Ultrasonic-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material and preparation method thereof
Through ultrasonic-assisted polydopamine mediation method, para-aramid fibers are modified, which solves the problem of difficulty in hydrophilic modification, and achieves the modification of the fiber surface and improves the mechanical properties, and is suitable for structural components in high-strength usage scenarios.
Patent Information
- Application Number
- CN202510020680.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-05-06
AI Technical Summary
The prior art has problems in the hydrophilicity of modified para-aramid fibers, which are complicated to control, have low performance and poor surface wetting ability.
Using an ultrasonic-assisted polydopamine-mediated method, the PDA@PPTA composite was formed by combining sodium dodecylbenzenesulfonate, para-aramid fiber, Tris-HCl buffer solution, dopamine hydrochloride and polycarbonate PC plastic particles, and kneaded with polycarbonate to improve the roughness and wettability of the fiber surface.
It significantly improves the water dispersion and mechanical properties of the fiber, improves the interface interaction between the fiber and the matrix, and improves the overall performance of the composite material.
Smart Images
Figure CN119931296A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material and a preparation method thereof, and belongs to the field of interface chemistry. Background Art
[0002] Para-aramid fiber, full name poly(p-phenylene terephthalamide) fiber. As a chemical synthetic fiber, para-aramid fiber has excellent high-strength and high-modulus mechanical properties, good heat-resistant insulation properties and chemical stability, etc. It is widely used in the aerospace field, such as structural materials for rockets and aircraft, thermal insulation materials, protective materials and high-performance electronic equipment; however, the highly regular molecular chain segments, high crystallinity and skin-core model structure of PPTA fiber make its surface smooth, with few polar groups and poor hydrophilicity, resulting in poor water dispersibility of the fiber and flocculation during the aramid papermaking process, which reduces the uniformity of the paper and affects various performance indicators of the paper.
[0003] At present, in the research on hydrophilic modification of PPTA fibers, commonly used physical methods include plasma treatment, high-energy ray irradiation treatment, ultrasonic treatment, etc., which improve the hydrophilicity of fibers by increasing the active sites or contact area on the fiber surface. However, most of these methods have high requirements for instruments and equipment and high costs. Long-term treatment will greatly reduce the mechanical properties of fibers. Chemical methods mainly include chemical etching and chemical grafting, which achieve the purpose of hydrophilicity by introducing active groups such as -OH, -COOH, -NH2, and -SO3H on the fiber surface. However, these methods have complicated reaction conditions and are difficult to control, take a long time, and the reagents are toxic and difficult to recover, which changes the existence form of para-aramid fibers.
[0004] Surface coating is to select a coating agent with similar miscibility to the coated object (mostly polyurethane, aliphatic polymers and other organic solvents) for coating modification, but most organic solvents are highly toxic, difficult to degrade and difficult to handle;
[0005] After phosphoric acid treatment, the fiber surface showed notches and a small amount of fibrils, the specific surface area increased and more active groups such as -OH and -COOH were exposed, but high concentration phosphoric acid treatment reduced the mechanical properties of para-aramid fiber;
[0006] Ultrasonic treatment uses the cavitation effect of ultrasound to physically treat the fiber to produce notches by generating impact energy when the cavitation bubble ruptures. However, long-term ultrasonic treatment will affect the cavitation effect and cause the fiber to flocculate again.
[0007] Therefore, it is urgent to propose an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material and a preparation method to solve the above technical problems. Summary of the invention
[0008] The present invention is to solve the problems of cumbersome and difficult to control preparation, low performance and poor surface wetting ability formed by common technology. A brief summary of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to determine the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.
[0009] The technical solution of the present invention:
[0010] An ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material, wherein the ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material is composed of sodium dodecylbenzene sulfonate, para-aramid fiber, Tris-HCl buffer solution, dopamine hydrochloride and polycarbonate PC plastic particles;
[0011] The mass fraction of the sodium dodecylbenzene sulfonate is 1-2 parts, the mass fraction of the para-aramid fiber is 1-5 parts, the mass fraction of the Tris-HCl buffer solution is 100 parts, the mass fraction of dopamine hydrochloride is 0.1-0.3 parts, and the mass fraction of the polycarbonate PC plastic particles is 50 parts.
