PET / PBT composite material and preparation method thereof

Abstract

The present invention provides a PET / PBT composite material and a preparation method thereof, and relates to the field of polymer composite materials, the PET / PBT composite material comprises the following raw materials by weight: 30-50 parts of PBT resin; 20 to 40 parts of PET resin; 10 to 20 parts of polyethylene naphthalate; 5 to 15 parts of modified nano aromatic amide fiber; 8 to 15 parts of ethylene-methacrylic acid copolymer neutralized by metal ions; 3-8 parts of a compatilizer; 0.3 to 1 part of an antioxidant; and 0.5 to 1.5 parts of a lubricant. The modified nano aromatic amide fiber provides rigidity, the ionic polymer provides toughness, the modified nano aromatic amide fiber and the ionic polymer are combined, the fiber serves as a rigid framework to bear main loads, and the ionic polymer distributed on the interface of the fiber and a matrix efficiently dissipates impact energy and prevents crack propagation through reversible fracture of dynamic bonds of the ionic polymer. Meanwhile, high strength, high modulus, ultrahigh toughness and high heat resistance are realized.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials, and more specifically, to a PET / PBT composite material and its preparation method. Background Technology

[0002] Polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) are two important thermoplastic polyesters. Alloying can combine the rapid crystallization of PBT with the high heat resistance and stiffness of PET. Alloyed composite materials are widely used in the electronics, electrical, and automotive industries. However, existing technologies for PBT / PET composites have significant shortcomings in high-end applications requiring high heat resistance, ultra-high toughness, and sustainability.

[0003] To address the heat resistance and toughness issues of PBT / PET alloys, patent CN116285257B proposes a method that uses hexamethylenediamine to react with the end groups of PBT / PET to form amide bonds, and then utilizes grafted silica to form a hydrogen bond network with amino groups, thereby improving heat resistance and toughness. While this approach has some effectiveness, the hydrogen bonding it relies on exhibits poor stability under long-term high-temperature or humid aging conditions, and the hydrogen bond network is easily disrupted, leading to performance degradation. Furthermore, the introduction of amine monomers may exacerbate the hydrolysis risk of polyester during high-temperature processing, and the complex synthesis process is detrimental to the stability and cost control of large-scale industrial production.

[0004] To increase the glow wire ignition temperature of PBT / PET alloys and reduce smoke emissions, patent CN118206853B employs a polymeric brominated flame retardant and a complex synergist system composed of phosphates, polyborosiloxanes, and phenyl silicone resins. Pretreatment of the components is required to achieve high GWIT and low smoke emissions. While this approach offers excellent performance, the excessive number of components and the complexity of the system necessitate extremely high control over the production process and pose potential risks related to raw material supply and cost fluctuations.

[0005] Secondly, adding a single component to PET / PBT composites is insufficient to overcome the performance bottlenecks of the composite material. Methods include using glass fiber reinforcement, elastomer toughening, and nucleating agents to accelerate crystallization. However, improving toughness often sacrifices rigidity and heat resistance, as seen in CN116574363B; while improving heat resistance usually leads to increased brittleness. For example, patent CN117820822B effectively improved the processability of rPET by introducing PA10T as a nucleating agent and utilizing a halogen-free phosphorus-nitrogen flame retardant system, but its toughening method still relies on traditional elastomers, making it difficult to simultaneously achieve ultra-toughness and extremely high heat resistance.

[0006] In summary, there is an urgent need in this field for a composite material that can meet the stringent requirements of high-end electronic and automotive components for comprehensive material performance, while simultaneously addressing the contradiction between high heat resistance, ultra-high toughness, and long-term thermal stability. Summary of the Invention

[0007] The purpose of this invention is to provide a PET / PBT composite material in which modified nano-aramid fibers provide rigidity and ionomers provide toughness. When the two are combined, the fibers act as a rigid skeleton to bear the main load, while the ionomers distributed at the fiber-matrix interface efficiently dissipate impact energy and prevent crack propagation through the reversible breakage of their dynamic bonds. At the same time, it achieves high strength, high modulus, ultra-high toughness and high heat resistance.

