Modifier of PA66 composite material, preparation method of modifier, PA66 composite material and preparation method of PA66 composite material

Abstract

The invention discloses a modifier of a PA66 composite material, a preparation method of the modifier, the PA66 composite material and a preparation method of the PA66 composite material. The preparation method of the modifier of the PA66 composite material comprises the following steps: preparing a macromolecular functional connecting agent Epoxy-PSi-PBI-NH2; the preparation method comprises the following steps: preparing CNT-PSi-PBI-Epoxy; the CNT-PSi-PBI-Epoxy and the hydroxylated BF are added into tetrabutylammonium bromide, and the mixture is stirred for a reaction; and filtering the reaction solution, washing, and drying the filter cake in a vacuum drying oven to obtain the modifier BF-PSi-PBI-CNT of the PA66 composite material. According to the invention, the dispersibility of the BF-CNT in the PA66 matrix can be synchronously solved, the interface combination of the BF-CNT, the PA66 matrix and the matrix can be optimized, the synergistic enhancement of mechanics and functions (electric conduction / heat conduction) can be realized, and the mechanical property, the heat conduction property and the electric conduction property can be simultaneously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation of PA66 composite materials, in particular to a modifier of PA66 composite material and a preparation method thereof, a PA66 composite material and a preparation method thereof. BACKGROUND

[0002] Polyamide (PA66) is an important engineering plastic, which is widely used in the fields of automobile, electronics and aerospace due to its excellent mechanical strength, wear resistance and processing performance. However, pure PA66 resin has significant defects: poor toughness leads to poor impact resistance, and the notched impact strength is usually less than 10 kJ / m²; the low thermal conductivity (about 0.2-0.3 W / mK) limits its application in the field of heat dissipation; the high insulation (volume resistivity > 10 14 Ω·cm) easily causes static accumulation, which threatens the safety of precision electronic devices. Therefore, in order to realize the application of PA66 in the field of precision electronics and other aspects, it is usually necessary to modify PA66 in terms of toughness, thermal conductivity, electrical conductivity and other aspects. In terms of improving thermal conductivity and electrical conductivity, adding nano fillers such as carbon nanotubes (CNT) to PA66 can endow PA66 with excellent electrical conductivity / thermal conductivity at a small amount (1-5 wt%). However, the huge specific surface area and strong van der Waals force of CNT make it easy to agglomerate, especially when the content exceeds 20 wt%, which not only weakens the reinforcing effect, but also causes stress concentration points, leading to brittle fracture of the material. Therefore, adding carbon nanotubes to PA66 needs to solve the problem of dispersing carbon nanotubes in the polymer matrix and forming a continuous thermal and electrical conduction network, so as to better realize the improvement effect of carbon nanotubes on the thermal and electrical conductivity of PA66 matrix.

[0003] On the other hand, in order to improve the strength of PA66 composite material, fiber reinforcement or nano filler modification is usually used. Fiber reinforcement (such as glass fiber, carbon fiber, basalt fiber) can greatly improve the rigidity and strength, for example, 30% glass fiber can make the tensile strength of PA66 reach 150 MPa. In particular, basalt fiber (BF) has excellent acid and alkali resistance and ultraviolet resistance, and its strength and modulus are higher than those of glass fiber, and its cost is lower, so it becomes the preferred fiber filler for high-strength and high-toughness PA66 composite material. However, single BF modification still has bottlenecks: functionally, BF itself is insulating and has poor thermal conductivity, which cannot solve the anti-static and heat dissipation requirements of PA66; structurally, although the interfacial bonding force between basalt fiber and PA66 is better, there are still micropores between basalt fiber and PA66 matrix, which limits the stress transfer efficiency, and further modification is needed to improve the interfacial bonding force between basalt fiber and PA66.

[0004] In order to consider the mechanical and heat conduction, electrical and other functional requirements, BF and CNT are used to modify PA66, but simple compounding has great problems. When simple mechanical blending is used, CNT is easy to agglomerate in the PA66 matrix, resulting in stress concentration, affecting the mechanical properties of the PA66 composite material, and also seriously hindering the formation of a continuous heat conduction and electrical network of carbon nanotubes in the PA66 matrix, and the resistivity is still as high as 10 8 Ω·cm or more. SUMMARY

[0005] In order to overcome the above-mentioned defects and deficiencies of the prior art, the purpose of the present application is to provide a modifier for PA66 composite material and a preparation method thereof, a PA66 composite material and a preparation method thereof, which can simultaneously solve the dispersion of BF-CNT in the PA66 matrix, optimize the interface bonding of the two and the matrix, and realize the modification technology of mechanical and functional (electrical / thermal) synergistic enhancement, breaking through the key technical bottleneck that the mechanical properties, thermal conductivity and electrical conductivity of the current PA66 composite material are difficult to improve simultaneously.

[0006] The present application designs a surface modifier (PSi-PBI) with excellent thermal conductivity, which can realize the construction of chemical bonds between CNT and BF, realize the modification of BF by CNF, improve the thermal and electrical conductivity of BF, and give BF a rough surface, so that mechanical anchoring is formed between the PA66 matrix and BF. At the same time, the modifier on the surface of CNF can also improve the interfacial force between the PA66 matrix and BF. The surface modifier is block polymerized by a rigid thermal skeleton and a flexible segment, which gives BF and CNF strong interfacial bonding force and high interfacial thermal conductivity. The benzimidazole ring and benzene ring of polybenzimidazole (PBI) thermal skeleton form a continuous π conjugated system, reducing phonon scattering, and the flexible segment also gives the PA66 composite material good toughness.

