A glass fiber reinforced PET composite material and its preparation method

Abstract

The present invention relates to a glass fiber reinforced PET composite material and a preparation method thereof, belonging to the technical field of polymer composite materials. The composite material comprises the following raw materials in parts by weight: 100 parts of PET masterbatch, 32 - 45 parts of modified glass fiber, 0.19 - 0.24 part of nucleating agent, 1.6 - 2 parts of lubricant, and 0.12 - 0.15 part of antioxidant; the modified glass fiber is prepared by grafting mercapto groups on the surface of glass fiber with KH-580 to form mercapto-functionalized glass fiber, forming a terminal hydroxyl quaternary ammonium salt by reacting tert-butyldimethylamine with 2-bromoethanol, and then substituting with octenyltrichlorosilane to form a modifier, and introducing the modifier molecule onto the surface of glass fiber by adding the alkenyl group containing an alkyl long chain introduced in the modifier molecule to the mercapto group grafted on the surface; the modified glass fiber improves the strength of the composite material and maintains a high impact resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer composite materials, and specifically relates to a glass fiber reinforced PET composite material and a preparation method thereof. Background Art

[0002] Polyethylene terephthalate (PET) is a high-performance engineering plastic with excellent mechanical strength, heat resistance and chemical stability; glass fiber is an inorganic non-metallic material with high strength, high modulus, heat resistance, corrosion resistance and other advantages; the composite material formed by compounding PET and glass fiber has high strength and modulus, can replace some metal materials, and has a wide range of applications in lightweight structural parts.

[0003] Traditional glass fiber reinforced PET composite materials improve mechanical properties through the interfacial bonding between fibers and the matrix, but there are the following problems: the polar ester groups of PET molecular chains have limited interaction with the hydroxyl groups on the surface of glass fibers, resulting in low interfacial bonding strength and poor stress transfer efficiency, and high content of glass fibers is likely to lead to a decrease in melt fluidity, affecting the molding process. Using coupling agents to treat glass fibers, only through simple physical adsorption or single chemical bond connection, cannot effectively buffer impact energy, resulting in a contradiction between the improvement of strength and impact resistance of existing glass fiber reinforced PET composite materials, which severely restricts the application of this composite material. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background art, the purpose of the present invention is to provide a glass fiber reinforced PET composite material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A glass fiber reinforced PET composite material, comprising the following raw materials in parts by weight: 100 parts of PET masterbatch, 32 - 45 parts of modified glass fiber, 0.19 - 0.24 parts of nucleating agent, 1.6 - 2 parts of lubricant, and 0.12 - 0.15 parts of antioxidant.

[0007] The modified glass fiber is prepared by the following method:

[0008] Step A1: Premix tert-butyldimethylamine, 2-bromoethanol and anhydrous acetonitrile, heat up to 70 - 80 °C, slowly add triethylamine and stir for reaction for 4 - 5 h, and remove acetonitrile by rotary evaporation to obtain end-hydroxy quaternary ammonium salt;

[0009] Furthermore, the dosage ratio of tert-butyldimethylamine, 2-bromoethanol, triethylamine and anhydrous acetonitrile is 0.1 mol: 0.11 - 0.12 mol: 4 - 6 mL: 50 - 65 mL. Triethylamine promotes the quaternization reaction of 2-bromoethanol and tert-butyldimethylamine. The specific reaction route is as follows:

[0010]

[0011] Step A2: Mix the terminal hydroxyl quaternary ammonium salt and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature at 5 - 15°C in a water bath, add octenyltrichlorosilane and stir for reaction for 2.5 - 3 h, then raise the temperature of potassium hydroxide for reflux for 1 - 1.5 h, rotary evaporate to remove tetrahydrofuran, wash the substrate with water and dry it to obtain the modifier;

[0012] Further, the dosage ratio of octenyltrichlorosilane, terminal hydroxyl quaternary ammonium salt, potassium hydroxide and anhydrous tetrahydrofuran is 0.1 mol: 0.3 mol: 2 - 3 g: 130 - 160 mL. The terminal hydroxyl quaternary ammonium salt substitutes with octenyltrichlorosilane to form a compound with a branched tert-butyl end. The specific reaction route is as follows:

[0013]

[0014] Step A3: Mix the silane coupling agent KH-580, acetic acid and aqueous ethanol solution, add chopped glass fibers and impregnate for coupling for 24 h, discharge and dry to obtain mercapto-functionalized glass fibers;

[0015] Further, the dosage ratio of chopped glass fibers, silane coupling agent KH-580, acetic acid and aqueous ethanol solution is 50 g: 3.5 - 4.5 mL: 1.2 - 1.6 mL: 80 - 100 mL. The volume fraction of the aqueous ethanol solution is 30%. The silane coupling agent KH-580 is hydrolyzed and coupled and loaded onto the surface of the chopped glass fibers, introducing organic mercapto groups to the surface.

[0016] Step A4: Mix the modifier, photoinitiator and dioxane, spray the mixture onto the surface of the mercapto-functionalized glass fibers, send them into a UV curing machine, control the UV irradiation intensity at 450 - 600 mW / cm 2 , control the temperature at 80 - 100°C, react for 0.8 - 1.2 h, spray and wash and then dry to obtain modified glass fibers;

[0017] Further, the dosage ratio of mercapto-functionalized glass fibers, modifier, photoinitiator and dioxane is 50 g: 1.9 - 2.4 g: 20 - 30 mg: 25 - 30 mL. Under UV initiation, the modifier adds to the organic mercapto groups on the surface of the mercapto-functionalized glass fibers, binding the modifier to the glass fibers through an alkyl chain containing a thioether structure.

[0018] Further, the lubricant is pentaerythritol stearate.

[0019] Further, the antioxidant is a composite of antioxidant 1010 and antioxidant 168.

[0020] A preparation method of a glass fiber reinforced PET composite material, specifically: mixing PET masterbatch, nucleating agent, lubricant and antioxidant, feeding them from the main feeding port of an extruder, feeding modified glass fiber from the side feeding port, plasticizing and extruding at 260 - 270 °C, and pelletizing to obtain the glass fiber reinforced PET composite material.

[0021] Advantages of the present invention:

[0022] The present invention uses a modified glass fiber to reinforce PET to prepare a composite material. The modified glass fiber is prepared by grafting a mercapto group on the surface of the glass fiber with KH - 580 to form a mercapto - functionalized glass fiber. A terminal - hydroxyl quaternary ammonium salt is formed by reacting tert - butyldimethylamine and 2 - bromoethanol, and then it is substituted with octenyltrichlorosilane to form a modifier. The alkenyl group containing an alkyl long - chain introduced into the modifier molecule adds to the mercapto group grafted on the surface, introducing the modifier molecule onto the surface of the glass fiber. Compared with the existing glass fiber reinforced PET, the modified glass fiber introduces a quaternary ammonium structure between the bonding interface of PET and the glass fiber. It carries a positive charge, while the ester group in the PET molecular chain contains an electronegative oxygen atom, and the two form an electrostatic interaction, enhancing the interfacial compatibility and bonding performance. The modifier introduces a branched tert - butyl structure onto the surface of the glass fiber, which entangles with the non - polar segments of PET, synergistically enhancing the interfacial mechanical interlock and improving the strengthening effect of the glass fiber. On the other hand, the branched tert - butyl forms a micro - support structure at the bonding interface, dispersing the impact stress, and the alkyl chain segment containing a thioether structure absorbs the impact energy through molecular chain slippage, significantly improving the impact resistance of the composite material. Specific embodiments

[0023] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0024] Example 1, preparing a glass fiber reinforced PET composite material, the specific implementation process is as follows:

[0025] (1) Preparation of modified glass fiber

[0026] Step A1: Take tert - butyldimethylamine, 2 - bromoethanol and anhydrous acetonitrile for premixing, heat up to 80 °C, stir at 150 rpm and slowly add triethylamine for reaction for 4 h. Among them, the dosage ratio of tert - butyldimethylamine, 2 - bromoethanol, triethylamine and anhydrous acetonitrile is 0.1 mol: 0.12 mol: 6 mL: 65 mL. Rotary evaporation is used to remove acetonitrile to obtain the terminal - hydroxyl quaternary ammonium salt.

