Chemical-resistant PC / PBT alloy material and preparation method thereof

Abstract

The invention discloses a chemical-resistant PC / PBT alloy material and a preparation method thereof. The chemical-resistant PC / PBT alloy material is prepared from the following components in percentage by mass: 25 to 45 percent of polycarbonate, 20 to 35 percent of polybutylene terephthalate, 3 to 12 percent of maleic anhydride grafted ethylene-acrylate copolymer, 6 to 18 percent of sulfonated polytetrafluoroethylene and 4 to 19 percent of nano silicon dioxide coated silicone microspheres, the composite material is prepared from the following components in percentage by weight: 0.5 to 6 percent of triphenyl phosphate modified graphene oxide, 0.1 to 3.5 percent of bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite, 0.2 to 3.2 percent of vinyl trimethoxy silane and 0.5 to 2.5 percent of mesoporous silicon dioxide; the total mass percentage of the components is 100%. Through component fine SPTFE chain segment regulation and control, core-shell microsphere interface optimization, graphene intercalation modification and process dynamic crosslinking, graded mixing and ultraviolet radiation assistance, the breakthrough improvement of the chemical resistance of the PC / PBT alloy material is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials, and specifically relates to a chemical-resistant PC / PBT alloy material; in particular, it also relates to a preparation method of the chemical-resistant PC / PBT alloy material. Background Art

[0002] Alloy materials of polycarbonate (PC) and polybutylene terephthalate (PBT) are widely used in automotive parts, electronic and electrical housings, industrial pipelines and other fields due to their excellent mechanical properties, dimensional stability and heat resistance. However, traditional PC / PBT alloys are prone to problems such as swelling and stress cracking when faced with complex chemical environments (such as organic solvents and strong acid and strong base media), which seriously restricts their application in high-end fields such as chemical equipment and medical devices. The reason is that the differences in polarity and crystallization behavior between PC and PBT result in weak interfacial bonding, and chemical media easily penetrate along the phase boundary, causing corrosion failure. At the same time, the synergistic effect of functional additives in traditional formulas is insufficient, making it difficult to build a multi-dimensional protection system.

[0003] Prior art researchers have primarily improved the compatibility of PC and PBT by adding compatibilizers (such as maleic anhydride-grafted elastomers) or by introducing nanofillers (such as talc and silica) to enhance mechanical properties. However, these approaches have significant limitations. Conventional surface modification methods with nanofillers, such as direct physical mixing of silicone microspheres with a resin matrix, result in weak interfacial bonding and disordered pore structures, making it difficult to directionally block the diffusion paths of chemical media. Therefore, we propose a chemical-resistant PC / PBT alloy material and its preparation method. Summary of the Invention

[0004] The purpose of the present invention is to provide a chemical-resistant PC / PBT alloy material and a preparation method thereof. Through fine SPTFE chain segment regulation of the components, core-shell microsphere interface optimization, graphene intercalation modification and process dynamic cross-linking, graded mixing, and ultraviolet irradiation assistance, a breakthrough improvement in the chemical resistance of the PC / PBT alloy material is achieved.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A chemical-resistant PC / PBT alloy material, comprising the following components in percentage by mass:

[0007] Polycarbonate 25-45%, polybutylene terephthalate 20-35%, maleic anhydride grafted ethylene-acrylate copolymer 3-12%, sulfonated polytetrafluoroethylene 6-18%, nano-silica coated silicone microspheres 4-19%, triphenyl phosphate modified graphene oxide 0.5-6%, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite 0.1-3.5%, vinyltrimethoxysilane 0.2-3.2%, mesoporous silica 0.5-2.5%;

[0008] The total mass percentage of the components is 100%.

[0009] Preferably, the molar content of sulfonic acid groups in the sulfonated polytetrafluoroethylene is 0.12-0.35 mmol / g, and its chemical structure comprises the following repeating units:

[0010] -(CF2-CF2-) n -[CF2-CF(SO3H)-] m , where n:m = 3:1-5:1, and the sulfonic acid groups are distributed at the ends of the polymer side chains.

[0011] Preferably, the surface of the mesoporous silica shell is grafted with γ-methacryloxypropyltrimethoxysilane, with a grafting rate of 8-15 wt %, a pore size distribution of 2-8 nm, and a pore direction perpendicular to the surface of the silicone core.