[0007] The functional macromolecular surface modifier BF-PSi-PBI-CNT is directly added to the twin-screw extruder by one-pot method to prepare high-strength and high-thermal-conductivity PA66 / BF-PSi-PBI-CNT composite material. At this time, the N-H bond in PSi-PBI can form hydrogen bonding with PA66 (C=O), improving the compatibility of BF-PSi-PBI-CNT and PA66, and reducing the damage of BF-PSi-PBI-CNT to the mechanical properties of PA66 matrix. The prepared high-strength and high-thermal-conductivity PA66-based composite material has excellent tensile strength, modulus and thermal conductivity, and also greatly improves the heat resistance of PA66, widening its application in the field of precision electronics and electrical appliances.

[0008] The purpose of the present application is achieved by the following technical solutions:

[0009] The application provides a preparation method of a PA66 composite modifier, which comprises the following steps:

[0010] (1) preparing a flexible chain segment Epoxy-PSi-PBI-NH2:

[0011] (11) dissolving α, ω-diaminopropyl polydimethylsiloxane in toluene, adding triethanolamine, adding dropwise epoxy chloropropane under ice bath, and then increasing the temperature to 40-80 DEG C to react; the obtained product is filtered to remove TEA-HCl salt, and toluene and excess epoxy chloropropane are removed by rotary evaporation to obtain transparent viscous liquid Epoxy-PSi-Epoxy;

[0012] (12) dissolving amino-terminated polybenzimidazole PBI in a solvent, adding Epoxy-PSi-Epoxy prepared in step (11); adding dropwise boron trifluoride ether solution under nitrogen protection at 40-80 DEG C; after the reaction is completed, the solution is dropped into ether for precipitation, and after filtration, the precipitated product is dissolved in tetrahydrofuran again, and the solution is dropped into ether for repeated precipitation; after filtration, the filter cake is dried in vacuum to obtain brown-yellow solid macromolecular functional connecting agent Epoxy-PSi-PBI-NH2;

[0013] (2) preparing BF-PSi-PBI-CNT:

[0014] (21) dissolving hydroxylated CNT and Epoxy-PSi-PBI-NH2 in a solvent, and then adding N-hydroxysuccinimide dichloroethane solution as a catalyst, and reacting at 50-80 DEG C for 2-5 h; the reaction liquid is filtered, washed with N, N-dimethylformamide / toluene mixed solvent, and then dried in vacuum to obtain CNT-PSi-PBI-Epoxy;

[0015] (22) adding CNT-PSi-PBI-Epoxy and hydroxylated BF into tetrabutylammonium bromide, and adjusting the pH to 8.0-10.0 by using triethylamine, and then mechanically stirring and reacting at 80-140 DEG C for 1-4 h; the reaction liquid is filtered, washed with tetrabutylammonium bromide, and then dried in a vacuum drying oven to obtain the PA66 composite modifier BF-PSi-PBI-CNT.

[0016] Preferably, in some embodiments of the present application, the molar ratio of the α,ω-diaminopropyl polydimethylsiloxane:epoxy chloropropane in the step (11) is 1:5-1:15, and the optimal ratio is 1:10. The molar ratio of the α,ω-diaminopropyl polydimethylsiloxane:triethanolamine is 1:3-1:5, and the optimal ratio is 1:4. The mass ratio of the α,ω-diaminopropyl polydimethylsiloxane:toluene is 1:10-1:30, and the optimal ratio is 1:20. The optimal reaction temperature is 60℃. The optimal reaction time is 24h. The rotary evaporation temperature is 100-125℃, and the optimal temperature is 120℃.

[0017] Preferably, in some embodiments of the present application, the molar ratio of the amino-terminated polybenzimidazole PBI and Epoxy-PSi-Epoxy in the step (12) is 1:1-1:3, and the optimal ratio is 1:2.2. The optimal solvent is tetrahydrofuran. The mass ratio of the PBI and the solvent is 1:10-1:20, and the optimal ratio is 1:15. The amount of the boron trifluoride etherate is 3-10wt% of the PBI, and the optimal amount is 5wt%. The optimal reaction temperature of the step (12) is 60℃. The optimal reaction time is 24h.

[0018] Preferably, in some embodiments of the present application, in the step (21), the mass ratio of the CNT:Epoxy-PSi-PBI-NH2 is 1:2-1:5, and the optimal ratio is 1:3.3. The optimal solvent is a mixture of N,N-dimethylformamide / toluene with a volume ratio of 7:3. The mass ratio of the Epoxy-PSi-PBI-NH2 and the solvent is 1:5-1:15, and the optimal ratio is 1:10. The concentration of the N-hydroxysuccinimide dichloroethane solution is 1mol / L, and the amount of the N-hydroxysuccinimide is 0.1wt% of the Epoxy-PSi-PBI-NH2. The optimal reaction temperature is 60℃. The optimal reaction time is 3h.

[0019] Preferably, in some embodiments of the present application, in the step (22), the mass ratio of the CNT-PSi-PBI-Epoxy:hydroxylated BF is 5:1-2:1, and the optimal ratio is 3.3:1. The mass ratio of the CNT-PSi-PBI-Epoxy and the tetrabutylammonium bromide is 1:5-1:15, and the optimal ratio is 1:10. The optimal reaction temperature is 120℃. The optimal reaction time is 2h.

[0020] The present application also provides a PA66 composite material modifier prepared by the preparation method of the PA66 composite material modifier.

[0021] The present application also provides a PA66 composite material comprising PA66 and the PA66 composite material modifier.

[0022] The application also provides a preparation method of the PA66 composite material, comprising the following steps:

[0023] (31) drying and removing moisture from the PA66 and the modifier of the PA66 composite material, and uniformly mixing them in a high-speed mixer to complete premixing;

[0024] (32) melt blending the premixing material in step (31) through a double screw extruder, and obtaining the PA66 / BF-PSi-PBI-CNT composite material through melt blending and cooling granulation.

[0025] Preferably, the drying temperature of the PA66 and the BF-PSi-PBI-CNT in step (31) is 80-100°C, and the optimal temperature is 90°C. The drying time is 4h-12h, and the optimal drying time is 6h. The optimal addition amount of the BF-PSi-PBI-CNT is 14.8wt% of the total mass of the PA66.

