Modified bio-based polyester film and preparation method thereof

Abstract

The invention relates to the technical field of polyester films, and relates to a modified bio-based polyester film and a preparation method thereof, the modified bio-based polyester film is a polyfurandicarboxylic acid hexanediol ester-b-polyfurandicarboxylic acid diethylene glycol polyester film, the raw materials of the poly (hexanediol furandicarboxylate)-b-poly (diethylene glycol furandicarboxylate) comprise poly (hexanediol furandicarboxylate), poly (diethylene glycol furandicarboxylate), MAX phase modified Ti3SiC2 and a chain extender. The modified bio-based polyester film has the characteristics of high strength, high rigidity, good toughness and the like, and keeps excellent gas barrier property.

Description

Technical Field

[0001] This invention belongs to the field of polyester film technology, and relates to a modified bio-based polyester film and its preparation method. Background Technology

[0002] Polyethylene furanoate (PEF), as an emerging bio-based polymer material, has great application potential. Against the backdrop of increasingly severe resource consumption and environmental pollution problems, bio-based materials have become an important development direction in the field of polymer materials due to their renewability and environmental friendliness. Polyethylene furanoate is one of the important representatives of this trend. Bio-based polyfuran polyesters (PEFs) exhibit outstanding performance, possessing excellent mechanical, heat resistance, and gas barrier properties. Their glass transition temperature is significantly higher than that of traditional petroleum-based polyethylene terephthalate (PET), and their CO2 and O2 barrier properties are also greatly improved, making PEFs promising for applications in plastic packaging, textiles, and films. Particularly in the plastic packaging sector, PEFs are considered one of the ideal alternatives to PET, potentially driving the green transformation of the plastics industry. The core raw material for PEFs is 2,5-furandicarboxylic acid (FDCA), a monomer that can be converted from various biomass resources, such as sugar beets and corn stalks, through biological or chemical methods. Avantium's YXY® technology stands out, as it efficiently catalyzes the conversion of fructose into FDCA, providing a stable raw material supply for the large-scale production of PEFs.

[0003] However, the synthesis of polyfuran-based biopolymer polyester (PEF) using 2,5-furandicarboxylic acid (FDCA) as a raw material typically suffers from low molecular weight and low elongation at break. The low molecular weight may affect the material's mechanical and processing properties, while the low elongation at break limits its industrial applications. Furthermore, the high viscosity, brittleness, and low crystallization rate of PEF increase the difficulty of processing and molding. Films made from PEF also exhibit poor barrier properties. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the existing technology by proposing a modified bio-based polyester film that combines high strength, high rigidity, and good toughness with excellent gas barrier properties through polycondensation of polyhexylene furanate (PHF) and polydiethylene furanate (PDEGF) under the action of MAX phase modified Ti3SiC2 and chain extender.

[0005] The objective of this invention can be achieved through the following technical solutions: A modified bio-based polyester film, which is a polyhexanediol polyfurandicarboxylate-b-polyfurandicarboxylate polyester film. The raw materials for the polyhexyl difuranate-b-polyhexyl difuranate include: 20-100 parts of polyhexyl difuranate (PHF), 20-80 parts of polyhexyl difuranate (PDEGF), 21-20 parts of MAX phase modified Ti3SiC, and 1-10 parts of chain extender; The structural formula of the polyhexyl difuranate-b-polydiethylene difuranate is shown in the following formula (1): Equation (1); Where n≥1, m≥1.

[0006] Preferably, n > 2 and m > 1.

[0007] Preferably, the polyhexylene difuranate-b-polydiethylene difuranate is prepared by polycondensation of polyhexylene difuranate (PHF) and polydiethylene difuranate (PDEGF) under the action of MAX phase modified Ti3SiC2 and chain extender.

[0008] Preferably, the raw materials for the polyhexylene difuranate-b-polyhexylene difuranate include: 55-65 parts of polyhexylene difuranate (PHF), 36-44 parts of polyhexylene difuranate (PDEGF), 2-10 parts of MAX phase modified Ti3SiC2, and 2-8 parts of chain extender.

[0009] Preferably, the proportion of MAX phase modified Ti3SiC2 in the raw material of the polyhexylene difuranate-b-polyfuranate diethylene glycol ester is 5-20%.

