High-impact-resistant petg nanocellulose composite sheet and method for preparing the same

Abstract

The application provides a high-impact-resistance PETG nanocellulose composite sheet and a preparation method thereof, and belongs to the technical field of high polymer materials; the nanocellulose is surface-modified through acetylation and silanization, so that the nanocellulose has both physical dispersibility in a PETG matrix and the ability of chemical bonding with the matrix through an epoxy group, and serves as a rigid reinforcing framework; secondly, a core-shell structure toughening agent is prepared, a rubber core of the toughening agent is used for absorbing impact energy, and a compatible shell ensures uniform dispersion of the toughening agent in the matrix, so that toughness is provided; a multifunctional reactive compatilizer is prepared, the compatilizer serves as a "molecular bridge", a polymethyl methacrylate main chain of the compatilizer ensures compatibility with each phase through physical entanglement, and an epoxy group of a side chain of the compatilizer chemically reacts with the modified nanocellulose and the PETG matrix in melt blending, so that the reinforcing phase and the toughening phase are firmly anchored in the matrix, and a chain extension effect is achieved, and finally, the strength and toughness of the system are synergized.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology and relates to a high-impact PETG nanocellulose composite sheet and its preparation method. Background Technology

[0002] PETG (polyethylene terephthalate-1,4-cyclohexanediol) is a non-crystalline copolyester widely used in medical devices, cosmetic packaging, electronic product casings, and high-end sheet materials due to its excellent transparency, good chemical resistance, and outstanding processing and molding properties. However, compared with traditional engineering plastics, pure PETG has relatively low toughness, especially in low-temperature or thick-walled products, where its tendency to brittle fracture limits its application in situations requiring stringent impact resistance. Therefore, modifying PETG to achieve high performance, particularly by simultaneously improving its impact toughness and mechanical strength, has become a technical bottleneck in expanding its application range.

[0003] Nanocellulose, as a biomass nanomaterial derived from renewable resources, has excellent specific strength, specific modulus and low density, making it an ideal polymer reinforcement. However, its application in PETG faces two major obstacles: (1) The surface of nanocellulose is rich in highly polar hydroxyl groups, which makes it extremely difficult to disperse uniformly in the non-polar or weakly polar PETG matrix. It often exists in the form of micron-sized aggregates, which becomes a defect of the material; (2) Even if partial dispersion is achieved, there is a lack of effective interfacial interaction between the hydrophilic nanocellulose and the hydrophobic PETG, which makes it impossible to form a strong interfacial layer. As a result, the stress cannot be effectively transferred from the matrix to the reinforcing phase, and the reinforcing effect is greatly reduced.

[0004] Furthermore, attempting to simultaneously introduce rigid fillers and flexible toughening agents into PETG to achieve both strength and toughness complicates the system. The lack of inherent compatibility among PETG, inorganic fillers, and elastomers leads to chaotic interfaces and severe phase separation. This prevents each component from fulfilling its intended function. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a high-impact PETG nanocellulose composite sheet and its preparation method. This application modifies the surface of nanocellulose through acetylation and silanization, enabling it to possess both physical dispersion in the PETG matrix and the ability to chemically bond with the matrix through epoxy groups, serving as a rigid reinforcing skeleton. Secondly, a core-shell toughening agent is prepared, with a rubber core absorbing impact energy and a compatible shell ensuring uniform dispersion in the matrix, thereby providing toughness. A multifunctional reactive compatibilizer is prepared, acting as a "molecular bridge." Its polymethyl methacrylate backbone ensures compatibility with each phase through physical entanglement, while its side-chain epoxy groups chemically react with the modified nanocellulose and the PETG matrix during melt blending, firmly anchoring the reinforcing and toughening phases in the matrix and acting as chain extenders, ultimately achieving a synergistic effect of strength and toughness in the system.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a high-impact PETG nanocellulose composite sheet, the method comprising:

[0008] S1: Prepare a toluene dispersion of azeotropic dehydrated nanocellulose, add pyridine to obtain a pre-reaction solution, add acetic anhydride dropwise to obtain reaction solution A, cool after reaction, centrifuge, wash, and dry to obtain acetylated nanocellulose; disperse KH-560 in a mixed solvent for pre-hydrolysis to obtain a silane-modified solution, add acetylated nanocellulose to obtain reaction solution B, adjust pH and react, cool, centrifuge, wash, and dry to obtain composite modified nanocellulose;

[0009] S2: Sodium dodecyl sulfate is added to deionized water to obtain an emulsifier solution. Potassium persulfate solution is added under a nitrogen atmosphere to obtain a basic reaction solution. A core monomer mixture is added dropwise to obtain reaction solution C. The reaction is carried out at a constant temperature to obtain a cross-linked polybutyl acrylate core emulsion. A shell monomer mixture is added dropwise and potassium persulfate solution is added to obtain reaction solution D. The reaction is carried out, cooled, and then demulsified with calcium chloride solution. The mixture is filtered, washed, and dried to obtain a core-shell toughening agent.

[0010] S3: Methyl methacrylate and glycidyl methacrylate are added to toluene, heated under nitrogen atmosphere, and then azobisisobutyronitrile is added to obtain reaction solution E. The reaction yields a pretreated solution, which is cooled and then poured into n-hexane. The solution is filtered, washed, and dried to obtain a reactive compatibilizer.

[0011] S4: PETG chips, core-shell toughening agent, and reactive compatibilizer are added to a twin-screw extruder for melt blending to obtain a premix. Composite modified nanocellulose is added and fully melted to obtain a mixture. The mixture is then extruded, calendered, and cooled to obtain a high-impact PETG nanocellulose composite sheet.

