Preparation method of high-strength aluminum-based reinforced modified polyamide composite material

Abstract

The invention relates to the technical field of polymer-based composite materials, in particular to a preparation method of a high-strength aluminum-based reinforced modified polyamide composite material, which is characterized in that a high-performance composite material with tensile strength of more than or equal to 100MPa is prepared by main reinforcement of glass fiber GF and synergistic toughening of foamed aluminum particles FA and by combining interface modification and process optimization. According to the formula, the GF accounts for 20-30%, the FA accounts for 10-20%, the nylon resin accounts for 50-65%, the binding force of a reinforcing phase and a matrix is improved through dual interface modification, and it is guaranteed that the GF length retention rate is larger than or equal to 85% through the side feeding technology. The tensile strength of the obtained composite material can reach 125-150 MPa, the notch impact strength is 8.5-10.5 kJ / m < 2 >, the density is 1.10-1.18 g / cm < 3 >, and the composite material has high strength, light weight and good processing stability, and is suitable for high-strength demand scenes such as automobile parts and aerospace secondary bearing parts.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer-based composite materials, and in particular to a method for preparing a high-strength aluminum-based reinforced modified polyamide composite material. Background Art

[0002] Nylon (polyamide, PA) is widely used in structural parts due to its excellent wear resistance, oil resistance, and processability. However, its pure resin tensile strength is only 50-80 MPa, which is difficult to meet the needs of mid-to-high-end load-bearing. The main way to increase strength is to add a reinforcing phase, but this has the following problems:

[0003] Glass fiber (GF) reinforcement: GF can significantly improve strength (pure GF reinforced PA66 tensile strength is about 120-150MPa), but the density is higher (usually >1.3g / cm 3 ), and uneven fiber dispersion can easily lead to performance fluctuations.

[0004] Foam aluminum particles (FA) reinforcement: FA has low density (0.2-0.6g / cm 3 ), but its strength is weak and its interface bonding with nylon is poor, so its strength improvement is limited (<90MPa) when filled alone.

[0005] Core defects of existing technologies:

[0006] Poor interface compatibility: The polarity of the oxide film on the surface of foamed aluminum and nylon is very different. Direct blending is likely to form interface defects, resulting in low stress transfer efficiency.

[0007] Insufficient synergistic effect of the reinforcing phase: The traditional process does not give full play to the synergistic effect of GF and FA, and cannot improve the interfacial adhesion of foam aluminum while ensuring fiber dispersion.

[0008] Therefore, according to the above-mentioned related technologies, it is urgent to develop a method for preparing a high-strength aluminum-based reinforced modified polyamide composite material. Summary of the Invention

[0009] In view of this, the purpose of the present invention is to propose a method for preparing a high-strength aluminum-based reinforced modified polyamide composite material, so as to provide a method for preparing a polyamide-based composite material through glass fiber main reinforcement + foam aluminum synergistic toughening + interface strengthening treatment, so as to achieve a tensile strength ≥100MPa while maintaining good processing performance and cost-effectiveness.

[0010] Based on the above objectives, the present invention provides a method for preparing a high-strength aluminum-based reinforced modified polyamide composite material.

[0011] A method for preparing a high-strength aluminum-based reinforced modified polyamide composite material comprises the following steps:

[0012] Step S1. Soak the main reinforcement phase in KH-550 ethanol solution for 15 minutes and dry it at 120°C for 2 hours to hydroxylate the surface, forming hydrogen bonds and chemical bonds with the matrix, thereby increasing the fiber pull-out resistance;

[0013] Step S2: The auxiliary reinforcing phase is pickled with 5% hydrochloric acid for 10 minutes to remove the oxide film, and then coated with a 2% titanate coupling agent solution and dried at 60°C for 3 hours to polarize the surface and form a covalent bond with the compatibilizer, thereby improving the interfacial bonding strength;

[0014] Step S3. Using twin-screw extrusion to blend, the matrix and compatibilizer are first melted, the auxiliary reinforcement phase is added in the compression section, and the main reinforcement phase is added in the metering section through a side feed port to prevent premature shearing of the fibers in the main reinforcement phase. During the process, 0.5wt%-1wt% DCP peroxide is added for in-situ crosslinking;

[0015] After step S4, thermal oxygen annealing is performed: heat preservation at 120°C for 4 hours to eliminate internal stress, promote secondary crystallization of the crystal region and the fiber interface, and improve tensile strength.

