High-toughness pet composite material and preparation method thereof

Abstract

The present application relates to a kind of high toughness PET composite material and its preparation method, belong to polyester material technical field.The high toughness PET composite material provided by the present application mainly includes the raw material for: PET, thermoplastic polyester elastomer, modified string bead-shaped silicon carbon nanotube composite filler, composite chain extender and antioxidant.By adding composite chain extender in PET, the amorphous area ratio can be increased and the crystalline zone grain is refined, and the impact force is effectively dispersed;Thermoplastic polyester elastomer is mixed with matrix in melt blending mode, further improve the toughness of composite material;The addition of modified string bead-shaped silicon carbon nanotube composite filler can effectively solve the problem of tensile strength decline, and its string bead-shaped structure also avoids the problem of poor dispersibility of filler.In addition, the present application uses melt extrusion-drawing process to prepare composite material, by controlling the stretching rate and stretching temperature, the structure orientation and crystallization rate are controlled, so as to optimize the toughness and rigidity of composite material.

Description

Technical Field

[0001] This invention belongs to the field of polyester material technology and relates to a high-toughness PET composite material and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) is a widely used thermoplastic that has gained widespread recognition for its excellent physical and chemical properties. It has excellent temperature resistance, mechanical properties and chemical stability, and plays an irreplaceable role in the fields of packaging, fiber and engineering plastics. However, its brittleness and low impact strength limit its application range.

[0003] Existing technologies include chain extension modification, blending modification, and inorganic material modification to improve the toughness of PET materials. Some studies have proposed reducing the crystallinity of PET by adding pyromellitic anhydride and oxazoline chain extenders. Blending this with thermoplastic polyester elastomers significantly improves the impact strength of PET, but greatly reduces its tensile strength, failing to resolve the conflict between increased impact strength and decreased tensile strength. Furthermore, some studies have proposed adding nanofillers to PET to create composite materials that combine the excellent properties of both nanofillers and polymer matrices. Existing technologies mention that mixing carboxylated multi-walled carbon nanotubes with PET exhibits good compatibility and can improve mechanical strength. However, when the addition amount of carboxylated multi-walled carbon nanotubes reaches 5% (mass fraction), some agglomeration occurs in the composite material, negatively impacting its properties.

[0004] Chinese patent CN101580631B discloses a toughening modified material for polyethylene terephthalate (PET) and its preparation method. This invention uses a relatively simple method to obtain a soft-shell-hard-core structure (sandbag structure) of elastomer-coated filler, thereby producing a composite material with high toughness and high rigidity, achieving synergistic toughening of polyethylene terephthalate by elastomer / nano-calcium carbonate. This invention uses elastomer to coat nano-calcium carbonate and then melt-blends it with PET substrate. Its sandbag structure becomes unstable or is destroyed under high-temperature stirring conditions, failing to achieve good mechanical effects.

[0005] In summary, considering the advantages and disadvantages of existing technologies, this invention proposes a high-toughness PET composite material and its preparation method, optimizing existing problems and improving the overall mechanical properties of the material. Summary of the Invention

[0006] This invention relates to a high-toughness PET composite material and its preparation method, belonging to the field of polyester material technology. The high-toughness PET composite material provided by this invention mainly comprises the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender, and antioxidant. By adding a composite chain extender to PET, the proportion of amorphous regions can be increased and the grain size of crystalline regions can be refined, effectively dispersing impact force. The thermoplastic polyester elastomer is mixed with the matrix by melt blending, further enhancing the toughness of the composite material. The addition of modified beaded silicon-carbon nanotube composite filler effectively solves the problem of decreased tensile strength, and its beaded structure also avoids the problem of poor filler dispersion. Furthermore, this invention uses a melt extrusion-traction stretching process to prepare the composite material. By controlling the stretching rate and stretching temperature, the structural orientation and crystallization rate are controlled, thereby optimizing the toughness and rigidity of the composite material.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A high-toughness PET composite material, comprising the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender, and antioxidant, wherein the mass ratio of the modified beaded silicon-carbon nanotube composite filler to PET is 6-10:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:2.