[0012] As a preferred technical solution of the present invention, in step S1, the mass fraction of the toluene dispersion of the azeotropic dehydrated nanocellulose is 1-3%, for example, it can be 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8% or 3.0%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] In some optional embodiments, the toluene dispersion of the azeotropic dehydrated nanocellulose is added with pyridine at 80-90°C, for example at 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0014] In some optional embodiments, the mass ratio of the azeotropic dehydrated nanocellulose to pyridine is 1:(1-3), for example, it can be 1:1.0, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2.0, 1:2.2, 1:2.4, 1:2.6, 1:2.8 or 1:3.0, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0015] In some optional embodiments, the mass ratio of the azeotropic dehydrated nanocellulose to acetic anhydride is 1:(10-20), for example, it can be 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0016] In some optional embodiments, the reaction time of the reaction solution A is 3-5 hours, for example, it can be 3.0 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4.0 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours or 5.0 hours, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0017] In some alternative embodiments, the KH-560 is dispersed in a mixed solvent and pre-hydrolyzed at pH 4.4-4.7, for example at pH 4.40, 4.43, 4.46, 4.49, 4.52, 4.55, 4.58, 4.61, 4.64, 4.67 or 4.70, but not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0018] In some optional embodiments, the pre-hydrolysis time is 10-15 min, for example, it can be 10.0 min, 10.5 min, 11.0 min, 11.5 min, 12.0 min, 12.5 min, 13.0 min, 13.5 min, 14.0 min, 14.5 min or 15.0 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0019] In some optional embodiments, the volume ratio of ethanol to deionized water in the mixed solvent is (90-95):(10-5), for example, it can be (90.0, 90.5, 91.0, 91.5, 92.0, 92.5, 93.0, 93.5, 94.0, 94.5 or 95.0):(10.0, 9.5, 9.0, 8.5, 8.0, 7.5, 7.0, 6.5, 6.0, 5.5 or 5.0), but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0020] In some optional embodiments, the mass ratio of the acetylated nanocellulose to KH-560 is 1:(0.05-0.15), for example, it can be 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, 1:0.10, 1:0.11, 1:0.12, 1:0.13, 1:0.14 or 1:0.15, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0021] In some alternative embodiments, the pH of the reaction solution B is adjusted to 5.8-6.2, for example, it can be 5.8, 5.84, 5.88, 5.92, 5.96, 6, 6.04, 6.08, 6.12, 6.16 or 6.2, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0022] In some optional embodiments, the reaction temperature after adjusting the pH of the reaction solution B is 50-60°C, for example, it can be 50°C, 51°C, 52°C, 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C or 60°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] In some optional embodiments, the reaction time after adjusting the pH of the reaction solution B is 45-60 min, for example, it can be 45 min, 46.5 min, 48 min, 49.5 min, 51 min, 52.5 min, 54 min, 55.5 min, 57 min, 58.5 min or 60 min, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0024] As a preferred technical solution of the present invention, in step S2, the amount of sodium dodecyl sulfate in the emulsifier solution accounts for 15-30% of the total amount, for example, it can be 15.0%, 16.5%, 18.0%, 19.5%, 21.0%, 22.5%, 24.0%, 25.5%, 27.0%, 28.5% or 30.0%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] In some optional embodiments, the emulsifier solution is added to a potassium persulfate solution at 75-85°C under a nitrogen atmosphere. For example, it can be added at 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, or 85°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] In some optional embodiments, the amount of potassium persulfate in the base reaction solution accounts for 10-20% of the total amount, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0027] In some optional embodiments, the molar ratio of butyl acrylate to allyl acrylate in the core monomer mixture is 1:(0.01-0.02), for example, it can be 1:0.010, 1:0.011, 1:0.012, 1:0.013, 1:0.014, 1:0.015, 1:0.016, 1:0.017, 1:0.018, 1:0.019 or 1:0.020, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0028] In some optional embodiments, the mass ratio of the total mass of nuclear monomers to deionized water in the nuclear monomer mixture is 1:(2.5-4), for example, it can be 1:2.50, 1:2.65, 1:2.80, 1:2.95, 1:3.10, 1:3.25, 1:3.40, 1:3.55, 1:3.70, 1:3.85 or 1:4.00, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0029] In some optional embodiments, the amount of sodium dodecyl sulfate in the nuclear monomer mixture accounts for 30-40% of the total amount, for example, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0030] In some optional embodiments, the mass ratio of the total mass of the nuclear monomer to the total mass of sodium dodecyl sulfate is 1:(0.02-0.03), for example, it can be 1:0.020, 1:0.021, 1:0.022, 1:0.023, 1:0.024, 1:0.025, 1:0.026, 1:0.027, 1:0.028, 1:0.029 or 1:0.030, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0031] In some optional embodiments, the total molar ratio of potassium persulfate to the nuclear monomer is 1:(250-350), for example, it can be 1:250, 1:260, 1:270, 1:280, 1:290, 1:300, 1:310, 1:320, 1:330, 1:340 or 1:350, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0032] In some optional embodiments, the reaction solution C is kept at a constant temperature for 1-1.5 hours, for example, 1.00 hours, 1.05 hours, 1.10 hours, 1.15 hours, 1.20 hours, 1.25 hours, 1.30 hours, 1.35 hours, 1.40 hours, 1.45 hours, or 1.50 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0033] In some optional embodiments, the molar ratio of methyl methacrylate to styrene in the shell monomer mixture is (0.25-0.45):1, for example, it can be 0.25:1, 0.27:1, 0.29:1, 0.31:1, 0.33:1, 0.35:1, 0.37:1, 0.39:1, 0.41:1, 0.43:1 or 0.45:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0034] In some optional embodiments, the mass ratio of the total mass of shell monomers to deionized water in the shell monomer mixture is 1:(2-3), for example, it can be 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9 or 1:3.0, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0035] In some optional embodiments, the amount of sodium dodecyl sulfate in the shell monomer mixture is the remainder.