[0016] Preferably, the main reinforcement phase in step S1 accounts for 20%-30%, and the main reinforcement phase is glass fiber with an aspect ratio of ≥50, which forms a strong interface bond with the matrix nylon resin after surface treatment.

[0017] Preferably, the matrix in step S1 accounts for 50%-65%, and the matrix is nylon resin, which is used to provide toughness and processing fluidity.

[0018] Preferably, the auxiliary reinforcement phase in step S2 accounts for 10%-20%, and the auxiliary reinforcement phase is foamed aluminum particles, which are used to improve impact toughness and dimensional stability and reduce density.

[0019] Preferably, the proportion of the compatibilizer in step S2 is 3%-5%, and the compatibilizer is maleic anhydride grafted nylon, which is used to improve the compatibility between the matrix nylon resin and the foam aluminum particles.

[0020] Preferably, in step S3, the proportion of KH-550 is 1%-2%, and the proportion of titanate is 1%-2%.

[0021] Preferably, the equipment parameters of the twin-screw extrusion blending in step S3 are: aspect ratio (L / D) = 40:1.

[0022] Preferably, in the twin-screw extrusion blending in step S3, the temperature of zone 1 is 220°C, the temperature of zone 2 is 250°C, the temperature of zone 3 is 240°C, the temperature of zone 4 is 230°C, and the temperature of the die head is 210°C.

[0023] Preferably, the screw speed of the twin-screw extrusion blending in step S3 is 300 rpm and the feeding rate is 10 kg / h.

[0024] Preferably, during the twin-screw extrusion blending in step S3, the barrel temperature is 250-270°C, the mold temperature is 80-100°C to promote nylon crystallization, the injection pressure is 100-130 MPa to ensure fiber orientation, and the holding pressure is 80-100 MPa to reduce shrinkage defects.

[0025] Beneficial effects of the present invention:

[0026] The present invention provides a method for preparing a high-strength aluminum-based reinforced modified polyamide composite material. The present invention significantly improves the tensile strength through the synergy of glass fiber main reinforcement and foam aluminum, and improves the bonding force between the reinforcement phase and the matrix through double interface modification, thereby improving the stress transfer efficiency. Furthermore, through side feeding technology and screw combination optimization, the glass fiber is ensured to be evenly dispersed, the foam aluminum particles are kept at a high integrity rate, and the product performance fluctuation coefficient is maintained at a low level. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0028] Example 1: A method for preparing a high-strength aluminum-based reinforced modified polyamide composite material, comprising the following steps:

[0029] S1. Soak glass fibers with an aspect ratio ≥50 in a KH-550 ethanol solution for 15 minutes and then dry at 120°C for 2 hours to hydroxylate the surface and form hydrogen and chemical bonds with the matrix. The KH-550 content is 1%.

[0030] S2. The aluminum foam particles were pickled with 5% hydrochloric acid for 10 minutes to remove the oxide film. The particles were then coated with a 2% titanate coupling agent solution and dried at 60°C for 3 hours to polarize the surface and form covalent bonds with the compatibilizer, thereby enhancing the interfacial bonding strength. The titanate content was 1%.

[0031] S3. Using twin-screw extrusion blending, nylon resin and maleic anhydride grafted nylon are first melted, foamed aluminum particles are added in the compression section, and glass fiber is added in the metering section through a side feed port to prevent premature shearing of the glass fiber fibers. 0.5wt% DCP peroxide is added during the process for in-situ crosslinking. The nylon resin accounts for 50% to provide toughness and processing fluidity, the maleic anhydride grafted nylon accounts for 3% to improve the compatibility between the nylon resin and the foamed aluminum particles, the glass fiber accounts for 20%, and the glass fiber forms a strong interface bond with the matrix nylon resin after surface treatment. The foamed aluminum particles account for 10% to improve impact toughness and dimensional stability and reduce density.