[0012] Preferably, the para-aramid fiber is para-aramid fiber PPTA chopped fiber.
[0013] Preferably, the Tris-HCl buffer solution is obtained by mixing tris(hydroxymethyl)aminomethane hydrochloride) powder and 0.1 M hydrochloric acid.
[0014] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0015] Step 1: dissolving sodium dodecylbenzene sulfonate in deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 1-3×10-3M;
[0016] Step 2: Soak the PPTA chopped fibers in a sodium dodecylbenzene sulfonate solution, and heat and keep warm;
[0017] Step 3: Take out the soaked PPTA fiber, wash it with distilled water, and place it in a vacuum drying oven to dry;
[0018] Step 4: Transfer the dried PPTA fiber to a Tris-HCl buffer solution and place it in an ultrasonic reactor, then dissolve dopamine hydrochloride in the Tris-HCl buffer solution and stir evenly, and after the reaction is completed, a PDA@PPTA complex is obtained;
[0019] Step 5: Mix the PDA@PPTA compound and polycarbonate, add them into an internal mixer for mixing, and obtain a mixed PDA@PPTA / PC compound.
[0020] Preferably, the heating temperature in step 2 is 40-60° C., and the insulation reaction time is 3 h.
[0021] Preferably, the temperature of the vacuum drying oven is 100-120° C., and the drying time is 3-5 hours.
[0022] Preferably, the stirring rate in step 4 is 100-200 rpm.
[0023] Preferably, the ultrasonic frequency is 22-40 kHz, and the ultrasonic reaction time is 3-6 h.
[0024] Preferably, the temperature of the internal mixer is set to 180-200° C., and the shear stirring rate is 60-80 rpm.
[0025] The present invention has the following beneficial effects:
[0026] The present invention uses oxidative free radicals generated by high-frequency ultrasound (>20kHz) to initiate and accelerate the polymerization of dopamine. In the presence of oxygen, the sonochemical rate of thin film deposition is twice as fast as that of traditional methods.
[0027] The present invention combines with polycarbonate and aramid fibers by forming hydrogen bonds, π-π stacking, covalent bonds, etc., to increase the fiber surface roughness and wettability, thereby improving mechanical interlocking and interface interaction;
[0028] The composite material of vegetation of the present invention can be effectively applied to structural components, high-efficiency bearings, etc. in high-intensity usage scenarios, and has important social and industrial value. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 These are the FTIR spectra images of aramid fiber PPTA and polydopamine-modified aramid fiber PDA@PPTA. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.
[0031] Specific implementation method 1: Combination Figure 1The present embodiment is described. The present embodiment is an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material. The ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material is composed of sodium dodecylbenzene sulfonate, para-aramid fiber, Tris-HCl buffer solution, dopamine hydrochloride and polycarbonate PC plastic particles;
[0032] The mass fraction of the sodium dodecylbenzene sulfonate is 1-2 parts, the mass fraction of the para-aramid fiber is 1-5 parts, the mass fraction of the Tris-HCl buffer solution is 100 parts, the mass fraction of dopamine hydrochloride is 0.1-0.3 parts, and the mass fraction of polycarbonate PC plastic particles is 50 parts. The components in the composite material ratio play a complementary role.
[0033] Polydopamine improves the bonding force between the fiber and the matrix, the fiber enhances the strength of the material, while polycarbonate provides toughness, and ultrasound ensures fiber dispersion. The quantitative ratio of each component can ensure that the composite material achieves a good balance between reinforcement and toughness.
[0034] Specific implementation method 2: Combination Figure 1 The present embodiment is described as an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material, wherein the para-aramid fiber is para-aramid fiber PPTA chopped fiber.
[0035] Short-cut fibers, such as fibers with a length of 1-5 mm, are easier to disperse in the matrix than long fibers and can provide a more uniform reinforcement effect. Short-cut fibers can improve processability in composite materials and reduce the difficulty of material processing without affecting the mechanical properties of the composite materials.
[0036] Due to their short length, short-cut para-aramid fibers can effectively avoid the orientation differences and aggregation problems that may be caused by long fibers, further improving the overall uniformity of the composite material.
