Impact-resistant plastic film based on unidirectional carbon fiber reinforcement and preparation method of impact-resistant plastic film

Abstract

The invention discloses an impact-resistant plastic film based on unidirectional carbon fiber reinforcement and a preparation method of the impact-resistant plastic film, belongs to the technical field of film preparation, and aims to solve the technical problem that the impact resistance and barrier property of a plastic film in the prior art need to be further improved. According to the invention, by constructing a multi-scale synergistic structure composed of silane grafted carbon fibers, dispersed barrier resin particles and dynamic network polyurethane resin, the synergistic unification of interface anchoring, mesoscopic barrier and chain segment self-adaptive adjustment functions of the carbon fiber reinforced plastic film is realized; the structural system ensures that the film has a stable mechanical bearing path and a complex zigzag diffusion channel, and keeps the structural reconstruction capability under the action of a thermal medium, so that the obtained carbon fiber reinforced plastic film simultaneously obtains relatively high pendulum bob impact resistance energy, low water vapor permeation amount and low oxygen permeation amount, and the performance attenuation is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin film preparation, in particular to an impact-resistant plastic film based on unidirectional carbon fiber reinforcement and a preparation method thereof. BACKGROUND

[0002] The unidirectional carbon fiber reinforced impact-resistant plastic film is mainly applied to the field of structural protection and functional film with light weight, flexibility and high specific strength requirements in the prior art. Generally, the unidirectional carbon fiber is introduced into a thermoplastic or thermosetting resin to form an effective load transfer channel under the action of impact load, so as to improve the energy absorption capacity and anti-fracture capacity of the film.

[0003] At the same time, in order to improve the water vapor and oxygen barrier properties of the film, the diffusion path is often prolonged and the permeation rate is reduced by adjusting the molecular structure of the resin, building a multi-layer composite interface or adding inorganic barrier components. Related research and engineering practice are mainly focused on the orientation structure of carbon fiber, the interface bonding mode and the barrier system of the matrix, so as to achieve a proper structural balance between mechanical properties and barrier properties.

[0004] At present, the interface between the carbon fiber and the matrix in the unidirectional carbon fiber reinforced plastic film mainly depends on the weak chemical combination formed by physical infiltration or conventional sizing, which is difficult to maintain a stable load transfer path under impact or unidirectional stretching conditions. In addition, the matrix itself lacks self-regulating ability to local stress, and is prone to structural damage such as interface instability and fiber pull-out when disturbed by the outside world, thereby affecting the overall mechanical integrity and impact resistance of the film under dynamic load.

[0005] At the same time, the traditional film mainly depends on the compactness of the resin itself or inorganic barrier fillers to improve the diffusion path, but the internal structure is difficult to form a stable multi-scale tortuous channel, and the micro diffusion path is easy to be enlarged due to chain relaxation in a humid and hot environment, so that the permeation rate of water vapor and oxygen is significantly increased. In addition, the interface structure and matrix network lack effective restriction and stable maintenance mechanism under environmental disturbance, and are prone to increase in free volume, barrier path collapse and other phenomena, resulting in insufficient environmental stability of the film, which shows that the mechanical properties and barrier properties change significantly with the change of external conditions.

[0006] In view of the technical defects in this regard, a solution is proposed. SUMMARY

[0007] The present application aims to provide an impact-resistant plastic film based on unidirectional carbon fiber reinforcement and a preparation method thereof, which solves the technical problem that the impact resistance and barrier properties of the plastic film in the prior art need to be further improved.

[0008] The purpose of the application can be realized by the following technical scheme: the one-way carbon fiber reinforced impact-resistant plastic film is prepared from the following raw materials: 8-12 parts of silane grafted carbon fiber, 80-100 parts of dynamic network polyurethane resin, 45-50 parts of dispersed barrier resin particles, 0.01 parts of antioxidant 1010, 0.01 parts of antioxidant 168 and 0.2-0.3 parts of polydimethylsiloxane;

[0009] The silane grafted carbon fiber is prepared by the following method:

[0010] A1, dopamine and deionized water are added to the reaction kettle and stirred, and 10wt% sodium hydroxide aqueous solution is used to adjust the pH of the reaction system to 8-9, then mild micro-oxidized carbon fiber is added, stirred at room temperature for 25-35min, then diethylenetriamine is added and stirred for 20-30min, and then treated to obtain dopamine-amine polymer modified carbon fiber;

[0011] A2, 3-aminopropyltriethoxysilane, anhydrous ethanol and deionized water are added to the reaction kettle and stirred, the reaction system is adjusted to pH=4-5 using acetic acid and dopamine-amine polymer modified carbon fiber is added, then the reaction kettle is heated to 55-65℃, and stirred for 2-3h, and then treated to obtain silane grafted carbon fiber.

[0012] The reaction principle for preparing silane grafted carbon fiber is:

[0013] Under alkaline conditions, dopamine reacts with the activated groups on the surface of carbon fiber to form an amine group polymer layer, which has abundant amino functional groups, then the addition of diethylenetriamine promotes the further stabilization of dopamine polymer, forming a more stable adhesion layer on the surface of carbon fiber, then under acidic conditions, silanization reaction occurs, 3-aminopropyltriethoxysilane reacts with the amine functional groups on the surface of carbon fiber through its amino group to form a chemical bond, thereby grafting silane molecules onto the surface of carbon fiber, which not only enhances the compatibility of carbon fiber and matrix material, but also provides active sites for further reaction, and finally silane grafted carbon fiber is prepared.