[0010] Preferably, the mass ratio of polyhexylene furanate (PHF) to polydiethylene furanate (PDEGF) is 1:(1.1~1.9).

[0011] Preferably, the preparation method of the polyhexylfuran dicarboxylate (PHF) includes: mixing 2,5-dimethyl furanoxide (DMFD), 1,6-hexanediol (HDO) and a catalyst under an inert gas atmosphere, heating and stirring the mixture at a first reaction temperature, and then heating and pressurizing it at a second reaction temperature to obtain the final product.

[0012] Further preferred, the first reaction temperature is 160~190℃, the heating and stirring reaction time is 1~5h, and the stirring speed is 100~600rpm; the second reaction temperature is 200~260℃, the heating and pressurizing reaction time is 0.1~3h, and the pressure is 10~300Pa.

[0013] More preferably, the mass ratio of 2,5-dimethyl furanate (DMFD), 1,6-hexanediol (HDO), and catalyst is (30~50):(45~70):(1~10).

[0014] More preferably, the catalyst includes one or more of tetrabutyl titanate (TBT), tetraisopropyl titanate (TIPT), and antimony trioxide (Sb2O3).

[0015] Preferably, the preparation method of the polydiethylene furanate (PDEGF) includes: mixing 2,5-dimethyl furanate (DMFD), diethylene glycol (DEG) and catalyst under an inert gas atmosphere, heating and stirring at a first reaction temperature, and then heating and pressurizing at a second reaction temperature to obtain the product.

[0016] More preferably, the mass ratio of 2,5-dimethyl furanate (DMFD), diethylene glycol (DEG), and catalyst is (30~50):(45~70):(1~10).

[0017] Further preferred, the first reaction temperature is 160~190℃, the heating and stirring reaction time is 1~5h, and the stirring speed is 100~600rpm; the second reaction temperature is 200~260℃, the heating and pressurizing reaction time is 0.1~3h, and the pressure is 10~300Pa.

[0018] More preferably, the catalyst includes one or more of tetrabutyl titanate (TBT), tetraisopropyl titanate (TIPT), and antimony trioxide (Sb2O3).

[0019] As a preferred option, small molecule ethylene glycol is grafted onto the surface of MAX phase modified Ti3SiC2.

[0020] As a preferred method, the preparation method of MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) and heating for the first time to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles with ethylene glycol and heating for the second time to obtain MAX phase modified Ti3SiC2.

[0021] Further preferably, the mass ratio of the Ti3SiC2 nanoparticles to γ-aminopropyltriethoxysilane (APTES) is (0.5~5):1.

[0022] Further preferably, the mass ratio of the APTES-coated Ti3SiC2 particles to ethylene glycol is (0.5~5):1.

[0023] More preferably, the mass ratio of the APTES-coated Ti3SiC2 particles to ethylene glycol is (1.4~3):1.

[0024] Further preferably, the first heating temperature is 60~95℃ and the time is 1~10h; the second heating temperature is 60~95℃ and the time is 1~10h.

[0025] More preferably, the first heating temperature is greater than the second heating temperature.

[0026] Preferably, the chain extender includes one or more of hexamethylene diisocyanate (HDI), 4,4'-diphenylmethane diisocyanate (MDI), and isophorone diisocyanate (IPDI).

[0027] Preferably, the modified bio-based polyester film is prepared by bistretching polyhexanediol-b-polyfurandiol diethylene glycol ester and then heat-treating it for shaping.

[0028] A method for preparing a modified bio-based polyester film includes: mixing raw materials, melt extruding and granulating, drying, melt casting and casting, biaxial stretching, heat treatment and shaping, and cooling to obtain the film.

[0029] Preferably, the raw materials include: 55-65 parts of hexanediol polyfuran dicarboxylate (PHF), 36-44 parts of diethylene glycol polyfuran dicarboxylate (PDEGF), 2-10 parts of MAX phase modified Ti3SiC2, and 2-8 parts of chain extender.

[0030] Preferably, the melt extrusion granulation temperature is 160~195℃ and the melting time is 1~30min.

[0031] Preferably, the drying temperature is 60~90℃ and the time is 6~24h.

[0032] Preferably, the temperature of the molten cast sheet is 260~320℃.