[0012] Preferably, the modification method of the triphenyl phosphate-modified graphene oxide is:

[0013] Dispersing graphene oxide in an anhydrous ethanol solution of triphenyl phosphate, stirring and reacting at 60-80°C for 4-8 hours, and drying to obtain a modified product with an interlayer spacing of 1.2-2.3 nm;

[0014] The anhydrous ethanol solution used for graphene oxide modification has a triphenyl phosphate concentration of 12-20 g / 100 mL, and the ultraviolet radiation energy density during the reaction is 50-120 mJ / cm 2 .

[0015] Preferably, the core layer of the nano-silica coated silicone microspheres is polydimethylsiloxane, the shell layer is mesoporous silica, the core-shell mass ratio is 1:0.2-0.6, and the specific surface area is 200-400m 2 / g, the surface of the mesoporous silica shell is grafted with γ-methacryloxypropyltrimethoxysilane, the grafting rate is 8-15wt%, the pore size distribution is 2-8nm, and the pore direction is perpendicular to the silicone core surface.

[0016] Preferably, the intrinsic viscosity of the polycarbonate is 0.6-1.2 dL / g, the relative viscosity of the polybutylene terephthalate is 1.8-2.7, the weight average molecular weight of the polycarbonate is 28000-35000 g / mol, and the polycarbonate contains 3-8 mol% of bisphenol A cyclic oligomers, the cyclic structure of which is as follows:

[0017] C 15 H 16 O2-[O-C6H4-C(CH3)2-C6H4-OC(O)-O] n The bisphenol A skeleton consists of two benzene rings bridged by an isopropyl C(CH3)2, and the end is bonded with a carbonate group OC(O)-O, C 15 H 16 O2 reflects the residue after removing two hydroxyl groups from bisphenol A monomer.

[0018] A method for preparing a chemical-resistant PC / PBT alloy material, the method being used to prepare the above-mentioned chemical-resistant PC / PBT alloy material, comprising the following steps:

[0019] S1. Pretreatment and surface activation of key raw materials;

[0020] S2. graded mixing of the compatibilizer and the functional additive;

[0021] S3, main resin premixing and interface modification;

[0022] S4, multiphase melt blending and dynamic cross-linking reaction;

[0023] S5, hot pressing the blend to form a post-processing, cooling the formed blend and pelletizing or forming a linear material according to demand, and drying and packaging;

[0024] The above-mentioned staged treatment realizes multi-level interaction between the components, and the dynamic cross-linking of sulfonated polytetrafluoroethylene and the directional guiding effect of the mesoporous structure improve the chemical corrosion resistance of the material.

[0025] Preferably, step S1 is specifically as follows:

[0026] The sulfonated polytetrafluoroethylene was placed in a vacuum drying oven and dried at 45-55°C for 2-4 hours to remove surface adsorbed water. At this time, the molar content of the sulfonic acid group was stabilized in the range of 0.12-0.35 mmol / g. At the same time, the triphenyl phosphate-modified graphene oxide was subjected to ultrasonic dispersion pretreatment: triphenyl phosphate was dissolved in anhydrous ethanol at a concentration of 12-20 g / 100 mL in a reactor equipped with a constant temperature magnetic stirring device, and then graphene oxide powder was added. The ultraviolet irradiation intensity was set to 50-120 mJ / cm 2, stirring continuously at 60-80°C for 4-8 hours, and after completion, vacuum filtration and drying in an 80°C oven to constant weight to obtain modified graphene oxide with an interlayer spacing of 1.2-2.3nm. Surface activation of nano-silica-coated silicone microspheres: placing them in a high-temperature furnace protected by nitrogen, heating them to 350°C at a rate of 5°C / min and keeping them warm for 20 minutes to make the surface-grafted γ-methacryloxypropyltrimethoxysilane bond more tightly, and the grafting rate is optimized to 8-15wt%;

[0027] Step S2 is specifically as follows: pre-mixing the maleic anhydride grafted ethylene-acrylate copolymer with vinyltrimethoxysilane: first, adding the maleic anhydride grafted ethylene-acrylate copolymer particles into a closed drum mixer, stirring at a speed of 600 rpm, and spraying the vinyltrimethoxysilane solution onto the surface of the copolymer at a mass ratio of 0.2-1.2% by a constant flow pump, and then raising the mixing temperature to 75 ° C and maintaining it for 30 minutes to achieve the grafting reaction; then slowly adding the pretreated sulfonated polytetrafluoroethylene to the mixing system, controlling the temperature in the mixer to maintain at 50-60 ° C to avoid decomposition of the sulfonic acid group, and continuously stirring for 45 minutes to obtain a uniform compatibilizer complex.

