High-transparency, high-hardness and high-toughness composite material with nano organic-inorganic hybrid interpenetrating network structure and preparation method of high-transparency, high-hardness and high-toughness composite material

Abstract

The invention belongs to the field of nano composite materials, and particularly relates to a high-transparency, high-hardness and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure and a preparation method of the high-transparency, high-hardness and high-toughness composite material. The composite material comprises a polymer nanofiber network skeleton and an organic-inorganic hybrid nanofluid, wherein the organic-inorganic hybrid nanofluid and the polymer nanofiber network skeleton are communicated with each other and are cross-linked and cured to form an interpenetrating network structure. According to the nano organic-inorganic hybrid interpenetrating network structure provided by the invention, organic combination of high transparency, high hardness and high toughness of a composite material with the thickness of more than 100 microns is realized, and the nano organic-inorganic hybrid interpenetrating network structure shows wide application potential in the fields of consumer electronics, optical devices, automobile manufacturing, building furniture, aerospace and the like.

Description

Technical Field

[0001] The present invention belongs to the field of nanocomposite materials, and particularly relates to a high-transparency, high-hardness, and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure and a preparation method thereof. Background Art

[0002] Materials with high transparency, high hardness, and high toughness exhibit important application values in fields such as consumer electronics, optical devices, automotive manufacturing, architectural furniture, and aerospace. However, traditional material systems have obvious limitations: metallic materials generally lack optical transparency; although inorganic non-metallic materials possess high hardness and high modulus, due to their intrinsic brittleness, stress concentration is likely to occur under external forces, leading to crack propagation and brittle failure; while organic polymer materials have excellent toughness, transparency, and processing properties, they are limited by relatively low hardness and modulus. By constructing an organic-inorganic hybrid composite material system, the advantages of the two types of components can be effectively integrated - while retaining the toughness and processability of the polymer material, the hardness and modulus can be significantly improved. However, to achieve the synergistic optimization of these properties, precise control of the composite composition and microstructure is required, and its design and preparation still face major challenges.

[0003] The mainstream structures of current organic-inorganic hybrid composite materials can be divided into three categories (as Figure 1 shown): The first category is the inorganic particle-reinforced structure (Structure I), where inorganic particles are uniformly / randomly dispersed in the polymer matrix to improve mechanical properties. However, with the increase in the content of inorganic components, the transparency and toughness of the composite material will sharply decline; the second category is the continuous filler network structure (Structure II), where a continuous inorganic network penetrating the matrix is constructed to endow the material with thermal / electrical conductivity functional characteristics while enhancing mechanical properties. However, since the characteristic size of the network generally exceeds the visible light wavelength, such a structure usually results in the material being opaque; the third category is the "shell-like" layered structure (Structure III), where the strength-toughness balance is achieved through the alternating stacking of organic components and inorganic lamellae. However, due to the stacking density of inorganic layers and the refractive index difference between the organic and inorganic phases, it is difficult to balance transparency, and the problem of large-area processing of this system has long been unresolved.

[0004] Although the invention patent (CN202510154760.6) discloses a super-flexible and ultra-thin hybrid glass film, this strategy can only achieve a light transmittance of more than 90% within the thickness range of less than 50 μm. With the increase in thickness, the refractive index differences of the multi-phase and multi-component inside the composite material and the disadvantage of the low light transmittance itself will lead to a significant decrease in the optical transparency of the material (for example, the light transmittance of a 100-μm-thick material is as low as 80%), and it is impossible to prepare high-transparency, high-hardness, and high-toughness materials at greater thicknesses (such as above 100 μm). In addition, since the used oligosilsesquioxane in the material is prepared by hydrolyzing trifunctional (T-type) siloxane, the crosslinking density and rigidity of the material network are relatively low, and the hardness and modulus are at most no more than 5 GPa and 30 GPa, still having a large gap compared with inorganic materials.

[0005] So far, the preparation of high-transparency, high-hardness, and high-toughness composite materials with greater thicknesses, such as in the range of 50 - 600 μm, is still a technical bottleneck problem that urgently needs to be broken through in this field. Summary of the Invention

[0006] To solve the above problems, the present invention proposes a composite material with a nano-scale organic-inorganic hybrid interpenetrating network structure. This material not only has high transparency, high hardness, and high toughness, but also has significant advantages such as a simple preparation process and easy large-area processing.