[0033] Preferably, the bidirectional tension includes longitudinal tension and transverse tension; The longitudinal stretching temperature is 75~95℃, the longitudinal stretching ratio is 2.25~2.35, and the stretching cooling temperature is 10~40℃. The transverse stretching temperature is 105~130℃, the transverse stretching ratio is 2.15~2.25, and the stretching cooling temperature is 10~40℃.

[0034] Preferably, the heat treatment setting temperature is 110~150℃ and the time is 1~30s.

[0035] Compared with the prior art, the present invention has the following beneficial effects: 1. The polyhexylene difuranate-b-polydiethylene glycol difuranate of the present invention is synthesized by multi-block copolyester, which obtains better elongation at break than single PHF without sacrificing its crystallinity. 2. The polyhexylene difuranate-b-polydiethylene glycol difuranate of the present invention uses MAX phase modified Ti3SiC2 as a nucleating agent. The small molecule ethylene glycol grafted on its surface promotes the nucleation process of polyester, thereby increasing the melting and crystallization temperature of polyester and significantly enhancing the flexibility of polyester. 3. The raw material of the polyhexylene difuranate-b-polydiethylene glycol difuranate of the present invention includes PDEGF. The higher molecular weight and strong intermolecular forces brought by the ether oxygen atoms of PDEGF effectively improve the tensile strength of polyester. 4. The modified bio-based polyester film of the present invention has the characteristics of high strength, high rigidity and good toughness, while maintaining excellent gas barrier properties. Detailed Implementation

[0036] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0037] Unless otherwise specified, the materials used in this invention are commercially available products, and the methods used are conventional technical means.

[0038] The modified bio-based polyester film of the present invention has a film thickness of 50~150μm.

[0039] The modified bio-based polyester film, namely polyhexanediol polyfurandicarboxylate-b-polyfurandicarboxylate, has the following structural formula (1): Equation (1); Where n≥1, m≥1; The method for preparing the polyhexylene difuranate-b-polydiethylene glycol difuranate polyester film includes: (1) Weigh the raw materials: 55-62 parts of polyhexylene furanate (PHF), 28-36 parts of PDEGF, 21-10 parts of MAX phase modified Ti3SiC, and 90-110 parts of chain extender; The preparation method of the polyhexylfuran dicarboxylate (PHF) includes: mixing 2,5-dimethyl furanoxide (DMFD), 1,6-hexanediol (HDO), and a catalyst in a mass ratio of (30~50):(45~70):(1~10) under an inert gas atmosphere, heating and stirring at a first reaction temperature of 160~190℃ for 1~5 h at a stirring speed of 100~600 rpm; heating and pressing at a second reaction temperature of 200~260℃ for 0.1~3 h at a pressure of 10~300 Pa; dissolving in chloroform, precipitating with methanol, repeating the process twice, and then drying to obtain the final product. The catalyst includes one or more of tetrabutyl titanate (TBT), tetraisopropyl titanate (TIPT), and antimony trioxide (Sb2O3); The preparation method of the polydiethylene furanate (PDEGF) includes: mixing 2,5-dimethyl furanate (DMFD), diethylene glycol (DEG), and catalyst in a mass ratio of (30~50):(45~70):(1~10) under an inert gas atmosphere, heating and stirring at a first reaction temperature of 160~190℃ for 1~5h at a stirring speed of 100~600rpm; heating and pressing at a second reaction temperature of 200~260℃ for 0.1~3h at a pressure of 10~300Pa; dissolving in chloroform, precipitating with methanol, repeating twice, and then drying to obtain the product. The catalyst includes one or more of tetrabutyl titanate (TBT), tetraisopropyl titanate (TIPT), and antimony trioxide (Sb2O3); The preparation method of the MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) in a mass ratio of (0.5~5):1, and heating at 60~95℃ for 1~10h to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles in a mass ratio of (0.5~5):1 with ethylene glycol and heating at 60~95℃ for 1~10h to obtain MAX phase modified Ti3SiC2. The chain extender includes one or more of hexamethylene diisocyanate (HDI), 4,4'-diphenylmethane diisocyanate (MDI), and isophorone diisocyanate (IPDI); (2) After mixing the raw materials, melt-blend them at 160~195℃ for 1~30min and then extrude and granulate them; then send them to a drying tower to dry at 60~90℃ for 6~24h; then send them to an extruder to melt at 260~320℃. After the melt passes through a coarse filter, a metering pump and a fine filter, it is sent to a die and cast into a film; the film is then biaxially stretched, with a longitudinal stretching temperature of 75~95℃, a longitudinal stretching ratio of 2.25~2.35 and a stretching cooling temperature of 10~40℃, a transverse stretching temperature of 105~130℃, a transverse stretching ratio of 2.15~2.25 and a stretching cooling temperature of 10~40℃; then heat-treat and shape it at 110~150℃ for 1~30s, and cool it with cold air and roll it up to obtain a film.