[0014] Further, in step A1, the amount ratio of dopamine, deionized water, mild micro-oxidized carbon fiber and diethylenetriamine is 1-2g:100mL:1g:10-12g, and the post-treatment includes: after stirring is completed, the carbon fiber is collected by filtration, washed with deionized water until neutral, then the fiber material is transferred to a drying box with a temperature of 60℃ for vacuum drying for 2-3h to obtain dopamine-amine polymer modified carbon fiber;

[0015] Further, in step A2, the amount ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol, deionized water and dopamine-amine polymerization for modifying the carbon fiber is 8-12 mL:100 mL:10 mL:1 g, and the post-treatment includes: after stirring is completed, the carbon fiber is collected by filtration and washed with deionized water until neutral, and then the fiber material is transferred to a drying oven with a temperature of 100-120 DEG C for vacuum drying for 2-3 h to obtain the silane grafted carbon fiber.

[0016] Further, the preparation method of the mildly micro-oxidized carbon fiber is as follows: the carbon fiber and 2-3 mol / L nitric acid aqueous solution are added into a reaction container for stirring, the reaction liquid is heated to 50-60 DEG C after the system is uniformly dispersed, and the system is kept at the temperature for 1.0-1.5 h, and the post-treatment obtains the mildly micro-oxidized carbon fiber.

[0017] The reaction principle for preparing the mildly micro-oxidized carbon fiber is as follows:

[0018] Under the conditions of mild acidity and moderate heating, the nitric acid molecules are subjected to controlled oxidation with the surface carbon atoms to produce a small amount of carboxyl, hydroxyl and other oxygen-containing functional groups on the fiber surface, thereby forming a lightly activated surface structure. This process realizes limited and uniform surface oxidation without destroying the main crystal lattice of the carbon fiber, and finally the mildly micro-oxidized carbon fiber is prepared.

[0019] Further, in the process of preparing the mildly micro-oxidized carbon fiber, the amount ratio of the carbon fiber and 2-3 mol / L nitric acid aqueous solution is 1 g:100-120 mL, wherein the length of the carbon fiber is 10-12 mm and the radius is 8-10 μm, and the post-treatment includes: after stirring is completed, the carbon fiber is collected by filtration and washed with deionized water until neutral, and then the fiber material is transferred to a drying oven with a temperature of 60 DEG C for vacuum drying for 2-3 h to obtain the mildly micro-oxidized carbon fiber.

[0020] Further, the dynamic network polyurethane resin is prepared by the following method:

[0021] B1, polytetrahydrofuran, sebacic acid and glycerol carbonate are added into a reaction kettle for stirring, the reaction kettle is heated to 150-160 DEG C after being uniformly mixed, and the post-treatment obtains a polyester prepolymer;

[0022] B2, the polyester prepolymer and diethylenetriamine are added into a reaction kettle for stirring, the reaction kettle is heated to 200-210 DEG C after being uniformly mixed, and the system is kept at the temperature for 2 h, and the post-treatment obtains the dynamic network polyurethane resin.

[0023] The reaction principle for preparing the dynamic network polyurethane resin is as follows:

[0024] First, polytetrahydrofuran and sebacic acid undergo condensation under heating conditions to generate a polyester prepolymer with flexible ether segments and aliphatic diacid as the backbone. The glycerol carbonate introduced into the prepolymer contains an active cyclic carbonate structure, providing reaction sites for the subsequent network formation. Under further heating conditions, diethylenetriamine undergoes ring-opening addition with the cyclic carbonate in the prepolymer, forming a multi-point linkage structure between the amine group and the carbonate, constructing a polyurethane network with reversible exchange characteristics. This network is composed of ester bonds, urethane bonds, and bonds formed after the carbonate ring-opening, giving the system a dynamic recombination ability, thus forming a structurally stable and flowable dynamic network polyurethane resin.

[0025] Further, in step B1, the ratio of polytetrahydrofuran, sebacic acid and glycerol carbonate is 100-120g:100-120g:8-12g. The post-treatment includes: keeping the mixture warm and stirring for 3-4 hours, cooling it to room temperature after the reaction is completed, and transferring the reaction product to a drying oven at 80°C for vacuum drying for 2-3 hours to obtain a polyester prepolymer.

[0026] Furthermore, in step B2, the ratio of the polyester prepolymer to diethylenetriamine is 100g:18-20g. The post-treatment includes: cooling to room temperature after the reaction is completed, and transferring the reaction product to a drying oven at 80°C for vacuum drying for 2-3 hours to obtain a dynamic network polyurethane resin.

[0027] Furthermore, the method for preparing the dispersion barrier resin microparticles is as follows: phenyl acrylate, perfluoroalkyl ethyl acrylate and methacryloxypropyltriethoxysilane are added to a reaction vessel and stirred. After the mixture is uniform, azobisisobutyronitrile is added and stirring is continued. The reaction vessel is heated to 85-95℃ and kept at this temperature for 4-6 hours. The dispersion barrier resin microparticles are then obtained through post-treatment.