[0032] After S4, thermal oxygen annealing is performed: keep the temperature at 120℃ for 4 hours to eliminate internal stress, promote secondary crystallization at the interface between the crystal region and the fiber, and increase the tensile strength by an additional 5%.

[0033] The equipment parameters for the twin-screw extrusion blending in step S3 are: aspect ratio (L / D) = 40:1, temperature of zone 1 is 220°C, temperature of zone 2 is 250°C, temperature of zone 3 is 240°C, temperature of zone 4 is 230°C, temperature of the die head is 210°C, screw speed is 300rpm, feed rate is 10kg / h, barrel temperature is 250°C, mold temperature is 80°C, to promote nylon crystallization, injection pressure is 100MPa, which can ensure fiber orientation, and holding pressure is 80MPa, which can reduce shrinkage defects.

[0034] Example 2: A method for preparing a high-strength aluminum-based reinforced modified polyamide composite material, comprising the following steps:

[0035] S1. Soak glass fibers with an aspect ratio ≥50 in a KH-550 ethanol solution for 15 minutes and then dry at 120°C for 2 hours to hydroxylate the surface and form hydrogen and chemical bonds with the matrix. The KH-550 content is 1.5%.

[0036] S2. The aluminum foam particles were pickled with 5% hydrochloric acid for 10 minutes to remove the oxide film. The particles were then coated with a 2% titanate coupling agent solution and dried at 60°C for 3 hours to polarize the surface and form covalent bonds with the compatibilizer, thereby enhancing the interfacial bonding strength. The titanate content was 1.5%.

[0037] S3. Using twin-screw extrusion blending, nylon resin and maleic anhydride grafted nylon are first melted, foamed aluminum particles are added in the compression section, and glass fiber is added in the metering section through a side feed port to prevent premature shearing of the glass fiber fibers. 0.7wt% DCP peroxide is added during the process for in-situ crosslinking. The nylon resin accounts for 55% to provide toughness and processing fluidity, the maleic anhydride grafted nylon accounts for 3.5% to improve the compatibility between the nylon resin and the foamed aluminum particles, the glass fiber accounts for 23%, and the glass fiber forms a strong interface bond with the matrix nylon resin after surface treatment. The foamed aluminum particles account for 13% to improve impact toughness and dimensional stability and reduce density.

[0038] After S4, thermal oxygen annealing is performed: keep the temperature at 120℃ for 4 hours to eliminate internal stress, promote secondary crystallization at the interface between the crystal region and the fiber, and increase the tensile strength by an additional 7%.

[0039] The equipment parameters for the twin-screw extrusion blending in step S3 are: aspect ratio (L / D) = 40:1, temperature of zone 1 is 220°C, temperature of zone 2 is 250°C, temperature of zone 3 is 240°C, temperature of zone 4 is 230°C, temperature of the die head is 210°C, screw speed is 300rpm, feed rate is 10kg / h, barrel temperature is 255°C, mold temperature is 85°C, to promote nylon crystallization, injection pressure is 110MPa, which can ensure fiber orientation, and holding pressure is 85MPa, which can reduce shrinkage defects.

[0040] Example 3: A method for preparing a high-strength aluminum-based reinforced modified polyamide composite material, comprising the following steps:

[0041] S1. Glass fibers with an aspect ratio ≥50 were soaked in a KH-550 ethanol solution for 15 minutes and then dried at 120°C for 2 hours to hydroxylate the surface and form hydrogen and chemical bonds with the matrix. The KH-550 content was 1.8%.

[0042] S2. The aluminum foam particles were pickled with 5% hydrochloric acid for 10 minutes to remove the oxide film. The particles were then coated with a 2% titanate coupling agent solution and dried at 60°C for 3 hours to polarize the surface and form covalent bonds with the compatibilizer, thereby enhancing the interfacial bonding strength. The titanate content was 1.8%.