[0040] The modified bio-based polyester film prepared by this invention has a tensile strength ≥30 MPa, an elongation at break ≥480%, a crystallinity ≤22.0%, and an oxygen permeability ≤1.50 (cm²). 3 / (m 2 , 24h, 0.1MPa)). Example 1

[0041] In this embodiment, the thickness of the modified bio-based polyester film is 125 μm.

[0042] Modified bio-based polyester film, namely polyhexanediol polyfuran dicarboxylate-b-polyfuran dicarboxylate film; The method for preparing the modified bio-based polyester film includes: (1) Weigh the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI). The preparation method of polyhexylfuran dicarboxylate (PHF) includes: mixing 2,5-dimethyl furanoxide (DMFD), 1,6-hexanediol (HDO), and tetrabutyl titanate (TBT) in a mass ratio of 43:53:4 under a nitrogen atmosphere, heating and stirring at a first reaction temperature of 180℃ for 2 hours at a stirring speed of 200 rpm; raising the temperature to a second reaction temperature of 230℃ and heating and pressurizing for 0.5 hours at a pressure of 80 Pa; dissolving in chloroform and precipitating with methanol, repeating this process twice, and then drying at 30℃ to obtain the final product. The preparation method of poly(diethylene glycol difuranate) (PDEGF) includes: mixing 2,5-dimethyl furanate (DMFD), diethylene glycol (DEG), and tetrabutyl titanate (TBT) in a mass ratio of 43:53:4 under an inert gas atmosphere, heating and stirring at a first reaction temperature of 180℃ for 2 hours at a stirring speed of 200 rpm; raising the temperature to a second reaction temperature of 230℃ and heating and pressurizing for 0.5 hours at a pressure of 80 Pa; dissolving in chloroform and precipitating with methanol, repeating this process twice, and then drying at 30℃ to obtain the final product. The preparation method of MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) at a mass ratio of 1.5:1 and heating at 75°C for 3 hours to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles at a mass ratio of 2:1 with ethylene glycol and heating at 70°C for 4 hours to obtain MAX phase modified Ti3SiC2. (2) After mixing the raw materials, melt and blend them at 180°C for 5 min and then extrude and granulate them; then send them to a drying tower and dry them at 70°C for 12 h; then send them to an extruder and melt them at 280°C. The melt passes through a coarse filter, a metering pump and a fine filter and is then sent to a die for casting; the casting is biaxially stretched with a longitudinal stretching temperature of 85°C, a longitudinal stretching ratio of 2.3 and a stretching cooling temperature of 30°C, a transverse stretching temperature of 110°C, a transverse stretching ratio of 2.2 and a stretching cooling temperature of 30°C; then heat-treat and shape them at 130°C for 15 s, cool them with cold air and roll them up to obtain a film.

[0043] The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 2

[0044] In this embodiment, the thickness of the modified bio-based polyester film is 125 μm.