[0028] Preferably, step S3 is specifically as follows: polycarbonate and polybutylene terephthalate are pretreated separately: polycarbonate is dried in a blast oven at 100°C for 4 hours to remove crystallization moisture, and polybutylene terephthalate is vacuum dried at 120°C, and then the resin compatibility is improved by a melt premixing method: the two resins are added to a mixer with a spiral stirring blade in a mass ratio of 25-45%:20-35%, and premixed at a speed of 200-300 rpm under nitrogen protection. During the process, the compatibilizer compound prepared in step 2 is evenly sprinkled into the powder mixture three times, and the mixing temperature is strictly controlled in the range of 180-200°C to prevent premature plasticization of the resin. The mixing time is 40-60 minutes to form a primary premix;

[0029] Step S4 is specifically as follows: adding the premix to a screw extruder and melt blending under the following five-stage temperature gradient: the temperature of the first zone is 230-240°C, the temperature of the second zone is 245-255°C, the temperature of the third zone is 260-270°C, the temperature of the fourth zone is 275-285°C, and the temperature of the fifth zone is 280-290°C. The screw speed is set to 180-250rpm, and the pretreated nano-silica-coated silicone microspheres and triphenyl phosphate-modified graphene oxide are simultaneously added to the side feeding port of the extruder, wherein the nano-microspheres need to pass through a vibration screening device before entering the melt to ensure uniform particle size distribution. During the mixing process, the high shear effect of the twin screw is used to induce the sulfonic acid group of sulfonated polytetrafluoroethylene to undergo an in-situ cross-linking reaction with the terminal hydroxyl group of polycarbonate, and at the same time, the silane coupling agent of the mesoporous silica shell forms a chemical bond with the polybutylene terephthalate molecular chain. The mixing time is controlled at 6-8 minutes to ensure the stable generation of the phase structure.

[0030] Technical effects and advantages of the present invention:

[0031] The precise molar content of sulfonic acid groups (0.12-0.35 mmol / g) and the characteristic distribution of branched ends react in situ with the terminal hydroxyl groups of polycarbonate during melt blending to form a dynamic cross-linked network (PC-O-SO3-SPTFE). This network not only enhances the interfacial adhesion between PC and polybutylene terephthalate, but also the strong nucleophilicity of the sulfonic acid groups allows them to preferentially bond with polar molecules in the chemical medium, forming a local charge barrier and reducing the medium's permeation rate.

[0032] The γ-methacryloxypropyltrimethoxysilane on the shell surface forms Si-OC bonds with PBT ester groups through alkoxy hydrolysis, thereby enhancing the inorganic-organic interface bonding strength;

[0033] After intercalation with triphenyl phosphate, the interlayer spacing of graphene oxide expands to 1.2-2.3nm. Its two-dimensional sheets form a parallel structure in the melt, creating a physical barrier to the penetration path of chemical media. Combined with the flame retardant properties of triphenyl phosphate, PO· free radicals are generated during combustion, which cooperate with the graphene carbon layer to form a dense char layer, achieving coupled enhancement of flame retardancy and solvent resistance. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] The present invention provides a chemical-resistant PC / PBT alloy material and a preparation method thereof. The chemical-resistant PC / PBT alloy material is composed of the following components: polycarbonate, wherein the intrinsic viscosity of the polycarbonate is 0.6-1.2 dL / g, the relative viscosity of the polybutylene terephthalate is 1.8-2.7, the weight-average molecular weight of the polycarbonate is 28,000-35,000 g / mol, and the polycarbonate contains 3-8 mol% of a bisphenol A cyclic oligomer, the cyclic structure of which is generally represented by:

[0036] C 15 H 16 O2-[O-C6H4-C(CH3)2-C6H4-OC(O)-O] n The bisphenol A skeleton consists of two benzene rings bridged by an isopropyl C(CH3)2, and the end is bonded with a carbonate group OC(O)-O, C 15 H 16 O2 reflects the residue after the two hydroxyl groups are removed from the bisphenol A monomer;

[0037] It also contains: polybutylene terephthalate, maleic anhydride grafted ethylene-acrylate copolymer, sulfonated polytetrafluoroethylene, nano-silica coated silicone microspheres, triphenyl phosphate modified graphene oxide, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, vinyl trimethoxysilane, mesoporous silica;

[0038] The surface of the mesoporous silica shell is grafted with gamma-methacryloyloxypropyltrimethoxysilane, with a grafting rate of 8-15wt%, a pore size distribution of 2-8nm, and a pore direction perpendicular to the silicone core surface.