[0043] S3. Using twin-screw extrusion blending, nylon resin and maleic anhydride grafted nylon are first melted, foamed aluminum particles are added in the compression section, and glass fiber is added in the metering section through a side feed port to prevent premature shearing of the glass fiber fibers. 0.8wt% DCP peroxide is added during the process for in-situ crosslinking. The nylon resin accounts for 60% to provide toughness and processing fluidity, the maleic anhydride grafted nylon accounts for 4% to improve the compatibility between the nylon resin and the foamed aluminum particles, the glass fiber accounts for 26%, and the glass fiber forms a strong interface bond with the matrix nylon resin after surface treatment. The foamed aluminum particles account for 16% to improve impact toughness and dimensional stability and reduce density.

[0044] After S4, thermal oxygen annealing is performed: keep the temperature at 120℃ for 4 hours to eliminate internal stress, promote secondary crystallization at the interface between the crystal region and the fiber, and increase the tensile strength by an additional 8%.

[0045] The equipment parameters for the twin-screw extrusion blending in step S3 are: aspect ratio (L / D) = 40:1, temperature of zone 1 is 220°C, temperature of zone 2 is 250°C, temperature of zone 3 is 240°C, temperature of zone 4 is 230°C, temperature of the die head is 210°C, screw speed is 300rpm, feed rate is 10kg / h, barrel temperature is 260°C, mold temperature is 90°C, to promote nylon crystallization, injection pressure is 120MPa, which can ensure fiber orientation, and holding pressure is 90MPa, which can reduce shrinkage defects.

[0046] Example 4: A method for preparing a high-strength aluminum-based reinforced modified polyamide composite material, comprising the following steps:

[0047] S1. Soak glass fibers with an aspect ratio ≥50 in a KH-550 ethanol solution for 15 minutes and then dry at 120°C for 2 hours to hydroxylate the surface and form hydrogen and chemical bonds with the matrix. The KH-550 content is 2%.

[0048] S2. The aluminum foam particles were pickled with 5% hydrochloric acid for 10 minutes to remove the oxide film. The particles were then coated with a 2% titanate coupling agent solution and dried at 60°C for 3 hours to polarize the surface and form covalent bonds with the compatibilizer, thereby enhancing the interfacial bonding strength. The titanate content was 2%.

[0049] S3. Using twin-screw extrusion blending, nylon resin and maleic anhydride grafted nylon are first melted, foamed aluminum particles are added in the compression section, and glass fiber is added in the metering section through a side feed port to prevent premature shearing of the glass fiber fibers. During the process, 1wt% DCP peroxide is added for in-situ crosslinking. The nylon resin accounts for 65% to provide toughness and processing fluidity, the maleic anhydride grafted nylon accounts for 5% to improve the compatibility between the nylon resin and the foamed aluminum particles, the glass fiber accounts for 30%, and the glass fiber forms a strong interface bond with the matrix nylon resin after surface treatment. The foamed aluminum particles account for 20%, and the foamed aluminum particles are used to improve impact toughness and dimensional stability and reduce density;

[0050] After S4, thermal oxygen annealing is performed: keep the temperature at 120℃ for 4 hours to eliminate internal stress, promote secondary crystallization at the interface between the crystal region and the fiber, and increase the tensile strength by an additional 10%.

[0051] The equipment parameters for the twin-screw extrusion blending in step S3 are: aspect ratio (L / D) = 40:1, temperature of zone 1 is 220°C, temperature of zone 2 is 250°C, temperature of zone 3 is 240°C, temperature of zone 4 is 230°C, temperature of the die head is 210°C, screw speed is 300rpm, feed rate is 10kg / h, barrel temperature is 270°C, mold temperature is 100°C, to promote nylon crystallization, injection pressure is 130MPa, which can ensure fiber orientation, and holding pressure is 100MPa, which can reduce shrinkage defects.