[0027] Step A2: Mix the terminal hydroxyl quaternary ammonium salt and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature of the water bath at 15°C, add octene trichlorosilane, stir and react at 90rpm for 2.5h, then reflux the potassium hydroxide at the temperature for 1h, wherein the amount ratio of octene trichlorosilane, terminal hydroxyl quaternary ammonium salt, potassium hydroxide and anhydrous tetrahydrofuran is 0.1mol:0.3mol:3g:160mL, remove tetrahydrofuran by rotary evaporation, wash the substrate with water, and dry it to obtain a modifier.

[0028] Step A3: prepare an ethanol aqueous solution with a volume fraction of 30%, take a mixture of silane coupling agent KH-580, acetic acid and ethanol aqueous solution, and then add chopped glass fiber for impregnation coupling for 24 hours, wherein the amount ratio of chopped glass fiber, silane coupling agent KH-580, acetic acid and ethanol aqueous solution is 50g:4.5mL:1.6mL:100mL, and dry the material to obtain thiolated glass fiber.

[0029] Step A4: Mix the modifier, photoinitiator and dioxane, spray the mixture onto the surface of the thiolated glass fiber, and send it into a UV curing machine to control the UV irradiation intensity to 600mW / cm 2 , the temperature is 100°C, and the irradiation baking reaction is carried out for 0.8h, wherein the usage ratio of thiolated glass fiber, modifier, photoinitiator and dioxane is 50g:2.4g:30mg:30mL. Finally, it is sprayed with water for cleaning and dried to obtain modified glass fiber.

[0030] (2) Preparation of composite materials

[0031] The raw materials are calculated by weight: 100 parts of PET masterbatch, using TRN-8385FC resin masterbatch raw material; 32 parts of modified glass fiber, which is homemade in this embodiment; 0.24 parts of nucleating agent, using JW-30 commercially available nucleating agent; 1.6 parts of lubricant, using industrial grade pentaerythritol stearate; 0.12 parts of antioxidant, using antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1;

[0032] The PET masterbatch, nucleating agent, lubricant and antioxidant were mixed at a high speed of 600 rpm for 15 minutes in a high-speed mixer, the mixture was fed from the main feeding port of the extruder, and the modified glass fiber was fed from the side feeding port. The mixture was plasticized, extruded and pelletized at 260°C to obtain a glass fiber reinforced PET composite material.

[0033] Example 2, preparing a glass fiber reinforced PET composite material, the specific implementation process is as follows:

[0034] (1) Preparation of modified glass fiber

[0035] Step A1: premix tert-butyldimethylamine, 2-bromoethanol and anhydrous acetonitrile, heat to 70°C, stir at 120rpm and slowly add triethylamine to react for 5h, wherein the amount ratio of tert-butyldimethylamine, 2-bromoethanol, triethylamine and anhydrous acetonitrile is 0.1mol:0.11mol:4mL:50mL, and remove acetonitrile by rotary evaporation to obtain terminal hydroxyl quaternary ammonium salt.

[0036] Step A2: Mix the terminal hydroxyl quaternary ammonium salt and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature of the water bath to 5°C, add octene trichlorosilane, stir and react at 60rpm for 3h, then reflux the potassium hydroxide at the temperature for 1.5h, wherein the amount ratio of octene trichlorosilane, terminal hydroxyl quaternary ammonium salt, potassium hydroxide and anhydrous tetrahydrofuran is 0.1mol:0.3mol:2g:130mL, remove tetrahydrofuran by rotary evaporation, wash the substrate with water, and dry it to obtain a modifier.

[0037] Step A3: prepare an ethanol aqueous solution with a volume fraction of 30%, take a mixture of silane coupling agent KH-580, acetic acid and ethanol aqueous solution, and then add chopped glass fiber for impregnation coupling for 24 hours, wherein the amount ratio of chopped glass fiber, silane coupling agent KH-580, acetic acid and ethanol aqueous solution is 50g:3.5mL:1.2mL:80mL, and dry the material to obtain thiolated glass fiber.