[0008] Another objective of this invention is to provide a method for preparing PET / PBT composite materials, in which modified fibers and other raw materials are fed separately and then melt-blended, ensuring the integrity and dispersibility of each component.

[0009] The invention solves its technical problem by employing the following technical solutions.

[0010] On one hand, embodiments of the present invention provide a PET / PBT composite material, comprising the following raw materials by weight:

[0011] 30-50 parts PBT resin; 20-40 parts PET resin; 10-20 parts polyethylene naphthalate; 5-15 parts modified nano-aramid fiber; 8-15 parts metal ion neutralized ethylene-methacrylic acid copolymer; 3-8 parts compatibilizer; 0.3-1 part antioxidant; 0.5-1.5 parts lubricant.

[0012] The functions and effects of each ingredient are as follows:

[0013] PBT resin, as the matrix skeleton, provides excellent processing fluidity, rapid crystallization, and basic mechanical strength.

[0014] PET resin, a rigidity and cost adjuster, provides higher rigidity, heat resistance, and lower raw material costs.

[0015] Poly(2,6-naphthalenedicarboxylate) enhances heat resistance; its more rigid naphthalene ring structure significantly improves the glass transition temperature and heat distortion temperature of the alloy at the molecular chain level.

[0016] Modified nano-aramid fibers, as rigid reinforcing skeletons and heterogeneous nucleating agents, provide a rigid scaffold at the nanoscale, greatly improving strength, modulus, and heat resistance; at the same time, they serve as efficient nucleation sites, accelerating crystallization.

[0017] The metal ion-neutralized ethylene-methacrylic acid copolymer, a dynamic interface agent and a super-toughening phase, exhibits dynamic and reversible ionic bonds that break and recombine when the network is subjected to stress, dissipating enormous energy and achieving super-toughness; it also serves as an interface sealant.

[0018] The compatibilizer's reactive functional groups react with the fiber and polyester matrix to form strong covalent bonds between the interfaces of each component, ensuring effective stress transfer.

[0019] Antioxidants prevent polymers from oxidative degradation during high-temperature processing and use, maintain molecular chain integrity, and ensure long-term performance stability.

[0020] Lubricants improve processing performance, reduce intermolecular and equipment friction, and improve melt flowability, mold release, and product surface finish.

[0021] In some embodiments of the present invention, the modified nano-aramid fiber is a nano-aramid fiber with a polydopamine layer coated on its surface and grafted with a hyperbranched polymer.

[0022] In some embodiments of the present invention, the method for preparing the modified nano-aramid fiber includes the following steps:

[0023] The nano-aramid fibers were dispersed in Tris-HCl buffer, dopamine hydrochloride was added, and the mixture was stirred and polymerized at room temperature and pH=8.5 for 12-24 hours. After centrifugation, washing and drying, the pre-coated fibers were obtained.

[0024] The pre-coated fibers were dispersed in a solvent, and the terminal amino hyperbranched polymer was added. The mixture was reacted at 40-60℃ for 6-12 hours. After washing and centrifugation, the modified nano-aramid fibers were obtained.

[0025] In some embodiments of the present invention, the terminal amino hyperbranched polymer is at least one of terminal amino hyperbranched polyamide-amine, terminal amino hyperbranched polyetheramine, terminal amino hyperbranched polyethyleneimine, and terminal amino hyperbranched polyesteramine; the weight-average molecular weight of the terminal amino hyperbranched polymer is 2000-15000 g / mol.

[0026] In some embodiments of the present invention, the mass ratio of nano-aramid fiber, dopamine hydrochloride, and terminal amino hyperbranched polymer is 1:(0.3-0.8):(0.2-0.6).

[0027] In some embodiments of the present invention, the method for preparing the metal ion-neutralized ethylene-methacrylic acid copolymer includes the following steps:

[0028] Ethylene-methacrylic acid copolymer particles, metal salts, and dispersants are fed into a twin-screw extruder, melt-mixed at 180-220°C, extruded, granulated, and dehydrated to obtain the metal ion-neutralized ethylene-methacrylic acid copolymer.