[0052] Comparative Example 1:

[0053] No interface modification treatment was performed, and the differences from the embodiment are as follows:

[0054] In step S1, the glass fiber (GF) is not soaked in the KH-550 ethanol solution but is directly dried;

[0055] In step S2, the foamed aluminum particles (FA) are not pickled with hydrochloric acid and coated with titanate and are used directly.

[0056] Other parameters are the same as those in Example 1 (glass fiber accounts for 20%, foam aluminum particles account for 10%, nylon resin accounts for 50%, and maleic anhydride grafted nylon accounts for 3%).

[0057] performance:

[0058] Tensile strength: about 82 MPa (34.4% lower than 125 MPa in Example 1). The stress transfer efficiency is low (from 85% to below 60%) due to interfacial debonding.

[0059] Notched impact strength: about 5.2kJ / m 2 (Compared to 8.5 kJ / m in Example 12 The interface between aluminum foam and substrate is prone to become the source of cracks.

[0060] Principle analysis: The hydroxyl groups on the surface of unmodified glass fiber are not activated and cannot form chemical bonds with nylon resin; the oxide film on the surface of foamed aluminum is not removed, the polarity difference leads to poor interfacial compatibility, and the reinforcement phase cannot effectively carry loads.

[0061] Comparative Example 2:

[0062] Single reinforcement phase (glass fiber only), difference from the embodiment:

[0063] Formula: Remove the foam aluminum particles, increase the proportion of glass fiber to 30%, the proportion of nylon resin to 50%, and the amount of compatibilizer and coupling agent remains unchanged.

[0064] Process: Step S2 is omitted, and only glass fiber (without foamed aluminum particles) is added in step S3. Other parameters are the same as those in Example 1.

[0065] performance:

[0066] Tensile strength: about 130 MPa (4% higher than Example 1), but the density is from 1.1 g / cm 3 Increased to 1.35g / cm 3 (Increase of 22.7%).

[0067] Notched impact strength: about 6.0kJ / m 2 (A decrease of 29.4% compared with Example 1), the toughness of the glass fiber reinforced system is insufficient.

[0068] Principle analysis: Although the strength of single glass fiber reinforcement is slightly higher, the density is significantly increased, and the toughening effect of foam aluminum particles is lacking, the impact performance is reduced, and the synergistic optimization of "high strength + lightweight" cannot be achieved.

[0069] Comparative Example 3:

[0070] Single reinforcement phase (only aluminum foam particles), difference from the embodiment:

[0071] Formula: Remove glass fiber, increase the proportion of foam aluminum particles to 30%, nylon resin to 50%, and the amount of compatibilizer and coupling agent remains unchanged.

[0072] Process: Step S1 is omitted, and only foamed aluminum particles (without glass fiber) are added in step S3. Other parameters are the same as those in Example 1.

[0073] performance:

[0074] Tensile strength: about 88 MPa (29.6% lower than Example 1). FA has weak strength and poor interface bonding and cannot effectively bear tensile loads.

[0075] Density: about 0.9g / cm 3 (A decrease of 18.2% compared with Example 1), but the strength does not reach 100 MPa, which cannot meet the mid-to-high-end load-bearing requirements.

[0076] Principle analysis: When aluminum foam particles are reinforced alone, the strength improvement is limited due to insufficient interface adhesion (failure to cooperate with glass fibers to form a skeleton), which proves the necessity of dual-reinforcement phase coordinated design.

[0077] Comparative Example 4:

[0078] No compatibilizer (maleic anhydride grafted nylon) was used, and the difference from the embodiment is as follows:

[0079] Formula: maleic anhydride grafted nylon (MAPA) is removed, the compatibilizer accounts for 0%, and the proportions of other components are the same as in Example 1.

[0080] Process: In step S3, only nylon resin was melted without adding MAPA, and other parameters remained unchanged.

[0081] performance:

[0082] Tensile strength: about 95 MPa (24% lower than that in Example 1). Due to the mismatch in polarity between the nylon and aluminum foam interfaces, the stress transfer efficiency dropped below 70%.