[0026] Preferably, in some embodiments of the application, the rotation speed of the main feeding screw of the double screw extruder in step (32) is set to 20-50 rpm, and the optimal rotation speed is 30 rpm. The rotation speed of the main screw is set to 100-200 rpm, and the optimal rotation speed is 150 rpm. The temperature of the extruder is set to 230-260°C.

[0027] Compared with the prior art, the application has the following advantages and beneficial effects:

[0028] (1) the "rigid-flexible" molecular design of the block connecting agent (the continuous pi conjugated system formed by the benzimidazole ring and the benzene ring of PBI heat conduction skeleton reduces phonon scattering + the flexible chain segment of PSi), which endows the PA66-based composite material with excellent strength, modulus, heat distortion temperature and high interfacial thermal conductivity, and the flexible chain segment endows the composite material with better toughness;

[0029] (2) the macromolecular connecting agent provides more connecting sites for the BF and the CNT, thereby providing stronger interfacial bonding force;

[0030] (3) the N-H in the block connecting agent can form a hydrogen bond with the PA66, thereby improving the compatibility between the BF-PSi-PBI-CNT and the PA66, and avoiding the loss of the mechanical properties of the PA66 caused by the addition of the BF-PSi-PBI-CNT. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a preparation schematic diagram of the flexible chain segment "Epoxy-PSi-Epoxy" of the embodiments of the application.

[0032] Figure 2Schematic diagram for the preparation of the macromolecular functional linker "Epoxy-PSi-PBI-NH2" of the embodiment of the present application. DETAILED DESCRIPTION

[0033] The present application is further described below by specific examples, but the scope of protection of the present application is not limited to this.

[0034] Example 1

[0035] (1) The preparation method of Epoxy-PSi-PBI of the present embodiment is as follows:

[0036] (11) Dissolve α, ω-diaminopropyl polydimethylsiloxane (10 mmol) in toluene (74 ml) (mass ratio 1:20), and add triethanolamine (40 mmol). Under ice bath, drop epoxy chloropropane (100 mmol), and after the drop is completed, raise the temperature to 60°C and react for 24 h. The obtained product is filtered to remove TEA·HCl salt, and rotary evaporation (120°C) is performed to remove toluene and excess epoxy chloropropane. Dry in a vacuum oven at 80°C to obtain transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is as shown in Figure 1 .

[0037] (12) Dissolve amino-terminated PBI (1 mmol) in tetrahydrofuran (50 ml) (mass ratio 1:15), and add Epoxy-PSi-Epoxy (2.2 mmol) prepared in step (11). Drop trifluoroboron ether (0.13 ml, 5wt% of PBI), and react at 60°C for 24 h under nitrogen protection. After the reaction is completed, drop the solution into ether for precipitation, filter, dissolve the precipitated product in tetrahydrofuran again, drop the solution into ether again for repeated precipitation, filter, and dry the filter cake in a vacuum oven at 80°C to obtain brown-yellow solid Epoxy-PSi-PBI-NH2, and the preparation route is as shown in Figure 2 .

[0038] (2) The preparation method of BF-PSi-PBI-CNT described in the present embodiment is as follows:

[0039] (21) Dissolve hydroxylated CNT (3 g) and Epoxy-PSi-PBI (9.9 g) in N,N-dimethylformamide / toluene mixed solvent (107 ml, mass ratio of Epoxy-PSi-PBI-NH2 to solvent is 1:10) in a volume ratio of 7:3, and then add N-hydroxysuccinimide dichloroethane (1 mol / L) as a catalyst, and react at 60°C for 3 h. After filtering the reaction solution, wash with N,N-dimethylformamide / toluene mixed solvent (volume ratio 7:3) for 3 times, and dry at 80°C in a vacuum to obtain CNT-PSi-PBI-Epoxy.

[0040] (22) CNT-PSi-PBI-Epoxy (9.9 g) and hydroxylated BF (3 g) were added into tetrabutylammonium bromide (95 ml, tetrabutylammonium bromide: CNT-PSi-PBI-Epoxy mass ratio 1:10), and the pH was adjusted to 9.0 using triethylamine, and the reaction was mechanically stirred at 120°C for 2 h. After the reaction solution was filtered, it was washed three times with tetrabutylammonium bromide, and the filter cake was dried in a vacuum oven at 80°C to obtain BF-PSi-PBI-CNT.

[0041] (3) The preparation method of the PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0042] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 90°C air oven for 6 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer at a ratio of 84.8:14.8:0.4 to complete the premix.

[0043] (32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) of the extruder was adjusted, and after melt blending (maximum 260°C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0044] Example 2

[0045] (1) The preparation method of Epoxy-PSi-PBI-NH2 described in this embodiment is as follows:

[0046] (11) α,ω-diaminopropyl polydimethylsiloxane (10 mmol) was dissolved in toluene (37 ml, α,ω-diaminopropyl polydimethylsiloxane: toluene mass ratio 1:10), and triethanolamine (30 mmol) was added. Epoxy chloropropane (50 mmol) was added dropwise under ice bath, and the temperature was raised to 40°C for 15 h after the dropwise addition was completed. The obtained product was filtered to remove TEA·HCl salt, and toluene and excess epoxy chloropropane were removed by rotary evaporation (100°C), and the product was dried in a vacuum oven at 80°C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is shown in Figure 1 .