[0037] Specific implementation method three: Combination Figure 1 The present embodiment is described. The present embodiment is an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material. The Tris-HCl buffer solution is obtained by mixing tris(hydroxymethyl)aminomethane hydrochloride) powder and 0.1 M hydrochloric acid.
[0038] Dissolve 3 parts of Tris in 250 parts of deionized water, add 15-25 parts of 0.1 M concentrated hydrochloric acid, and mix well to obtain a Tris-HCl buffer with the required pH value.
[0039] The main function of Tris-HCl buffer solution in the preparation process of this composite material is to provide a suitable pH environment to promote the formation of polydopamine and the surface modification of para-aramid fibers. Under the condition of ultrasound assistance, the reaction efficiency can be improved, and a good interface bonding between the fiber and the polycarbonate matrix can be ensured, thereby improving the mechanical, thermal and chemical properties of the composite material.
[0040] Specific implementation method four: Combination Figure 1 The present embodiment is described. The present embodiment is an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material preparation method, comprising the following steps:
[0041] Step 1: dissolving sodium dodecylbenzene sulfonate in deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 1-3×10-3M;
[0042] Step 2: Soak the PPTA chopped fibers in a sodium dodecylbenzene sulfonate solution, and heat and keep warm;
[0043] Step 3: Take out the soaked PPTA fiber, wash it with distilled water, and place it in a vacuum drying oven to dry;
[0044] Step 4: Transfer the dried PPTA fiber to a Tris-HCl buffer solution and place it in an ultrasonic reactor, then dissolve dopamine hydrochloride in the Tris-HCl buffer solution and stir evenly, and after the reaction is completed, a PDA@PPTA complex is obtained;
[0045] Step 5: Mix the PDA@PPTA compound and polycarbonate, add them into an internal mixer for mixing, and obtain a mixed PDA@PPTA / PC compound. This method not only improves the bonding force between the fiber and the matrix, but also optimizes the mechanical properties and interface strength of the composite material.
[0046] Tris-HCl buffer solution can stabilize the pH value of the solution, usually in the pH range of 7 to 10. In an alkaline environment, dopamine molecules will self-polymerize to form polydopamine. The hydroxide ions in the Tris-HCl buffer solution can promote the oxidative polymerization of dopamine molecules, generate a polydopamine coating and deposit it on the surface of the PPTA fiber. Since the Tris-HCl buffer solution has good buffering capacity, it can maintain a constant pH value of the solution, prevent pH fluctuations caused by changes during the reaction, and thus ensure the stability of the polymerization reaction.
[0047] Polydopamine contains functional groups such as phenolic hydroxyl and amine groups. These functional groups have strong hydrophilicity, affinity and reactivity, and can produce chemical adsorption or van der Waals force on the surface of PPTA fibers, enhance the activity of the fiber surface, and facilitate the combination with the polycarbonate matrix.
[0048] Specific implementation method five: Combination Figure 1 The present embodiment is described as follows. The present embodiment is an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material preparation method. In step 2, the heating temperature is 40-60° C., and the heat preservation reaction time is 3 hours.
[0049] Heating can promote the cross-linking of the polycarbonate matrix and the polydopamine layer on the fiber surface, forming a stronger interfacial bonding force, thereby improving the mechanical properties and thermal stability of the composite material. In the range of 40-60°C, it can avoid the degradation of polydopamine and other materials due to excessively high temperatures, while maintaining the stability of the reaction.
[0050] The number of washings in step three is 3. The first washing removes most of the solvent or impurities, and the second and third washings ensure that all residues are completely removed, especially the residues deep inside the inner and outer surfaces of the fiber. Excessive washing times may cause unnecessary physical or chemical damage to the fiber.
[0051] Specific implementation method six: Combination Figure 1 The present embodiment is described as a method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material. The temperature of the vacuum drying oven is 100-120° C., and the drying time is 3-5 hours.
[0052] During the composite molding process, the presence of water and solvents may lead to a weak bond between the matrix and the fiber, and even affect the overall mechanical properties of the composite. Through vacuum drying, the internal structure of the composite is more stable and the interface bonding is better, thereby improving the final performance of the composite. 3-5 hours is enough time for the water in the composite to evaporate completely, and at the same time, it will not be overheated to cause material degradation. 100-120℃ avoids thermal degradation of the polydopamine coating at high temperatures. This temperature can accelerate the volatilization process of the solvent, while ensuring that the para-aramid fiber and polycarbonate matrix material will not be damaged by excessive temperatures.