[0009] Furthermore, the preparation method of the modified beaded silicon-carbon nanotube composite filler includes the following steps:

[0010] (1) Take multi-walled carbon nanotubes and place them in a tube furnace with nitrogen gas introduced. Raise the temperature inside the furnace, then introduce silane gas and keep it warm. Then lower the temperature inside the furnace to room temperature to obtain composite filler.

[0011] (2) Place the composite filler in a container, then add mixed acid and heat and stir, cool and filter, wash the solid with deionized water until neutral, and dry it in a vacuum drying oven until constant weight to obtain the modified beaded silicon carbon nanotube composite filler.

[0012] Further, in step (1), the heating rate of the furnace is 5-6℃ / min, the holding time and temperature are 40-60min and 450-500℃ respectively, and the ratio between the mass of the multi-walled carbon nanotubes and the flow rate of silane gas is 0.4g:100sccm.

[0013] Further, in step (2), the solid-liquid ratio of the composite filler to the mixed acid is 5-10g:60-80mL, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68% respectively, the heating and stirring temperature and time are 55-65℃ and 3-5h respectively, and the drying temperature is 40-50℃.

[0014] A method for preparing a high-toughness PET composite material, the method comprising the following steps:

[0015] A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours.

[0016] A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture.

[0017] A3: The mixture is extruded as melt through an extruder, stretched using a three-roll press, and cooled to room temperature to obtain sheet-like high-toughness PET composite material.

[0018] Furthermore, in step A2, the temperature and time for melt blending are 280-300℃ and 3-5 min, respectively, and the blending speed is 60-70 r / min.

[0019] Further, in step A3, the temperature and rotation speed of the extruder are 250-265℃ and 80-100 r / min, respectively; the roller temperature of the three-roll tablet press is 90-110℃; and the ratio of the stretching rate of the traction stretching to the melt outflow rate is 1.35-1.52:1, wherein the stretching rate of the traction stretching is 20-30 mm / min.

[0020] Furthermore, the specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are: 100-120 parts of PET, 3-8 parts of thermoplastic polyester elastomer, 0.5-0.6 parts of composite chain extender, and 0.04-0.1 parts of antioxidant.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention utilizes beaded silicon-carbon nanotube composite filler anchored in PET. The beaded structure prevents the filler from slipping under stress and has good dispersibility, thereby increasing the amount of filler added to PET and improving tensile strength. The modified beaded silicon-carbon nanotube composite filler obtained after modification is also very stable at high temperatures.

[0023] 2. Furthermore, the present invention uses a melt extrusion-traction stretching process to prepare composite materials. By adjusting the stretching rate and stretching temperature, the structural orientation and crystallization rate are controlled, thereby optimizing the toughness and rigidity of the composite materials. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with embodiments, is provided below.

[0025] The PET manufacturer involved in this invention is DuPont, USA, grade FR531 NC010; the thermoplastic polyester elastomer manufacturer is BASF, model 695A15N; 1,3-phenylene-dioxazoline was purchased from Wuhan Camick Technology Co., Ltd., CAS number 34052-90-9; pyromellitic anhydride was purchased from Shandong Xindongneng Chemical Co., Ltd., CAS number 89-32-7; multi-walled carbon nanotubes were purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with a fineness of 10nm; the antioxidant is antioxidant 1010, purchased from Jinan Shanhai Chemical Technology Co., Ltd., CAS number 31570-04-4.

[0026] Example 1

[0027] A high-toughness PET composite material, comprising the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender and antioxidant, wherein the mass ratio of modified beaded silicon-carbon nanotube composite filler to PET is 6:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:2.

[0028] The preparation method of the modified beaded silicon-carbon nanotube composite filler includes the following steps:

[0029] (1) Take multi-walled carbon nanotubes and place them in a tube furnace with nitrogen gas introduced. Raise the temperature inside the furnace, then introduce silane gas and keep it warm. Then lower the temperature inside the furnace to room temperature to obtain composite filler.

[0030] (2) Place the composite filler in a container, then add mixed acid and heat and stir, cool and filter, wash the solid with deionized water until neutral, and dry it in a vacuum drying oven until constant weight to obtain the modified beaded silicon carbon nanotube composite filler.