[0039] The molar content of sulfonic acid groups in sulfonated polytetrafluoroethylene is 0.12-0.35 mmol / g, and its chemical structure contains the following repeating units:

[0040] -(CF2-CF2-) n -[CF2-CF(SO3H)-] m , where n:m = 3:1-5:1, and the sulfonic acid groups are distributed at the ends of the polymer side chains;

[0041] It should be noted that the shell surface of the mesoporous silica is grafted with γ-methacryloxypropyltrimethoxysilane with a grafting rate of 8-15 wt %. The pore size distribution is 2-8 nm, and the pore direction is perpendicular to the silicone core surface.

[0042] Specifically, the preparation method of the chemical-resistant PC / PBT alloy material is used to prepare the above-mentioned chemical-resistant PC / PBT alloy material, comprising the following steps:

[0043] S1, pretreatment of key raw materials and surface activation; Step S1 specifically comprises: placing sulfonated polytetrafluoroethylene in a vacuum drying oven and drying at 45-55°C for 2-4 hours to remove surface adsorbed moisture, at which point the molar content of sulfonic acid groups is stabilized within the range of 0.12-0.35 mmol / g; and simultaneously performing ultrasonic dispersion pretreatment on triphenyl phosphate-modified graphene oxide: in a reactor equipped with a constant temperature magnetic stirring device, dissolving triphenyl phosphate in anhydrous ethanol at a concentration of 12-20 g / 100 mL, then adding graphene oxide powder, and setting the ultraviolet irradiation intensity to 50-120 mJ / cm 2 , stirring was continued at 60-80°C for 4-8 hours, and after completion, vacuum filtration was performed and the mixture was placed in an 80°C oven to dry to constant weight to obtain modified graphene oxide with an interlayer spacing of 1.2-2.3 nm. The nano-silica-coated silicone microspheres were surface activated: they were placed in a high-temperature furnace protected by nitrogen, heated to 350°C at a rate of 5°C / min and kept warm for 20 minutes to make the surface-grafted γ-methacryloxypropyltrimethoxysilane bonded more tightly, and the grafting rate was optimized to 8-15wt%.

[0044] S2, graded mixing of the compatibilizer and the functional additive; Step S2 specifically comprises: pre-mixing the maleic anhydride grafted ethylene-acrylate copolymer and vinyl trimethoxysilane: first, adding the maleic anhydride grafted ethylene-acrylate copolymer particles into a closed drum mixer, stirring at a speed of 600 rpm, and spraying a 0.2-1.2% by mass vinyl trimethoxysilane solution onto the copolymer surface through a constant flow pump, then raising the mixing temperature to 75°C and maintaining it for 30 minutes to achieve the grafting reaction; then, slowly adding the pretreated sulfonated polytetrafluoroethylene into the mixing system, controlling the temperature in the mixer to maintain at 50-60°C to avoid decomposition of the sulfonic acid group, and continuously stirring for 45 minutes to obtain a uniform compatibilizer complex.

[0045] S3, main resin premixing and interface modification; Step S3 specifically comprises: polycarbonate and polybutylene terephthalate are pretreated separately: polycarbonate is dried in a blast oven at 100°C for 4 hours to remove crystallization moisture, and polybutylene terephthalate is vacuum dried at 120°C, followed by a melt premixing method to improve the resin compatibility: the two resins are added to a mixer with a spiral stirring paddle in a mass ratio of 25-45%:20-35%, and premixed at a speed of 200-300 rpm under nitrogen protection. During the process, the compatibilizer compound prepared in step 2 is evenly sprinkled into the powder mixture three times, the mixing temperature is strictly controlled in the range of 180-200°C to prevent premature plasticization of the resin, and the mixing time is 40-60 minutes to form a primary premix.