[0028] The reaction principle for preparing dispersed barrier resin particles is as follows:

[0029] Under heating conditions, azobisisobutyronitrile decomposes to generate free radicals, which promote the chain polymerization of phenyl acrylate, perfluoroalkyl ethyl acrylate and methacrylate containing triethoxysilane structure, generating copolymers with both organic segments and silane functional groups. After drying and milling, structurally stable dispersion barrier resin particles are obtained.

[0030] Furthermore, in the process of preparing the dispersion barrier resin microparticles, the ratio of phenyl acrylate, perfluoroalkyl ethyl acrylate, methacryloxypropyltriethoxysilane and azobisisobutyronitrile is 40mL:80mL:20-24mL:1g. The post-treatment includes: cooling after the reaction, vacuum drying in a drying oven at 80℃ for 3-4h, and milling through a 200-mesh sieve to obtain the dispersion barrier resin microparticles.

[0031] The present invention also discloses a method for preparing an impact-resistant plastic film based on unidirectional carbon fiber reinforcement, comprising the following steps:

[0032] S1. Add silane-grafted carbon fiber, dynamic network polyurethane resin, dispersed barrier resin particles, antioxidant 1010, antioxidant 168 and polydimethylsiloxane to a mixing tank and stir for 20-30 minutes to obtain a premix.

[0033] S2. The premixed material is added to a twin-screw extruder, and after melt extrusion and stretching by traction rollers, a unidirectional carbon fiber primary film is obtained. After cooling by cooling rollers and drying, a carbon fiber reinforced plastic film is obtained.

[0034] The reaction principle for preparing dispersed barrier resin particles is as follows:

[0035] In the molten state, the premixed system enables the dynamic network polyurethane resin and dispersed resin particles to form a continuous phase. Silane-grafted carbon fibers achieve stable interfacial bonding in the polymer matrix. During melt extrusion, the carbon fibers are oriented under tensile stress along the melt flow direction, constructing a longitudinally continuously distributed reinforcing structure. Subsequent stretching further orients the polymer chain segments, enhancing the mechanical uniformity inside the film. After cooling and setting, the fiber orientation is maintained and forms a stable composite system with the solidified polymer matrix, thereby obtaining a carbon fiber reinforced plastic film with continuous structural characteristics.

[0036] Further, in step S2, the method for preparing the carbon fiber reinforced plastic film is as follows: the premixed material is added to a twin-screw extruder, the temperature is set to 200-220℃ and the screw speed is 100-120rpm for melt extrusion, and a molten sheet is formed through a flat die. The molten sheet passes through two sets of traction rollers in sequence. The speed of the front traction roller is 3m / min, and the linear speed of the rear traction roller is 10-15 times that of the front traction roller, so that the sheet is unidirectionally stretched in the longitudinal direction and the carbon fibers are arranged along the film extrusion direction to obtain a unidirectional carbon fiber primary film. After being cooled by a cooling roller at 20-40℃, it is placed in a vacuum oven at 40-60℃ and dried for 1-2 hours to obtain a carbon fiber reinforced plastic film with a thickness of 100μm.

[0037] The present invention has the following beneficial effects:

[0038] 1. In the carbon fiber reinforced plastic film prepared by this invention, silane-grafted carbon fibers first establish a continuous reinforcing pathway with orientation characteristics. The surface chemical bonding structure enables more efficient load transfer between the fiber and matrix interface. This mechanism is further amplified in the dynamic network polyurethane, where polyurethane segments undergo reversible exchange under external force disturbance, enabling self-regulation of local stress concentration areas and maintaining the mechanical stability of the interface around the fiber. At the same time, the microscale fixed sites formed by the dispersed barrier resin particles in the matrix inhibit local structural relaxation and reduce the risk of fiber pull-out or interface instability. The three components respectively undertake the functions of load bearing, stress relief, and interface stabilization at different structural levels, so that the film still has good mechanical integrity after unidirectional stretching and obtains high impact response capability.

[0039] 2. The stable distribution of the dispersed barrier resin particles prepared by this invention in the polymer matrix creates a multi-scale tortuous diffusion path within the film, which acts as the dominant component for barrier behavior. The orderly dispersion of the particles not only extends the diffusion path of water vapor and oxygen but also further compresses the free volume through the segment regularization interaction with the dynamic network polyurethane, resulting in higher density of the diffusion channels at the molecular scale. At the same time, the longitudinal arrangement of silane-grafted carbon fibers forms a continuous oriented skeleton at the macroscopic scale, creating an additional geometric bypass effect for gas transport. The three types of materials construct a hierarchical barrier system from the microscopic, mesoscopic to macroscopic levels, enabling the film to exhibit stable and balanced barrier performance while maintaining processing fluidity and flexible structure, reflecting the systematic synergistic characteristics of the structural design.