[0029] In some embodiments of the present invention, the metal salt is zinc oxide or magnesium oxide; the dispersant is calcium stearate.

[0030] In some embodiments of the present invention, the degree of neutralization of metal ions in the metal ion-neutralized ethylene-methacrylic acid copolymer is 40-60%.

[0031] In some embodiments of the present invention, the compatibilizer is at least one of ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, and maleic anhydride-grafted ethylene-octene copolymer; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 1:3; and the lubricant is at least one of calcium stearate, zinc stearate, vinyl bis-stearamide, and lignite wax ester.

[0032] On the other hand, embodiments of the present invention provide a method for preparing a PET / PBT composite material, comprising the following steps:

[0033] S1, dry PBT resin, PET resin, and polyethylene (2,6-naphthalenedicarboxylate) in a vacuum oven at 120-140℃ for 4-6 hours;

[0034] S2, add the dried raw materials, metal ion-neutralized ethylene-methacrylic acid copolymer, compatibilizer, antioxidant, and lubricant to a high-speed mixer and mix at room temperature for 5-10 minutes until homogeneous;

[0035] S3, the raw materials that are mixed evenly in step S2 are added into the twin-screw extruder through the main feed port, and the modified nano-aramid fibers are fed into the twin-screw extruder through the side feed port. The temperature of each section is controlled at 230-265℃. After melt extrusion, cooling and pelletizing, the PET / PBT composite material is obtained.

[0036] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0037] The composite material provided by this invention uses modified nano-aramid fibers to provide rigidity and ionomers to provide toughness. When combined, the fibers act as a rigid skeleton to bear the main load, while the ionomers distributed at the fiber-matrix interface efficiently dissipate impact energy and prevent crack propagation through the reversible breakage of their dynamic bonds. At the same time, it achieves high strength, high modulus, ultra-high toughness and high heat resistance.

[0038] PBT resin, PET resin, and polyethylene naphthalate (PEN) form a multi-component polyester system. PBT ensures processability, PET balances cost and rigidity, and PEN increases the upper limit of the composite material's heat resistance. The three components exhibit good compatibility, forming a composite matrix with tunable properties. This ensures excellent performance while providing flexibility and cost control in formulation design. Nanofibers, acting as heterogeneous nucleating agents, significantly increase the crystallization rate and shorten the molding cycle. Furthermore, the ionomer network temporarily disintegrates at high processing temperatures without affecting flowability; upon cooling, the network rebuilds, immediately providing a reinforcing effect.

[0039] The preparation method provided by this invention involves feeding the modified fiber and other raw materials separately and then melting and blending them, which ensures the integrity and dispersibility of each component. The modified fiber is added through the side feed port, which avoids it from undergoing long-term high temperature and high shear in the main feed section, effectively protecting the fiber aspect ratio and surface modification layer, and ensuring reinforcement efficiency. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0042] Example 1

[0043] Prepare modified nano-aramid fibers according to the following steps:

[0044] The nano-aramid fibers were dispersed in Tris-HCl buffer, dopamine hydrochloride was added, and the mixture was stirred and polymerized at room temperature and pH=8.5 for 12-24 hours. After centrifugation, washing and drying, the pre-coated fibers were obtained.

[0045] The pre-coated fibers were dispersed in a solvent, and an amino-terminated hyperbranched polymer (amino-terminated hyperbranched polyamide-amine) was added. The mixture was reacted at 40-60℃ for 6-12 hours. After washing and centrifugation, the modified nano-aramid fibers were obtained.

[0046] Among them, the weight-average molecular weight of terminal amino hyperbranched polyamide-amine is 2000-15000 g / mol.

[0047] Based on the above steps, the proportions of each raw material were adjusted to obtain modified nano-aramid fiber A, modified nano-aramid fiber B, and modified nano-aramid fiber C.

[0048] Modified nano-aramid fiber A: The mass ratio of nano-aramid fiber, dopamine hydrochloride, and terminal amino hyperbranched polymer is 1:0.5:0.4.

