A glass fiber reinforced polycarbonate composite material with both optical and mechanical properties and its preparation method

Abstract

This invention discloses a glass fiber reinforced polycarbonate composite material with both optical and mechanical properties, and its preparation method. The composite material is made from the following components in parts by weight: 100 parts of isosorbide-based polycarbonate containing a Cardo structure; 10-40 parts of glass fiber; 0.3-2.0 parts of glucose derivative, wherein the glucose derivative is pentanoyl glucose formed by acylation of all five hydroxyl groups on the pyranose ring; 3-12 parts of core-shell toughening agent, the core of which is an organosilicon elastomer and the shell is an acrylate polymer; and 1-5 parts of olefin copolymer containing epoxy functional groups as a reactive compatibilizer. This invention is the first to synergistically introduce pentanoyl glucose, core-shell toughening agent, and reactive compatibilizer into glass fiber reinforced isosorbide-based polycarbonate containing a Cardo structure. The pentanoyl glucose not only synergistically reduces birefringence with the Cardo structure, but also forms hydrogen bonds with the glass fiber surface to assist dispersion, achieving an excellent balance between optical and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a glass fiber reinforced polycarbonate composite material with both optical and mechanical properties and its preparation method, and particularly to a glass fiber reinforced isosorbide-type polycarbonate composite material containing glucose derivatives, core-shell toughening agents and reactive compatibilizers. Background Technology

[0002] Polycarbonate (PC) is widely used in optical lenses, optical disc substrates, display films, automotive parts, and electronic appliance housings due to its excellent optical transparency, heat resistance, and mechanical strength. However, traditional bisphenol A type polycarbonate is prone to molecular chain orientation during molding, resulting in significant birefringence, which limits its application in precision optical components.

[0003] To address this issue, researchers have developed various modified polycarbonates. On one hand, by introducing Cardo-structured monomers (such as 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, abbreviated as BPEF) for copolymerization, optical polycarbonates with high refractive index and low birefringence can be obtained. On the other hand, by adding glass fibers for reinforcement, structural polycarbonates with high rigidity and high dimensional stability can be obtained. However, the existing technology has the following technological gaps: First, while optical-grade polycarbonates (such as PC with a Cardo structure) possess excellent light transmittance and low birefringence, their mechanical strength is insufficient, making it difficult to meet the requirements for optical structural components (such as automotive camera lens barrels and AR glasses frames). Second, although glass fiber reinforced polycarbonates have excellent mechanical properties, the introduction of glass fibers leads to a significant decrease in light transmittance, an increase in birefringence, and an increase in haze, making them unsuitable for optical applications. Furthermore, there are no reports in the current technology of combining glucose derivatives with glass fiber reinforced systems.

[0004] Through in-depth research on glucose derivatives, the inventors of this invention unexpectedly discovered that glucose derivatives with specific structures (especially pentaacyl glucose formed by acylation of all five hydroxyl groups on the pyranose ring, such as glucose pentaacetate) can not only synergistically reduce birefringence with Cardo-structured polycarbonates, but also play a role in auxiliary dispersion and interface improvement in glass fiber reinforced systems. Based on this, by introducing core-shell toughening agents and reactive compatibilizers, this invention successfully developed a glass fiber reinforced polycarbonate composite material with both excellent optical and mechanical properties, resolving the technical contradiction of optical materials being "transparent but not strong" and reinforcing materials being "strong but not transparent." Summary of the Invention

[0005] The present invention aims to provide a glass fiber reinforced polycarbonate composite material with low birefringence, high light transmittance, high rigidity and high toughness, and its preparation method, so as to overcome the defects of existing optical polycarbonates that are difficult to balance optical and mechanical properties.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a glass fiber reinforced polycarbonate composite material possessing both optical and mechanical properties, comprising the following components in parts by weight: a) 100 parts by weight of isosorbide-based polycarbonate containing a Cardo structure; b) 10-40 parts by weight of glass fiber; c) 0.3-2.0 parts by weight of a glucose derivative, wherein the glucose derivative is a pentacyl glucose formed by acylation of all five hydroxyl groups on the pyranose ring, wherein the acyl group is independently selected from acetyl, propionyl or butyryl; d) 3-12 parts by weight of a core-shell toughening agent, wherein the core of the toughening agent is an organosilicon elastomer and the outer shell is an acrylate polymer; e) 1-5 parts by weight of a reactive compatibilizer, wherein the compatibilizer is an olefin copolymer containing epoxy functional groups.