[0053] Specific implementation method seven: Combination Figure 1 This embodiment is described. In this embodiment, an ultrasound-assisted method for preparing a polydopamine-mediated para-aramid fiber / polycarbonate composite material is provided. In step four, the stirring rate is 100-200 rpm.
[0054] A moderate stirring rate of 100-200rpm can effectively control the dispersion of fibers in polycarbonate, avoid fiber agglomeration, ensure the uniformity of the composite material, and avoid excessively high stirring rates that may cause fiber breakage or shear deformation of the polycarbonate matrix. Excessively low stirring rates may cause uneven dispersion of the fibers, affecting the overall performance of the composite material.
[0055] Specific implementation method eight: Combination Figure 1 The present embodiment is described as an ultrasound-assisted method for preparing a polydopamine-mediated para-aramid fiber / polycarbonate composite material. The ultrasound frequency is 22-40 kHz, and the ultrasound reaction time is 3-6 h.
[0056] Ultrasonic waves within this frequency range can effectively promote the synthesis and modification reaction of polydopamine (PDA), and help form a uniform polydopamine coating on the surface of aramid fibers. The ultrasonic reaction time of 3-6 hours is a reasonable range, which can ensure that polydopamine is fully modified on the surface of aramid fibers and forms a stable coating. Too short a reaction time may result in an uneven or insufficiently dense polydopamine coating, while too long a reaction time may cause excessive deposition or polymerization of the coating, affecting the material properties.
[0057] Specific implementation method nine: Combination Figure 1 The present embodiment is described as an ultrasound-assisted method for preparing a polydopamine-mediated para-aramid fiber / polycarbonate composite material. The temperature of the internal mixer is set to 180-200° C., and the shear stirring rate is 60-80 rpm.
[0058] Polycarbonate exhibits better fluidity at higher temperatures and can be more easily mixed with aramid fibers. In the temperature range of 180-200°C, polycarbonate can be fully melted, reducing its viscosity, thereby improving mixing efficiency and promoting uniform distribution of aramid fibers.
[0059] Moderate shear stirring rate can effectively promote the interfacial bonding between fiber and polycarbonate, especially under the modification of polydopamine coating, which helps to enhance the interfacial affinity. Higher stirring rate helps to break the agglomeration between fibers and improve the mechanical properties and structural uniformity of the composite material.
[0060] The temperature of the internal mixer is controlled at 180-200℃ and the shear stirring rate is 60-80rpm, which can promote the good fusion between the para-aramid fiber and the polycarbonate matrix, and improve the mechanical properties of the composite material, such as tensile strength, impact strength and toughness. The good melt fluidity of polycarbonate and the good dispersion of aramid fiber work together to ensure the uniformity and high performance of the composite material.
[0061] Example 1
[0062] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0063] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 3×10-3 M;
[0064] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0065] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0066] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 7, and transfer the reaction container to an ultrasonic reactor with an ultrasonic frequency set to 22 kHz. Weigh 0.2 g of dopamine hydrochloride and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 h to obtain a PDA@PPTA complex;
[0067] Step 5: Weigh 5 g of PDA@PPTA compound and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PDA@PPTA / PC compound.
[0068] Example 2
[0069] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0070] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 3×10-3 M;
[0071] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0072] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0073] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 8.5, and transfer the reaction container to an ultrasonic reactor with an ultrasonic frequency set to 25 kHz. Weigh 0.2 g of dopamine hydrochloride and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 hours to obtain a PDA@PPTA complex;
[0074] Step 5: Weigh 5 g of PDA@PPTA compound and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PDA@PPTA / PC compound.
[0075] Example 3
[0076] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0077] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 3×10-3 M;
[0078] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0079] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0080] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 10, and transfer the reaction container to an ultrasonic reactor with an ultrasonic frequency set to 25 kHz. Weigh 0.2 g of dopamine hydrochloride and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 hours to obtain a PDA@PPTA complex;
[0081] Step 5: Weigh 5 g of PDA@PPTA compound and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PDA@PPTA / PC compound.