[0007] Technical solution of the present invention:

[0008] In the first aspect, the present invention provides a high-transparency, high-hardness, and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure. The composite material includes a polymer nanofiber network skeleton and an organic-inorganic hybrid nanofluid, wherein the organic-inorganic hybrid nanofluid penetrates and crosslinks with the polymer nanofiber network skeleton to form an interpenetrating network structure, and the specific structure is as Figure 1 shown in (Structure IV).

[0009] Further, the thickness of the polymer nanofiber network skeleton is 0.5 μm to 600 μm or higher, and the composite material has a light transmittance greater than 90%.

[0010] Further, the polymer nanofiber network skeleton includes at least one of a polyethylene (PE), polypropylene (PP), cyclic olefin copolymer (COC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PBN), polycarbonate (PC), polyamide (PA), polyimide (PI), polyethersulfone (PES), polyetheretherketone (PEEK), polyurethane (PU), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF) nanofiber network skeleton.

[0011] Further, the preparation method of the polymer nanofiber network framework includes at least one of dry method, wet single-axis / biaxial stretching, electrospinning or melt blowing method.

[0012] Further, the fiber diameter of the polymer nanofiber network framework is 10 nanometers to 200 nanometers.

[0013] Further, it is the continuous phase in the composite material, and there are a large number of nano-pores between the polymer nanofiber networks.

[0014] Further, the diameter of the nano-pores in the polymer nanofiber network framework is 10 nanometers to 300 nanometers.

[0015] Further, the porosity of the polymer nanofiber network framework is 20% to 90%; more preferably 50% to 80%.

[0016] Further, the thickness of the polymer nanofiber network framework is 0.5 μm to 600 μm, preferably 50 μm to 600 μm.

[0017] Further, the organic-inorganic hybrid nanofluid is composed of a liquid silicone resin and inorganic nanoparticles.

[0018] Further, the organic-inorganic hybrid nanofluid has good fluidity, can form an interpenetrating continuous phase after being compounded with the above polymer nanofiber network framework, and has chemical reaction activity, and can construct a cross-linked network structure through chemical reactions.

[0019] Further, the liquid silicone resin is selected from liquid MT, MDT, MDQ, MDTQ, MTQ, MQ, DT, DQ, DTQ or TQ silicone resins.

[0020] Further, the liquid silicone resin contains the following basic repeating units:

[0021]

[0022] Among them, R is an organic group.

[0023] Further, the organic group includes one or more combinations of epoxy group, amino group, acrylate group, methacrylate group, vinyl group, mercapto group, hydrogen-containing group, isocyanate group, hydroxyl group, alkoxy group, etc.

[0024] Further, the inorganic nanoparticles are at least one of silica, titanium dioxide, alumina, zirconia particles or their graded mixture.

[0025] Further, the particle size of the inorganic nanoparticles is 1 - 200 nanometers.

[0026] Further, the surface of the inorganic nanoparticles has reactive functional groups and can undergo a chemical reaction with the liquid silicone resin.

[0027] Further, the crosslinking and curing are initiated by an initiator.

[0028] Further, the initiator includes at least one of a thermal initiator, triethylamine, a platinum catalyst, or a photoinitiator.

[0029] Further, the thermal initiator includes at least one of azobisisobutyronitrile, azobis(2 - amidinopropane) hydrochloride, or azodiisopropylimidazoline hydrochloride, or a mixture of the above thermal initiators.

[0030] Further, the photoinitiator includes at least one of 2 - hydroxy - 2 - methylphenylpropanone, 1 - hydroxycyclohexyl phenyl ketone, phenylbis(2,4,6 - trimethylbenzoyl)phosphine oxide, 2 - hydroxy - 2 - methyl - 1 - [4 - (2 - hydroxyethoxy)phenyl] - 1 - propanone, benzoin dimethyl ether, triphenylsulfonium hexafluoroantimonate, or 2,2 - diethoxyacetophenone, or a mixture of the above photoinitiators, and a platinum catalyst.

[0031] In a second aspect, the present invention provides a method for preparing a highly transparent, high - hardness, and high - toughness composite material with a nano - organic - inorganic hybrid interpenetrating network structure as described herein, which includes the following steps:

[0032] (1) Prepare a polymer nanofiber network framework with nano - pores;

[0033] (2) Perform surface modification on the inorganic nanoparticles to introduce reactive functional groups, and then fully mix the modified inorganic nanoparticles with the liquid silicone resin to obtain an optically transparent organic - inorganic hybrid nanofluid;

[0034] (3) Composite the organic - inorganic hybrid nanofluid obtained in step (2) with the polymer nanofiber network framework obtained in step (1), and through crosslinking and curing, obtain a composite material with a nano - organic - inorganic hybrid interpenetrating network structure.