[0007] Preferably, the glucose derivative is glucose pentaacetate, and the amount added is 0.5-1.5 parts by weight.

[0008] Preferably, the glass fiber is a flat glass fiber with a cross-sectional aspect ratio of 2:1 to 6:1.

[0009] Preferably, the isosorbide-type polycarbonate containing a Cardo structure is selected from at least one of polycarbonates containing a fluorene structure and polycarbonates containing a benzene-anthracene Cardo structure, and its refractive index is ≥1.60.

[0010] Preferably, the reactive compatibilizer is an ethylene-acrylate-glycidyl methacrylate terpolymer.

[0011] Preferably, the raw material further comprises 0.1-0.5 parts by weight of antioxidant, 0.1-0.5 parts by weight of ultraviolet absorber and 0.1-0.3 parts by weight of lubricant.

[0012] More preferably, the antioxidant is a compound antioxidant composed of antioxidant 1076 and antioxidant 168 in a mass ratio of 1:0.5-2; the ultraviolet absorber is selected from at least one of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P), 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327), and 2-hydroxy-4-n-octyloxybenzophenone (UV-531); the lubricant is pentaerythritol stearate or liquid paraffin.

[0013] Secondly, the present invention provides a molding method for preparing the above-mentioned composite material, comprising the following steps: (1) Pre-drying: The isosorbide-type polycarbonate containing Cardo structure, glass fiber, glucose derivative, core-shell toughening agent, reactive compatibilizer and various additives are dried at 80-120℃ for 4-8 hours to make the moisture content <0.02%; (2) Premixing: Weigh the dried components according to the formula, put them into a high-speed mixer, and mix for 5-15 minutes at a speed of 500-1500 rpm to obtain the premix; (3) Melt extrusion: The premixed material is added to a twin-screw extruder, melt-blended and extruded at 200-280℃ to obtain composite material granules; (4) Molding: After drying the obtained granules, they are made into optical-mechanical integrated components of the required shape by injection molding or extrusion molding.

[0014] Preferably, the process parameters of the twin-screw extruder in step (3) are: screw length-to-diameter ratio 30-40, screw speed 150-250 rpm, temperature set as follows: zone 1 40-60℃, zones 2 to 4 250-280℃, zones 5 to 9 240-260℃, and die head 250-260℃.

[0015] Preferably, the process parameters for injection molding in step (4) are: barrel temperature 240-280℃, mold temperature 80-120℃, injection pressure 60-120MPa, holding pressure 30-80MPa, and cooling time 10-30 seconds.

[0016] Compared with the prior art, the present invention has the following advantages: (1) Excellent optical-mechanical properties: This invention introduces glucose derivatives, core-shell toughening agents and reactive compatibilizers into glass fiber reinforced isosorbide-based polycarbonate systems containing Cardo structures for the first time. The resulting composite material has a light transmittance ≥85% and a birefringence ≤7.0×10⁻ 5 With tensile strength ≥90 MPa, notched impact strength ≥15 kJ / m², and heat distortion temperature ≥135℃, it achieves an excellent balance between optical and mechanical properties.

[0017] (2) Unexpected synergistic effects: Studies have found that pentacyl glucose (such as glucose pentaacetate) plays multiple roles in the multi-component system of this invention: on the one hand, there are π-π interactions and dipole-dipole interactions between its acyl group and the Cardo structure, which effectively inhibits the orderly arrangement of PC molecular chains, thereby further reducing birefringence while maintaining high light transmittance; on the other hand, its acyl group may form hydrogen bonds with the hydroxyl groups on the glass fiber surface, which helps to improve the dispersion and interfacial bonding of glass fibers in the matrix. Experiments show that adding 0.5-1.5% glucose pentaacetate can reduce birefringence by 15-25% and improve the uniformity of glass fiber distribution. This synergistic effect is not possessed by single-function additives.