[0082] Example 4
[0083] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0084] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 3×10-3 M;
[0085] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0086] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0087] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 8.5, and transfer the reaction container to an ultrasonic reactor with an ultrasonic frequency set to 25 kHz. Weigh 0.1 g of dopamine hydrochloride and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 hours to obtain a PDA@PPTA complex;
[0088] Step 5: Weigh 5 g of PDA@PPTA compound and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PDA@PPTA / PC compound.
[0089] Example 5
[0090] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0091] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 3×10-3 M;
[0092] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0093] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0094] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 8.5, and transfer the reaction container to an ultrasonic reactor with an ultrasonic frequency set to 25 kHz. Weigh 0.2 g of dopamine hydrochloride and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 hours to obtain a PDA@PPTA complex;
[0095] Step 5: Weigh 5 g of PDA@PPTA compound and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PDA@PPTA / PC compound.
[0096] Comparative Example 1
[0097] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0098] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to a concentration of 3 × 10 -3 M sodium dodecylbenzenesulfonate solution;
[0099] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0100] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0101] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 8.5, and place the reaction container in a fume hood. Weigh 0.2 g of dopamine hydrochloride and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 h to obtain a PDA@PPTA complex;
[0102] Step 5: Weigh 5 g of PDA@PPTA compound and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PDA@PPTA / PC compound.
[0103] Comparative Example 2
[0104] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0105] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a concentration of 3×10 -3 M sodium dodecylbenzene sulfonate solution;
[0106] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0107] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0108] Step 4: Weigh 5 g of PPTA and 100 g of polycarbonate raw material, and add the mixture into an internal mixer through a feed port. The temperature of the internal mixer is 180° C. and the stirring speed is 80 rpm to obtain a mixed PPTA / PC composite.
[0109] Comparative Example 3
[0110] A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material comprises the following steps:
[0111] Step 1: Weigh 1.05 g of sodium dodecylbenzene sulfonate and dissolve it in 1000 mL of deionized water to prepare a concentration of 3×10 -3 M sodium dodecylbenzene sulfonate solution;
[0112] Step 2: Weigh 5 g of PPTA chopped fibers and add them to sodium dodecylbenzene sulfonate, heat the reaction vessel to 60°C, and keep the reaction warm for 3 hours;
[0113] Step 3: The soaked PPTA fiber is taken out and washed with distilled water for 3 times, and then placed in a vacuum drying oven at 100°C for 3 hours until it is completely dried;
[0114] Step 4: Transfer the dried PPTA fiber to 100 mL of Tris-HCl buffer solution with a pH of 8.5, and transfer the reaction container to an ultrasonic reactor with an ultrasonic frequency set to 25 kHz. Weigh 0.2 g of catechol and dissolve it in Tris-HCl buffer, and ensure that the reaction time is 4 hours to obtain a PDA@PPTA complex;
[0115] Step 5: Weigh 5g of PDA@PPTA compound and 100g of polycarbonate raw material, and add the mixture into the internal mixer through the feed port. The temperature of the internal mixer is 180°C and the stirring speed is 80rpm to obtain a mixed CA@PPTA / PC compound.
[0116] The preparation formulas of Tris-HCl buffer with different pH values are as follows:
[0117]
[0118] The performance of the ultrasonic-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material obtained from Examples 1 to 6 and Comparative Examples 1 to 3 was tested, and the results are shown in the following table:
[0119]
[0120] The contact angle performance test of the ultrasonic-assisted polydopamine-mediated para-aramid fiber obtained from Examples 1 to 6 and Comparative Examples 1 to 3 is as follows:
[0121]
[0122]
[0123] 1. Fourier Transform Infrared Spectroscopy (FTIR)
[0124] The sample to be tested is dried to remove moisture, 200 mg of spectrally pure KBr is weighed, the dry KBr powder is placed in an agate mortar, and then 1-3% of the sample is added and ground under an infrared lamp until the particle size is less than 2 μm. The ground sample and KBr powder are carefully placed in a mold and pressed into tablets using a tablet press.