[0038] Step A4: Mix the modifier, photoinitiator and dioxane, spray the mixture onto the surface of the thiolated glass fiber, and send it into a UV curing machine to control the UV irradiation intensity to 450mW / cm 2 , the temperature is 80°C, and the irradiation baking reaction is carried out for 1.2 hours, wherein the usage ratio of thiolated glass fiber, modifier, photoinitiator and dioxane is 50g:1.9g:20mg:25mL. Finally, it is sprayed with water for cleaning and dried to obtain modified glass fiber.

[0039] (2) Preparation of composite materials

[0040] The raw materials are calculated by weight: 100 parts of PET masterbatch, using TRN-8385FC resin masterbatch raw material; 45 parts of modified glass fiber, which is homemade in this embodiment; 0.19 parts of nucleating agent, using JW-30 commercially available nucleating agent; 2 parts of lubricant, using industrial grade pentaerythritol stearate; 0.15 parts of antioxidant, using antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1;

[0041] The PET masterbatch, nucleating agent, lubricant and antioxidant were mixed at a high speed of 600 rpm for 15 minutes in a high-speed mixer, the mixture was fed from the main feeding port of the extruder, and the modified glass fiber was fed from the side feeding port. The mixture was plasticized, extruded and pelletized at 270°C to obtain a glass fiber reinforced PET composite material.

[0042] Example 3, preparing a glass fiber reinforced PET composite material, the specific implementation process is as follows:

[0043] (1) Preparation of modified glass fiber

[0044] Step A1: premix tert-butyldimethylamine, 2-bromoethanol and anhydrous acetonitrile, heat to 75°C, stir at 150rpm and slowly add triethylamine to react for 4.5h, wherein the amount ratio of tert-butyldimethylamine, 2-bromoethanol, triethylamine and anhydrous acetonitrile is 0.1mol:0.12mol:5mL:60mL, and remove acetonitrile by rotary evaporation to obtain terminal hydroxyl quaternary ammonium salt.

[0045] Step A2: Mix the terminal hydroxyl quaternary ammonium salt and anhydrous tetrahydrofuran, introduce dry nitrogen protection, control the temperature of the water bath to 10°C, add octene trichlorosilane, stir and react at 90rpm for 2.8h, then reflux the potassium hydroxide at the temperature for 1.2h, wherein the amount ratio of octene trichlorosilane, terminal hydroxyl quaternary ammonium salt, potassium hydroxide and anhydrous tetrahydrofuran is 0.1mol:0.3mol:3g:150mL, remove tetrahydrofuran by rotary evaporation, wash the substrate with water, and dry it to obtain a modifier.

[0046] Step A3: prepare an ethanol aqueous solution with a volume fraction of 30%, take a silane coupling agent KH-580, acetic acid and an ethanol aqueous solution and mix them, then add short glass fibers and soak and couple them for 24 hours, wherein the amount ratio of short glass fibers, silane coupling agent KH-580, acetic acid and ethanol aqueous solution is 50g:4mL:1.4mL:90mL, and dry the material to obtain thiolated glass fibers.

[0047] Step A4: Mix the modifier, photoinitiator and dioxane, spray the mixture onto the surface of the thiolated glass fiber, and send it into a UV curing machine to control the UV irradiation intensity to 550mW / cm 2 , the temperature is 90°C, and the irradiation baking reaction is carried out for 1 hour, wherein the usage ratio of thiolated glass fiber, modifier, photoinitiator and dioxane is 50g:2.2g:25mg:30mL, and finally it is sprayed with water for cleaning and dried to obtain modified glass fiber.