[0083] Interface morphology: Observation showed that there was an obvious gap between the foam aluminum particles and the matrix, and the debonding phenomenon was serious.

[0084] Principle analysis: MAPA acts as a compatibilizer, and its maleic anhydride groups react with the polar groups on the surface of aluminum foam to form a transition layer. After its loss, the interfacial compatibility deteriorates, proving the key role of the compatibilizer in interfacial bonding.

[0085] Comparative Example 5:

[0086] The difference between the traditional blending process (no side feeding technology) and the embodiment is as follows:

[0087] Process: In step S3, the glass fiber and the foamed aluminum particles are added simultaneously from the main feeding port, and the glass fiber is not added from the side feeding port. Other parameters are the same as those in Example 1.

[0088] Equipment parameters: screw speed, temperature, etc. remain unchanged, but the order of adding glass fiber is changed.

[0089] performance:

[0090] Fiber length retention rate: dropped from 85% to below 60%. The glass fiber was sheared and broken due to premature entry into the extruder, and the aspect ratio was reduced.

[0091] Tensile strength: about 105 MPa (16% lower than Example 1). The fiber reinforcement efficiency is reduced due to length loss.

[0092] Dispersion uniformity: The glass fiber dispersion index increased from ≤1.2 to 1.8, agglomeration was obvious, and the performance fluctuation coefficient increased from <5% to 12%.

[0093] Principle analysis: Side feeding technology prevents glass fiber from being sheared for a long time in the extruder, retaining the aspect ratio to form an effective reinforcement network. Traditional blending processes cannot take into account both fiber length and dispersion.

[0094] Comparative Example 6:

[0095] No thermal oxygen annealing treatment was performed, and the difference from the embodiment is as follows:

[0096] In step S4, the thermal oxygen annealing step of keeping the temperature at 120° C. for 4 hours is omitted, and the mold is directly injection molded and then cooled.

[0097] Other parameters are the same as those in Example 1.

[0098] performance:

[0099] Tensile strength: about 115 MPa (decreased by 8% compared with Example 1). Since the internal stress has not been eliminated, the crystallization between the crystal region and the fiber interface is not perfect.

[0100] Dimensional stability: The shrinkage rate increases from 0.8% to 1.5%, and the risk of product deformation increases.

[0101] Principle analysis: Thermal oxygen annealing promotes secondary crystallization of nylon, eliminates internal molding stress, and improves interface bonding density. After its loss, the strength and stability decrease.

[0102] Comparative Example 7:

[0103] Replace the coupling agent type, the difference from the embodiment:

[0104] In step S1, the glass fiber is not treated with KH-550, but with a titanate coupling agent;

[0105] In step S2, the aluminum foam particles are not treated with titanate but with KH-550;

[0106] Other parameters are the same as those in Example 1.

[0107] performance:

[0108] Interface bonding strength: The shear strength of the interface between glass fiber and matrix is reduced from 35MPa to 25MPa, and the interface bonding strength of foam aluminum is reduced from an increase of 35% to an increase of 15%.

[0109] Tensile strength: about 100 MPa (20% lower than that of Example 1). This is because the coupling agent does not match the surface properties of the reinforcement phase and cannot form an effective chemical bond.

[0110] Principle analysis: The hydroxyl groups on the glass fiber surface are more reactive with the silaneoxy groups of KH-550, and the coordination effect between the metal ions on the foamed aluminum surface and the titanate is better. A single coupling agent cannot take into account the interfacial properties of both, which proves the necessity of differentiated coupling agent selection.

[0111] Comparative Example Design Summary: The above comparative examples clearly demonstrate the indispensability of key technologies described in the patent, including dual-reinforcement phase synergy, interface modification, side-feeding process, compatibilizer addition, thermal oxygen annealing, and differentiated coupling agent selection. Each comparative example exhibits a significant decrease in performance (strength, toughness, processing stability, etc.) due to the lack of specific technical features.