[0040] 3. The dynamic network polyurethane prepared by this invention exhibits reversible chain segment exchange and structural self-regulation capabilities under environmental disturbances, which are the core components for maintaining system stability. This regulatory effect is directional under the constraint of silane-grafted carbon fibers. Specifically, the orientation skeleton of the fibers provides macroscopic structural constraints for the polyurethane, allowing its chain segment rearrangement to occur within a controlled space, thereby avoiding irreversible relaxation of the overall structure. At the same time, the dispersed barrier resin particles form a high-rigidity lattice in local areas, restricting chain segment disorder and volume expansion, making the barrier path less prone to collapse in humid and hot environments. The three factors form a complementary mechanism in terms of network reconstruction, mechanical constraint, and local steady-state control, enabling the film to maintain low mechanical decay and limited barrier changes under thermal or humid conditions, demonstrating the advantages of systematic environmental stability. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In this application, the carbon fiber used was purchased from Mitsubishi Chemical, with the product number TR 50S 6L; the antioxidant 1010 used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number P750268; the antioxidant 168 used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number T822863; the polydimethylsiloxane used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number P708881; and the polytetrahydrofuran used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number P902444.

[0043] Example 1

[0044] This embodiment provides a method for preparing silane-grafted carbon fibers, including the following steps:

[0045] Step I: Preparation of mildly oxidized carbon fibers

[0046] Weigh 10.0g of carbon fiber with a length of 10mm and a radius of 8μm and add 1000.0mL of 2mol / L nitric acid aqueous solution to the reaction vessel and stir. After the system is evenly dispersed, heat the reaction solution to 50℃ and keep it at this temperature for 1.0h. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 60℃ and vacuum dry for 2h to obtain mildly oxidized carbon fiber.

[0047] Step II: Preparation of dopamine-amine polymerized modified carbon fibers

[0048] Weigh 10.0g of dopamine and 1000.0mL of deionized water and add them to the reaction vessel. After stirring, adjust the pH of the reaction system to 8 using 10wt% sodium hydroxide aqueous solution. Then add 10.0g of mildly oxidized carbon fiber and stir at room temperature for 25min. Add 100.0g of diethylenetriamine and continue stirring for 20min. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 60℃ and vacuum dry for 2h to obtain dopamine-amine polymerized modified carbon fiber.

[0049] Step III: Preparation of silane-grafted carbon fibers

[0050] Weigh out 80.0 mL of 3-aminopropyltriethoxysilane, 1000.0 mL of anhydrous ethanol and 100.0 mL of deionized water and add them to the reaction vessel and stir. Adjust the pH of the reaction system to 4 with acetic acid and add 10.0 g of dopamine-amine polymerized modified carbon fiber. Then heat the reaction vessel to 55℃ and keep it at this temperature for 2 hours. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 100℃ and vacuum dry for 2 hours to obtain silane-grafted carbon fiber.

[0051] Example 2

[0052] This embodiment provides a method for preparing silane-grafted carbon fibers, including the following steps:

[0053] Step I: Preparation of mildly oxidized carbon fibers

[0054] Weigh 10.0g of carbon fiber with a length of 12mm and a radius of 10μm and add 1200.0mL of 3mol / L nitric acid aqueous solution to the reaction vessel and stir. After the system is evenly dispersed, heat the reaction solution to 60℃ and keep it at this temperature for 1.5h. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 60℃ and vacuum dry for 3h to obtain mildly oxidized carbon fiber.

[0055] Step II: Preparation of dopamine-amine polymerized modified carbon fibers

[0056] Weigh 20.0g of dopamine and 1000.0mL of deionized water and add them to the reaction vessel. After stirring, adjust the pH of the reaction system to 9 using 10wt% sodium hydroxide aqueous solution. Then add 10.0g of mildly oxidized carbon fiber and stir at room temperature for 35min. Add 120.0g of diethylenetriamine and continue stirring for 30min. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 60℃ and vacuum dry for 3h to obtain dopamine-amine polymerized modified carbon fiber.

[0057] Step III: Preparation of silane-grafted carbon fibers

[0058] Weigh out 120.0 mL of 3-aminopropyltriethoxysilane, 1000.0 mL of anhydrous ethanol and 100.0 mL of deionized water and add them to the reaction vessel. Stir the mixture and adjust the pH of the reaction system to 5 with acetic acid. Add 10.0 g of dopamine-amine polymerized modified carbon fiber. Then heat the reaction vessel to 65°C and keep it at that temperature for 3 hours. After stirring, filter and collect the carbon fiber. Wash it with deionized water until it is neutral. Then transfer the fiber material to a drying oven at 120°C and vacuum dry it for 3 hours to obtain silane-grafted carbon fiber.

[0059] Example 3

[0060] This embodiment provides a method for preparing silane-grafted carbon fibers, including the following steps:

[0061] Step I: Preparation of mildly oxidized carbon fibers

[0062] Weigh 10.0g of carbon fiber with a length of 10mm and a radius of 9μm and add 1100.0mL of 2.5mol / L nitric acid aqueous solution to the reaction vessel and stir. After the system is evenly dispersed, heat the reaction solution to 55℃ and keep it at this temperature for 1.2h. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 60℃ for vacuum drying for 3h to obtain mildly oxidized carbon fiber.