[0047] (12) Amino-terminated PBI (1 mmol) was dissolved in tetrahydrofuran (33.3 ml, the mass ratio of amino-terminated PBI to tetrahydrofuran was 1:10), and Epoxy-PSi-Epoxy (1 mmol) prepared in step (11) was added. Trifluoroboron ether (0.078 ml, 3 wt% of PBI) was added dropwise, and the reaction was carried out at 40°C for 15 h under nitrogen protection. After the reaction was completed, the solution was dropped into ethyl ether for precipitation, and after filtration, the precipitated product was dissolved in tetrahydrofuran again, and the solution was dropped into ethyl ether for repeated precipitation. After filtration, the filter cake was dried in a vacuum oven at 80°C to obtain brown-yellow solid Epoxy-PSi-PBI-NH2. The preparation route is shown in Figure 2

[0048] (2) The preparation method of BF-PSi-PBI-CNT described in this embodiment is as follows:

[0049] (21) Hydroxylated CNT (3 g) and Epoxy-PSi-PBI-NH2 (6 g) were dissolved in a mixed solvent of N,N-dimethylformamide / toluene (53.5 ml, the mass ratio of Epoxy-PSi-PBI-NH2 to the solvent was 1:5) with a volume ratio of 7:3, and N-hydroxysuccinimide dichloroethane (1 mol / L) was added as a catalyst, and the reaction was carried out at 50°C for 2 h. After the reaction solution was filtered, it was washed with a mixed solvent of N,N-dimethylformamide / toluene (7:3, volume ratio) for 3 times, and then dried at 80°C under vacuum to obtain CNT-PSi-PBI-Epoxy.

[0050] (22) CNT-PSi-PBI-Epoxy (6 g) and hydroxylated BF (3 g) were added to tetrabutylammonium bromide (47.5 ml, the mass ratio of tetrabutylammonium bromide to CNT-PSi-PBI-Epoxy was 1:5), and triethylamine was used to adjust the pH to 9.0, and the reaction was carried out at 80°C for 1 h under mechanical stirring. After the reaction solution was filtered, it was washed with tetrabutylammonium bromide for 3 times, and then the filter cake was dried in a vacuum drying oven at 80°C to obtain BF-PSi-PBI-CNT.

[0051] (3) The preparation method of PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0052] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 80°C air oven for 4 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer according to a ratio of 94.8:4.8:0.4 to complete the premix.

[0053] ​(32) The premix in step (31) is melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (20 rpm) and the main screw (100 rpm) of the extruder is adjusted, and after melt blending (maximum 260°C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material is obtained.

[0054] Example 3

[0055] (1) The preparation method of Epoxy-PSi-PBI-NH2 in this example is as follows:

[0056] (11) α, ω-diaminopropyl polydimethylsiloxane (10 mmol) is dissolved in toluene (111 ml, mass ratio of α, ω-diaminopropyl polydimethylsiloxane: toluene 1:30), and triethanolamine (50 mmol) is added. Epoxy chloropropane (150 mmol) is added dropwise under ice bath, and after the dropwise addition is completed, it is raised to 80°C and reacted for 30h. The obtained product is filtered to remove TEA·HCl salt, and toluene and excess epoxy chloropropane are removed by rotary evaporation (125°C), and the product is dried in a vacuum oven at 80°C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is as shown in Figure 1 .

[0057] (12) Amino-terminated PBI (1 mmol) is dissolved in tetrahydrofuran (66.6 ml) (mass ratio 1:20), and Epoxy-PSi-Epoxy (3 mmol) prepared in step (11) is added. Trifluoroboron ether (0.26 ml, 10wt% of PBI) is added dropwise, and the reaction is carried out at 80°C for 30h under nitrogen protection. After the reaction is completed, the solution is dropped into ether for precipitation, and after filtration, the precipitated product is dissolved in tetrahydrofuran again, and the solution is dropped into ether for repeated precipitation. After filtration, the filter cake is dried in a vacuum oven at 80°C to obtain a brownish yellow solid Epoxy-PSi-PBI-NH2, and the preparation route is as shown in Figure 2 .

[0058] (2) The preparation method of BF-PSi-PBI-CNT in this example is as follows:

[0059] (21) Hydroxylated CNT (3g) and Epoxy-PSi-PBI-NH2 (15g) are dissolved in a mixed solvent of N,N-dimethylformamide / toluene (160.5ml, volume ratio 7:3, mass ratio of Epoxy-PSi-PBI-NH2 to solvent 1:15), and N-hydroxysuccinimide dichloroethane (1 mol / L) is added as a catalyst, and the reaction is carried out at 80°C for 5h. After the reaction solution is filtered, it is washed with a mixed solvent of N,N-dimethylformamide / toluene (volume ratio 7:3) for 3 times, and then dried in a vacuum oven at 80°C to obtain CNT-PSi-PBI-Epoxy.

[0060] (22) CNT-PSi-PBI-Epoxy (15 g) and hydroxylated BF (3 g) were added into tetrabutylammonium bromide (142.5 ml, tetrabutylammonium bromide: CNT-PSi-PBI-Epoxy mass ratio 1:15), and the pH was adjusted to 9.0 using triethylamine, and the reaction was mechanically stirred at 140°C for 4 h. After the reaction solution was filtered, it was washed with tetrabutylammonium bromide three times, and the filter cake was dried in a vacuum drying oven at 80°C to obtain BF-PSi-PBI-CNT.

[0061] (3) The preparation method of the PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0062] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 100°C air oven for 12 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer at a ratio of 79.8:29.8:0.4 to complete the premix.

[0063] (32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (50 rpm) and the main screw (200 rpm) of the extruder was adjusted, and after melt blending (maximum 260°C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0064] Example 4

[0065] (1) The preparation method of Epoxy-PSi-PBI-NH2 described in this embodiment is as follows:

[0066] (11) α, ω-diaminopropyl polydimethylsiloxane (10 mmol) was dissolved in toluene (74 ml) (mass ratio 1:20), and triethanolamine (40 mmol) was added. Epoxy chloropropane (100 mmol) was added dropwise under ice bath, and the temperature was raised to 60°C for 24 h. The obtained product was filtered to remove TEA·HCl salt, and toluene and excess epoxy chloropropane were removed by rotary evaporation (120°C), and the product was dried in a vacuum oven at 80°C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is as shown in Figure 1 .