[0035] Further, the method for preparing the polymer nanofiber network framework with nano - pores includes at least one of dry method, wet single - axis / biaxial stretching, electrospinning, and melt - blowing.

[0036] Further, the thickness of the prepared polymer nanofiber network framework is 0.5 μm - 600 μm, preferably 50 μm - 600 μm.

[0037] Further, the fiber diameter of the prepared polymer nanofiber network framework is 10 nanometers to 200 nanometers.

[0038] Further, the method for surface modification of inorganic nanoparticles is well-known in the art, and those skilled in the art can conventionally select the reactive functional groups to be introduced according to actual applications.

[0039] Further, step (2) further includes mixing an initiator with the inorganic nanoparticles and the liquid silicone resin.

[0040] Further, the mixing is carried out in a solvent.

[0041] Further, the solvent includes at least one of the following substances: dichloromethane, chloroform, toluene, xylene, ether, tetrahydrofuran, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, acetonitrile, benzonitrile, methanol or ethanol.

[0042] Further, step (2) further includes removing the solvent after the mixing is completed.

[0043] Further, the mass ratio of the liquid silicone resin to the inorganic nanoparticles is 5-90:10-80, preferably 20-75:20-80.

[0044] In the present invention, one of the key features of the high-transparency, high-hardness, and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure is that the diameter of the nanofibers is less than 200 nm, which is much smaller than the visible light wavelength, enabling the composite material to still have high transparency at a relatively large thickness of 50~600 μm, and the hardness and toughness of the composite material are regulated according to the type, diameter, nano-pore size and content of the polymer nanofiber network framework, and the types and contents of MT, MDT, MDQ, MDTQ, MTQ, MQ, DT, DQ, DTQ, and TQ silicone resins and inorganic nanoparticles in the organic-inorganic hybrid nanofluid.

[0045] Further, the curing includes light curing or heat curing.

[0046] Further, the heat curing is carried out at 50-100 °C.

[0047] In the present invention, the high-transparency, high-hardness, and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure can be applied to fields such as consumer electronics, optical devices, automotive manufacturing, architectural furniture, and aerospace.

[0048] Advantages of the Invention

[0049] Compared with the prior art, the beneficial effects of the present invention include: providing a high-transparency, high-hardness, and high-toughness composite material with a novel nano organic-inorganic hybrid interpenetrating network structure. The novel organic-inorganic hybrid structure refers to an interpenetrating network structure formed by the continuous interpenetration and cross-linking and curing of a polymer nanofiber network skeleton and an organic-inorganic hybrid nanofluid containing inorganic nanoparticles. The high-transparency, high-hardness, and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure is prepared by first constructing a polymer nanofiber network skeleton with a large number of nano-pores, and then interpenetrating and cross-linking and curing an organic-inorganic hybrid nanofluid mixed with inorganic nanoparticles with the polymer nanofiber network skeleton. Among them, the polymer nanofiber network skeleton and the organic-inorganic hybrid nanofluid are respectively two continuous phases in the composite material. The polymer nanofiber network skeleton phase provides the energy dissipation ability of the composite material and exhibits excellent toughness. The organic-inorganic hybrid nanofluid containing inorganic nanoparticles provides high hardness and high modulus of the material after cross-linking and curing, and can effectively inhibit the fatigue relaxation of the organic component and improve the durability of the composite material. By regulating the type, diameter, nano-pore size and content of the polymer nanofiber network skeleton, and the type and content of the organic-inorganic hybrid nanofluid, the transparency, hardness and toughness of the material can be regulated. The high-transparency, high-strength and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure provided by the present invention can be applied in the fields of consumer electronics, optical devices, automobile manufacturing, architectural furniture and aerospace, etc. Brief Description of the Drawings

[0050] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0051] Figure 1 There are three mainstream organic-inorganic hybrid structures (Structure I, II, III) and the nano organic-inorganic hybrid interpenetrating network structure (Structure IV) described in the present invention.