[0112] Performance testing:

[0113] 1. Tensile strength:

[0114] 1. Standard: ASTM D638 Type I specimen

[0115] 2. Equipment: Electronic universal material testing machine (such as Instron 5967)

[0116] 3. Conditions: tensile speed 5mm / min, test temperature 23±2℃, humidity 50±5%

[0117] 4. Data: Take the average value of 5 specimens and calculate the maximum stress at fracture.

[0118] 2. Bending strength:

[0119] 1. Standard: ASTM D790

[0120] 2. Equipment: Same as above

[0121] 3. Conditions: span 40mm, loading speed 2mm / min

[0122] 4. Data: Record the maximum bending stress when the specimen breaks.

[0123] 3. Notched impact strength:

[0124] 1. Standard: ASTM D256 (Simple beam impact)

[0125] 2. Equipment: Pendulum impact testing machine (such as ZBC 2302-2)

[0126] 3. Conditions: Notch type A (V-notch, depth 2mm), impact energy 5.5J

[0127] 4. Data: Take the average value of 5 samples, unit kJ / m 2 .

[0128] 4. Density:

[0129] 1. Method: Drainage method (GB / T 1033.1-2008)

[0130] 2. Equipment: analytical balance (precision 0.1mg), distilled water

[0131] 3. Data: Calculate the difference in mass between the sample in air and water to determine the density.

[0132] 5. Fiber dispersion and interface bonding:

[0133] 1. Method: Scanning electron microscopy (SEM, such as Hitachi S-3400N)

[0134] 2. Conditions: Sample fracture surface gold spraying, acceleration voltage 15kV

[0135] 3. Data: Observe the dispersion uniformity (dispersion index) of glass fiber (GF) and the debonding of foam aluminum particles (FA) interface.

[0136] The results are shown in Tables 1 and 2 below:

[0137] Table 1 Performance test data table

[0138]

[0139]

[0140] Table 2 Performance test data table

[0141]

[0142]

[0143] Data Analysis:

[0144] (1) Example Data Analysis: Impact of Parameter Optimization on Performance:

[0145] 1. Relationship between the ratio of reinforcing phase and performance:

[0146] As the glass fiber (GF) proportion increases from 20% to 30% (Examples 1-4), the tensile strength increases from 125 MPa to 150 MPa (+20%), and the flexural strength increases synchronously, indicating that GF has a significant load-bearing effect as the main reinforcement phase.

[0147] When the proportion of foam aluminum particles (FA) increases from 10% to 20%, the notched impact strength increases from 8.5kJ / m2 Increased to 10.5kJ / m 2 (+23.5%), and the density only increased by 7.3%, proving the toughening and lightweight effects of FA.

[0148] 2. Influence of the amount of interfacial modifier:

[0149] As the proportion of KH-550 and titanate coupling agent increased from 1% to 2% (Examples 1-4), the interfacial bonding strength gradually increased, as shown by a linear increase in tensile strength, and the fiber dispersion index was always ≤1.2, indicating that an appropriate amount of coupling agent can optimize interfacial bonding, and an excessive amount does not lead to performance degradation.

[0150] 3. Synergistic effect of process parameters:

[0151] When the barrel temperature is increased from 250°C to 270°C (Examples 1-4), the nylon resin melts more fully, the wettability with the reinforcement phase is improved, and the increase in tensile strength is positively correlated with the temperature, but the density increases slightly (due to the increase in FA and GF filling amounts).

[0152] (2) Comparative data analysis: Necessity verification of key technologies

[0153] 1. The decisive role of interface modification (Comparative Example 1 vs. Example 1)

[0154] Without interface modification, the tensile strength decreased by 34.4% and the notched impact strength decreased by 38.8%. Observations showed that the GF pull-out length increased and obvious gaps existed at the FA interface, proving that interface modification is the core technology for improving stress transfer efficiency.

[0155] 2. Dual-enhanced phase synergistic effect (Comparative Examples 2-3 vs. Example 1)

[0156] Although the strength of single GF reinforcement reaches 130MPa, the density increases by 22.7% and the impact toughness decreases by 29.4%; the density of single FA reinforcement decreases by 18.2%, but the strength does not reach 100MPa, which verifies that the composite of GF and FA can break through the "strength-density" contradiction.