[0045] The preparation method of modified bio-based polyester film, namely polyhexanediol polyfuranate-b-polydiethylene glycol difuranate film, includes: (1) Weigh the raw materials: 60 parts of polyhexylene furanate dicarboxylate (PHF), 40 parts of polydiethylene furanate dicarboxylate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender isophorone diisocyanate (IPDI). The preparation method of polyhexylfuran dicarboxylate (PHF) includes: mixing 2,5-dimethyl furanoxide (DMFD), 1,6-hexanediol (HDO), and tetrabutyl titanate (TBT) in a mass ratio of 43:53:4 under a nitrogen atmosphere, heating and stirring at a first reaction temperature of 180℃ for 2 hours at a stirring speed of 300 rpm; heating and pressing at a second reaction temperature of 230℃ for 0.5 hours at a pressure of 120 Pa; dissolving in chloroform and precipitating with methanol, repeating this process twice, and then drying at 30℃ to obtain the final product. The preparation method of poly(diethylene glycol difuranate) (PDEGF) includes: mixing 2,5-dimethyl furanate (DMFD), diethylene glycol (DEG), and tetrabutyl titanate (TBT) in a mass ratio of 43:53:4 under an inert gas atmosphere, heating and stirring at a first reaction temperature of 180℃ for 2 hours at a stirring speed of 400 rpm; raising the temperature to a second reaction temperature of 230℃ and heating and pressurizing for 0.5 hours at a pressure of 200 Pa; dissolving in chloroform and precipitating with methanol, repeating this process twice, and then drying at 30℃ to obtain the final product. The preparation method of MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) at a mass ratio of 2:1 and heating at 75°C for 3 hours to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles at a mass ratio of 2:1 with ethylene glycol and heating at 70°C for 4 hours to obtain MAX phase modified Ti3SiC2. (2) After mixing the raw materials, melt and blend them at 180°C for 5 min and then extrude and granulate them; then send them to a drying tower and dry them at 70°C for 12 h; then send them to an extruder and melt them at 280°C. The melt passes through a coarse filter, a metering pump and a fine filter and is then sent to a die for casting. The casting is then biaxially stretched with a longitudinal stretching temperature of 85°C, a longitudinal stretching ratio of 2.3 and a stretching cooling temperature of 30°C, a transverse stretching temperature of 110°C, a transverse stretching ratio of 2.2 and a stretching cooling temperature of 30°C; then heat-treat and shape it at 140°C for 15 s, and cool it with cold air and roll it up to obtain a film.

[0046] The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 3

[0047] Compared with Example 1, the difference lies in the raw materials: 80 parts of polyhexylene difuranate (PHF), 20 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI).

[0048] The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 4

[0049] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), 20 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI).

[0050] The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 5

[0051] Compared with Example 1, the difference lies in the raw materials: 20 parts of polyhexylene difuranate (PHF), 80 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI).

[0052] The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 6

[0053] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI). The preparation method of MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) at a mass ratio of 0.5:1 and heating at 75°C for 3 hours to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles at a mass ratio of 2:1 with ethylene glycol and heating at 70°C for 4 hours to obtain MAX phase modified Ti3SiC2. The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 7

[0054] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI). The preparation method of MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) at a mass ratio of 1.5:1 and heating at 75°C for 3 hours to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles at a mass ratio of 0.5:1 with ethylene glycol and heating at 70°C for 4 hours to obtain MAX phase modified Ti3SiC2. The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Example 8

[0055] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI). The preparation method of MAX phase modified Ti3SiC2 includes: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane (APTES) at a mass ratio of 1.5:1 and heating at 75°C for 3 hours to obtain APTES-coated Ti3SiC2 particles; mixing APTES-coated Ti3SiC2 particles at a mass ratio of 5:1 with ethylene glycol and heating at 70°C for 4 hours to obtain MAX phase modified Ti3SiC2. The properties of the modified bio-based polyester film prepared in this embodiment are shown in Table 1. Comparative Example 1

[0056] Compared with Example 1, the difference lies in the raw materials: 100 parts of polyhexylene furanate (PHF), 10 parts of MAX phase modified Ti3SiC2, and 4 parts of chain extender hexamethylene diisocyanate (HDI).

[0057] The properties of the modified bio-based polyester film prepared in this comparative example are shown in Table 1. Comparative Example 2

[0058] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), 10 parts of modified Ti3SiC2 nanoparticles, and 4 parts of chain extender hexamethylene diisocyanate (HDI). The preparation method of modified Ti3SiC2 nanoparticles includes: mixing Ti3SiC2 particles with ethylene glycol at a mass ratio of 2:1 and heating at 70°C for a second time for 4 hours to obtain modified Ti3SiC2 nanoparticles.

[0059] The properties of the modified bio-based polyester film prepared in this comparative example are shown in Table 1. Comparative Example 3

[0060] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene furanate (PHF), 40 parts of polydiethylene furanate (PDEGF), 10 parts of Ti3SiC2 nanoparticles, and 4 parts of chain extender hexamethylene diisocyanate (HDI).