[0052] Figure 2 It is a preparation flow chart of the high-transparency, high-hardness, and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure of the present invention. First, a polymer nanofiber network skeleton with a large number of nano-pores is constructed, and then an organic-inorganic hybrid nanofluid is interpenetrated and cross-linked and cured with the polymer nanofiber network skeleton to obtain a high-transparency, high-strength and high-toughness composite material with a nano organic-inorganic hybrid interpenetrating network structure.

[0053] Figure 3 It is the visible spectrum experimental result of the composite material with a nano organic-inorganic hybrid interpenetrating network structure prepared in Example 5 of the present invention. The thickness of the composite material is 600 μm, and the light transmittance is 93%. Detailed implementation manners

[0054] The present invention will be further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. In the following embodiments, the preparation methods of liquid MT, MDT, MDQ, MDTQ, MTQ, MQ, DT, DQ, DTQ and TQ silicone resins and the inorganic nanoparticles used have been widely reported in the literature and will not be exemplified here.

[0055] Example 1

[0056] (1) Prepare a polyethylene nanofiber network skeleton with a large number of nanopores by wet biaxial stretching. First, mix 10 parts of polyethylene with 90 parts of white oil evenly to prepare a polyethylene-white oil blend, and press it into a cast sheet with a thickness of 10 cm; then, perform biaxial stretching on the cast sheet at a high temperature of 180 °C, with a stretching ratio of 15×15. After washing with n-hexane and drying, a polyethylene nanofiber network skeleton with a thickness of 100 μm, a porosity of 50%, and a fiber diameter of about 50 nm is obtained;

[0057] (2) By mass, mix 75 parts of an epoxy group-containing TQ type silicone resin with a molecular weight of 2000, 25 parts of silica nanoparticles modified with epoxy groups (20 nm), an initiator (triphenylsulfonium hexafluoroantimonate, 1 part) and ethyl acetate (solvent, 50 parts) evenly. After removing ethyl acetate, a transparent viscous slurry A is formed;

[0058] (3) Immerse slurry A in the polyethylene nanofiber network skeleton to make it penetrate each other with the polyethylene nanofiber network skeleton. After ultraviolet (365 nm) curing for 3 minutes, the target composite material is obtained.

[0059] Example 2

[0060] The difference from Example 1 is that in step 2, the epoxy group-containing TQ type silicone resin is replaced with 50 parts, and the silica nanoparticles are replaced with 50 parts.

[0061] Example 3

[0062] The difference from Example 1 is that in step 2, the epoxy group-containing TQ type silicone resin is replaced with 25 parts, and the silica nanoparticles are replaced with 75 parts.

[0063] Example 4

[0064] Different from Example 1, in Step 1, the draw ratio was replaced with 10×10. After washing with n-hexane and drying, a polyethylene nanofiber network framework with a thickness of about 300 μm, a porosity of 50%, and a fiber diameter of about 80 nm was obtained.

[0065] Example 5

[0066] Different from Example 1, in Step 1, the draw ratio was replaced with 7×7. After washing with n-hexane and drying, a polyethylene nanofiber network framework with a thickness of about 600 μm, a porosity of 50%, and a fiber diameter of about 120 nm was obtained.

[0067] Example 6

[0068] Different from Example 5, in Step 1, the 10 parts of polyethylene and 90 parts of white oil were replaced with 20 parts of polyethylene and 80 parts of white oil, obtaining a polyethylene nanofiber network framework with a thickness of about 700 μm, a porosity of 40%, and a fiber diameter of about 150 nm.

[0069] Example 7

[0070] Different from Example 5, in Step 1, the 10 parts of polyethylene and 90 parts of white oil were replaced with 5 parts of polyethylene and 95 parts of white oil, obtaining a polyethylene nanofiber network framework with a thickness of about 400 μm, a porosity of 60%, and a fiber diameter of about 100 nm.

[0071] Example 8

[0072] Different from Example 1, in Step 2, the particle size of the nano-silica was replaced with ~80 nm.

[0073] Example 9

[0074] Different from Example 1, in Step 2, the particle size of the nano-silica was replaced with ~180 nm.

[0075] Example 10

[0076] Different from Example 5, in Step 2, the epoxy group TQ type silicone resin was replaced with an epoxy group DTQ type silicone resin.

[0077] Example 11

[0078] Different from Example 5, in Step 2, the epoxy group TQ type silicone resin was replaced with an epoxy group DT type silicone resin.

[0079] Example 12

[0080] Different from Example 5, in Step 2, the epoxy group TQ type silicone resin was replaced with an epoxy group DQ type silicone resin.