[0048] (2) Preparation of composite materials

[0049] The raw materials are calculated by weight: 100 parts of PET masterbatch, using TRN-8385FC resin masterbatch raw material; 38 parts of modified glass fiber, which is homemade in this embodiment; 0.22 parts of nucleating agent, using JW-30 commercially available nucleating agent; 1.8 parts of lubricant, using industrial grade pentaerythritol stearate; 0.13 parts of antioxidant, using antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1;

[0050] Mix PET masterbatch, nucleating agent, lubricant and antioxidant in a high-speed mixer at 600 rpm for 15 min. Feed the mixture from the main feeding port of the extruder and feed the modified glass fiber from the side feeding port. Plasticize, extrude and pelletize at 260 °C to obtain glass fiber reinforced PET composite material.

[0051] Example 4: Prepare glass fiber reinforced PET composite material. The specific implementation process is as follows:

[0052] (1)Preparation of modified glass fiber

[0053] Step A1: Premix tert-butyldimethylamine, 2-bromoethanol and anhydrous acetonitrile, heat up to 80 °C, stir at 150 rpm and slowly add triethylamine to react for 4.2 h. The dosage ratio of tert-butyldimethylamine, 2-bromoethanol, triethylamine and anhydrous acetonitrile is 0.1 mol: 0.11 mol: 5 mL: 55 mL. Rotate and evaporate to remove acetonitrile to obtain terminal hydroxyl quaternary ammonium salt.

[0054] Step A2: Mix terminal hydroxyl quaternary ammonium salt and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature in a water bath at 5 °C, add octenyltrichlorosilane, stir and react at 90 rpm for 3 h, then heat potassium hydroxide to reflux for 1 h. The dosage ratio of octenyltrichlorosilane, terminal hydroxyl quaternary ammonium salt, potassium hydroxide and anhydrous tetrahydrofuran is 0.1 mol: 0.3 mol: 3 g: 150 mL. Rotate and evaporate to remove tetrahydrofuran, wash the substrate with water and dry to obtain the modifier.

[0055] Step A3: Prepare an ethanol aqueous solution with a volume fraction of 30%. Mix silane coupling agent KH-580, acetic acid and ethanol aqueous solution, and then add chopped glass fiber to impregnate and couple for 24 h. The dosage ratio of chopped glass fiber, silane coupling agent KH-580, acetic acid and ethanol aqueous solution is 50 g: 4 mL: 1.5 mL: 100 mL. Discharge and dry to obtain mercapto-functionalized glass fiber.

[0056] Step A4: Mix the modifier, photoinitiator and dioxane, spray the mixture onto the surface of mercapto-functionalized glass fiber, feed it into a UV curing machine, control the UV irradiation intensity at 500 mW / cm 2 , the temperature at 90 °C, irradiate and bake for reaction for 1.1 h. The dosage ratio of mercapto-functionalized glass fiber, modifier, photoinitiator and dioxane is 50 g: 2.1 g: 30 mg: 30 mL. Finally, spray and wash with water and dry to obtain modified glass fiber.

[0057] (2)Preparation of composite material

[0058] The raw materials are calculated by weight: 100 parts of PET masterbatch, using TRN-8385FC resin masterbatch raw material; 40 parts of modified glass fiber, which is homemade in this embodiment; 0.21 parts of nucleating agent, using JW-30 commercially available nucleating agent; 1.8 parts of lubricant, using industrial grade pentaerythritol stearate; 0.14 parts of antioxidant, using antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1;

[0059] The PET masterbatch, nucleating agent, lubricant and antioxidant were mixed at a high speed of 600 rpm for 15 minutes in a high-speed mixer, the mixture was fed from the main feeding port of the extruder, and the modified glass fiber was fed from the side feeding port. The mixture was plasticized, extruded and pelletized at 270°C to obtain a glass fiber reinforced PET composite material.

[0060] In Comparative Example 1, referring to Example 4, the modified glass fiber was replaced by mercaptolated glass fiber in equal amounts, and the rest of the implementation process was exactly the same.

[0061] Comparative Example 2, referring to Comparative Example 1, one portion of RQT-TG2885 toughening agent is added to the raw materials of the composite material, and the toughening agent is blended with the PET masterbatch, and the rest of the implementation process is exactly the same.