[0157] 3. Irreplaceability of compatibilizers and process technologies

[0158] When there is no compatibilizer (Comparative Example 4), the tensile strength decreases by 24% and the interface debonding is serious; the traditional blending process (Comparative Example 5) loses GF length, the strength decreases by 16%, and the dispersibility deteriorates; the lack of annealing (Comparative Example 6) leads to residual internal stress and a decrease in strength of 8%, which proves the necessity of the coordination of each process step.

[0159] 4. Scientificity of Differentiated Selection of Coupling Agents (Comparative Example 7 vs. Example 1)

[0160] After replacing the coupling agent type, the interface bonding strength decreased and the tensile strength dropped to 100 MPa, confirming that the differentiated modification design of GF (hydroxyl surface) and FA (metal oxide film) can maximize the interface bonding efficiency.

[0161] (3) Conclusion

[0162] 1. The data of the embodiment show that by optimizing the ratio of GF to FA (20-30%:10-20%), controlling the amount of interfacial modifier (1-2%) and coordinating the process parameters (side feeding + hot oxygen annealing), a tensile strength of 125-150 MPa and an impact toughness of 8.5-10.5 kJ / m can be achieved. 2 High performance balance.

[0163] 2. The comparative examples verify the indispensability of the patented technical solution of "dual-reinforced phase synergy + interface modification + process optimization". The absence of each key technology leads to significant performance degradation, which in turn proves the creativity and technological advancement of the patented technology.

[0164] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0165] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength aluminum-based reinforced modified polyamide composite material, characterized in that: The following steps are involved: Step S1. Soak the main reinforcing phase in KH-550 ethanol solution for 15 min and dry at 120 ° C for 2 h to obtain a pretreated main reinforcing phase; Step S2. The auxiliary reinforcement phase is pickled with 5% hydrochloric acid for 10 minutes to remove the oxide film, then coated with a 2% titanate solution, and dried at 60°C for 3 hours to obtain a pretreated auxiliary reinforcement phase; Step S3. Using twin-screw extrusion blending, the matrix and compatibilizer are first melted, the pretreated auxiliary reinforcing phase is added in the compression section, and the pretreated main reinforcing phase is added in the metering section through the side feed port, and 0.5wt%-1wt% DCP peroxide is added during the process; After step S4, thermal oxidation annealing is performed: heat preservation at 120° C. for 4 hours to obtain a high-strength aluminum-based reinforced modified polyamide composite material.

2. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: In step S1, the main reinforcement phase accounts for 20%-30%, and the main reinforcement phase is glass fiber with an aspect ratio of ≥50.

3. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: In step S1, the proportion of the matrix is 50%-65%, and the matrix is nylon resin.

4. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: The proportion of KH-550 in step S1 is 1%-2%, and the proportion of titanate in step S2 is 1%-2%.

5. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: In step S2, the proportion of the auxiliary reinforcement phase is 10%-20%, and the auxiliary reinforcement phase is foamed aluminum particles.

6. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: The proportion of the compatibilizer in step S2 is 3%-5%, and the compatibilizer is maleic anhydride grafted nylon.

7. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: The equipment parameters of the twin-screw extrusion blending in step S3 are: aspect ratio L / D=40:

1.

8. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: In step S3, the temperature of zone 1 of the twin-screw extrusion blending is 220°C, the temperature of zone 2 is 250°C, the temperature of zone 3 is 240°C, the temperature of zone 4 is 230°C, and the temperature of the die head is 210°C.

9. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: The screw speed of the twin-screw extrusion blending in step S3 is 300 rpm, and the feeding rate is 10 kg / h.

10. The method for preparing a high-strength aluminum-based reinforced modified polyamide composite material according to claim 1, characterized in that: During the twin-screw extrusion blending in step S3, the barrel temperature is 250-270° C., the mold temperature is 80-100° C., the injection pressure is 100-130 MPa, and the holding pressure is 80-100 MPa.

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