[0018] (3) Excellent interfacial bonding and toughening effect: The core-shell toughening agent (organosilicon core provides low-temperature toughness, and acrylate shell ensures compatibility) and the reactive compatibility agent (epoxy groups react with PC terminal hydroxyl groups and glass fiber surface hydroxyl groups to form "molecular bridges") work together to significantly strengthen the interfacial bonding force between glass fiber and matrix, make up for the brittleness caused by the introduction of glass fiber, and improve the long-term fatigue performance and resistance to damp heat aging of the material.

[0019] (4) Excellent processing performance: The addition of glucose derivatives moderately improves the fluidity of PC melt, increasing the melt flow rate by 15-25%, which is beneficial for injection molding complex optical-mechanical integrated components. At the same time, the glass transition temperature of the material is basically maintained (decreases by ≤5℃), avoiding the defect of a significant decrease in heat resistance caused by traditional plasticizers.

[0020] (5) Green and environmentally friendly: The isosorbide-type polycarbonate and glucose derivative used in this invention are both derived from renewable biomass resources, which meet the requirements of sustainable development and provide a green solution for optical-mechanical integrated polycarbonate materials.

[0021] (6) Significant Critical Effect: This invention unexpectedly discovered that the amount of glucose derivative added has a critical effect on the overall performance. When the amount added is in the range of 0.5%-1.5%, the material exhibits the best overall optical and mechanical properties; when the amount added exceeds 2.0%, the haze begins to increase and the light transmittance decreases. This discovery provides clear technical guidance for those skilled in the art. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0023] Cardo-containing isosorbide-based polycarbonate (BPEF copolyisosorbide-based PC): self-made, refractive index 1.62, birefringence 5.2×10⁻ 5 Melt flow rate 12.0 g / 10min (300℃ / 1.2kg); Fiberglass: Flat fiberglass, cross-sectional aspect ratio 4:1, length 3-4.5mm, commercially available; Glucose pentaacetate: purity ≥98%, commercially available; Core-shell toughening agent: Organosilicon-acrylate core-shell structure, with a core of polyorganosiloxane and a shell of polymethyl methacrylate, commercially available; Reactive compatibilizer: Ethylene-acrylate-glycidyl methacrylate terpolymer, commercially available; Antioxidant 1076 and Antioxidant 168: Commercially available; UV absorber UV-329: Commercially available; Pentaerythritol stearate: Commercially available.

[0024] Performance testing methods: Transmittance / haze: Tested according to GB / T 2410-2008 standard using a transmittance / haze meter, with a sample thickness of 2 mm; Birefringence: Measured using an ellipsometer at a wavelength of 633 nm; Refractive index: determined using an Abbe refractometer; Tensile strength: tested according to GB / T 1040-2006 standard; Notched impact strength: Tested according to GB / T 1843-2008 standard, cantilever beam notched impact; Heat distortion temperature: tested according to GB / T 1634-2004 standard, load 1.80MPa; Melt flow rate (MFR): Tested according to GB / T 3682-2000 standard, 300℃ / 1.2kg; Glass transition temperature (Tg): Differential scanning calorimetry (DSC) was used with a heating rate of 10℃ / min. Example

[0025] Weigh each component (parts by weight) according to the following formula: Isosorbide-based polycarbonate containing Cardo structure: 100 parts; Flat glass fiber: 20 parts; Glucose pentaacetate: 0.8 parts; Core-shell toughening agent: 8 parts; Reactive compatibilizer: 3 parts; Antioxidant 1076: 0.15 parts; Antioxidant 168: 0.15 parts; UV absorber UV-329: 0.25 parts; Pentaerythritol stearate: 0.2 parts.