[0031] The heating rate of the furnace in step (1) is 5℃ / min, the holding time and temperature are 40min and 450℃ respectively, and the ratio between the mass of the multi-walled carbon nanotubes and the flow rate of silane gas is 0.4g:100sccm.

[0032] In step (2), the solid-liquid ratio of the composite filler to the mixed acid is 5g:60mL. The mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68%, respectively. The heating and stirring temperature and time are 55℃ and 3h, respectively, and the drying temperature is 40℃.

[0033] A method for preparing a high-toughness PET composite material, the method comprising the following steps:

[0034] A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours.

[0035] A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture.

[0036] A3: The mixture is extruded as melt through an extruder, stretched using a three-roll press, and cooled to room temperature to obtain sheet-like high-toughness PET composite material.

[0037] In step A2, the temperature and time for melt blending are 280°C and 3 min, respectively, and the blending speed is 60 r / min.

[0038] In step A3, the temperature and rotation speed of the extruder are 250℃ and 80r / min, respectively, the roller temperature of the three-roll tablet press is 90℃, and the ratio of the stretching rate to the melt outflow rate is 1.35:1, wherein the stretching rate of the traction stretching is 20mm / min.

[0039] The specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are as follows: 100 parts PET, 3 parts thermoplastic polyester elastomer, 0.5 parts composite chain extender, and 0.04 parts antioxidant.

[0040] Example 2

[0041] A high-toughness PET composite material, comprising the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender and antioxidant, wherein the mass ratio of modified beaded silicon-carbon nanotube composite filler to PET is 8:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:2.

[0042] The preparation method of the modified beaded silicon-carbon nanotube composite filler includes the following steps:

[0043] (1) Take multi-walled carbon nanotubes and place them in a tube furnace with nitrogen gas introduced. Raise the temperature inside the furnace, then introduce silane gas and keep it warm. Then lower the temperature inside the furnace to room temperature to obtain composite filler.

[0044] (2) Place the composite filler in a container, then add mixed acid and heat and stir, cool and filter, wash the solid with deionized water until neutral, and dry it in a vacuum drying oven until constant weight to obtain the modified beaded silicon carbon nanotube composite filler.

[0045] The heating rate of the furnace in step (1) is 5.5℃ / min, the holding time and temperature are 50min and 475℃ respectively, and the ratio between the mass of the multi-walled carbon nanotubes and the flow rate of silane gas is 0.4g:100sccm.

[0046] In step (2), the solid-liquid ratio of the composite filler to the mixed acid is 7g:70mL. The mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68%, respectively. The heating and stirring temperature and time are 60℃ and 4h, respectively, and the drying temperature is 45℃.

[0047] A method for preparing a high-toughness PET composite material, the method comprising the following steps:

[0048] A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours.

[0049] A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture.

[0050] A3: The mixture is extruded as melt through an extruder, stretched using a three-roll press, and cooled to room temperature to obtain sheet-like high-toughness PET composite material.

[0051] In step A2, the temperature and time for melt blending are 290°C and 4 min, respectively, and the blending speed is 65 r / min.

[0052] In step A3, the temperature and rotation speed of the extruder are 258°C and 90 r / min, respectively, the roller temperature of the three-roll tablet press is 100°C, and the ratio of the stretching rate to the melt flow rate is 1.40:1, wherein the stretching rate is 25 mm / min.

[0053] The specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are as follows: 110 parts PET, 6 parts thermoplastic polyester elastomer, 0.55 parts composite chain extender, and 0.07 parts antioxidant.

[0054] Example 3

[0055] A high-toughness PET composite material, comprising the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender and antioxidant, wherein the mass ratio of modified beaded silicon-carbon nanotube composite filler to PET is 10:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:2.

[0056] The preparation method of the modified beaded silicon-carbon nanotube composite filler includes the following steps:

[0057] (1) Take multi-walled carbon nanotubes and place them in a tube furnace with nitrogen gas introduced. Raise the temperature inside the furnace, then introduce silane gas and keep it warm. Then lower the temperature inside the furnace to room temperature to obtain composite filler.