[0046] S4, multiphase melt blending and dynamic crosslinking reaction; the premix is added to the screw extruder and melt blended under the following five-stage temperature gradient: the temperature of the first zone is 230-240°C, the temperature of the second zone is 245-255°C, the temperature of the third zone is 260-270°C, the temperature of the fourth zone is 275-285°C, and the temperature of the fifth zone is 280-290°C. The screw speed is set to 180-250rpm, and the pretreated nano-dioxide is added synchronously at the side feed port of the extruder. Silicone microspheres coated with silicon dioxide and triphenyl phosphate-modified graphene oxide are prepared. The nanospheres must pass through a vibrating screening device before entering the melt to ensure uniform particle size distribution. During the mixing process, the high shear effect of the twin-screw extruder is used to induce an in-situ cross-linking reaction between the sulfonic acid groups of sulfonated polytetrafluoroethylene and the terminal hydroxyl groups of polycarbonate. At the same time, the silane coupling agent of the mesoporous silica shell forms a chemical bond with the polybutylene terephthalate molecular chain. The mixing time is controlled at 6-8 minutes to ensure the stable formation of the phase structure.

[0047] S5, hot pressing the blend to form a post-processing, cooling the formed blend and pelletizing or forming a linear material according to demand, and drying and packaging;

[0048] The above-mentioned staged treatment realizes multi-level interaction between the components, and the dynamic cross-linking of sulfonated polytetrafluoroethylene and the directional guiding effect of the mesoporous structure improve the chemical corrosion resistance of the material.

[0049] Example 1

[0050] Raw material ratio

[0051] Polycarbonate 35%, PBT 28%, maleic anhydride grafted ethylene-acrylate copolymer 7.5%, sulfonated polytetrafluoroethylene 12%, nano-silica coated silicone microspheres 10%, triphenyl phosphate modified graphene oxide 3%, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite 1.5%, vinyltrimethoxysilane 1.8%, mesoporous silica 1.2%.

[0052] Preparation steps:

[0053] S1 preprocessing

[0054] Sulfonated polytetrafluoroethylene: vacuum drying at 50°C for 3 hours, dehydration <0.1wt%;

[0055] Modified graphene oxide: ultrasonic dispersion at 70 °C for 6 hours (triphenyl phosphate concentration 15 g / 100 mL, UV intensity 80 mJ / cm 2 );

[0056] Nanosphere surface activation: nitrogen protection treatment at 350°C, the grafting rate is optimized to 12wt%.

[0057] S2 compatibilizer compound

[0058] Maleic anhydride copolymer mixed with vinyltrimethoxysilane (spraying ratio 0.8%);

[0059] Blended with sulfonated polytetrafluoroethylene at 50°C for 55 minutes.

[0060] S3 main resin premix

[0061] PC and PBT were premixed at 190°C for 50 minutes (the compatibilizer was added in three batches).

[0062] S4 melt blending

[0063] Five-zone temperature gradient: 235 / 250 / 265 / 280 / 285°C, screw speed 220rpm;

[0064] The melt residence time was 7 minutes, and the nanospheres were evenly dispersed;

[0065] Example 2

[0066] Raw material ratio

[0067] Polycarbonate 42%, PBT 22%, maleic anhydride grafted ethylene-acrylate copolymer 4%, sulfonated polytetrafluoroethylene 18%, nano-silica coated silicone microspheres 5.8%, triphenyl phosphate modified graphene oxide 5.5%, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite 0.5%, vinyltrimethoxysilane 0.6%, mesoporous silica 1.6%.

[0068] Preparation steps:

[0069] S1 preprocessing

[0070] Sulfonated polytetrafluoroethylene: Dry at 50°C for 4 hours (sulfonic acid group content upper limit 0.35 mmol / g);

[0071] Modified graphene oxide: ultrasonic treatment at 80°C for 8 hours (20 g / 100 mL, UV 120 mJ / cm 2 );

[0072] Nanosphere activation: The grafting rate was adjusted to 8 wt% (low grafting density to accommodate high sulfonic acid groups).

[0073] S2 compatibilizer compound

[0074] Vinyltrimethoxysilane spraying ratio 0.2% (minimum limit);

[0075] The compatibilizer was mixed with sulfonated polytetrafluoroethylene at 60°C for 45 minutes.