[0049] Modified nano-aramid fiber B: The mass ratio of nano-aramid fiber, dopamine hydrochloride, and terminal amino hyperbranched polymer is 1:0.3:0.2.

[0050] Modified nano-aramid fiber C: The mass ratio of nano-aramid fiber, dopamine hydrochloride, and terminal amino hyperbranched polymer is 1:0.8:0.6.

[0051] Example 2

[0052] The metal ion-neutralized ethylene-methacrylic acid copolymer was prepared according to the following steps:

[0053] Ethylene-methacrylic acid copolymer particles (weight average molecular weight 100,000 g / mol), metal salt (zinc oxide), and dispersant (calcium stearate) are fed into a twin-screw extruder, melt-mixed at 180-220°C, extruded, granulated, and dehydrated to obtain the metal ion-neutralized ethylene-methacrylic acid copolymer.

[0054] Among them, the amount of ethylene-methacrylic acid copolymer particles and zinc oxide were calculated according to different degrees of neutralization to prepare zinc ion neutralized ethylene-methacrylic acid copolymer AC;

[0055] The degree of neutralization of polymer A is 50%, that of polymer B is 40%, and that of polymer C is 60%.

[0056] Example 3

[0057] The composite material was prepared according to the following proportions and steps:

[0058] 40 parts PBT resin; 30 parts PET resin; 15 parts polyethylene naphthalate; 10 parts modified nano-aramid fiber A; 10 parts copolymer A; 5 parts compatibilizer; 0.8 parts antioxidant; 1 part lubricant.

[0059] The compatibilizer is an ethylene-methyl acrylate-glycidyl methacrylate copolymer; the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2; and the lubricant is calcium stearate.

[0060] The preparation steps of the composite material are as follows:

[0061] S1, PBT resin, PET resin, and polyethylene (2,6-naphthalenedicarboxylate) are dried in a vacuum oven at 120-140℃ for 6 hours to reduce the moisture content to below 0.03%;

[0062] S2, add the dried raw materials, metal ion-neutralized ethylene-methacrylic acid copolymer, compatibilizer, antioxidant, and lubricant to a high-speed mixer and mix at room temperature for 5-10 minutes until homogeneous;

[0063] S3, the raw materials that are mixed evenly in step S2 are added into the twin-screw extruder through the main feed port, and the modified nano-aramid fibers are fed into the twin-screw extruder through the side feed port. The temperature of each section is controlled at 230-265℃. After melt extrusion, cooling and pelletizing, the PET / PBT composite material is obtained.

[0064] The twin-screw extruder has a length-to-diameter ratio of 50:1. The temperatures in each zone from the feed inlet to the die head are set as follows: Zone 1 230℃, Zone 2 250℃, Zone 3 260℃, Zone 4 265℃, Zone 5 265℃, Zone 6 260℃, Zone 7 255℃, Zone 8 250℃, and Die Head 245℃. The screw speed is set to 400 rpm.

[0065] Example 4

[0066] The difference from Example 3 is that the formulation of the composite material is as follows:

[0067] 30 parts PBT resin; 20 parts PET resin; 10 parts polyethylene naphthalate; 5 parts modified nano-aramid fiber A; 8 parts copolymer A; 3 parts compatibilizer; 0.3 parts antioxidant; 0.5 parts lubricant. The preparation method is the same as in Example 3.

[0068] Example 5

[0069] The difference from Example 3 is that the formulation of the composite material is as follows:

[0070] 50 parts PBT resin; 40 parts PET resin; 20 parts polyethylene naphthalate; 15 parts modified nano-aramid fiber A; 15 parts copolymer A; 8 parts compatibilizer; 1 part antioxidant; 1.5 parts lubricant. The preparation method is the same as in Example 3.

[0071] Example 6

[0072] The difference from Example 3 is that modified nano-aramid fibers B and polymer B are used in the formulation of the composite material. The preparation method is the same as in Example 3.

[0073] Example 7

[0074] The difference from Example 3 is that the composite material formulation uses modified nano-aramid fibers C and polymer C. The preparation method is the same as in Example 3.