[0063] Step II: Preparation of dopamine-amine polymerized modified carbon fibers

[0064] Weigh 15.0g of dopamine and 1000.0mL of deionized water and add them to the reaction vessel. Stir and adjust the pH of the reaction system to 9 using 10wt% sodium hydroxide aqueous solution. Then add 10.0g of mildly oxidized carbon fiber and stir at room temperature for 30min. Add 120.0g of diethylenetriamine and continue stirring for 25min. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 60℃ and vacuum dry for 3h to obtain dopamine-amine polymerized modified carbon fiber.

[0065] Step III: Preparation of silane-grafted carbon fibers

[0066] Weigh out 100.0 mL of 3-aminopropyltriethoxysilane, 1000.0 mL of anhydrous ethanol and 100.0 mL of deionized water and add them to the reaction vessel and stir. Adjust the pH of the reaction system to 4 with acetic acid and add 10.0 g of dopamine-amine polymerized modified carbon fiber. Then heat the reaction vessel to 60℃ and keep it at this temperature for 3 hours. After stirring, filter and collect the carbon fiber, wash it with deionized water until neutral, and then transfer the fiber material to a drying oven at 120℃ and vacuum dry for 3 hours to obtain silane-grafted carbon fiber.

[0067] Example 4

[0068] This embodiment provides a method for preparing a dynamic network polyurethane resin, including the following steps:

[0069] Step (1): Preparation of polyester prepolymer

[0070] Weigh out 100.0g of polytetrahydrofuran, 100.0g of sebacic acid and 8.0g of glycerol carbonate and add them to the reaction vessel. Stir until the mixture is homogeneous. Then heat the reaction vessel to 150℃ and keep it at that temperature for 3 hours. After the reaction is complete, cool it to room temperature and transfer the reaction product to a drying oven at 80℃ for vacuum drying for 2 hours to obtain the polyester prepolymer.

[0071] Step 2: Preparation of dynamic network polyurethane resin

[0072] Weigh out 100.0g of polyester prepolymer and 18.0g of diethylenetriamine and add them to the reactor and stir. After the mixture is homogeneous, heat the reactor to 200℃ and keep it at that temperature for 2 hours. After the reaction is complete, cool it to room temperature and transfer the product to a drying oven at 80℃ for vacuum drying for 2 hours to obtain dynamic network polyurethane resin.

[0073] Example 5

[0074] This embodiment provides a method for preparing a dynamic network polyurethane resin, including the following steps:

[0075] Step (1): Preparation of polyester prepolymer

[0076] Weigh out 120.0g of polytetrahydrofuran, 120.0g of sebacic acid and 12.0g of glycerol carbonate and add them to the reaction vessel. Stir until the mixture is homogeneous. Then heat the reaction vessel to 160℃ and keep it at that temperature for 4 hours. After the reaction is complete, cool it to room temperature and transfer the reaction product to a drying oven at 80℃ for vacuum drying for 3 hours to obtain the polyester prepolymer.

[0077] Step 2: Preparation of dynamic network polyurethane resin

[0078] Weigh out 100.0g of polyester prepolymer and 20.0g of diethylenetriamine and add them to the reactor and stir. After the mixture is homogeneous, heat the reactor to 210℃ and keep it at that temperature for 2 hours. After the reaction is complete, cool it to room temperature and transfer the product to a drying oven at 80℃ for vacuum drying for 3 hours to obtain dynamic network polyurethane resin.

[0079] Example 6

[0080] This embodiment provides a method for preparing a dynamic network polyurethane resin, including the following steps:

[0081] Step (1): Preparation of polyester prepolymer

[0082] Weigh out 110.0g of polytetrahydrofuran, 110.0g of sebacic acid and 10.0g of glycerol carbonate and add them to the reaction vessel. Stir until the mixture is homogeneous. Then heat the reaction vessel to 160℃ and keep it at that temperature for 4 hours. After the reaction is complete, cool it to room temperature and transfer the reaction product to a drying oven at 80℃ for vacuum drying for 3 hours to obtain the polyester prepolymer.

[0083] Step 2: Preparation of dynamic network polyurethane resin

[0084] Weigh out 100.0g of polyester prepolymer and 20.0g of diethylenetriamine and add them to the reactor and stir. After the mixture is homogeneous, heat the reactor to 210℃ and keep it at that temperature for 2 hours. After the reaction is complete, cool it to room temperature and transfer the product to a drying oven at 80℃ for vacuum drying for 3 hours to obtain dynamic network polyurethane resin.

[0085] Example 7

[0086] This embodiment provides a method for preparing an impact-resistant plastic film based on unidirectional carbon fiber reinforcement, including the following steps:

[0087] Step 1: Preparation of dispersed barrier resin microparticles

[0088] Weigh out 40.0 mL of phenyl acrylate, 80.0 mL of perfluoroalkyl ethyl acrylate and 20.0 mL of methacryloxypropyltriethoxysilane and add them to the reaction vessel. Stir until the mixture is homogeneous, then add 1.0 g of azobisisobutyronitrile and continue stirring. Heat the reaction vessel to 85°C and keep it at that temperature for 4 hours. After the reaction is complete, cool it and dry it under vacuum in an 80°C drying oven for 3 hours. Grind the dried product through a 200-mesh sieve to obtain dispersed barrier resin particles.