[0125] 2. Tensile strength
[0126] According to the standard GB / T1040-79, the sample is subjected to tensile strength test. The sample is hot pressed into a perfect defect-free type III specimen in a mold, and the specimen is clamped in the chuck of a universal testing machine. Ensure that both ends of the specimen are parallel and perpendicular to the movement direction of the testing machine. Set the tensile speed to 10mm / min and the test temperature to room temperature. Start the universal testing machine and gradually increase the tensile force applied to the specimen until the specimen is damaged or the predetermined tensile degree is reached and the recording is stopped.
[0127] 3. Bending strength test
[0128] The bending strength test of the sample was carried out according to the test standard ASTM D790. The sample was hot pressed into a perfect defect-free bending specimen in a mold. The dynamic universal testing machine applied a bending force to the sample at a speed of 5mm / min and continued to load until the sample reached the preset maximum deformation.
[0129] It can be seen from the test results that the ultrasonic-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material prepared by the present invention has excellent tensile properties and bending properties. The degree of polydopamine polymerization in Example 2 is moderate, and the uniform morphology of dopamine brings the optimal interface bonding ability between polycarbonate and para-aramid fiber, thereby obtaining the optimal mechanical properties, which is the preferred experimental condition. In Examples 3 and 5, the polymerization rate of polydopamine is fast, and polydopamine accumulation occurs, which reduces the mechanical properties of the composite material. In the control group 1, there is a lack of ultrasonic assistance, and the polymerization rate of polydopamine is greatly affected. In the control group 2, there is a lack of polydopamine as an interface modifier, and the interface of the composite material is uneven and there are a large number of defects. In the control group 3, catechol with a similar structure is used to replace polydopamine as an interface modifier, and the hydrophilicity is poor. The results show that the ultrasonic-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material proposed by the present invention can effectively improve the interface compatibility of aramid fiber and polycarbonate, thereby improving the mechanical properties of the effective composite material.
[0130] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.
[0131] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. An ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material, characterized in that: The ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material is composed of sodium dodecylbenzene sulfonate, para-aramid fiber, Tris-HCl buffer solution, dopamine hydrochloride and polycarbonate PC plastic particles; The mass fraction of the sodium dodecylbenzene sulfonate is 1-2 parts, the mass fraction of the para-aramid fiber is 1-5 parts, the mass fraction of the Tris-HCl buffer solution is 100 parts, the mass fraction of dopamine hydrochloride is 0.1-0.3 parts, and the mass fraction of the polycarbonate PC plastic particles is 50 parts.
2. The ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 1, characterized in that: Para-aramid fiber is para-aramid fiber PPTA chopped fiber.
3. The ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 1, characterized in that: The Tris-HCl buffer solution is obtained by mixing tris(hydroxymethyl)aminomethane hydrochloride) powder and 0.1 M hydrochloric acid.
4. A method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material, characterized in that: The steps include: Step 1: dissolving sodium dodecylbenzene sulfonate in deionized water to prepare a sodium dodecylbenzene sulfonate solution with a concentration of 1-3×10-3M; Step 2: Soak the PPTA chopped fibers in a sodium dodecylbenzene sulfonate solution, and heat and keep warm; Step 3: Take out the soaked PPTA fiber, wash it with distilled water, and place it in a vacuum drying oven to dry; Step 4: Transfer the dried PPTA fiber to a Tris-HCl buffer solution and place it in an ultrasonic reactor, then dissolve dopamine hydrochloride in the Tris-HCl buffer solution and stir evenly, and after the reaction is completed, a PDA@PPTA complex is obtained; Step 5: Mix the PDA@PPTA compound and polycarbonate, add them into an internal mixer for mixing, and obtain a mixed PDA@PPTA / PC compound.
5. The method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 4, characterized in that: In step 2, the heating temperature is 40-60°C, and the insulation reaction time is 3h.
6. The method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 4, characterized in that: The temperature of the vacuum drying oven is 100-120° C., and the drying time is 3-5 hours.
7. The method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 4, characterized in that: In step 4, the stirring rate is 100-200 rpm.
8. The method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 4, characterized in that: The ultrasonic frequency is 22-40 kHz, and the ultrasonic reaction time is 3-6 hours.
9. The method for preparing an ultrasound-assisted polydopamine-mediated para-aramid fiber / polycarbonate composite material according to claim 4, characterized in that: The temperature of the internal mixer was set at 180-200° C., and the shear stirring rate was 60-80 rpm.