[0075] Example 8

[0076] The difference from Example 3 is that modified nano-aramid fibers A and polymer B are used in the formulation of the composite material. The preparation method is the same as in Example 3.

[0077] Example 9

[0078] The difference from Example 3 is that the composite material formulation uses modified nano-aramid fibers A and polymer C. The preparation method is the same as in Example 3.

[0079] Example 10

[0080] The difference from Example 3 is that modified nano-aramid fibers B and polymer A are used in the formulation of the composite material. The preparation method is the same as in Example 3.

[0081] Example 11

[0082] The difference from Example 3 is that modified nano-aramid fibers B and polymer C are used in the formulation of the composite material. The preparation method is the same as in Example 3.

[0083] Example 12

[0084] The difference from Example 3 is that modified nano-aramid fibers C and polymer A are used in the formulation of the composite material. The preparation method is the same as in Example 3.

[0085] Example 13

[0086] The difference from Example 3 is that modified nano-aramid fibers C and polymer B are used in the formulation of the composite material. The preparation method is the same as in Example 3.

[0087] Comparative Example 1

[0088] The difference from Example 3 is that nano-aramid fibers are used instead of the modified nano-aramid fibers in Example 3. All other raw materials and preparation methods are the same as in Example 3.

[0089] Comparative Example 2

[0090] The difference from Example 3 is that the zinc-neutralized ethylene-methacrylic acid copolymer is used instead of the zinc-ion-neutralized ethylene-methacrylic acid copolymer in Example 3. All other raw materials and preparation methods are the same as in Example 3.

[0091] Comparative Example 3

[0092] The difference from Example 3 is that nano-aramid fibers are used instead of the modified nano-aramid fibers in Example 3, and ethylene-methacrylic acid copolymer is used instead of the zinc ion-neutralized ethylene-methacrylic acid copolymer in Example 3. All other raw materials and preparation methods are the same as in Example 3.

[0093] Comparative Example 4

[0094] The difference from Example 3 is that modified nano-aramid fibers are not added; instead, PET resin is used to supplement the fibers. All other raw materials and preparation methods are the same as in Example 3.

[0095] Comparative Example 5

[0096] The difference from Example 3 is that the ethylene-methacrylic acid copolymer for zinc ion neutralization is not added; instead, PET resin is used to supplement the amount. All other raw materials and preparation methods are the same as in Example 3.

[0097] Experimental Example

[0098] The composite material properties of each embodiment and comparative example were tested using the following method. Each data point was tested three times, and the average value was taken. The results are shown in Table 1.

[0099] Tensile strength: ISO 527-2, unit MPa;

[0100] Flexural modulus: ISO 178, unit MPa;

[0101] Notched impact strength of cantilever beam: ISO 180 / A, unit kJ / m 2 ;

[0102] Heat distortion temperature (HDT): ISO 75-2, 1.82 MPa, unit °C;

[0103] Table 1

[0104]

[0105] From the data in Table 1, we can conclude that:

[0106] Compared with Comparative Examples 1-3, Example 3 exhibits the best overall performance, with the highest impact strength and heat distortion temperature. Comparative Example 1 (unmodified fiber only): impact strength drops sharply to 14.2 kJ / m. 2This demonstrates that fiber surface modification is crucial for improving toughness. The stiffness (flexural modulus) is acceptable, indicating that the fiber itself has a reinforcing effect, but poor interfacial bonding leads to increased brittleness. Comparative Example 2 (only the ionomer was not neutralized): Impact strength and heat distortion temperature decreased significantly, indicating that the dynamic ion bond network plays a decisive role in toughening and improving heat resistance. Tensile and flexural strength were also reduced due to poor compatibility. Comparative Example 3 (neither of these): Impact strength was only 9.8 kJ / m. 2 Unmodified fibers and acid copolymers lack synergy and may even have inferior performance to the matrix due to poor interface.

[0107] Comparative Example 4 (no fiber): The decrease in rigidity (flexural modulus), strength, and heat resistance indicates that the nano-aramid fiber is the main reinforcing and heat-resistant skeleton. Comparative Example 5 (no ionomer): The extremely low impact strength indicates that the ionomer is the main toughening phase, and its absence causes the material to revert to the brittleness of ordinary engineering plastics.