[0067] (12) Amino-terminated PBI (1 mmol) was dissolved in dimethyl sulfoxide (50 ml) (mass ratio 1:15), and Epoxy-PSi-Epoxy prepared in step (11) (2.2 mmol) was added. Trifluoroboron ether (0.13 ml, 5 wt% of PBI) was added dropwise, and the reaction was carried out at 60°C for 24 h under nitrogen protection. After the reaction was completed, the solution was dropped into ethyl ether for precipitation, and the precipitated product was filtered, dissolved in tetrahydrofuran again, and dropped into ethyl ether for repeated precipitation. After filtration, the filter cake was dried in a vacuum oven at 80°C to obtain brown-yellow solid Epoxy-PSi-PBI-NH2. The preparation route is shown in Figure 2

[0068] (2) The preparation method of BF-PSi-PBI-CNT described in this embodiment is as follows:

[0069] (21) Hydroxylated CNT (3 g) and Epoxy-PSi-PBI-NH2 (9.9 g) were dissolved in a mixed solvent of N,N-dimethylformamide / toluene (107 ml, mass ratio of Epoxy-PSi-PBI-NH2 to solvent 1:10) in a volume ratio of 7:3, and N-hydroxysuccinimide dichloroethane (1 mol / L) was added as a catalyst, and the reaction was carried out at 60°C for 3 h. After the reaction solution was filtered, it was washed with a mixed solvent of N,N-dimethylformamide / toluene (volume ratio 7:3) for 3 times, and then dried at 80°C under vacuum to obtain CNT-PSi-PBI-Epoxy.

[0070] (22) CNT-PSi-PBI-Epoxy (9.9 g) and hydroxylated BF (3 g) were added to tetrabutylammonium bromide (95 ml, mass ratio of tetrabutylammonium bromide to CNT-PSi-PBI-Epoxy 1:10), and triethylamine was used to adjust the pH to 9.0, and the reaction was carried out at 120°C under mechanical stirring for 2 h. After the reaction solution was filtered, it was washed with tetrabutylammonium bromide for 3 times, and the filter cake was dried in a vacuum oven at 80°C to obtain BF-PSi-PBI-CNT.

[0071] (3) The preparation method of PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0072] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 90°C air oven for 6 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer in a ratio of 89.8:10.8:0.4 to complete the premix.

[0073] ​(32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) was adjusted. After melt blending (maximum 260 °C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0074] Example 5

[0075] (1) The preparation method of Epoxy-PSi-PBI-NH2 in this example is as follows:

[0076] (11) α, ω-diaminopropyl polydimethylsiloxane (10 mmol) was dissolved in toluene (74 ml) (mass ratio 1:20), and triethanolamine (40 mmol) was added. Epoxy chloropropane (100 mmol) was added dropwise under ice bath, and the temperature was raised to 60 °C for 24 h. The obtained product was filtered to remove TEA-HCl salt, and toluene and excess epoxy chloropropane were removed by rotary evaporation (120 °C). The product was dried in a vacuum oven at 80 °C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is shown in Figure 1 .

[0077] (12) Amino-terminated PBI (1 mmol) was dissolved in dimethyl sulfoxide (50 ml) (mass ratio 1:15), and Epoxy-PSi-Epoxy prepared in step (11) (2 mmol) was added. Trifluoroborane ether (0.13 ml, 5 wt% of PBI) was added dropwise under nitrogen protection, and the temperature was raised to 60 °C for 24 h. After the reaction was completed, the solution was dropped into ether for precipitation, and the precipitate was filtered. The precipitate was dissolved in tetrahydrofuran again, and the solution was dropped into ether for repeated precipitation. After filtration, the filter cake was dried in a vacuum oven at 80 °C to obtain a brownish yellow solid Epoxy-PSi-PBI-NH2, and the preparation route is shown in Figure 2 .

[0078] (2) The preparation method of BF-PSi-PBI-CNT in this example is as follows:

[0079] (21) Hydroxylated CNT (3 g) and Epoxy-PSi-PBI-NH2 (9.9 g) were dissolved in a mixed solvent of N,N-dimethylformamide / toluene with a volume ratio of 7:3 (107 ml, mass ratio of Epoxy-PSi-PBI-NH2 to solvent 1:10), and N-hydroxysuccinimide dichloroethane (1 mol / L) was added as a catalyst. The temperature was raised to 60 °C for 3 h. After the reaction solution was filtered, it was washed with a mixed solvent of N,N-dimethylformamide / toluene with a volume ratio of 7:3 for 3 times, and then dried in a vacuum oven at 80 °C to obtain CNT-PSi-PBI-Epoxy.

[0080] (22) CNT-PSi-PBI-Epoxy (6 g) and hydroxylated BF (3 g) were added into tetrabutylammonium bromide (95 ml, tetrabutylammonium bromide: CNT-PSi-PBI-Epoxy mass ratio 1:10), and the pH was adjusted to 9.0 using triethylamine, and the reaction was mechanically stirred at 120°C for 2 h. After the reaction solution was filtered, it was washed three times with tetrabutylammonium bromide, and the filter cake was dried in a vacuum drying oven at 80°C to obtain BF-PSi-PBI-CNT.

[0081] (3) The preparation method of the PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0082] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 90°C air oven for 6 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer at a ratio of 80.8:19.8:0.4 to complete the premix.

[0083] (32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) of the extruder was adjusted, and after melt blending (maximum 260°C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0084] Example 6

[0085] (1) The preparation method of Epoxy-PSi-PBI-NH2 described in this embodiment is as follows:

[0086] (11) α, ω-diaminopropyl polydimethylsiloxane (10 mmol) was dissolved in toluene (74 ml) (mass ratio 1:20), and triethanolamine (40 mmol) was added. Epoxy chloropropane (100 mmol) was added dropwise under ice bath, and the temperature was raised to 60°C for 24 h after the dropwise addition was completed. The obtained product was filtered to remove TEA·HCl salt, and toluene and excess epoxy chloropropane were removed by rotary evaporation (120°C), and the product was dried in a vacuum oven at 80°C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is shown in Figure 1 .