[0026] Prepare according to the following steps: (1) Dry all components at 100℃ for 6 hours; (2) Add the dried components to a high-speed mixer and mix at 1000 rpm for 8 minutes; (3) Add the premixed material into a twin-screw extruder for extrusion granulation. The screw length-to-diameter ratio is 35, the screw speed is 200 rpm, and the temperature is set to 50℃ in zone 1, 260℃ in zones 2 to 4, 250℃ in zones 5 to 9, and 255℃ at the die head. (4) The obtained granules are dried at 100°C for 4 hours, and then the standard test strips are made by injection molding. The injection temperature is 250°C, the mold temperature is 100°C, the injection pressure is 80MPa, the holding pressure is 50MPa, and the cooling time is 20 seconds. Example

[0027] The difference from Example 1 is that the amount of glucose pentaacetate added is 1.2 parts, while the other components and preparation methods are the same. Example

[0028] The difference from Example 1 is that the amount of glucose pentaacetate added is 0.5 parts, while the other components and preparation methods are the same. Example

[0029] The difference from Example 1 is that the amount of flat glass fiber added is 30 parts, while the other components and preparation methods are the same. Example

[0030] The difference from Example 1 is that the amount of core-shell toughening agent added is 12 parts, while the other components and preparation methods are the same.

[0031] Comparative Example 1: The difference from Example 1 is that glucose pentaacetate is not added, while the remaining components and preparation method are the same.

[0032] Comparative Example 2: The difference from Example 1 is that no core-shell toughening agent is added, while the remaining components and preparation method are the same.

[0033] Comparative Example 3: The difference from Example 1 is that no reactive compatibilizer is added, while the remaining components and preparation method are the same.

[0034] Comparative Example 4: The difference from Example 1 is that an equal amount of conventional glass fiber (circular cross-section) is used instead of flat glass fiber, while the remaining components and preparation methods are the same.

[0035] Comparative Example 5: The difference from Example 1 is that an equal amount of conventional bisphenol A type polycarbonate is used instead of isosorbide type polycarbonate containing Cardo structure, while the other components and preparation methods are the same.

[0036] Performance test results: The performance of the composite materials prepared in each embodiment and comparative example was tested, and the results are shown in Table 1.

[0037]

[0038] (1) Optical modification effect of glucose pentaacetate: Comparing Examples 1-3 with Comparative Example 1, it can be seen that after adding glucose pentaacetate, the birefringence increased from 5.8 × 10⁻ 5 Significantly reduced to 4.4-4.9×10⁻ 5 The light transmittance decreased by 15-24%, while the transmittance remained basically unchanged (≥86.8%), and the haze improved slightly. This indicates that pentacylglucose does indeed play a role in inhibiting the orderly arrangement of molecular chains and reducing birefringence, without negatively affecting the transmittance.

[0039] (2) Toughening effect of core-shell toughening agent: Comparing Example 1 and Comparative Example 2, it can be seen that after adding the core-shell toughening agent, the notched impact strength increased significantly from 8.5 kJ / m² to 18.5 kJ / m², an increase of 118%, while the tensile strength decreased slightly (from 108 MPa to 105 MPa), but still remained at a high level. This indicates that the core-shell toughening agent effectively compensated for the brittleness caused by the introduction of glass fiber, achieving an excellent balance between rigidity and toughness.

[0040] (3) Interfacial strengthening effect of reactive compatibilizer: Comparing Example 1 and Comparative Example 3, it can be seen that after adding reactive compatibilizer, the tensile strength increased from 92 MPa to 105 MPa (an increase of 14%), the notched impact strength increased from 12.5 kJ / m² to 18.5 kJ / m² (an increase of 48%), and the heat distortion temperature increased from 138℃ to 141℃. This indicates that the reactive compatibilizer effectively strengthens the interfacial bonding between glass fiber and the matrix, achieving a comprehensive improvement in mechanical properties.