[0058] (2) Place the composite filler in a container, then add mixed acid and heat and stir, cool and filter, wash the solid with deionized water until neutral, and dry it in a vacuum drying oven until constant weight to obtain the modified beaded silicon carbon nanotube composite filler.

[0059] The heating rate of the furnace in step (1) is 6℃ / min, the holding time and temperature are 60min and 500℃ respectively, and the ratio between the mass of the multi-walled carbon nanotubes and the flow rate of silane gas is 0.4g:100sccm.

[0060] In step (2), the solid-liquid ratio of the composite filler to the mixed acid is 10g:80mL. The mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68%, respectively. The heating and stirring temperature and time are 65℃ and 5h, respectively, and the drying temperature is 50℃.

[0061] A method for preparing a high-toughness PET composite material, the method comprising the following steps:

[0062] A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours.

[0063] A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture.

[0064] A3: The melt of the mixture is extruded through an extruder, stretched using a three-roll press, and cooled to room temperature to obtain a sheet-like high-toughness PET composite material.

[0065] In step A2, the temperature and time for melt blending are 300°C and 5 min, respectively, and the blending speed is 70 r / min.

[0066] In step A3, the temperature and rotation speed of the extruder are 265℃ and 100 r / min, respectively, the roller temperature of the three-roll tablet press is 110℃, and the ratio of the stretching rate to the melt outflow rate is 1.52:1, wherein the stretching rate of the traction stretching is 30 mm / min.

[0067] The specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are as follows: 120 parts PET, 8 parts thermoplastic polyester elastomer, 0.6 parts composite chain extender, and 0.1 parts antioxidant.

[0068] Comparative Example 1

[0069] Based on Example 2, a high-toughness PET composite material is provided, comprising the following raw materials: PET, thermoplastic polyester elastomer, modified carbon nanotube filler, composite chain extender and antioxidant, wherein the mass ratio of modified beaded silicon-carbon nanotube composite filler to PET is 8:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:2.

[0070] The preparation method of the modified carbon nanotube filler is as follows:

[0071] Multi-walled carbon nanotubes are placed in a container, then mixed acid is added and heated and stirred. After cooling and filtration, the solid is washed with deionized water until neutral and then dried in a vacuum drying oven to constant weight to obtain modified carbon nanotube filler.

[0072] The solid-liquid ratio of the filler to the mixed acid is 7g:70mL. The mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68%, respectively. The heating and stirring temperature and time are 60℃ and 4h, respectively, and the drying temperature is 45℃.

[0073] A method for preparing a high-toughness PET composite material, the method comprising the following steps:

[0074] A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours.

[0075] A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture.

[0076] A3: The melt of the mixture is extruded through an extruder, stretched using a three-roll press, and cooled to room temperature to obtain a sheet-like high-toughness PET composite material.

[0077] In step A2, the temperature and time for melt blending are 290°C and 4 min, respectively, and the blending speed is 65 r / min.

[0078] In step A3, the temperature and rotation speed of the extruder are 258°C and 90 r / min, respectively, the roller temperature of the three-roll tablet press is 100°C, and the ratio of the stretching rate to the melt flow rate is 1.40:1, wherein the stretching rate is 25 mm / min.

[0079] The specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are as follows: 110 parts PET, 6 parts thermoplastic polyester elastomer, 0.55 parts composite chain extender, and 0.07 parts antioxidant.

[0080] Comparative Example 2

[0081] Based on Example 2, a high-toughness PET composite material is provided, comprising the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender, and antioxidant, wherein the mass ratio of modified beaded silicon-carbon nanotube composite filler to PET is 8:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:2.

[0082] The preparation method of the modified beaded silicon-carbon nanotube composite filler includes the following steps:

[0083] (1) Take multi-walled carbon nanotubes and place them in a tube furnace with nitrogen gas introduced. Raise the temperature inside the furnace, then introduce silane gas and keep it warm. Then lower the temperature inside the furnace to room temperature to obtain composite filler.