[0081] Example 13

[0082] Different from Example 5, in Step 2, the epoxy group-containing TQ type silicone resin is replaced with an epoxy group-containing MQ type silicone resin.

[0083] Example 14

[0084] Different from Example 5, in Step 2, the epoxy group-containing TQ type silicone resin is replaced with an epoxy group-containing MTQ type silicone resin.

[0085] Example 15

[0086] Different from Example 5, in Step 2, the epoxy group-containing TQ type silicone resin is replaced with an epoxy group-containing MDTQ type silicone resin.

[0087] Example 16

[0088] Different from Example 5, in Step 2, the epoxy group-containing TQ type silicone resin is replaced with an epoxy group-containing MDQ type silicone resin.

[0089] Example 17

[0090] Different from Example 5, in Step 2, the epoxy group-containing TQ type silicone resin is replaced with an epoxy group-containing MDT type silicone resin.

[0091] Example 18

[0092] Different from Example 5, in Step 2, the epoxy group-containing TQ type silicone resin is replaced with an epoxy group-containing MT type silicone resin.

[0093] Example 19

[0094] Different from Example 3, in Step 2, the epoxy group-containing TQ type silicone resin (25 parts) is replaced with an epoxy group (12.5 parts) and an amino group (12.5 parts) TQ type silicone resin; in Step 3, the curing method is to react at 80 °C for 2 h.

[0095] Example 20

[0096] Different from Example 3, in Step 2, the epoxy group-containing TQ type silicone resin (25 parts) is replaced with an acrylate group (12.5 parts) and a mercapto group (12.5 parts) TQ type silicone resin, and the initiator is 2-hydroxy-2-methylphenylpropanone (1 part).

[0097] Example 21

[0098] Different from Example 3, in Step 2, the epoxy group TQ type silicone resin (25 parts) was replaced with acrylate group TQ type silicone resin (25 parts), and the initiator was azobisisobutyronitrile (0.5 part).

[0099] Example 22

[0100] Different from Example 3, in Step 2, the epoxy group TQ type silicone resin (25 parts) was replaced with methacrylate group TQ type silicone resin (25 parts), and the initiator was azobisisobutyronitrile (0.5 part).

[0101] Example 23

[0102] Different from Example 3, in Step 2, the epoxy group TQ type silicone resin was replaced with vinyl TQ type silicone resin (12.5 parts) and hydrogen-containing TQ type silicone resin (12.5 parts), and the initiator was platinum catalyst (0.2 part); in Step 3, the curing method was to react at 100 °C for 4 h.

[0103] Example 24

[0104] Different from Example 3, in Step 2, the epoxy group TQ type silicone resin (25 parts) was replaced with isocyanate group (12.5 parts) and hydroxyl group (12.5 parts) TQ type silicone resin, and the curing condition was to react at 80 °C for 3 h.

[0105] Example 25

[0106] Different from Example 3, in Step 2, the epoxy group TQ type silicone resin (25 parts) was replaced with alkoxy TQ type silicone resin (25 parts), and the curing condition was to react at 80 °C for 10 h.

[0107] Example 26

[0108] (1) A polypropylene nanofiber network framework with a large number of nano-pores was prepared by wet biaxial stretching. First, 80 parts of polypropylene and 20 parts of white oil were mixed evenly to prepare a polyethylene white oil blend, which was then pressed into a 10 cm thick cast sheet; subsequently, the cast sheet was biaxially stretched at a high temperature of 200 °C, with a stretching ratio of 15×15. After washing with n-hexane and drying, a polypropylene nanofiber network framework with a thickness of 400 μm, a porosity of 60%, and a fiber diameter of about 100 nm was obtained;

[0109] (2) By mass, 25 parts of epoxy group TQ type silicone resin with a molecular weight of 2000, 75 parts of silica nanoparticles modified with epoxy groups, an initiator (triphenylsulfonium hexafluoroantimonate, 1 part), and ethyl acetate (solvent, 50 parts) were mixed evenly. After removing ethyl acetate, a transparent viscous slurry A was formed;

[0110] (3) Immerse Slurry A in the polypropylene nanofiber network framework so that it interpenetrates with the polypropylene nanofiber network framework. After ultraviolet (365 nm) curing for 3 minutes, the target composite material is obtained.