[0062] Samples were taken from the composite material prepared as above and injection molded into specimens. The tensile test was carried out according to ASTM D638-2022, the bending test was carried out according to ASTM D790-17, the impact test was carried out according to ASTM D256-24, and the melt mass flow rate test was carried out according to ASTM D1238-23 (270°C / 2.16kg). The specific test results are shown in Table 1:

[0063] Table 1

[0064]

[0065] It can be seen from the test data in Table 1 that the composite material prepared in the embodiment has higher tensile strength and flexural strength, the reinforcing effect of glass fiber on PET is significant, and the composite material maintains high impact resistance, has a high melt mass flow rate, and is easy to process and shape.

[0066] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0067] The above content is only an example and illustration of the present invention. Those skilled in the art to which this technology belongs can make various modifications, supplements, or use similar methods for substitution to the described specific embodiments. As long as it does not deviate from the invention or exceed the scope defined by this claim book, it shall fall within the protection scope of the present invention.

Claims

1. A glass fiber reinforced PET composite material, characterized in that, It includes the following raw materials by weight parts: 100 parts of PET masterbatch, 32 - 45 parts of modified glass fiber, 0.19 - 0.24 parts of nucleating agent, 1.6 - 2 parts of lubricant, and 0.12 - 0.15 parts of antioxidant; The modified glass fiber is prepared by the following method: Step A1: Premix tert - butyldimethylamine, 2 - bromoethanol and anhydrous acetonitrile, heat up to 70 - 80 °C, slowly add triethylamine and stir for reaction for 4 - 5 h to obtain a terminal - hydroxyl quaternary ammonium salt. Among them, the dosage ratio of tert - butyldimethylamine, 2 - bromoethanol, triethylamine and anhydrous acetonitrile is 0.1 mol: 0.11 - 0.12 mol: 4 - 6 mL: 50 - 65 mL; Step A2: Mix the terminal - hydroxyl quaternary ammonium salt and anhydrous tetrahydrofuran, introduce dry nitrogen for protection, control the temperature of the water bath at 5 - 15 °C, add octenyltrichlorosilane and stir for reaction for 2.5 - 3 h, then raise the temperature of potassium hydroxide for reflux for 1 - 1.5 h to obtain a modifier. Among them, the dosage ratio of octenyltrichlorosilane, terminal - hydroxyl quaternary ammonium salt, potassium hydroxide and anhydrous tetrahydrofuran is 0.1 mol: 0.3 mol: 2 - 3 g: 130 - 160 mL; Step A3: Mix silane coupling agent KH - 580, acetic acid and ethanol aqueous solution, add chopped glass fiber for impregnation coupling for 24 h, discharge and dry to obtain mercapto - functionalized glass fiber. Among them, the dosage ratio of chopped glass fiber, silane coupling agent KH - 580, acetic acid and ethanol aqueous solution is 50 g: 3.5 - 4.5 mL: 1.2 - 1.6 mL: 80 - 100 mL; Step A4: Mix the modifier, photoinitiator and dioxane, spray the mixture onto the surface of mercapto-functionalized glass fiber, send it into a UV curing machine, control the UV irradiation intensity at 450 - 600 mW / cm 2 , the temperature at 80 - 100 °C, react for 0.8 - 1.2 h, wash by spraying and then dry to obtain modified glass fiber, wherein the dosage ratio of mercapto-functionalized glass fiber, modifier, photoinitiator and dioxane is 50 g : 1.9 - 2.4 g : 20 - 30 mg : 25 - 30 mL.

2. A glass fiber reinforced PET composite material according to claim 1, characterized in that, The lubricant is pentaerythritol stearate.

3. A glass fiber reinforced PET composite material according to claim 1, characterized in that, The antioxidant is a composite of antioxidant 1010 and antioxidant 168.

4. A method for preparing a glass fiber reinforced PET composite material according to any one of claims 1-3, characterized in that, Specifically: Mix the PET masterbatch, nucleating agent, lubricant and antioxidant and feed them from the main feeding port of the extruder, feed the modified glass fiber from the side feeding port, plasticize and extrude at 260 - 270 °C, and pelletize to obtain the glass fiber - reinforced PET composite material.

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