[0036] In some optional embodiments, the mass ratio of the core monomer to the shell monomer is (2.5-4):1, for example, it can be 2.50:1, 2.65:1, 2.80:1, 2.95:1, 3.10:1, 3.25:1, 3.40:1, 3.55:1, 3.70:1, 3.85:1 or 4.00:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0037] In some optional embodiments, the reaction temperature of the reaction solution D is 85-90°C, for example, it can be 85.0°C, 85.5°C, 86.0°C, 86.5°C, 87.0°C, 87.5°C, 88.0°C, 88.5°C, 89.0°C, 89.5°C or 90.0°C, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0038] In some optional embodiments, the reaction time of the reaction solution D is 1.5-2 hours, for example, 1.50 hours, 1.55 hours, 1.60 hours, 1.65 hours, 1.70 hours, 1.75 hours, 1.80 hours, 1.85 hours, 1.90 hours, 1.95 hours, or 2.00 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0039] In some optional embodiments, the calcium chloride solution has a mass fraction of 5-10 wt.%, for example, 5.0 wt.%, 5.5 wt.%, 6.0 wt.%, 6.5 wt.%, 7.0 wt.%, 7.5 wt.%, 8.0 wt.%, 8.5 wt.%, 9.0 wt.%, 9.5 wt.% or 10.0 wt.%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0040] As a preferred technical solution of the present invention, in step S3, the mass ratio of the total mass of methyl methacrylate and glycidyl methacrylate to toluene is 1:(3-5), for example, it can be 1:3.0, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4.0, 1:4.2, 1:4.4, 1:4.6, 1:4.8 or 1:5.0, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0041] In some optional embodiments, the molar ratio of methyl methacrylate to glycidyl methacrylate is (9-19):1, for example, it can be 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1 or 19:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0042] In some optional embodiments, the addition of azobisisobutyronitrile after heating to 70-80°C under a nitrogen atmosphere can be done, for example, after 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, or 80°C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0043] In some optional embodiments, the molar ratio of the total molar amount of methyl methacrylate and glycidyl methacrylate to azobisisobutyronitrile is 1:(100-200), for example, it can be 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:160, 1:170, 1:180, 1:190 or 1:200, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0044] In some optional embodiments, the reaction time of the reaction solution E is 6-10 hours, for example, 6.0 hours, 6.4 hours, 6.8 hours, 7.2 hours, 7.6 hours, 8.0 hours, 8.4 hours, 8.8 hours, 9.2 hours, 9.6 hours, or 10.0 hours, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0045] In some optional embodiments, the volume ratio of n-hexane to pretreatment liquid is (10-15):1, for example, it can be 10.0:1, 10.5:1, 11.0:1, 11.5:1, 12.0:1, 12.5:1, 13.0:1, 13.5:1, 14.0:1, 14.5:1 or 15.0:1, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0046] As a preferred technical solution of the present invention, in step S4, the temperature of the melt blending is 190-220℃, for example, it can be 190℃, 193℃, 196℃, 199℃, 202℃, 205℃, 208℃, 211℃, 214℃, 217℃ or 220℃, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0047] In some optional embodiments, the amount of the core-shell toughening agent is 5-15% of the mass of the PETG slices, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0048] In some optional embodiments, the amount of reactive compatibilizer is 1-5% of the mass of PETG slices, for example, it can be 1.0%, 1.4%, 1.8%, 2.2%, 2.6%, 3.0%, 3.4%, 3.8%, 4.2%, 4.6% or 5.0%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0049] In some optional embodiments, the amount of the composite modified nanocellulose is 1-3% of the mass of PETG, for example, it can be 1.0%, 1.2%, 1.4%, 1.6%, 1.8%, 2.0%, 2.2%, 2.4%, 2.6%, 2.8% or 3.0%, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0050] Secondly, the present invention provides a high-impact PETG nanocellulose composite sheet, which is prepared by the method for preparing the high-impact PETG nanocellulose composite sheet.

[0051] This application addresses the fundamental problem of poor dispersibility and weak interfacial bonding of nanocellulose in a hydrophobic PETG matrix caused by its strong hydrophilicity through surface chemical modification. The modification is carried out in two steps: First, through acetylation, acetic anhydride reacts with the numerous hydroxyl groups on the surface of nanocellulose to convert the hydrophilic hydroxyl groups into hydrophobic acetyl groups. This process reduces the surface polarity and surface energy of nanocellulose, laying the foundation for its physical dispersion in PETG melt.

[0052] Subsequently, a second step of silanization modification was carried out based on acetylation. KH-560, a silane coupling agent containing epoxy functional groups, was selected. Its alkoxy groups are converted into highly reactive silanol groups under acidic hydrolysis conditions. These silanol groups can undergo dehydration condensation reactions with the small amount of hydroxyl groups remaining on the surface of the acetylated nanocellulose, preferentially constructing a Si-O-Si network and forming a composite interface with the residual hydroxyl groups of cellulose. Reactive epoxy groups were introduced onto the surface of the nanocellulose. These epoxy groups act as "chemical anchors," enabling them to chemically bond with the end groups of the PETG matrix or the functional groups of the reactive compatibilizer during subsequent melt blending. This elevates physical dispersion and interfacial wetting to the level of chemical bonding, constructing a strong interfacial layer and ensuring that stress can be effectively transferred from the matrix to the reinforcing phase.

[0053] This application describes a core-shell toughening agent prepared via a two-step emulsion polymerization method. Its function is to provide efficient impact energy absorption performance to the PETG matrix. The core layer of this toughening agent is composed of cross-linked polybutyl acrylate. The cross-linked polybutyl acrylate core, which is rubbery at room temperature, acts as flexible "soft particles" dispersed within the rigid PETG matrix. When the material is subjected to impact, it can dissipate impact energy by inducing numerous micro-yielding behaviors such as crazes and shear bands in the matrix, thereby preventing the propagation of macroscopic cracks and imparting high impact toughness to the material. The addition of allyl acrylate aims to form a slightly cross-linked network within the cross-linked polybutyl acrylate core, ensuring the stability of its particle morphology during high-temperature melt processing.