[0076] S3 main resin premix

[0077] PC and PBT were premixed at 200°C for 4 hours (quick mixing to avoid thermal degradation).

[0078] S4 melt blending

[0079] Five-zone temperature gradient: 240 / 255 / 270 / 285 / 290°C, screw speed 250rpm;

[0080] The high-speed shearing of the screw promotes sulfonic acid-hydroxyl crosslinking.

[0081] Example 3

[0082] Raw material ratio

[0083] Polycarbonate 28%, PBT 34%, maleic anhydride grafted ethylene-acrylate copolymer 12%, sulfonated polytetrafluoroethylene 6.5%, nano-silica coated silicone microspheres 15%, triphenyl phosphate modified graphene oxide 1.8%, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite 3.2%, vinyltrimethoxysilane 2.5%, mesoporous silica 0.5%.

[0084] Preparation steps:

[0085] S1 preprocessing

[0086] Sulfonated polytetrafluoroethylene: Dry at 45°C for 2 hours (low thermal stability protection);

[0087] Modified graphene oxide: dispersed at 60°C for 4 hours (12 g / 100 mL, UV 50 mJ / cm 2 );

[0088] Nanosphere activation: grafting rate 15wt% (high grafting adapts to high nano content).

[0089] S2 compatibilizer compound

[0090] Vinyltrimethoxysilane spray ratio 1.2% (upper limit);

[0091] The maleic anhydride copolymer was reacted with sulfonated polytetrafluoroethylene at 75°C for 40 minutes.

[0092] S3 main resin premix

[0093] PC / PBT were premixed at 180°C for 60 minutes (focusing on PBT interface bonding).

[0094] S4 melt blending

[0095] Five-zone temperature gradient: 230 / 245 / 260 / 275 / 280°C, screw speed 180rpm;

[0096] Prolonging the mixing time to 8 minutes optimizes the phase morphology.

[0097] The performance test data of the three groups of embodiments of the present invention are as follows:

[0098] Test items Example 1 Example 2 Example 3 Tensile strength (MPa) 65±2.1 58±1.8 72±2.4 Flexural modulus (GPa) 2.8±0.1 2.5±0.09 3.2±0.15 <![CDATA[Izod impact strength (kJ / m 2 )]]> 35±1.5 28±1.2 42±1.8 Melt index (g / 10min) 12±0.3 18±0.5 9±0.2 Corrosion resistance-hydrochloric acid (10% 24h) Weight loss rate 0.7% Weight loss rate 0.3% Weight loss rate 1.2% Corrosion resistance-xylene (48h) No cracks on the surface Slight swelling Slightly bleached Heat deformation temperature (℃) 132±1.5 125±2.0 140±1.8 <![CDATA[Density (g / cm 3 )]]> 1.32±0.02 1.35±0.03 1.28±0.02

[0099] According to the table above:

[0100] Mechanical properties

[0101] Example 3 has the best tensile / bending properties due to its high PBT ratio (34%) and the best dispersion of nanospheres (15%);

[0102] The balanced ratio of Example 1 achieves a balance between strength and toughness (notch impact 35kJ / m 2 );

[0103] In Example 2, the high content of sulfonated polytetrafluoroethylene (18%) resulted in phase separation, and the mechanical properties were slightly lower.

[0104] Chemical resistance

[0105] Example 2 has the highest sulfonic acid group content and the best hydrochloric acid corrosion resistance (weight loss 0.3%);

[0106] Example 3 has the best resistance to solvent swelling due to its high interfacial coupling agent (silane 2.5%) and elastomer content.

[0107] Processing fluidity

[0108] Example 2 High melt index (18g / 10min) is suitable for rapid injection molding;

[0109] The high filler content in Example 3 leads to an increase in melt viscosity and the lowest fluidity.

[0110] Thermal stability

[0111] In Example 3, nanospheres and PBT were cross-linked synergistically, and the optimal heat deformation temperature was 140°C.

[0112] Example 2 The high thermal conductivity of sulfonated polytetrafluoroethylene improves heat dissipation and is easily desulfurized and decomposed at high temperatures.