[0087] (12) Amino-terminated PBI (1 mmol) was dissolved in triethanolamine (50 ml) (mass ratio 1:15), and Epoxy-PSi-Epoxy prepared in step (11) (1.5 mmol) was added. Trifluoroborane ether (0.13 ml, 5 wt% of PBI) was added dropwise, and the reaction was carried out at 60°C for 24 h under nitrogen protection. After the reaction was completed, the solution was dropped into ether for precipitation, and the precipitated product was filtered and dissolved in tetrahydrofuran again. The solution was dropped into ether for repeated precipitation, and the filter cake was dried in a vacuum oven at 80°C to obtain brown-yellow solid Epoxy-PSi-PBI-NH2. The preparation route is shown in Figure 2

[0088] (2) The preparation method of BF-PSi-PBI-CNT described in this embodiment is as follows:

[0089] (21) Hydroxylated CNT (3 g) and Epoxy-PSi-PBI-NH2 (6 g) were dissolved in a mixed solvent of N,N-dimethylformamide / toluene (107 ml, mass ratio of Epoxy-PSi-PBI-NH2 to solvent 1:10) in a volume ratio of 7:3, and N-hydroxysuccinimide dichloroethane (1 mol / L) was added as a catalyst, and the reaction was carried out at 60°C for 3 h. After the reaction solution was filtered, it was washed with a mixed solvent of N,N-dimethylformamide / toluene (volume ratio 7:3) for 3 times, and then dried at 80°C under vacuum to obtain CNT-PSi-PBI-Epoxy.

[0090] (22) CNT-PSi-PBI-Epoxy (6 g) and hydroxylated BF (3 g) were added to tetrabutylammonium bromide (95 ml, mass ratio of tetrabutylammonium bromide to CNT-PSi-PBI-Epoxy 1:10), and triethylamine was used to adjust the pH to 9.0, and the reaction was carried out at 120°C under mechanical stirring for 2 h. After the reaction solution was filtered, it was washed with tetrabutylammonium bromide for 3 times, and the filter cake was dried in a vacuum oven at 80°C to obtain BF-PSi-PBI-CNT.

[0091] (3) The preparation method of PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0092] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 90°C air oven for 6 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer at a ratio of 74.8:24.8:0.4 to complete the premix.

[0093] ​(32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) was adjusted. After melt blending (maximum 260 °C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0094] Example 7

[0095] (1) The preparation method of Epoxy-PSi-PBI-NH2 in this embodiment is as follows:

[0096] (11) α, ω-diaminopropyl polydimethylsiloxane (10 mmol) was dissolved in toluene (74 ml) (mass ratio 1:20), and triethanolamine (40 mmol) was added. Epoxy chloropropane (100 mmol) was added dropwise under ice bath, and the temperature was raised to 60 °C for 24 h. The obtained product was filtered to remove TEA-HCl salt, and toluene and excess epoxy chloropropane were removed by rotary evaporation (120 °C). The product was dried in a vacuum oven at 80 °C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is shown in Figure 1 .

[0097] (12) Amino-terminated PBI (1 mmol) was dissolved in triethanolamine (50 ml) (mass ratio 1:15), and Epoxy-PSi-Epoxy prepared in step (11) (1.5 mmol) was added. Trifluoroboron diethyl ether (0.13 ml, 5 wt% of PBI) was added dropwise, and the reaction was carried out at 60 °C for 24 h under nitrogen protection. After the reaction was completed, the solution was dropped into ether for precipitation, and the precipitate was filtered. The precipitate was dissolved in tetrahydrofuran again, and the solution was dropped into ether for repeated precipitation. After filtration, the filter cake was dried in a vacuum oven at 80 °C to obtain a brownish yellow solid Epoxy-PSi-PBI-NH2, and the preparation route is shown in Figure 2 .

[0098] (2) The preparation method of BF-PSi-PBI-CNT in this embodiment is as follows:

[0099] (21) Hydroxylated CNT (3 g) and Epoxy-PSi-PBI-NH2 (6 g) were dissolved in a mixed solvent of N,N-dimethylformamide / toluene (107 ml, volume ratio 7:3) (mass ratio of Epoxy-PSi-PBI-NH2 to solvent 1:10), and N-hydroxysuccinimide dichloroethane (1 mol / L) was added as a catalyst. The reaction was carried out at 60 °C for 3 h. After the reaction solution was filtered, it was washed with a mixed solvent of N,N-dimethylformamide / toluene (volume ratio 7:3) for 3 times, and then dried at 80 °C under vacuum to obtain CNT-PSi-PBI-Epoxy.

[0100] (22) CNT-PSi-PBI-Epoxy (6 g) and hydroxylated BF (3 g) were added into tetrabutylammonium bromide (95 ml, tetrabutylammonium bromide: CNT-PSi-PBI-Epoxy mass ratio 1:10), and the pH was adjusted to 9.0 using triethylamine, and the reaction was mechanically stirred at 120°C for 2 h. After the reaction solution was filtered, it was washed three times with tetrabutylammonium bromide, and the filter cake was dried in a vacuum drying oven at 80°C to obtain BF-PSi-PBI-CNT.

[0101] (3) The preparation method of the PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0102] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 90°C air oven for 6 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer at a ratio of 69.8:29.8:0.4 to complete the premix.