[0054] The toughening agent's shell is composed of a copolymer of methyl methacrylate and styrene. This shell enables physical compatibility with the PETG matrix. The shell's chemical structure has good affinity with the PETG matrix, which is beneficial for its stable dispersion in the matrix.

[0055] This application describes the preparation of a reactive compatibilizer via solution polymerization. This compatibilizer acts as a "molecular bridge" connecting different phase interfaces in the entire composite system. Firstly, its main chain is composed of polymethyl methacrylate segments, exhibiting good physical compatibility with the PETG matrix and the shell of the core-shell toughening agent. Through the physical entanglement of molecular chains, it can initially improve the interfacial condition between the components.

[0056] Secondly, its role lies in the highly reactive functional groups introduced onto its side chains—epoxy groups. During melt blending, these epoxy groups can perform multiple chemical bonding functions: 1) They undergo ring-opening reactions with the terminal hydroxyl or carboxyl groups of the PETG molecular chain, acting as chain extenders, which can repair PETG molecular chains that may degrade during processing, and improve the toughness and melt strength of the matrix itself. 2) They undergo ring-opening bonds with the terminal hydroxyl / carboxyl groups of PETG and the residual hydroxyl groups of modified nanocellulose, and together with the chain entanglement of the polymethyl methacrylate backbone, they enhance the interface. In this way, the compatibilizer tightly connects the three independent phases—the PETG matrix, the nanocellulose reinforcing phase, and the core-shell toughening agent—into an organic whole through chemical bonds and physical entanglement, ensuring the effective transfer of stress between different phases, and is the core link to achieve the "strong and tough synergy" of the system.

[0057] This application also exhibits synergistic enhancement. Firstly, there is a synergistic effect in mechanical properties: the composite modified nanocellulose acts as a rigid framework, providing strength and modulus, while the core-shell toughening agent acts as an energy-absorbing unit, providing impact toughness. The contradiction between these two properties is reconciled through a reactive compatibilizer, a "molecular bridge." This compatibilizer chemically bonds the matrix, nanocellulose, and toughening agent together, constructing an efficient stress transfer pathway. This allows impact energy to be directionally transferred to the toughening phase for dissipation, while the static load can be effectively borne by the reinforcing phase, thus breaking the traditional limitation of the trade-off between strength and toughness in materials. Secondly, the reactive compatibilizer itself also exhibits functional synergy. It not only acts as an interfacial coupling agent but also functions as a chain extender by reacting with the PETG end groups, enhancing the performance of the matrix itself.

[0058] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0059] This application employs a two-step method to modify the surface of nanocellulose to address its compatibility issues in a hydrophobic PETG matrix: The first step involves acetylation to convert hydrophilic hydroxyl groups on the nanocellulose surface into hydrophobic acetyl groups, thereby improving its physical dispersibility. The second step utilizes KH-560, a silane coupling agent containing epoxy functional groups, for grafting. The aim is to introduce reactive chemical anchors on the nanocellulose surface, enabling covalent bonding with the matrix during melt blending and constructing a strong interfacial layer for effective stress transfer.

[0060] This application describes the preparation of a core-shell toughening agent to enhance the impact toughness of PETG. The cross-linked polybutyl acrylate rubber core serves as a flexible dispersed phase, capable of absorbing impact energy by initiating crazing and shear banding in the matrix; its outer layer is physically compatible with the PETG matrix, ensuring that the toughening agent particles can be stably and uniformly dispersed in the PETG.

[0061] The reactive compatibilizer prepared in this application has a dual mechanism of action: its polymethyl methacrylate backbone and PETG matrix / toughening agent shell have an interfacial interdiffusion basis under melt blending conditions, which can form chain interpenetration and entanglement at the interface to improve interfacial bonding; its side chain epoxy groups further undergo ring-opening reactions with PETG end groups and modified nanocellulose residual hydroxyl groups, thereby chemically locking the interfacial structure and synergistically enhancing compatibility and mechanical properties. Detailed Implementation

[0062] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include technical solutions that employ any obvious substitutions and modifications made to the embodiments described herein.

[0063] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone further purification or processing.

[0064] Example 1

[0065] This embodiment provides a high-impact PETG nanocellulose composite sheet and its preparation method. The preparation method of the high-impact PETG nanocellulose composite sheet specifically includes the following steps:

[0066] S1: Prepare a toluene dispersion of azeotropic dehydrated nanocellulose with a mass fraction of 2.5%. Add pyridine at 88℃ to obtain a pre-reaction solution, wherein the mass ratio of nanocellulose to pyridine is 1:2.5. Add acetic anhydride dropwise to obtain reaction solution A, wherein the mass ratio of nanocellulose to acetic anhydride is 1:18. After reacting for 4.5 h, cool, centrifuge, wash, and dry to obtain acetylated nanocellulose. Disperse KH-560 in a mixed solvent and pre-hydrolyze at pH 4.6 for 12 min to obtain a silane-modified solution, wherein the volume ratio of ethanol to deionized water in the mixed solvent is 92:8. Add acetylated nanocellulose to obtain reaction solution B, wherein the mass ratio of acetylated nanocellulose to KH-560 is 1:0.12. Adjust the pH to 5.9 and react at 55℃ for 58 min. Cool, centrifuge, wash, and dry to obtain composite modified nanocellulose.