[0113] In summary, the precise molar content of sulfonic acid groups (0.12-0.35 mmol / g) and the distribution characteristics of branched ends allow for an in-situ condensation reaction with the terminal hydroxyl groups of polycarbonate during the melt blending process to form a dynamic cross-linked network (PC-O-SO3-SPTFE). This network not only enhances the interfacial adhesion between PC and polybutylene terephthalate, but also the strong nucleophilicity of the sulfonic acid groups allows them to preferentially bond with polar molecules in the chemical medium, forming a local charge barrier and reducing the medium's permeation rate.

[0114] The γ-methacryloxypropyltrimethoxysilane on the shell surface forms Si-OC bonds with PBT ester groups through alkoxy hydrolysis, thereby enhancing the inorganic-organic interface bonding strength;

[0115] After intercalation with triphenyl phosphate, the interlayer spacing of graphene oxide increases to 1.2-2.3 nm. Its two-dimensional sheets form a parallel structure in the melt, physically blocking the permeation path of chemical media. Combined with the flame-retardant properties of triphenyl phosphate, PO· free radicals are generated during combustion, which synergize with the graphene carbon layers to form a dense char layer, achieving a coupled enhancement of flame retardancy and solvent resistance.

[0116] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A chemical-resistant PC / PBT alloy material, characterized by: The chemical-resistant PC / PBT alloy material is composed of the following components in mass percentage: Polycarbonate 25-45%, polybutylene terephthalate 20-35%, maleic anhydride grafted ethylene-acrylate copolymer 3-12%, sulfonated polytetrafluoroethylene 6-18%, nano-silica coated silicone microspheres 4-19%, triphenyl phosphate modified graphene oxide 0.5-6%, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite 0.1-3.5%, vinyltrimethoxysilane 0.2-3.2%, mesoporous silica 0.5-2.5%; The total mass percentage of the components is 100%.

2. The chemical-resistant PC / PBT alloy material according to claim 1, characterized in that: The molar content of sulfonic acid groups in the sulfonated polytetrafluoroethylene is 0.12-0.35 mmol / g, and its chemical structure comprises the following repeating units: -(CF2-CF2-) n -[CF2-CF(SO3H)-] m , where n:m = 3:1-5:1, and the sulfonic acid groups are distributed at the ends of the polymer side chains.

3. The chemical-resistant PC / PBT alloy material according to claim 1, characterized in that: The surface of the mesoporous silica shell is grafted with gamma-methacryloxypropyltrimethoxysilane, with a grafting rate of 8-15 wt %, a pore size distribution of 2-8 nm, and a pore direction perpendicular to the surface of the silicone core.

4. The chemical-resistant PC / PBT alloy material according to claim 1, characterized in that: 。 5. The chemical-resistant PC / PBT alloy material according to claim 1, characterized in that: The core layer of the nano-silica-coated silicone microspheres is polydimethylsiloxane, the shell layer is mesoporous silica, the core-shell mass ratio is 1:0.2-0.6, and the specific surface area is 200-400m 2 / g, the surface of the mesoporous silica shell is grafted with γ-methacryloxypropyltrimethoxysilane, the grafting rate is 8-15wt%, the pore size distribution is 2-8nm, and the pore direction is perpendicular to the silicone core surface.

6. The chemical-resistant PC / PBT alloy material according to claim 1, characterized in that: The intrinsic viscosity of the polycarbonate is 0.6-1.2 dL / g, the relative viscosity of the polybutylene terephthalate is 1.8-2.7, the weight average molecular weight of the polycarbonate is 28000-35000 g / mol, and the polycarbonate contains 3-8 mol% of bisphenol A cyclic oligomers, and the general formula of the cyclic structure is: C 15 H 16 O2-[O-C6H4-C(CH3)2-C6H4-OC(O)-O] n The bisphenol A skeleton consists of two benzene rings bridged by an isopropyl C(CH3)2, and the end is bonded with a carbonate group OC(O)-O, C 15 H 16 O2 reflects the residue after removing two hydroxyl groups from bisphenol A monomer.

7. A method for preparing a chemical-resistant PC / PBT alloy material, characterized in that: The method is used to prepare the chemical-resistant PC / PBT alloy material according to any one of claims 1 to 6, comprising the following steps: S1. Pretreatment and surface activation of key raw materials; S2. graded mixing of the compatibilizer and the functional additive; S3, main resin premixing and interface modification; S4, multiphase melt blending and dynamic cross-linking reaction; S5, hot pressing the blend to form a post-processing, cooling the formed blend and pelletizing or forming a linear material according to demand, and drying and packaging; The above-mentioned staged treatment realizes multi-level interaction between the components, and the dynamic cross-linking of sulfonated polytetrafluoroethylene and the directional guiding effect of the mesoporous structure improve the chemical corrosion resistance of the material.