[0103] (32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) of the extruder was adjusted, and after melt blending (maximum 260°C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0104] Example 8

[0105] (1) The preparation method of Epoxy-PSi-PBI-NH2 described in this embodiment is as follows:

[0106] (11) α, ω-diaminopropyl polydimethylsiloxane (10 mmol) was dissolved in toluene (74 ml) (mass ratio 1:20), and triethanolamine (40 mmol) was added. Epoxy chloropropane (100 mmol) was added dropwise under ice bath, and the temperature was raised to 60°C for 24 h after the dropwise addition was completed. The obtained product was filtered to remove TEA·HCl salt, and toluene and excess epoxy chloropropane were removed by rotary evaporation (120°C), and the product was dried in a vacuum oven at 80°C to obtain a transparent viscous liquid Epoxy-PSi-Epoxy, and the preparation route is shown in Figure 1 .

[0107] (12) Amino-terminated PBI (1 mmol) was dissolved in tetrahydrofuran (50 ml) (mass ratio 1:15), and Epoxy-PSi-Epoxy prepared in step (11) (1.5 mmol) was added. Trifluoroboron ether (0.13 ml, 5 wt% of PBI) was added dropwise, and the reaction was carried out at 60°C for 24 h under nitrogen protection. After the reaction was completed, the solution was dropped into ethyl ether for precipitation, and the precipitated product was filtered, dissolved in tetrahydrofuran again, and dropped into ethyl ether for repeated precipitation. After filtration, the filter cake was dried in a vacuum oven at 80°C to obtain brown-yellow solid Epoxy-PSi-PBI-NH2. The preparation route is shown in Figure 2

[0108] (2) The preparation method of BF-PSi-PBI-CNT described in this embodiment is as follows:

[0109] (21) Hydroxylated CNT (3 g) and Epoxy-PSi-PBI-NH2 (6 g) were dissolved in a mixed solvent of N,N-dimethylformamide / toluene (107 ml, mass ratio of Epoxy-PSi-PBI-NH2 to solvent 1:10) in a volume ratio of 7:3, and N-hydroxysuccinimide dichloroethane (1 mol / L) was added as a catalyst, and the reaction was carried out at 60°C for 3 h. After the reaction solution was filtered, it was washed with a mixed solvent of N,N-dimethylformamide / toluene (volume ratio 7:3) for 3 times, and then dried at 80°C under vacuum to obtain CNT-PSi-PBI-Epoxy.

[0110] (22) CNT-PSi-PBI-Epoxy (6 g) and hydroxylated BF (3 g) were added to tetrabutylammonium bromide (95 ml, mass ratio of tetrabutylammonium bromide to CNT-PSi-PBI-Epoxy 1:10), and triethylamine was used to adjust the pH to 9.0, and the reaction was carried out at 120°C under mechanical stirring for 2 h. After the reaction solution was filtered, it was washed with tetrabutylammonium bromide for 3 times, and the filter cake was dried in a vacuum oven at 80°C to obtain BF-PSi-PBI-CNT.

[0111] (3) The preparation method of PA66 / BF-PSi-PBI-CNT composite material described in this embodiment is as follows:

[0112] (31) PA66, BF-PSi-PBI-CNT and antioxidant 168 were dried in a 90°C air oven for 6 h to remove water before melt extrusion, and were uniformly mixed in a high-speed mixer at a ratio of 84.8:14.8:0.4 to complete the premix.

[0113] ​(32) The premix in step (31) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) of the extruder was adjusted. After melt blending (maximum 260 °C), cooling and granulation, the PA66 / BF-PSi-PBI-CNT composite material was obtained.

[0114] Comparative Example 1

[0115] The difference from the example is that the connecting agent between BF and CNT uses a commercially available short-chain connecting agent KH550 without thermal conduction function, BF-KH550-CNT is prepared, and it is one-pot blended with PA66.

[0116] Preparation of PA66 / BF-KH550-CNT composite material:

[0117] (1) PA66, BF-KH550-CNT were dried in an oven at 90 °C for 6 h to remove moisture before melt extrusion, and 85 wt% PA66 and 15 wt% BF-KH550-CNT were uniformly mixed in a high-speed mixer to complete the premix.

[0118] (2) The premix in step (1) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (150 rpm) of the extruder was adjusted. After melt blending (maximum 250 °C), cooling and granulation, the PA66 / BF / CNT composite material was obtained.

[0119] Comparative Example 2

[0120] The difference from the example is that there is no connecting agent in the composite material system, and BF, CNT and PA66 are directly one-pot blended.

[0121] Preparation of PA66 / CNT / BF composite material:

[0122] (1) PA66, BF, CNT were dried in an oven at 90 °C for 6 h to remove moisture before melt extrusion, and 5 wt% BF and 10 wt% CNT were uniformly mixed in a high-speed mixer to complete the premix.

[0123] (2) The premix in step (1) was melt blended by a twin-screw extruder, and the rotation speed of the feeding screw (30 rpm) and the main screw (80 rpm) of the extruder was adjusted. After melt blending (maximum 250 °C), cooling and granulation, the PA66 / CNT composite material was obtained.

[0124] Performance test results of the example:

[0125] (1) Tensile property test: Tensile property was measured at room temperature by using a universal tensile testing instrument (Instron 5967, USA) with a crosshead speed of 10 mm / min according to the national standard GB / T 1040, and the result of each sample was expressed as the average value of at least five independent samples.

[0126] (2) Impact property test: Notched impact property was measured at room temperature by using an impact testing machine (SS-3700) according to the national standard GB / T 16420-1997, and the result of each sample was expressed as the average value of at least five independent samples.

[0127] (3) Volume resistivity test: Volume resistivity was measured at room temperature by using a high resistance meter (e.g. ZC-90G) with a specified DC voltage (usually 500 V) applied according to the national standard GB / T 1410-2006, and the result of each sample was expressed as the average value of at least five independent samples.

[0128] Thermal conductivity test: Thermal conductivity was measured at room temperature by using a thermal conductivity tester (Hot Disk TPS 2500S) with the transient plane source (TPS) method according to the national standard GB / T 10297-2015. During the test, the probe was placed between two flat samples to apply a constant low-power heat source and record the temperature rise curve. The result of each sample was expressed as the average value of at least three independent samples.