[0111] Example 27

[0112] Different from Example 26, the polypropylene nanofiber network framework is replaced with a cyclic olefin nanofiber network framework. The preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0113] Example 28

[0114] Different from Example 27, the cyclic olefin nanofiber network framework is replaced with polyethylene terephthalate (PET). The preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0115] Example 29

[0116] Different from Example 27, the cyclic olefin nanofiber network framework is replaced with polybutylene terephthalate (PBT). The preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0117] Example 30

[0118] Different from Example 27, the cyclic olefin nanofiber network framework is replaced with polyethylene naphthalate (PBN). The preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0119] Example 31

[0120] Different from Example 27, the cyclic olefin nanofiber network framework is replaced with polyamide (PA). The preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0121] Example 32

[0122] Different from Example 27, the cyclic olefin nanofiber network framework is replaced with polyimide (PI). The preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0123] Example 33

[0124] Different from Example 27, the cyclic polyolefin nanofiber network framework is replaced with polysulfone (PSF), and the preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0125] Example 34

[0126] Different from Example 27, the cyclic polyolefin nanofiber network framework is replaced with polyethersulfone (PES), and the preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0127] Example 35

[0128] Different from Example 27, the cyclic polyolefin nanofiber network framework is replaced with polyetheretherketone (PEEK), and the preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0129] Example 36

[0130] Different from Example 27, the cyclic polyolefin nanofiber network framework is replaced with polyurethane (PU), and the preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0131] Example 37

[0132] Different from Example 27, the cyclic polyolefin nanofiber network framework is replaced with polytetrafluoroethylene (PTFE), and the preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0133] Example 38

[0134] Different from Example 27, the cyclic polyolefin nanofiber network framework is replaced with polyvinylidene fluoride (PVDF), and the preparation method is electrospinning, with a thickness of 400 μm, a fiber diameter of 150 nm, and a porosity of 60%.

[0135] Example 39

[0136] Different from Example 3, in step 2, the nano-silica is replaced with titanium dioxide (particle size ~20 nm).

[0137] Example 40

[0138] Different from Example 3, in step 2, the nano-silica is replaced with aluminum oxide (particle size ~20 nm).

[0139] Example 41

[0140] Different from Example 3, in Step 2, the nano-silica is replaced with zirconia (particle size ~20 nm).

[0141] Comparative Example 1

[0142] Different from Example 1, in Step 2, 100 parts of epoxy group TQ type silicone resin with a molecular weight of 2000 is replaced, and silica is not added.

[0143] Comparative Example 2

[0144] Different from Example 1, in Step 3, the thickness of the polyethylene nanofiber network framework used is 50 μm, the porosity is about 50%, and the fiber diameter is about 230 nm.

[0145] Comparative Example 3

[0146] Different from Example 1, in Step 3, the thickness of the polyethylene nanofiber network framework used is 50 μm, the porosity is about 50%, and the fiber diameter is about 300 nm.

[0147] Testing Method

[0148] The performance of the composites with nano-organic-inorganic hybrid interpenetrating network structures prepared in Examples 1-41 and Comparative Examples 1-3 was tested. The specific performance testing methods are as follows:

[0149] (1) Transmittance Test

[0150] The transmittance was characterized by a UV-3600 ultraviolet-visible light tester from Shimadzu Corporation, Japan.

[0151] (2) Hardness Test

[0152] The hardness was characterized by nanoindentation testing, which was tested with a Piuma nanoindenter from Optics11, Netherlands.

[0153] (3) Modulus Test

[0154] The modulus was characterized by tensile testing. The tensile stress-strain curve was tested with an EM6.501-W tensile machine from Shenzhen Tesmart, China.

[0155] (4) Elongation at Break Test

[0156] The elongation at break was characterized by tensile testing. The tensile stress-strain curve was tested with an EM6.501-W tensile machine from Shenzhen Tesmart, China.

[0157] (5) Strength Test

[0158] The strength characterization comes from the tensile test, and the tensile stress-strain curve was tested by an EM6.501-W tensile machine from Shenzhen Tesmart Company, China.

[0159] Among them, in the transmittance experiment, a highly transparent, high-strength and high-toughness composite material with a nano-organic-inorganic hybrid interpenetrating network structure prepared in Example 5 was evaluated. The specific results are as Figure 3 shown Figure 3 In, the highly transparent, high-hardness and high-toughness composite material with a nano-organic-inorganic hybrid interpenetrating network structure prepared in Example 5 has a high transmittance, indicating that the nano-organic-inorganic hybrid interpenetrating network structure provided by the present invention can effectively achieve the high transparency of the composite material.