[0089] Step 2: Preparation of premix

[0090] Weigh out the following by weight: 8 parts of silane-grafted carbon fiber prepared in Example 1, 80 parts of dynamic network polyurethane resin prepared in Example 4, 45 parts of dispersed barrier resin microparticles, 0.01 parts of antioxidant 1010, 0.01 parts of antioxidant 168 and 0.2 parts of polydimethylsiloxane, and add them to a mixing tank and stir for 20 minutes to obtain a premix.

[0091] Step 3: Preparation of carbon fiber reinforced plastic film

[0092] The premixed material is added to a twin-screw extruder, and the temperature is set to 200℃ and the screw speed to 100rpm for melt extrusion. The molten sheet is formed through a flat die and then passed through two sets of traction rollers. The front traction roller has a speed of 3m / min, and the linear speed of the rear traction roller is 10 times that of the front traction roller. This causes the sheet to be unidirectionally stretched in the longitudinal direction and the carbon fibers to be aligned along the film extrusion direction, resulting in a unidirectional carbon fiber primary film. After being cooled by a 20℃ cooling roller, the film is placed in a 40℃ vacuum oven and dried for 1 hour to obtain a carbon fiber reinforced plastic film with a thickness of 100μm.

[0093] Example 8

[0094] This embodiment provides a method for preparing an impact-resistant plastic film based on unidirectional carbon fiber reinforcement, including the following steps:

[0095] Step 1: Preparation of dispersed barrier resin microparticles

[0096] Weigh out 40.0 mL of phenyl acrylate, 80.0 mL of perfluoroalkyl ethyl acrylate and 24.0 mL of methacryloxypropyltriethoxysilane and add them to the reaction vessel. Stir until the mixture is homogeneous, then add 1.0 g of azobisisobutyronitrile and continue stirring. Heat the reaction vessel to 95°C and keep it at that temperature for 6 hours. After the reaction is complete, cool the mixture and vacuum dry it in an oven at 80°C for 4 hours. Grind the dried mixture through a 200-mesh sieve to obtain dispersed barrier resin particles.

[0097] Step 2: Preparation of premix

[0098] Weigh out the following by weight: 12 parts of silane-grafted carbon fiber prepared in Example 2, 100 parts of dynamic network polyurethane resin prepared in Example 5, 50 parts of dispersed barrier resin microparticles, 0.01 parts of antioxidant 1010, 0.01 parts of antioxidant 168 and 0.3 parts of polydimethylsiloxane, and add them to a mixing tank and stir for 30 minutes to obtain a premix.

[0099] Step 3: Preparation of carbon fiber reinforced plastic film

[0100] The premixed material was added to a twin-screw extruder, and the temperature was set to 220℃ and the screw speed to 120rpm for melt extrusion. The molten sheet was formed through a flat die and then passed through two sets of traction rollers. The front traction roller had a speed of 3m / min and the rear traction roller had a linear speed 15 times that of the front traction roller. This caused the sheet to be unidirectionally stretched in the longitudinal direction and the carbon fibers to be aligned along the film extrusion direction, resulting in a unidirectional carbon fiber primary film. After being cooled by a 40℃ cooling roller, the film was dried in a 60℃ vacuum oven for 2 hours to obtain a carbon fiber reinforced plastic film with a thickness of 100μm.

[0101] Example 9

[0102] This embodiment provides a method for preparing an impact-resistant plastic film based on unidirectional carbon fiber reinforcement, including the following steps:

[0103] Step 1: Preparation of dispersed barrier resin microparticles

[0104] Weigh out 40.0 mL of phenyl acrylate, 80.0 mL of perfluoroalkyl ethyl acrylate and 21.0 mL of methacryloxypropyltriethoxysilane and add them to the reaction vessel. Stir until the mixture is homogeneous, then add 1.0 g of azobisisobutyronitrile and continue stirring. Heat the reaction vessel to 90°C and keep it at that temperature for 5 hours. After the reaction is complete, cool the vessel and vacuum dry it in an 80°C drying oven for 4 hours. Grind the dried product through a 200-mesh sieve to obtain dispersed barrier resin particles.

[0105] Step 2: Preparation of premix

[0106] By weight, weigh 10 parts of the silane-grafted carbon fiber prepared in Example 3, 90 parts of the dynamic network polyurethane resin prepared in Example 6, 50 parts of the dispersed barrier resin microparticles, 0.01 parts of antioxidant 1010, 0.01 parts of antioxidant 168 and 0.3 parts of polydimethylsiloxane and add them to the mixing tank and stir for 25 minutes to obtain the premix.

[0107] Step 3: Preparation of carbon fiber reinforced plastic film

[0108] The premixed material was added to a twin-screw extruder, and the temperature was set to 210℃ and the screw speed to 120rpm for melt extrusion. The molten sheet was formed through a flat die and then passed through two sets of traction rollers. The front traction roller had a speed of 3m / min and the rear traction roller had a linear speed 12 times that of the front traction roller. This caused the sheet to be unidirectionally stretched in the longitudinal direction and the carbon fibers to be aligned along the film extrusion direction, resulting in a unidirectional carbon fiber primary film. After being cooled by a 30℃ cooling roller, the film was dried in a 50℃ vacuum oven for 2 hours to obtain a carbon fiber reinforced plastic film with a thickness of 100μm.