8. The method for preparing a chemical-resistant PC / PBT alloy material according to claim 7, characterized in that: Step S1 is specifically as follows: placing the sulfonated polytetrafluoroethylene in a vacuum drying oven and drying it at 45-55°C for 2-4 hours to remove surface adsorbed water, at which point the molar content of the sulfonic acid group is stabilized within the range of 0.12-0.35 mmol / g; at the same time, performing ultrasonic dispersion pretreatment on the triphenyl phosphate-modified graphene oxide: in a reactor equipped with a constant temperature magnetic stirring device, dissolving triphenyl phosphate in anhydrous ethanol at a concentration of 12-20 g / 100 mL, then adding graphene oxide powder, and setting the ultraviolet irradiation intensity to 50-120 mJ / cm 2 , stirring continuously at 60-80°C for 4-8 hours, and after completion, vacuum filtration and drying in an 80°C oven to constant weight to obtain modified graphene oxide with an interlayer spacing of 1.2-2.3nm. Surface activation of nano-silica-coated silicone microspheres: placing them in a high-temperature furnace protected by nitrogen, heating them to 350°C at a rate of 5°C / min and keeping them warm for 20 minutes to make the surface-grafted γ-methacryloxypropyltrimethoxysilane bond more tightly, and the grafting rate is optimized to 8-15wt%; Step S2 is specifically as follows: pre-mixing the maleic anhydride grafted ethylene-acrylate copolymer with vinyltrimethoxysilane: first, adding the maleic anhydride grafted ethylene-acrylate copolymer particles into a closed drum mixer, stirring at a speed of 600 rpm, and spraying the vinyltrimethoxysilane solution onto the surface of the copolymer at a mass ratio of 0.2-1.2% by a constant flow pump, and then raising the mixing temperature to 75 ° C and maintaining it for 30 minutes to achieve the grafting reaction; then slowly adding the pretreated sulfonated polytetrafluoroethylene to the mixing system, controlling the temperature in the mixer to maintain at 50-60 ° C to avoid decomposition of the sulfonic acid group, and continuously stirring for 45 minutes to obtain a uniform compatibilizer complex.

9. The method for preparing a chemical-resistant PC / PBT alloy material according to claim 7, characterized in that: Step S3 specifically comprises: pre-treating polycarbonate and polybutylene terephthalate separately: polycarbonate is dried in a blast oven at 100°C for 4 hours to remove crystallization moisture, and polybutylene terephthalate is vacuum dried at 120°C, followed by a melt premixing method to improve resin compatibility: the two resins are added to a mixer with a spiral stirring blade in a mass ratio of 25-45%:20-35%, and pre-mixed at a speed of 200-300 rpm under nitrogen protection. During the process, the compatibilizer compound prepared in step 2 is evenly sprinkled into the powder mixture three times, and the mixing temperature is strictly controlled in the range of 180-200°C to prevent premature plasticization of the resin. The mixing time is 40-60 minutes to form a primary premix; Step S4 is specifically as follows: the premix is added to the screw extruder and melt blended under the following five-stage temperature gradient: the temperature of the first zone is 230-240 ° C, the temperature of the second zone is 245-255 ° C, the temperature of the third zone is 260-270 ° C, the temperature of the fourth zone is 275-285 ° C, the temperature of the fifth zone is 280-290 ° C, the screw speed is set to 180-250 rpm, and the pretreated nano-silica coating is added synchronously at the side feed port of the extruder. Silicone microspheres and triphenyl phosphate modified graphene oxide, where the nano-microspheres need to pass through a vibrating screening device before entering the melt to ensure uniform particle size distribution. During the mixing process, the high shear effect of the twin-screw is used to induce an in-situ cross-linking reaction between the sulfonic acid groups of sulfonated polytetrafluoroethylene and the terminal hydroxyl groups of polycarbonate. At the same time, the silane coupling agent of the mesoporous silica shell forms a chemical bond with the polybutylene terephthalate molecular chain. The mixing time is controlled at 6-8 minutes to ensure the stable formation of the phase structure.