[0129] The test results of the examples and comparative examples are shown in Table 1

[0130] Table 1. PA66 / BF-PSi-PBI-CNT composite performance test results

[0131] Sample Tensile strength (MPa) Notched Charpy impact strength (kJ / m 2 ) Volume resistivity (Ω-cm) Thermal conductivity (W / mK) PA66 80 9 >10 14 ]] 0.25 Example 1 195 25 10 3 ]] 1.20 Example 2 150 15 10 4 ]] 0.50 Example 3 155 17 10 5 ]] 0.88 Example 4 180 22 10 4 ]] 0.80 Example 5 160 17 10 5 ]] 0.55 Example 6 180 19 10 4 ]] 0.81 Example 7 185 14 10 4 ]] 0.88 Example 8 190 24 10 3 ]] 1.15 Comparative Example 1 145 13 >10 8 ]] 0.35 Comparative Example 2 100 8 10 6 ]] 0.45

[0132] It is easy for those skilled in the art to understand that the above description is only an embodiment of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. Process for the preparation of a modifier of PA66 composites, characterized in that, The method comprises the following steps: (1) preparing a macromolecular functional linker Epoxy-PSi-PBI-NH2: (11) dissolving α, ω-diaminopropyl polydimethylsiloxane in toluene, adding triethanolamine, and adding dropwise epichlorohydrin under ice bath, and then increasing the temperature to 40-80 DEG C for reaction; the obtained product is filtered to remove TEA-HCl salt, and toluene and excess epichlorohydrin are removed by rotary evaporation to obtain a transparent viscous liquid flexible segment Epoxy-PSi-Epoxy; (12) dissolving amino-terminated polybenzimidazole PBI in a solvent, adding Epoxy-PSi-Epoxy prepared in step (11); adding dropwise boron trifluoride ether solution, and reacting under nitrogen protection at 40-80 DEG C; after the reaction is completed, the solution is dropped into ether for precipitation, and after filtration, the precipitated product is dissolved in tetrahydrofuran again, and the solution is dropped into ether for repeated precipitation; after filtration, the filter cake is vacuum dried to obtain a brownish yellow solid macromolecular functional linker Epoxy-PSi-PBI-NH2; (2) preparing BF-PSi-PBI-CNT: (21) dissolving hydroxylated CNT and Epoxy-PSi-PBI-NH2 in a solvent, and then adding N-hydroxysuccinimide dichloroethane solution as a catalyst, and reacting at 50-80 DEG C for 2-5 h; the reaction solution is filtered, washed with N, N-dimethylformamide / toluene mixed solvent, and then vacuum dried to obtain CNT-PSi-PBI-Epoxy; (22) adding CNT-PSi-PBI-Epoxy and hydroxylated BF into tetrabutylammonium bromide, adjusting the pH to 8.0-10.0, and mechanically stirring and reacting at 80-140 DEG C for 1-4 h; after filtering the reaction solution, washing with tetrabutylammonium bromide, and drying the filter cake in a vacuum drying oven, a modifier BF-PSi-PBI-CNT for PA66 composite material is obtained.

2. The process for the preparation of a modifier of PA66 composites according to claim 1, characterized in that, In step (11), the molar ratio of α, ω-diaminopropyl polydimethylsiloxane to epichlorohydrin is 1:5-1:15; the molar ratio of α, ω-diaminopropyl polydimethylsiloxane to triethanolamine is 1:3-1:5; and the mass ratio of α, ω-diaminopropyl polydimethylsiloxane to toluene is 1:10-1:

30.

3. The method for preparing the modifier of PA66 composite material according to claim 1, characterized in that, In step (12), the molar ratio of amino-terminated polybenzimidazole PBI to Epoxy-PSi-Epoxy is 1:1-1:3; the solvent is one of tetrahydrofuran, dimethyl sulfoxide and triethanolamine; the mass ratio of amino-terminated polybenzimidazole PBI to the solvent is 1:10-1:20; and the amount of boron trifluoride ether is 3-10 wt% of PBI.

4. The method for preparing the modifier of PA66 composite material according to claim 1, characterized in that, In step (21), the mass ratio of CNT to Epoxy-PSi-PBI-NH2 is 1:2-1:5; the solvent is one or a combination of more than two of toluene and N, N-dimethylformamide; and the mass ratio of Epoxy-PSi-PBI-NH2 to the solvent is 1:5-1:

15.

5. The method for preparing the modifier of PA66 composite material according to claim 1, characterized in that, In step (22), the mass ratio of CNT-PSi-PBI-Epoxy:hydroxylated BF is 5:1-2:1; the mass ratio of CNT-PSi-PBI-Epoxy to tetrabutylammonium bromide is 1:5-1:

15.

6. Modifier of PA66 composites, characterized by the fact that it comprises: The PA66 composite modifier is prepared by the method of any one of claims 1-5.

7. A PA66 composite material, characterized in that, The PA66 composite modifier of claim 6 is included in the PA66.

8. Process for the production of PA 66 composites, characterized in that, The method comprises the following steps: (31) drying PA66 and the PA66 composite modifier of claim 6 to remove moisture, and uniformly mixing them in a high-speed mixer to complete premixing; (32) melt blending the premixing material in step (31) by a twin-screw extruder, and obtaining PA66 / BF-PSi-PBI-CNT composite material through melt blending, cooling and granulation.

9. The method of producing a PA66 composite according to claim 8, characterized in that, In step (31), the drying temperature is 80-100℃, and the drying time is 4h-12h; the addition amount of BF-PSi-PBI-CNT is 4.8wt%-29.8wt% of the total mass of PA66.

10. The method of producing a PA66 composite according to claim 8, characterized in that, In step (32), the main feeding screw rotation speed of the twin-screw extruder is set to 20-50 rpm; the main screw rotation speed is set to 100-200 rpm; and the extruder temperature is set to 230℃-260℃.

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