[0109] Comparative Example 1

[0110] The difference between this comparative example and Example 9 is that step III is omitted in the preparation process of the silane-grafted carbon fiber used in step II, and the dopamine-amine polymerized modified carbon fiber prepared in step II is used to replace the silane-grafted carbon fiber in an equal amount.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 9 is that step one is omitted, and the use of dispersing barrier resin particles is omitted in step two.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 9 is that step (2) of the preparation process of the dynamic network polyurethane resin used in step two is omitted, and the polyester prepolymer prepared in step (1) is used to replace the dynamic network polyurethane resin in an equal amount.

[0115] Performance testing:

[0116] The pendulum impact energy, water vapor transmission rate and oxygen transmission rate of the carbon fiber reinforced plastic films prepared in Examples 7-9 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 10004-2008 "Dry lamination and extrusion lamination of plastic composite films and bags for packaging".

[0117] The carbon fiber reinforced plastic films prepared in Examples 7-9 and Comparative Examples 1-3 were tested for the decrease rate of pendulum impact energy, the increase rate of water vapor transmission and the increase rate of oxygen transmission after high temperature medium treatment, in accordance with the standard GB / T 10004-2008 "Packaging Plastic Composite Films and Bags Dry Lamination and Extrusion Lamination". The specific data are shown in Table 1.

[0118] Table 1 - Performance Test Data for Each Sample

[0119]

[0120] Data Analysis:

[0121] Comparative analysis of the data in Table 1 reveals that the carbon fiber reinforced plastic film prepared in this invention exhibits a pendulum impact resistance of 18.5 J, a water vapor transmission rate of 2.0 g·(m²·24h)⁻¹, and an oxygen transmission rate of 7.2 cm³·(m²·24h·0.1 MPa)⁻¹. Furthermore, after heat treatment, the pendulum impact resistance decreases by 11%, the water vapor transmission rate increases by 23%, and the oxygen transmission rate increases by 17%. All these data are superior to the comparative example, indicating that…

[0122] In Comparative Example 1, after step III was omitted, the carbon fiber surface layer failed to construct a silanized interface structure, causing it to lose its chemical anchoring and interface bridging functions in the composite system. Without stable sites at the interface, the stress transmission chain between the fiber and the matrix became discontinuous, and the local load shifted in the interface region, leading to the accumulation of microslip and inducing early relaxation of the interface layer. At the same time, due to the lack of interface stability domains formed by silane bonding, the dynamic network polyurethane could not effectively regulate the interface stress when the exchange reaction was triggered, resulting in local failure of the stress reconstruction process. Furthermore, the decreased interface constraint ability would disturb the spatial distribution of the blocking particles in the interface neighborhood, weakening the synergistic coupling between the original multi-scale structures. Thus, the lack of interface chemical structure triggered the synergistic disintegration of the reinforcing phase, matrix phase, and filling dispersion structure, resulting in a systematic decline in the composite response performance.

[0123] In Comparative Example 2, after step one was eliminated, the microstructure lattice composed of barrier resin particles was lost, resulting in the matrix segments lacking necessary local spatial constraints during molding and subsequent environmental disturbances. Without the action of fixed points, the segments were prone to disordered diffusion, and the corresponding microscale structure tended to loosen. This disrupted the original multi-level structural coupling relationship within the system. Furthermore, without the mesoscopic level constructed by particles, the reversible chain segment exchange process of the dynamic network polyurethane also lost its local geometric constraints, causing the structural adjustment to show a trend of expanding range but decreasing effectiveness, resulting in weakened overall structural stability. At the same time, the fiber-reinforced structure lost some of the support for maintaining orientation due to matrix loosening, causing breakpoints in the "skeleton-matrix-particle" coupling chain in the multi-level structure. The absence of the multi-scale structural constraint system in this comparative example led to a decrease in the degree of internal structural ordering, thereby causing a systematic decline in composite performance.

[0124] After step (2) was removed in Comparative Example 3, the matrix resin failed to construct a dynamic network structure. Its chain segments did not have reversible exchange capabilities under thermal disturbance or mechanical load. As a result, the system lost the mechanism for dynamic reconstruction of local stress and structural relaxation. Without this structural adjustment link, the stress accumulated in the interface and matrix could not be redistributed, and microcracks or local damage areas were easily formed near the fiber interface, which damaged the integrity of the reinforcing network. At the same time, the irreversible relaxation of the chain segments under environmental influence caused the spatial arrangement around the barrier particles to shift in a diffusion manner, which led to the destruction of diffusion paths and interfacial synergy in the multi-scale structure. Due to the comprehensive weakening of the adjustment, constraint and structural locking capabilities caused by the lack of dynamic network, the synergistic system between the reinforcing phase, the filling phase and the matrix phase could not be maintained, resulting in an overall structural decline in composite performance.