[0067] S2: Sodium dodecyl sulfate (25% of the total amount) is added to deionized water to obtain an emulsifier solution. Potassium persulfate solution is added at 82°C under a nitrogen atmosphere to obtain the basic reaction solution, where potassium persulfate accounts for 18% of the total amount. A mixture of nuclear monomers is added dropwise to obtain reaction solution C, where the molar ratio of butyl acrylate to allyl acrylate in the nuclear monomer mixture is 1:0.018, the mass ratio of the total mass of nuclear monomers to deionized water in the nuclear monomer mixture is 1:3.5, the amount of sodium dodecyl sulfate in the nuclear monomer mixture accounts for 38% of the total amount, and the mass ratio of the total mass of nuclear monomers to the total amount of sodium dodecyl sulfate is 1:0.028. A cross-linked polybutyl acrylate core emulsion was obtained by reacting potassium sulfate to the core monomer at a total molar ratio of 1:320 and holding the reaction at a constant temperature for 1.2 h. A shell monomer mixture was added dropwise, and potassium persulfate solution was added to obtain reaction solution D. In the shell monomer mixture, the molar ratio of methyl methacrylate to styrene was 0.35:1, the total mass ratio of shell monomers to deionized water was 1:2.8, the amount of sodium dodecyl sulfate used in the shell monomer mixture was the remaining portion, and the mass ratio of core monomers to shell monomers was 3.5:1. The reaction was carried out at 88 °C for 1.8 h. After cooling, the emulsion was broken with an 8 wt.% calcium chloride solution, filtered, washed, and dried to obtain a core-shell toughening agent.

[0068] S3: Methyl methacrylate and glycidyl methacrylate are added to toluene, wherein the total mass ratio of methyl methacrylate and glycidyl methacrylate to toluene is 1:4.5, and the molar ratio of methyl methacrylate to glycidyl methacrylate is 15:1. After heating to 78°C under a nitrogen atmosphere, azobisisobutyronitrile is added to obtain reaction solution E, wherein the total molar amount of methyl methacrylate and glycidyl methacrylate to azobisisobutyronitrile is 1:180. After reacting for 9 hours, a pretreatment solution is obtained. After cooling, n-hexane is added, wherein the volume ratio of n-hexane to the pretreatment solution is 12:1. The solution is filtered, washed, and dried to obtain a reactive compatibilizer.

[0069] S4: PETG chips, core-shell toughening agent, and reactive compatibilizer are added to a twin-screw extruder and melt-blended at 215°C to obtain a premix. The amount of core-shell toughening agent is 12% of the mass of PETG chips, and the amount of reactive compatibilizer is 4% of the mass of PETG chips. Composite modified nanocellulose is added, with the amount of composite modified nanocellulose being 2.5% of the mass of PETG. The mixture is fully melted to obtain a blend, which is then extruded, calendered, and cooled to set, resulting in a high-impact PETG nanocellulose composite sheet.

[0070] Example 2

[0071] This embodiment provides a high-impact PETG nanocellulose composite sheet and its preparation method. The preparation method of the high-impact PETG nanocellulose composite sheet specifically includes the following steps:

[0072] S1: Prepare a toluene dispersion of azeotropic dehydrated nanocellulose with a mass fraction of 1%. Add pyridine at 80℃ to obtain a pre-reaction solution, wherein the mass ratio of nanocellulose to pyridine is 1:1. Add acetic anhydride dropwise to obtain reaction solution A, wherein the mass ratio of nanocellulose to acetic anhydride is 1:10. After reacting for 3 hours, cool, centrifuge, wash, and dry to obtain acetylated nanocellulose. Disperse KH-560 in a mixed solvent and pre-hydrolyze at pH 4.4 for 15 minutes to obtain a silane-modified solution, wherein the volume ratio of ethanol to deionized water in the mixed solvent is 95:5. Add acetylated nanocellulose to obtain reaction solution B, wherein the mass ratio of acetylated nanocellulose to KH-560 is 1:0.05. Adjust the pH to 6.0 and react at 58℃ for 50 minutes. Cool, centrifuge, wash, and dry to obtain composite modified nanocellulose.

[0073] S2: Add 15% sodium dodecyl sulfate (NDS) to deionized water to obtain an emulsifier solution. Add potassium persulfate solution at 75°C under a nitrogen atmosphere to obtain the basic reaction solution. The amount of potassium persulfate in the basic reaction solution is 10% of the total amount. Add the core monomer mixture dropwise to obtain reaction solution C. In the core monomer mixture, the molar ratio of butyl acrylate to allyl acrylate is 1:0.01, the mass ratio of the total mass of the core monomers to deionized water is 1:2.5, the amount of sodium dodecyl sulfate in the core monomer mixture is 30% of the total amount, and the mass ratio of the total mass of the core monomers to the total amount of sodium dodecyl sulfate is 1:0.02. A cross-linked polybutyl acrylate core emulsion was obtained by reacting potassium sulfate to the core monomer at a total molar ratio of 1:250 and maintaining the temperature for 1.5 h. A shell monomer mixture was added dropwise, and potassium persulfate solution was added to obtain reaction solution D. In the shell monomer mixture, the molar ratio of methyl methacrylate to styrene was 0.25:1, the total mass ratio of shell monomers to deionized water was 1:2, the amount of sodium dodecyl sulfate used in the shell monomer mixture was the remaining portion, and the mass ratio of core monomers to shell monomers was 2.5:1. The mixture was reacted at 85 °C for 1.5 h, cooled, and demulsified with a 5 wt.% calcium chloride solution. The emulsion was then filtered, washed, and dried to obtain a core-shell toughening agent.

[0074] S3: Methyl methacrylate and glycidyl methacrylate are added to toluene, wherein the total mass ratio of methyl methacrylate and glycidyl methacrylate to toluene is 1:3, and the molar ratio of methyl methacrylate to glycidyl methacrylate is 9:1. After heating to 70°C under a nitrogen atmosphere, azobisisobutyronitrile is added to obtain reaction solution E, wherein the total molar amount of methyl methacrylate and glycidyl methacrylate to azobisisobutyronitrile is 1:100. After reacting for 6 hours, a pretreatment solution is obtained. After cooling, n-hexane is added, wherein the volume ratio of n-hexane to the pretreatment solution is 15:1. The solution is filtered, washed, and dried to obtain a reactive compatibilizer.