[0084] (2) Place the composite filler in a container, then add mixed acid and heat and stir, cool and filter, wash the solid with deionized water until neutral, and dry it in a vacuum drying oven until constant weight to obtain the modified beaded silicon carbon nanotube composite filler.

[0085] The heating rate of the furnace in step (1) is 5.5℃ / min, the holding time and temperature are 50min and 475℃ respectively, and the ratio between the mass of the multi-walled carbon nanotubes and the flow rate of silane gas is 0.4g:100sccm.

[0086] In step (2), the solid-liquid ratio of the composite filler to the mixed acid is 7g:70mL. The mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68%, respectively. The heating and stirring temperature and time are 60℃ and 4h, respectively, and the drying temperature is 45℃.

[0087] A method for preparing a high-toughness PET composite material, the method comprising the following steps:

[0088] A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours.

[0089] A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture.

[0090] A3: The mixture is extruded into a mold and cooled to room temperature to obtain a sheet-like high-toughness PET composite material.

[0091] In step A2, the temperature and time for melt blending are 290°C and 4 min, respectively, and the blending speed is 65 r / min.

[0092] In step A3, the temperature and rotation speed of the extruder are 258°C and 90 r / min, respectively.

[0093] The specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are as follows: 110 parts PET, 6 parts thermoplastic polyester elastomer, 0.55 parts composite chain extender, and 0.07 parts antioxidant.

[0094] Comparative Example 3

[0095] Based on Example 2, the roller temperature of the three-roll tablet press was adjusted to 120°C, while other conditions remained the same as in Example 2.

[0096] Comparative Example 4

[0097] Based on Example 2, the roller temperature of the three-roll tablet press was adjusted to 80°C, while other conditions remained the same as in Example 2.

[0098] Comparative Example 5

[0099] Based on Example 2, the ratio of the stretching rate to the melt outflow rate was adjusted to 1.6:1, while other conditions remained the same as in Example 2.

[0100] Comparative Example 6

[0101] Based on Example 2, the ratio of the stretching rate to the melt outflow rate was adjusted to 1.2:1, while other conditions remained the same as in Example 2.

[0102] Performance testing

[0103] The sheet-like high-toughness PET composite materials prepared in Examples 1-3 and Comparative Examples 1-6 were cut into strips with a length, width, and thickness of 80 mm × 10 mm × 4 mm and used as samples.

[0104] The impact performance of the samples was determined according to GB / T 1043-93 "Impact Test Method for Rigid Plastics Simply Supported Beams", and the impact velocity of the pendulum was set to 2.9 m / s. Each group of samples was tested 3 times and the average value was taken.

[0105] The tensile properties of the specimens were tested according to ISO 527 standard using a UTM4104X electronic universal testing machine. The tensile speed was 20 mm / min, the test temperature was 25±2℃, and each group of specimens was tested 5 times and the average value was taken.

[0106] In addition, after the impact performance test is completed, the surface of the impact fracture surface of the sample is scanned to observe and record the morphology of the particles.

[0107] The test results are shown in Table 1.

[0108] Table 1 Test Results

[0109]

[0110] Analysis of the results in Table 1 shows that the impact strength and tensile strength of Examples 1-3 are greater than those of Comparative Examples 1-6, and the filler in the cross-sectional morphology is uniformly dispersed. Comparative Example 1 uses carboxylated carbon nanotubes as filler. When the ratio of carbon nanotubes to PET is 8:100, agglomeration occurs at a proportion exceeding 5% (mass fraction), leading to a decrease in mechanical properties. Comparative Example 2 does not employ a traction stretching process, resulting in a lack of orientation in the crystal structure of the material. Simultaneously, the heterogeneous nucleation of the filler at the interface is reduced, thus decreasing mechanical properties. Comparative Examples 3-4 adjust the roller temperature of the three-roller tablet press by increasing or decreasing it. When the temperature is too high, the proportion of crystals formed by heterogeneous nucleation of the filler at the interface increases, thereby reducing the impact strength. Conversely, when the temperature is too low... The increased temperature difference makes the material more brittle, thus weakening the tensile strength. When the temperature decreases, the filler at the interface does not have time to form crystals before being subjected to stress, resulting in weak stress at the interface and thus weakened mechanical properties. In Comparative Examples 5-6, the ratio of the stretching rate to the melt flow rate was adjusted up or down. When the ratio was too high, the material was subjected to increased stress, and although the impact strength was improved, the tensile strength decreased sharply. When the ratio was too low, the crystal structure orientation decreased and the crystal ratio decreased, resulting in a decrease in mechanical properties.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-toughness PET composite material, characterized in that, The high-toughness PET composite material comprises the following raw materials: PET, thermoplastic polyester elastomer, modified beaded silicon-carbon nanotube composite filler, composite chain extender and antioxidant, wherein the mass ratio of modified beaded silicon-carbon nanotube composite filler to PET is 6-10:100, and the composite chain extender is composed of pyromellitic anhydride and 1,3-phenylene-dioxazoline in a mass ratio of 3:

2.

2. The high-toughness PET composite material according to claim 1, characterized in that, The preparation method of the modified beaded silicon-carbon nanotube composite filler includes the following steps: (1) Take multi-walled carbon nanotubes and place them in a tube furnace with nitrogen gas introduced. Raise the temperature inside the furnace, then introduce silane gas and keep it warm. Then lower the temperature inside the furnace to room temperature to obtain composite filler. (2) Place the composite filler in a container, then add mixed acid and heat and stir, cool and filter, wash the solid with deionized water until neutral, and dry it in a vacuum drying oven until constant weight to obtain the modified beaded silicon carbon nanotube composite filler.

3. The high-toughness PET composite material according to claim 2, characterized in that, The heating rate of the furnace in step (1) is 5-6℃ / min, the holding time and temperature are 40-60min and 450-500℃ respectively, and the ratio between the mass of the multi-walled carbon nanotubes and the flow rate of silane gas is 0.4g:100sccm.

4. The high-toughness PET composite material according to claim 2, characterized in that, In step (2), the solid-liquid ratio of the composite filler to the mixed acid is 5-10g:60-80mL. The mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, wherein the mass fractions of concentrated sulfuric acid and concentrated nitric acid are 98% and 68%, respectively. The heating and stirring temperature and time are 55-65℃ and 3-5h, respectively, and the drying temperature is 40-50℃.

5. A method for preparing the high-toughness PET composite material as described in claim 1, characterized in that, The preparation method of the high-toughness PET composite material includes the following steps: A1: Place thermoplastic polyester elastomer in a vacuum drying oven at 100℃ for 6 hours, place PET, pyromellitic anhydride and antioxidant in a vacuum drying oven at 140℃ for 12 hours, and place 1,3-methylene-dioxazoline in a vacuum drying oven at 80℃ for 12 hours. A2: After the raw materials are dried, thermoplastic polyester elastomer and PET are melt-blended in an internal mixer. Then, antioxidants, 1,3-methylene-dioxazoline and pyromellitic anhydride are added and blended. Finally, modified beaded silicon-carbon nanotube composite filler is added and blended until the torque is stable to obtain the mixture. A3: The mixture is extruded as melt through an extruder, stretched using a three-roll press, and cooled to room temperature to obtain sheet-like high-toughness PET composite material.

6. The method for preparing a high-toughness PET composite material according to claim 5, characterized in that, In step A2, the temperature and time for melt blending are 280-300℃ and 3-5 min, respectively, and the blending speed is 60-70 r / min.

7. The method for preparing a high-toughness PET composite material according to claim 5, characterized in that, In step A3, the temperature and speed of the extruder are 250-265℃ and 80-100 r / min, respectively; the roller temperature of the three-roll tablet press is 90-110℃; and the ratio of the stretching rate to the melt flow rate is 1.35-1.52:1, wherein the stretching rate is 20-30 mm / min.

8. The high-toughness PET composite material according to claim 1, characterized in that, The specific weight proportions of PET, thermoplastic polyester elastomer, composite chain extender, and antioxidant in the raw materials are as follows: 100-120 parts of PET, 3-8 parts of thermoplastic polyester elastomer, 0.5-0.6 parts of composite chain extender, and 0.04-0.1 parts of antioxidant.

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