[0125] Ultimately, it is demonstrated that the three technical features employed in this invention—silane-grafted carbon fibers, dispersed barrier resin microparticles, and dynamic network polyurethane—are not interchangeable or used in isolation. Rather, they collectively constitute the necessary technical chain for the multi-scale synergistic structure within the material. Specifically, in Comparative Example 1, the absence of the interfacial silanization structure disrupted the chemical anchoring between the reinforcing phase and the matrix, leading to the instability of the interfacial load transfer path. In Comparative Example 2, the removal of the microparticle lattice resulted in the matrix segments losing their local geometric constraints, causing the diffusion and structural organization capabilities at the mesoscale to fail. In Comparative Example 3, the deletion of the dynamic network structure caused the system to lose its adaptive reconstruction mechanism in response to stress and segment relaxation, making it difficult for the multi-level structure to maintain overall stability. All three comparative examples exhibited a continuous degradation phenomenon after the structural chain was severed, indicating that the three technical features have a mutually supportive and indispensable synergistic relationship and together constitute the necessary technical solution for achieving the performance improvement of this invention.

[0126] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An impact-resistant plastic film based on unidirectional carbon fiber reinforcement, characterized in that, The raw material composition includes the following parts by weight: 8-12 parts silane-grafted carbon fiber, 80-100 parts dynamic network polyurethane resin, 45-50 parts dispersed barrier resin particles, 0.01 parts antioxidant 1010, 0.01 parts antioxidant 168 and 0.2-0.3 parts polydimethylsiloxane; The silane-grafted carbon fibers were prepared by the following method: A1. Add dopamine and deionized water to the reaction vessel and stir. Adjust the pH of the reaction system to 8-9 using 10wt% sodium hydroxide aqueous solution. Then add mildly oxidized carbon fiber. Stir at room temperature for 25-35 min. Add diethylenetriamine and continue stirring for 20-30 min. Post-treatment yields dopamine-amine polymerized modified carbon fiber. A2. Add 3-aminopropyltriethoxysilane, anhydrous ethanol and deionized water to the reaction vessel and stir. Adjust the pH of the reaction system to 4-5 with acetic acid and add dopamine-amine polymerization to modify the carbon fibers. Then heat the reaction vessel to 55-65℃ and keep it at that temperature for 2-3 hours. The post-treatment yields silane-grafted carbon fibers.

2. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 1, characterized in that, In step A1, the ratio of dopamine, deionized water, mildly micro-oxidized carbon fiber, and diethylenetriamine is 1-2g:100mL:1g:10-12g; in step A2, the ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol, deionized water, and dopamine-amine polymerized modified carbon fiber is 8-12mL:100mL:10mL:1g.

3. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 1, characterized in that, The preparation method of the mildly oxidized carbon fiber is as follows: carbon fiber and 2-3 mol / L nitric acid aqueous solution are added to a reaction vessel and stirred. After the system is evenly dispersed, the reaction solution is heated to 50-60℃ and stirred for 1.0-1.5 h. The mildly oxidized carbon fiber is then obtained by post-treatment.

4. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 3, characterized in that, In the preparation of mildly oxidized carbon fibers, the ratio of carbon fibers to 2-3 mol / L nitric acid aqueous solution is 1 g: 100-120 mL, wherein the length of the carbon fibers is 10-12 mm and the radius is 8-10 μm.

5. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 1, characterized in that, The dynamic network polyurethane resin is prepared by the following method: B1. Add polytetrahydrofuran, sebacic acid and glyceryl carbonate to a reaction vessel and stir. After the mixture is uniform, heat the reaction vessel to 150-160℃ and then process it to obtain a polyester prepolymer. B2. Add the polyester prepolymer and diethylenetriamine to the reactor and stir. After the mixture is uniform, heat the reactor to 200-210℃ and stir for 2 hours. The post-treatment yields the dynamic network polyurethane resin.

6. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 5, characterized in that, In step B1, the ratio of polytetrahydrofuran, sebacic acid and glycerol carbonate is 100-120g:100-120g:8-12g; in step B2, the ratio of polyester prepolymer and diethylenetriamine is 100g:18-20g.

7. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 1, characterized in that, The method for preparing the dispersion barrier resin microparticles is as follows: phenyl acrylate, perfluoroalkyl ethyl acrylate and methacryloxypropyltriethoxysilane are added to a reaction vessel and stirred. After the mixture is uniform, azobisisobutyronitrile is added and stirring is continued. The reaction vessel is heated to 85-95℃ and stirred for 4-6 hours. The dispersion barrier resin microparticles are then obtained through post-treatment.

8. The impact-resistant plastic film based on unidirectional carbon fiber reinforcement according to claim 7, characterized in that, In the process of preparing the dispersed barrier resin microparticles, the ratio of phenyl acrylate, perfluoroalkyl ethyl acrylate, methacryloxypropyltriethoxysilane and azobisisobutyronitrile is 40mL:80mL:20-24mL:1g.

9. The method for preparing an impact-resistant plastic film based on unidirectional carbon fiber reinforcement as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Add silane-grafted carbon fiber, dynamic network polyurethane resin, dispersed barrier resin particles, antioxidant 1010, antioxidant 168 and polydimethylsiloxane to a mixing tank and stir for 20-30 minutes to obtain a premix. S2. The premixed material is added to a twin-screw extruder, and after melt extrusion and stretching by traction rollers, a unidirectional carbon fiber primary film is obtained. After cooling by cooling rollers and drying, a carbon fiber reinforced plastic film is obtained.

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