[0075] S4: PETG chips, core-shell toughening agent, and reactive compatibilizer are added to a twin-screw extruder and melt-blended at 190°C to obtain a premix. The amount of core-shell toughening agent is 5% of the mass of PETG chips, and the amount of reactive compatibilizer is 1% of the mass of PETG chips. Composite modified nanocellulose is added, with the amount of composite modified nanocellulose being 1% of the mass of PETG. The mixture is fully melted to obtain a blend, which is then extruded, calendered, and cooled to set, resulting in a high-impact PETG nanocellulose composite sheet.

[0076] Example 3

[0077] This embodiment provides a high-impact PETG nanocellulose composite sheet and its preparation method. The preparation method of the high-impact PETG nanocellulose composite sheet specifically includes the following steps:

[0078] S1: Prepare a toluene dispersion of azeotropic dehydrated nanocellulose with a mass fraction of 1.5%. Add pyridine at 82℃ to obtain a pre-reaction solution, wherein the mass ratio of nanocellulose to pyridine is 1:1.5. Add acetic anhydride dropwise to obtain reaction solution A, wherein the mass ratio of nanocellulose to acetic anhydride is 1:12. After reacting for 3.5 h, cool, centrifuge, wash, and dry to obtain acetylated nanocellulose. Disperse KH-560 in a mixed solvent and pre-hydrolyze at pH 4.5 for 11 min to obtain a silane-modified solution, wherein the volume ratio of ethanol to deionized water in the mixed solvent is 91:9. Add acetylated nanocellulose to obtain reaction solution B, wherein the mass ratio of acetylated nanocellulose to KH-560 is 1:0.08. Adjust the pH to 6.0 and react at 58℃ for 45 min. Cool, centrifuge, wash, and dry to obtain composite modified nanocellulose.

[0079] S2: Sodium dodecyl sulfate (20% of the total amount) is added to deionized water to obtain an emulsifier solution. Potassium persulfate solution is added at 78°C under a nitrogen atmosphere to obtain the basic reaction solution. The amount of potassium persulfate in the basic reaction solution accounts for 12% of the total amount. A mixture of core monomers is then added dropwise to obtain reaction solution C. In the core monomer mixture, the molar ratio of butyl acrylate to allyl acrylate is 1:0.012, the mass ratio of the total mass of the core monomers to the deionized water is 1:3, the amount of sodium dodecyl sulfate in the core monomer mixture accounts for 32% of the total amount, and the mass ratio of the total mass of the core monomers to the total amount of sodium dodecyl sulfate is 1:0.022. A cross-linked polybutyl acrylate core emulsion was obtained by reacting potassium persulfate to the core monomer at a total molar ratio of 1:280 and holding the reaction at a constant temperature for 1.4 h. A shell monomer mixture was added dropwise, and potassium persulfate solution was added to obtain reaction solution D. In the shell monomer mixture, the molar ratio of methyl methacrylate to styrene was 0.3:1, the total mass ratio of shell monomers to deionized water was 1:2.2, the amount of sodium dodecyl sulfate used in the shell monomer mixture was the remaining portion, and the mass ratio of core monomers to shell monomers was 3:1. The reaction was carried out at 86 °C for 1.6 h. After cooling, the emulsion was broken with a 6 wt.% calcium chloride solution, filtered, washed, and dried to obtain a core-shell toughening agent.

[0080] S3: Methyl methacrylate and glycidyl methacrylate are added to toluene, wherein the total mass ratio of methyl methacrylate and glycidyl methacrylate to toluene is 1:3.5, and the molar ratio of methyl methacrylate to glycidyl methacrylate is 12:1. After heating to 72°C under a nitrogen atmosphere, azobisisobutyronitrile is added to obtain reaction solution E, wherein the total molar amount of methyl methacrylate and glycidyl methacrylate to azobisisobutyronitrile is 1:120. After reacting for 7 hours, a pretreatment solution is obtained. After cooling, n-hexane is added, wherein the volume ratio of n-hexane to the pretreatment solution is 14:1. The solution is filtered, washed, and dried to obtain a reactive compatibilizer.

[0081] S4: PETG chips, core-shell toughening agent, and reactive compatibilizer are added to a twin-screw extruder and melt-blended at 200°C to obtain a premix. The amount of core-shell toughening agent is 8% of the mass of PETG chips, and the amount of reactive compatibilizer is 2% of the mass of PETG chips. Composite modified nanocellulose is added, with the amount of composite modified nanocellulose being 1.5% of the mass of PETG. The mixture is fully melted to obtain a blend, which is then extruded, calendered, and cooled to set, resulting in a high-impact PETG nanocellulose composite sheet.

[0082] Example 4

[0083] This embodiment provides a high-impact PETG nanocellulose composite sheet and its preparation method. The preparation method of the high-impact PETG nanocellulose composite sheet specifically includes the following steps:

[0084] S1: Prepare a toluene dispersion of azeotropic dehydrated nanocellulose with a mass fraction of 3%. Add pyridine at 90℃ to obtain a pre-reaction solution, wherein the mass ratio of nanocellulose to pyridine is 1:3. Add acetic anhydride dropwise to obtain reaction solution A, wherein the mass ratio of nanocellulose to acetic anhydride is 1:20. After reacting for 5 hours, cool, centrifuge, wash, and dry to obtain acetylated nanocellulose. Disperse KH-560 in a mixed solvent and pre-hydrolyze at pH 4.7 for 10 minutes to obtain a silane-modified solution, wherein the volume ratio of ethanol to deionized water in the mixed solvent is 90:10. Add acetylated nanocellulose to obtain reaction solution B, wherein the mass ratio of acetylated nanocellulose to KH-560 is 1:0.15. Adjust the pH to 5.8 and react at 60℃ for 60 minutes. Cool, centrifuge, wash, and dry to obtain composite modified nanocellulose.