[0160] The results of the performance tests on the materials prepared in Examples 1-41 and Comparative Examples 1-3 are shown in Table 1 below.

[0161] Table 1. Results of performance tests on highly transparent, high-hardness and high-toughness composite materials

[0162] Thickness (μm) Transmittance (%) Hardness (GPa) Modulus (GPa) Elongation at break (%) Strength (MPa) Example 1 100 98 3 20 40 600 Example 2 100 97 5.5 29 30 550 Example 3 100 97 7 41 20 450 Example 4 300 96 3 18 50 580 Example 5 600 93 3 17 60 500 Example 6 700 89 2.9 15 70 480 Example 7 400 94 3 17 54 540 Example 8 100 96 4 25 35 580 Example 9 100 93 5 28 30 550 Example 10 600 93 2.9 16.5 62 480 Example 11 600 93 2.8 15 63 470 Example 12 600 93 2.7 14 65 465 Example 13 600 93 2.6 13.6 66 460 Example 14 600 93 2.5 13 67 450 Example 15 600 93 2.45 12.8 68 440 Example 16 600 93 2.4 12.3 70 420 Example 17 600 93 2.36 12 71 408 Example 18 600 93 2.2 11 75 390 Example 19 100 98 7.2 42 22 500 Example 20 100 97 6.9 38 23 480 Example 21 100 98 7.3 44 20 478 Example 22 100 97 7.2 42 18 470 Example 23 100 97 7.5 45 15 560 Example 24 100 98 6.8 36 30 410 Example 25 100 96 7.6 46 15 380 Example 26 400 96 7.1 20 40 600 Example 27 400 96 7 25 36 680 Example 28 400 96 7 10 30 580 Example 29 400 96 7 8 36 550 Example 30 400 96 7 15 20 600 Example 31 400 96 7 18 25 650 Example 32 400 96 7 17 24 640 Example 33 400 96 7 25 15 590 Example 34 400 96 7 30 14 500 Example 35 400 96 7 34 14 470 Example 36 400 96 7 9 60 300 Example 37 400 96 7 11 40 420 Example 38 400 96 7 12 32 450 Example 39 100 97 7.5 43 20 590 Example 40 100 97 8 45 18 579 Example 41 100 97 9 49 17 560 Comparative Example 1 100 98 0.4 3 45 200 Comparative Example 2 50 50 3 2.5 50 170 Comparative Example 3 50 20 3 2.1 60 140

[0163] According to the results of the performance tests on the highly transparent, high-hardness and high-toughness composite materials with a nano-organic-inorganic hybrid interpenetrating network structure in Examples 1-41 and Comparative Examples 1-3 in Table 1, it can be seen that the present invention first constructs a polymer nanofiber network skeleton with a large number of nano-pores, and then makes the hybrid nanofluid slurry mixed with inorganic nano-particles penetrate and crosslink with the polymer nanofiber network skeleton to obtain a highly transparent, high-hardness and high-toughness composite material with a nano-organic-inorganic hybrid interpenetrating network structure. The reasons are as follows: First, the fiber diameter (less than 200 nanometers) of the polymer nanofiber network skeleton is much smaller than the visible light wavelength. After being compounded with the transparent organic-inorganic hybrid nanofluid, even if the thickness increases significantly, it will not affect the transparency of the material; Second, the polymer nanofiber network skeleton has excellent flexibility and high degree of orientation, which can avoid stress concentration, thereby endowing the composite material with excellent toughness, especially elongation at break; Third, the organic-inorganic hybrid nanofluid slurry is filled with a very high content of inorganic nano-particles, and after curing, a nano-scale organic-inorganic hybrid crosslinked network is formed, which can endow the composite material with high hardness and high modulus; Fourth, by regulating the type, diameter, nano-pore size and content of the polymer nanofiber network skeleton, the type of the hybrid nanofluid, and the type and content of the inorganic nano-particles, the transparency, hardness and toughness of the composite material can be regulated.