[0041] (4) Advantages of flat glass fiber: Comparing Example 1 and Comparative Example 4, it can be seen that Example 1, which uses flat glass fiber, has advantages in light transmittance (87.2% vs 85.8%), haze (0.51% vs 0.82%), and birefringence (4.6×10⁻⁻⁶). 5 vs5.9×10⁻5 In terms of light scattering and orientation birefringence, flat glass fibers are superior to conventional circular glass fibers in all aspects, indicating that flat glass fibers help reduce light scattering and orientation birefringence.

[0042] (5) Advantages of Cardo structure isosorbide-based PC: Comparing Example 1 and Comparative Example 5, it can be seen that Example 1, which uses Cardo structure isosorbide-based PC, has advantages in transmittance (87.2% vs 84.2%), haze (0.51% vs 1.05%), and birefringence (4.6 × 10⁻⁻⁶). 5 vs 7.8×10⁻ 5 In terms of optical properties, the material is significantly superior to conventional bisphenol A type PC in terms of refractive index (1.618 vs 1.585), indicating that the synergistic effect of the Cardo structure and isosorbide unit provides the basis for the material's excellent optical properties.

[0043] (6) Optimization of the amount of glucose pentaacetate added: Examples 1-3 show that the overall performance is best when the amount of glucose pentaacetate added is 0.8-1.2 parts; the effect of reducing birefringence is slightly worse when the amount added is too low (0.5 parts); the amount added is too high (>1.5 parts, although not shown, but can be inferred from the trend) may lead to an increase in haze. This indicates that there is a "golden addition window".

[0044] (7) Effect of glass fiber content: Example 4 shows that when the glass fiber content is increased to 30 parts, the mechanical properties are further improved (tensile strength 118 MPa), but the light transmittance decreases slightly (85.1%), and the birefringence increases slightly (5.1 × 10⁻⁻⁶). 5 This indicates that a balance can be struck between optical and mechanical properties depending on the application requirements.

[0045] (8) Effect of toughening agent content: Example 5 shows that when the toughening agent content is increased to 12 parts, the impact strength is further improved to 22.5 kJ / m², but the tensile strength is slightly reduced (98 MPa), indicating that different toughness requirements can be met by adjusting the toughening agent content.

[0046] UV-Vis transmittance: The 2mm thick plate prepared in Example 1 was subjected to UV-Vis transmittance testing (wavelength range 300-800nm). The test results showed that the material had an average transmittance of 87.5% in the visible light region (400-700nm) and a maximum transmittance of 88.2% (at 550nm). The material rapidly cut off in the UV region (<380nm) due to absorption, with a transmittance of 82.5% at 380nm, indicating that the material has good UV shielding performance.

[0047] Damp heat aging performance: The materials prepared in Example 1 and Comparative Example 3 were subjected to a double 85% damp heat aging test (temperature 85°C, relative humidity 85%, aging for 1000 hours) to test the impact strength retention rate after aging. The results showed that the impact strength retention rate of Example 1 was 89%, and that of Comparative Example 3 was 72%. This indicates that the addition of the reactive compatibilizer significantly improved the damp heat aging resistance of the materials, resulting in a stronger interfacial bond.

[0048] While not limited to any specific theory, it is speculated that the superior performance of the technical solution of this invention may stem from the synergistic effect of the following factors: The acyl group of pentacyl glucose (such as glucose pentaacetate) has a π-π interaction with the aromatic ring containing the Cardo structure, and forms a dipole-dipole interaction with the carbonyl group on the PC chain, thereby breaking the ordered arrangement of the PC molecular chain and reducing orientation birefringence; The acyl group of pentacylglucose may form hydrogen bonds with the hydroxyl groups on the surface of glass fiber, which may help improve the dispersibility and interfacial bonding of glass fiber in the matrix. The silicone core of the core-shell toughening agent provides excellent low-temperature toughness, while the acrylate shell ensures good compatibility with the PC matrix. The epoxy groups of the reactive compatibilizer react with the hydroxyl groups at the PC end and the hydroxyl groups on the glass fiber surface to form strong chemical bridges, which significantly strengthens the interfacial bonding. Flat glass fibers, due to their large specific surface area, provide more interfacial bonding sites while reducing light scattering.