[0085] S2: Sodium dodecyl sulfate (30% of the total amount) is added to deionized water to obtain an emulsifier solution. Potassium persulfate solution is added at 85°C under a nitrogen atmosphere to obtain the basic reaction solution, where potassium persulfate accounts for 20% of the total amount. A mixture of core monomers is then added dropwise to obtain reaction solution C. In the core monomer mixture, the molar ratio of butyl acrylate to allyl acrylate is 1:0.02, the mass ratio of the total mass of the core monomers to deionized water is 1:4, and the amount of sodium dodecyl sulfate in the core monomer mixture accounts for 40% of the total amount; the mass ratio of the total mass of the core monomers to the total mass of sodium dodecyl sulfate is 1:0.03. The total molar ratio of potassium persulfate to core monomers was 1:350. After reacting at a constant temperature for 1 hour, a cross-linked polybutyl acrylate core emulsion was obtained. A shell monomer mixture was added dropwise and potassium persulfate solution was added to obtain reaction solution D. In the shell monomer mixture, the molar ratio of methyl methacrylate to styrene was 0.45:1, the mass ratio of the total mass of shell monomers to deionized water was 1:3, the amount of sodium dodecyl sulfate used in the shell monomer mixture was the remaining portion, and the mass ratio of core monomers to shell monomers was 4:1. The mixture was reacted at 90°C for 2 hours. After cooling, the emulsion was broken with a 10 wt.% calcium chloride solution, filtered, washed, and dried to obtain a core-shell toughening agent.

[0086] S3: Methyl methacrylate and glycidyl methacrylate are added to toluene, wherein the total mass ratio of methyl methacrylate and glycidyl methacrylate to toluene is 1:5, and the molar ratio of methyl methacrylate to glycidyl methacrylate is 19:1. After heating to 80°C under a nitrogen atmosphere, azobisisobutyronitrile is added to obtain reaction solution E, wherein the total molar amount of methyl methacrylate and glycidyl methacrylate to azobisisobutyronitrile is 1:200. After reacting for 10 hours, a pretreatment solution is obtained. After cooling, n-hexane is added, wherein the volume ratio of n-hexane to the pretreatment solution is 10:1. The solution is filtered, washed, and dried to obtain a reactive compatibilizer.

[0087] S4: PETG chips, core-shell toughening agent, and reactive compatibilizer are added to a twin-screw extruder and melt-blended at 220°C to obtain a premix. The amount of core-shell toughening agent is 15% of the mass of PETG chips, and the amount of reactive compatibilizer is 5% of the mass of PETG chips. Composite modified nanocellulose is added, with the amount of composite modified nanocellulose being 3% of the mass of PETG. The mixture is fully melted to obtain a blend, which is then extruded, calendered, and cooled to set, resulting in a high-impact PETG nanocellulose composite sheet.

[0088] Comparative Example 1

[0089] This comparative example provides a high-impact PETG nanocellulose composite sheet. The difference from Example 1 is that unmodified nanocellulose is used instead of composite modified nanocellulose. Other operating steps and process parameters are exactly the same as in Example 1.

[0090] Comparative Example 2

[0091] This comparative example provides a high-impact PETG nanocellulose composite sheet. The difference from Example 1 is that only the nanocellulose is acetylated to obtain acetylated nanocellulose for use. Other operating steps and process parameters are exactly the same as in Example 1.

[0092] Comparative Example 3

[0093] This comparative example provides a high-impact PETG nanocellulose composite sheet, which differs from Example 1 in that no reactive compatibilizer is added, while the other operating steps and process parameters are exactly the same as in Example 1.

[0094] Comparative Example 4

[0095] This comparative example provides a high-impact PETG nanocellulose composite sheet, which differs from Example 1 in that no core-shell toughening agent is added, while the other operating steps and process parameters are exactly the same as in Example 1.

[0096] The performance of the high-impact PETG nanocellulose composite sheets of Examples 1-4 and Comparative Examples 1-4 was tested, and the specific process is as follows:

[0097] The impact resistance of the samples was tested according to ASTM D256.

[0098] The tensile strength and elongation at break of the samples were tested according to ASTM D638.

[0099] The flexural strength and flexural modulus of the test sample were determined according to ASTM D790.

[0100] The test results are shown in Table 1.

[0101] Table 1. Performance test results of high-impact PETG nanocellulose composite sheets prepared in Examples 1-4 and Comparative Examples 1-4

[0102]

[0103] As shown in Table 1, the test results of Example 1 and Comparative Example 1 reveal that replacing the composite modified nanocellulose with unmodified nanocellulose caused severe agglomeration of the nanofiller in the hydrophobic matrix due to its strong hydrophilicity. This resulted in the loss of the reinforcing effect and the formation of numerous micron-sized defects. These agglomerates, acting as stress concentration points, induce premature initiation and propagation of microcracks under stress, leading to a decrease in tensile strength, flexural strength, and impact resistance, as well as a decrease in elongation at break, exhibiting brittle fracture. Furthermore, the flexural modulus decreased because there was no effective interfacial bonding between the agglomerates and the matrix, preventing stress transfer.

[0104] As shown in Table 1, the test results of Example 1 and Comparative Example 2 reveal that acetylation modification of nanocellulose alone lacks the chemical bonding ability introduced by silanization, resulting in only a weak physical interface between the nanofiller and the matrix. Although acetylation improves dispersibility and increases flexural modulus to some extent, the weak interface cannot effectively transfer load, thus reducing tensile and flexural strength. The combination of dispersed rigid particles and the weak interface promotes interface debonding and accelerates crack propagation under impact, leading to a decrease in impact resistance and elongation at break, exhibiting a significant embrittlement effect and failing to achieve a synergistic effect of strength and toughness.