[0108] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A PET / PBT composite material, characterized in that, By weight, it includes the following ingredients: 30-50 parts PBT resin; 20-40 parts PET resin; 10-20 parts polyethylene naphthalate; 5-15 parts modified nano-aramid fiber; 8-15 parts metal ion neutralized ethylene-methacrylic acid copolymer; 3-8 parts compatibilizer; 0.3-1 part antioxidant; 0.5-1.5 parts lubricant.

2. The PET / PBT composite material according to claim 1, characterized in that, The modified nano-aramid fiber is a nano-aramid fiber with a polydopamine layer coated on its surface and grafted with hyperbranched polymer.

3. The PET / PBT composite material according to claim 2, characterized in that, The preparation method of the modified nano-aramid fiber includes the following steps: The nano-aramid fibers were dispersed in Tris-HCl buffer, dopamine hydrochloride was added, and the mixture was stirred and polymerized at room temperature and pH=8.5 for 12-24 hours. After centrifugation, washing and drying, the pre-coated fibers were obtained. The pre-coated fibers were dispersed in a solvent, and the terminal amino hyperbranched polymer was added. The mixture was reacted at 40-60℃ for 6-12 hours. After washing and centrifugation, the modified nano-aramid fibers were obtained.

4. The PET / PBT composite material according to claim 3, characterized in that, The terminal amine hyperbranched polymer is at least one of terminal amine hyperbranched polyamide-amine, terminal amine hyperbranched polyetheramine, terminal amine hyperbranched polyethyleneimine, and terminal amine hyperbranched polyesteramine. The weight-average molecular weight of the terminal amino hyperbranched polymer is 2000-15000 g / mol.

5. The PET / PBT composite material according to claim 3, characterized in that, The mass ratio of nano-aramid fiber, dopamine hydrochloride, and terminal amino hyperbranched polymer is 1:(0.3-0.8):(0.2-0.6).

6. The PET / PBT composite material according to claim 1, characterized in that, The method for preparing the metal ion-neutralized ethylene-methacrylic acid copolymer includes the following steps: Ethylene-methacrylic acid copolymer particles, metal salts, and dispersants are fed into a twin-screw extruder, melt-mixed at 180-220°C, extruded, granulated, and dehydrated to obtain the metal ion-neutralized ethylene-methacrylic acid copolymer.

7. The PET / PBT composite material according to claim 6, characterized in that, The metal salt is zinc oxide or magnesium oxide; the dispersant is calcium stearate.

8. The PET / PBT composite material according to claim 6, characterized in that, In the metal ion-neutralized ethylene-methacrylic acid copolymer, the degree of metal ion neutralization is 40-60%.

9. The PET / PBT composite material according to claim 1, characterized in that, The compatibilizer is at least one of the following: ethylene-methyl acrylate-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, and maleic anhydride-grafted ethylene-octene copolymer. The antioxidant is a mixture of antioxidant 1010 and antioxidant 168, with a mass ratio of 1:1 to 1:

3. The lubricant is at least one of calcium stearate, zinc stearate, vinyl bis-stearamide, and lignite wax ester.

10. A method for preparing the PET / PBT composite material according to any one of claims 1-9, characterized in that, Includes the following steps: S1, dry PBT resin, PET resin, and polyethylene (2,6-naphthalenedicarboxylate) in a vacuum oven at 120-140℃ for 4-6 hours; S2, add the dried raw materials, metal ion-neutralized ethylene-methacrylic acid copolymer, compatibilizer, antioxidant, and lubricant to a high-speed mixer and mix at room temperature for 5-10 minutes until homogeneous; S3. The raw materials that are mixed evenly in step S2 are added into the twin-screw extruder through the main feed port, and the modified nano-aramid fibers are fed into the twin-screw extruder through the side feed port. The temperature of each section is controlled at 230-265℃. After melt extrusion, cooling and pelletizing, the PET / PBT composite material is obtained.

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