[0164] It should be noted that the description and drawings of the present invention provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments do not serve as additional limitations to the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosed content of the present invention more thorough and comprehensive. Moreover, the above technical features continue to be combined with each other to form various embodiments not listed above, which are all regarded as within the scope described in the description of the present invention. Further, for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A highly transparent, high-hardness, and high-toughness composite material with a nano-organic-inorganic hybrid interpenetrating network structure, characterized in that, The composite material comprises a polymer nanofiber network skeleton and an organic-inorganic hybrid nanofluid, wherein the organic-inorganic hybrid nanofluid penetrates and crosslinks with the polymer nanofiber network skeleton to form an interpenetrating network structure; The fiber diameter of the polymer nanofiber network skeleton is 10 nanometers to 200 nanometers; The organic-inorganic hybrid nanofluid is composed of a liquid silicone resin and inorganic nanoparticles.

2. The composite material according to claim 1, characterized in that, The thickness of the polymer nanofiber network skeleton is 0.5 μm to 600 μm and the composite material has a light transmittance of more than 90%.

3. The composite material according to claim 1, wherein, The polymer nanofiber network skeleton includes at least one of a polyethylene, polypropylene, cyclic polyolefin, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyamide, polyimide, polyethersulfone, polyetheretherketone, polyurethane, polytetrafluoroethylene, and polyvinylidene fluoride nanofiber network skeleton; The nanopore diameter in the polymer nanofiber network skeleton is 10 nanometers to 300 nanometers; The porosity of the polymer nanofiber network skeleton is 20 to 90%.

4. The composite material according to claim 3, characterized in that, The liquid silicone resin is selected from liquid MT, MDT, MDQ, MDTQ, MTQ, MQ, DT, DQ, DTQ, or TQ silicone resin; The liquid silicone resin contains the following basic repeating units: ； wherein, R is an organic group, and the organic group includes one or a combination of an epoxy group, an amino group, an acrylate group, a methacrylate group, a vinyl group, a mercapto group, a hydrogen-containing group, an isocyanate group, a hydroxyl group, and an alkoxy group.

5. The composite material according to claim 3, characterized in that, The inorganic nanoparticles are at least one of silica, titanium dioxide, alumina, and zirconia particles or a graded mixture thereof; The particle size of the inorganic nanoparticles is 1 to 200 nanometers; The surface of the inorganic nanoparticles has reactive functional groups and can chemically react with the liquid silicone resin.

6. The composite material according to claim 1, wherein The crosslinking and curing are initiated by an initiator; The initiator includes at least one of a thermal initiator, triethylamine, a platinum catalyst, or a photoinitiator; The thermal initiator includes at least one of azobisisobutyronitrile, azobis(isobutyramidine) dihydrochloride, or azodiisopropylimidazoline hydrochloride or a mixture of the above thermal initiators; The photoinitiator includes at least one of 2-hydroxy-2-methylphenylacetone, 1-hydroxycyclohexyl phenyl ketone, phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, benzoin dimethyl ether, triphenylsulfonium hexafluoroantimonate, or 2,2-diethoxyacetophenone, a platinum catalyst, or a mixture of the above photoinitiators.

7. A method for preparing a highly transparent, high-hardness and high-toughness composite material with a nano-organic-inorganic hybrid interpenetrating network structure according to any one of claims 1-6, characterized in that, It includes the following steps: (1) Prepare a polymer nanofiber network skeleton with nanopores; (2) Perform surface modification on the inorganic nanoparticles to introduce reactive functional groups, and then fully mix the modified inorganic nanoparticles with the liquid silicone resin to obtain an optically transparent organic-inorganic hybrid nanofluid; (3) Composite the organic-inorganic hybrid nanofluid obtained in step (2) with the polymer nanofiber network framework obtained in step (1), and through crosslinking and curing, a composite material with a nano organic-inorganic hybrid interpenetrating network structure is obtained.

8. The preparation method according to claim 7, characterized in that, The preparation method of the polymer nanofiber network framework with nano pores includes at least one of dry method, wet method uniaxial / biaxial stretching, electrospinning, and melt blowing.

9. The preparation method according to claim 7, characterized in that, The mixing in step (2) is carried out in a solvent, and further includes mixing an initiator with inorganic nanoparticles and liquid silicone resin together; The mass ratio of the liquid silicone resin to the inorganic nanoparticles is 5-90:10-80.

10. The preparation method according to claim 9, characterized in that, The solvent includes at least one of the following substances: dichloromethane, chloroform, toluene, xylene, ether, tetrahydrofuran, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, N, N-dimethylformamide, N, N-dimethylacetamide, acetonitrile, benzonitrile, methanol or ethanol.

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