[0105] As shown in Table 1, the test results of Example 1 and Comparative Example 3 reveal that without the addition of a reactive compatibilizer, the entire composite system loses the "molecular bridges" connecting the phases, failing to form an organic whole. Although the modified nanocellulose and the toughening agent each played a limited role, the lack of chemical bonds between the matrix, reinforcing phase, and toughening phase resulted in weak interfacial bonding and low efficiency in stress transfer and energy dissipation. Consequently, its impact resistance and elongation at break decreased, and the toughening effect was not fully realized. Simultaneously, the improvement in tensile strength and flexural strength was also limited by the weak interfacial structure.

[0106] As shown in Table 1, the test results of Example 1 and Comparative Example 4 reveal that the absence of a core-shell toughening agent results in the composite system lacking a core energy-absorbing unit. Although the composite modified nanocellulose forms a strong interface with the matrix with the help of a compatibilizer, improving the tensile strength, flexural strength, and flexural modulus of the material, the introduction of rigid fillers and the strong interface restrict the movement of the matrix molecular chains, inhibiting the toughening mechanism. Consequently, the material becomes brittle, its elongation at break decreases, and it has almost no energy absorption capacity under impact loads, leading to a decline in impact resistance.

[0107] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A process for the preparation of high impact PETG nanocellulose composite sheet material, characterized by, The preparation method comprises: S1: a toluene dispersion solution of azeotropically dehydrated nanocellulose is prepared, pyridine is added to obtain a pre-reaction solution, acetic anhydride is added dropwise to obtain reaction solution A, the mass ratio of the azeotropically dehydrated nanocellulose to acetic anhydride is 1:(10-20), after reaction, cooling, centrifugation, washing and drying, acetylated nanocellulose is obtained; KH-560 is dispersed in a mixed solvent to obtain a silane modification solution, the mass ratio of the acetylated nanocellulose to KH-560 is 1:(0.05-0.15), acetylated nanocellulose is added to obtain reaction solution B, after pH adjustment, reaction, cooling, centrifugation, washing and drying, composite modified nanocellulose is obtained; S2: sodium dodecyl sulfate is added to deionized water to obtain an emulsifier solution, potassium persulfate solution is added under a nitrogen atmosphere to obtain a basic reaction solution, core monomer mixed solution is added dropwise to obtain reaction solution C, the molar ratio of butyl acrylate to allyl acrylate in the core monomer mixed solution is 1:(0.01-0.02), the amount of sodium dodecyl sulfate in the core monomer mixed solution accounts for 30-40% of the total amount, and crosslinked polybutyl acrylate core emulsion is obtained after heat preservation reaction; shell monomer mixed solution and additional potassium persulfate solution are added dropwise to obtain reaction solution D, the molar ratio of methyl methacrylate to styrene in the shell monomer mixed solution is (0.25-0.45):1, the amount of sodium dodecyl sulfate in the shell monomer mixed solution is the remaining part, and the mass ratio of the core monomer to the shell monomer is (2.5-4):1, after reaction and cooling, the emulsion is broken with calcium chloride solution, and after filtration, washing and drying, a core-shell structure toughening agent is obtained; S3: methyl methacrylate and glycidyl methacrylate are added to toluene in a molar ratio of (9-19):1, azobisisobutyronitrile is added after warming under a nitrogen atmosphere to obtain reaction solution E, a pretreatment solution is obtained after reaction, and the pretreatment solution is poured into n-hexane after cooling, filtered, washed and dried to obtain a reactive compatibilizer; S4: PETG chips, a core-shell structure toughening agent and a reactive compatibilizer are added to a twin-screw extruder for melt blending to obtain a premix, and composite modified nanocellulose is added for sufficient melting to obtain a mixture, the amount of the core-shell structure toughening agent accounts for 5-15% of the mass of the PETG chips, the amount of the reactive compatibilizer accounts for 1-5% of the mass of the PETG chips, and the amount of the composite modified nanocellulose accounts for 1-3% of the mass of the PETG, and after extrusion, calendering and cooling and setting, a high-impact PETG nanocellulose composite sheet is obtained.

2. A process for the preparation of a high impact PETG nanocellulose composite sheet as claimed in claim 1, wherein, In S1: The mass ratio of the azeotropically dehydrated nanocellulose to pyridine is 1:(1-3).

3. A process for the preparation of a high impact PETG nanocellulose composite sheet as claimed in claim 1, wherein, In S1: The volume ratio of ethanol to deionized water in the mixed solvent is (90-95):(10-5).

4. A process for the preparation of a high impact PETG nanocellulose composite sheet as claimed in claim 1, wherein, In S2: The amount of sodium dodecyl sulfate in the emulsifier solution accounts for 15-30% of the total amount; The amount of potassium persulfate in the basic reaction solution accounts for 10-20% of the total amount.

5. A process for the preparation of a high impact PETG nanocellulose composite sheet as claimed in claim 1, wherein, In S2: The mass ratio of the total mass of the core monomer to the total amount of sodium dodecyl sulfate is 1:(0.02-0.03); The total molar ratio of potassium persulfate to the core monomer is 1:(250-350).

6. A process for the preparation of a high impact PETG nanocellulose composite sheet as claimed in claim 1, wherein, In S3: The mass ratio of the total mass of methyl methacrylate and glycidyl methacrylate to the mass of toluene is 1:(3-5).

7. A process for the preparation of a high impact PETG nanocellulose composite sheet as claimed in claim 1, wherein, In S3: The molar ratio of the total molar mass of methyl methacrylate and glycidyl methacrylate to the molar mass of azobisisobutyronitrile is 1:(100-200); The volume ratio of the n-hexane to the pretreatment liquid is (10-15):

1.

8. A high-impact PETG nanocellulose composite sheet prepared by the preparation method according to any one of claims 1-7.

Images