[0061] The properties of the modified bio-based polyester film prepared in this comparative example are shown in Table 1. Comparative Example 4

[0062] Compared with Example 1, the difference lies in the raw materials: 60 parts of polyhexylene difuranate (PHF), 40 parts of polydiethylene glycol difuranate (PDEGF), and 4 parts of chain extender hexamethylene diisocyanate (HDI).

[0063] The properties of the modified bio-based polyester film prepared in this comparative example are shown in Table 1.

[0064] Table 1. Performance of Modified Bio-based Polyester Films

[0065] As shown in the table above, the modified bio-based polyester film of the present invention possesses strength, rigidity, and toughness simultaneously, and achieves good gas barrier properties. Furthermore, the modified bio-based polyester film of the present invention has low crystallinity and a reduced crystallization rate, which avoids the formation of crystallization points in certain areas due to excessively rapid crystallization, thus affecting the quality of the polyester film. This makes the film easier to process, and the lower crystallinity also gives the polyester film higher flexibility.

[0066] In summary, this invention utilizes MAX-modified Ti3SiC2 and chain extenders to polycondense polyhexylfuran dicarboxylate (PHF) and polydiethylenefuran dicarboxylate (PDEGF) to produce a modified bio-based polyester film that combines high strength, high rigidity, and good toughness while maintaining excellent gas barrier properties.

[0067] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A modified bio-based polyester film, characterized in that: It is a poly(hexanediol furandicarboxylate)-b-poly(diethylene furandicarboxylate) polyester film, wherein the raw materials of the poly(hexanediol furandicarboxylate)-b-poly(diethylene furandicarboxylate) include: 20-100 parts of poly(hexanediol furandicarboxylate) , 20-80 parts of poly(diethylene furandicarboxylate) , 1-20 parts of MAX phase modified Ti3SiC2, and 1-10 parts of a chain extender; the structural formula of the poly(hexanediol furandicarboxylate)-b-poly(diethylene furandicarboxylate) is as shown in the following formula (1): Formula (1); Where n≥1, m≥1.

2. The modified bio-based polyester film according to claim 1, characterized in that: The proportion of MAX phase-modified Ti3SiC2 in the raw material of poly(hexanediol furandicarboxylate)-b-poly(diethylene furandicarboxylate) is 5-20%.

3. The modified bio-based polyester film according to claim 1, characterized in that: The surface of the MAX phase modified Ti3SiC2 is grafted with small molecule ethylene glycol.

4. The modified bio-based polyester film according to claim 1, characterized in that: The preparation method of the MAX phase modified Ti3SiC2 comprises: mixing Ti3SiC2 nanoparticles and γ-aminopropyltriethoxysilane and heating them for the first time to obtain APTES coated Ti3SiC2 particles, and mixing the APTES coated Ti3SiC2 particles and ethylene glycol and heating them for the second time to obtain MAX phase modified Ti3SiC2.

5. The modified bio-based polyester film according to claim 4, characterized in that: The mass ratio of the Ti3SiC2 nanoparticles to γ-aminopropyltriethoxysilane is (0.5-5):

1.

6. The modified bio-based polyester film according to claim 4, characterized in that: The mass ratio of the APTES-coated Ti3SiC2 particles to ethylene glycol is (0.5-5):

1.

7. The modified bio-based polyester film according to claim 1, characterized in that: The chain extender includes one or more of hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and isophorone diisocyanate.

8. A method for preparing a modified bio-based polyester film as claimed in claim 1, characterized in that: The preparation method comprises: mixing the raw materials, melt extruding granulation, drying, melt casting, biaxial stretching, heat treatment and shaping, and cooling to obtain the product; The raw materials include: 20-100 parts of poly(hexanediol furandicarboxylate), 20-80 parts of poly(diethylene furandicarboxylate), 1-20 parts of MAX phase-modified Ti3SiC2, and 1-10 parts of a chain extender.

9. The method for preparing the modified bio-based polyester film according to claim 8, characterized in that: The melt extrusion granulation has a melting temperature of 160-195° C. and a melting time of 1-30 min.

10. The method for preparing a modified bio-based polyester film according to claim 8, characterized in that: The temperature of the heat treatment setting is 110-150° C. and the time is 1-30 seconds.

Images