythritol and irradiate for 3-6 hours. After that, separate the product and purify it to obtain the flax fiber modified additive.

4. The high-strength, high-compression-resistance polypropylene material according to claim 3, characterized in that, In step one, the alkali treatment method for the flax fiber is as follows: Add flax fibers to a 10-30% sodium hydroxide aqueous solution, stir until homogeneous, heat to 60-70℃, stir continuously for 1-2 hours, cool down and discharge, wash until neutral, and vacuum dry.

5. The high-strength, high-compression-resistance polypropylene material according to claim 3, characterized in that, In step one, the catalyst is any one of dibutyltin dilaurate, stannous octoate, methyl thiotin, octyl thiotin, or dibutyltin diacetate.

6. The high-strength, high-compression-resistance polypropylene material according to claim 3, characterized in that, In step two, the norcamphorane derivative is prepared using the following method: 2-norborneol methanol and diallyl dichlorosilane were added to tetrahydrofuran and mechanically stirred until homogeneous. Then, an acid-binding agent was added. After the addition was complete, the temperature was raised to 60-65℃ and stirred continuously for 4-8 hours. The solvent was then evaporated to remove the product, which was collected and purified.

7. The high-strength, high-compression-resistance polypropylene material according to claim 6, characterized in that, The molar ratio of 2-norborneol methanol and diallyl dichlorosilane is 1-2:

1.

8. The high-strength, high-compression-resistance polypropylene material according to claim 6, characterized in that, The acid-binding agent is triethylamine or triethylenediamine.

9. The high-strength, high-compression-resistance polypropylene material according to claim 3, characterized in that, In step two, the photoinitiator is any one of Irgacure 184, Irgacure 2959, or Irgacure 907.

10. A method for preparing a high-strength, high-compression-resistance polypropylene material as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh each raw material according to the specified weight proportions to complete the material preparation; The second step is to add all the raw materials into a high-speed mixer and mechanically stir and mix them evenly at a speed of 300-500 r / min to obtain the mixed raw materials. The third step is to feed the mixed raw materials into the twin-screw extruder through the feed port, control the extrusion temperature to 190-220℃, and then perform melt extrusion granulation.

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