[0049] The synergistic effect of these factors allows for the dual regulation of optical properties and interfacial bonding with trace amounts of pentanoyl glucose. Combined with core-shell toughening agents and reactive compatibilizers, this ultimately achieves an excellent balance between optical and mechanical properties.

[0050] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A glass fiber reinforced polycarbonate composite material with both optical and mechanical properties, characterized in that, It is made from the following components in parts by weight: a) 100 parts by weight of isosorbide-based polycarbonate containing a Cardo structure; b) 10-40 parts by weight of glass fiber; c) 0.3-2.0 parts by weight of a glucose derivative, wherein the glucose derivative is a pentacyl glucose formed by acylation of all five hydroxyl groups on the pyranose ring, wherein the acyl group is independently selected from acetyl, propionyl or butyryl; d) 3-12 parts by weight of a core-shell toughening agent, wherein the core of the toughening agent is an organosilicon elastomer and the outer shell is an acrylate polymer; e) 1-5 parts by weight of a reactive compatibilizer, wherein the compatibilizer is an olefin copolymer containing epoxy functional groups.

2. The composite material of claim 1, wherein, The glucose derivative is glucose pentaacetate, and its addition amount is 0.5-1.5 parts by weight.

3. The composite material of claim 1, wherein, The glass fiber is a flat glass fiber with a cross-sectional aspect ratio of 2:1-6:

1.

4. The composite material according to claim 1, characterized in that, The isosorbide-type polycarbonate containing a Cardo structure is selected from at least one of polycarbonates containing a fluorene structure and polycarbonates containing a benzene-anthracene Cardo structure, and its refractive index is ≥1.

60.

5. The composite material according to claim 1, characterized in that, The reactive compatibilizer is an ethylene-acrylate-glycidyl methacrylate terpolymer.

6. The composite material according to claim 1, characterized in that, The raw materials also include 0.1-0.5 parts by weight of antioxidant, 0.1-0.5 parts by weight of ultraviolet absorber and 0.1-0.3 parts by weight of lubricant.

7. The composite material according to claim 6, characterized in that, The antioxidant is a compound antioxidant composed of antioxidant 1076 and antioxidant 168 in a mass ratio of 1:0.5-2; the ultraviolet absorber is selected from at least one of benzotriazole ultraviolet absorbers or benzophenone ultraviolet absorbers; the lubricant is pentaerythritol stearate or liquid paraffin.

8. The composite material according to any one of claims 1-7, characterized in that, The composite material has a light transmittance of ≥ 85%, a birefringence of ≤ 7.0 x 10⁻ 5 , a tensile strength of ≥ 90 MPa, a notched impact strength of ≥ 15 kJ / m², and a heat distortion temperature of ≥ 135℃.

9. A molding method for preparing the composite material as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Pre-drying: The isosorbide-type polycarbonate containing Cardo structure, glass fiber, glucose derivative, core-shell toughening agent, reactive compatibilizer and various additives are dried at 80-120℃ for 4-8 hours respectively; (2) Premixing: Weigh the dried components according to the formula, mix them evenly to obtain the premix; (3) Melt extrusion: The premixed material is added to a twin-screw extruder, melt-blended and extruded at 200-280℃ to obtain composite material granules; (4) Molding: After drying the obtained granules, they are made into optical-mechanical integrated components of the required shape by injection molding or extrusion molding.

10. The molding method according to claim 9, characterized in that, The process parameters of the twin-screw extruder in step (3) are: screw length-to-diameter ratio 30-40, screw speed 150-250 rpm, and temperature set from the feed section to the die head as 40-60℃, 250-280℃, 240-260℃, and 250-260℃ respectively; the process parameters of the injection molding in step (4) are: barrel temperature 240-280℃, mold temperature 80-120℃, injection pressure 60-120MPa, holding pressure 30-80MPa, and cooling time 10-30 seconds.

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