Strong-acid-and-alkali-resistant plastic material for fume hood surface decoration and preparation method of strong-acid-and-alkali-resistant plastic material

Abstract

The invention discloses a strong acid and alkali resistant plastic material for fume hood surface decoration and a preparation method of the strong acid and alkali resistant plastic material, belongs to the technical field of plastic material processing, and aims at solving the technical problem that in the prior art, the acid and alkali resistance and the bending modulus of a plastic material for fume hood surface decoration need to be further improved. The preparation method specifically comprises the following steps: stirring amino-modified fluorosilicone resin, paraformaldehyde and 1, 4-dioxane in a reaction kettle, dropwise adding an anacardol solution, heating the reaction kettle to 85-95 DEG C, carrying out heat preservation reaction for 6-8 hours, and carrying out post-treatment to obtain the anacardol-based benzoxazine resin. Perfluoro-modified polysiloxane benzoxazine is prepared, naphthalene-containing epoxy resin and imidazole-modified silicon carbide microspheres are compounded, in-situ catalysis synergistic curing is carried out by using filler interface imidazole, a compact organic-inorganic hybrid interpenetrating network is constructed, and the strong acid and alkali corrosion resistance and bending modulus of the material are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of plastic material processing technology, specifically to a plastic material for decorating the surface of a fume hood that is resistant to strong acids and alkalis, and its preparation method. Background Technology

[0002] As a crucial local exhaust system in chemical laboratories, laboratory fume hoods are constantly exposed to high concentrations of acids, alkalis, strong oxidants, and organic solvents. With the evolution of modern chemical analysis techniques and the increasing intensity of experiments, extremely stringent requirements are placed on the chemical corrosion resistance of the plastic materials used for fume hood decoration. The current industry trend has shifted from early ceramics and natural stone to high-performance polymer composite materials, focusing on improving the chemical inertness and physical stability of materials under extreme chemical environments. In particular, for highly corrosive media such as hydrofluoric acid and concentrated nitric acid, traditional fume hood materials are now being developed to address issues such as easy etching and blistering, aiming to achieve maintenance-free and high reliability throughout the material's entire lifecycle.

[0003] Currently, fume hood cabinet surface decoration materials mostly use phenolic resin solid chemical chemical boards, epoxy resin boards, or polypropylene (PP) boards. In order to further improve the corrosion resistance and mechanical strength of these matrix resins, physical blending is often used for reinforcement. Zeolite imidazole ester framework structural material (ZIF-8), as a typical representative of metal-organic framework materials (MOFs), has excellent chemical stability, regular pore structure and potential surface catalytic activity, and has also been gradually used for the functional modification of polymer materials. However, whether it is traditional filler or ZIF-8, if only physical blending is used, due to the large difference in surface energy between filler and resin, poor interfacial wettability, it is difficult to achieve dense bonding. Under the action of mechanical external force, it is very easy to peel off or generate microcracks, resulting in the exposure of the internal matrix, which in turn leads to the overall failure of the material.

[0004] In existing technologies, due to the natural incompatibility between the hydrophilic inorganic filler and the hydrophobic resin, the two lack chemical bonding and rely only on weak physical interlocking, resulting in microscopic defects at the interface. When exposed to strong acids and alkalis for a long time, the corrosive medium can penetrate through the interface gaps via capillary action, leading to internal swelling and interface dissociation failure. In addition, traditional single resin systems are unable to balance the contradiction between high crosslinking density and high toughness, resulting in high internal stress and high brittleness in highly dense materials, which are prone to brittle fracture under thermal shock or mechanical stress conditions in fume hoods.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a plastic material for fume hood surface decoration that is resistant to strong acids and alkalis and its preparation method, so as to solve the technical problem that the acid and alkali resistance and flexural modulus of the plastic material for fume hood surface decoration in the prior art need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solution: a method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis, comprising the following steps:

[0008] S1. Place perfluorooctyltrimethoxysilane, γ-aminopropyltriethoxysilane, ethanol and deionized water in a reaction vessel and stir. Add tetraethyl orthosilicate dropwise. Heat the reaction vessel to reflux and keep it at this temperature for 4-6 hours. After post-treatment, obtain an amino-modified fluorosilicone resin solution.

[0009] S2. Place amino-modified fluorosilicone resin, paraformaldehyde and 1,4-dioxane in a reaction vessel and stir. Add cashew phenol solution dropwise. Heat the reaction vessel to 85-95℃ and keep it at the temperature for 6-8 hours. After post-treatment, cashew phenol benzoxazine resin is obtained.

[0010] S3. Place cashew phenol-based benzoxazine resin and naphthalene-containing epoxy resin in a reaction vessel, heat the reaction vessel to 100-110℃, melt and mix for 20-30 min, add imidazole-modified silicon carbide microspheres, and shear and stir at high speed at 1000-1500 r / min for 30-40 min. Then degas under a vacuum of -0.09 MPa to -0.1 MPa for 10-15 min, and heat to cure to obtain plastic material for fume hood cabinet surface decoration.

[0011] Further, in step S1, the ratio of perfluorooctyltrimethoxysilane, γ-aminopropyltriethoxysilane, ethanol, deionized water, and tetraethyl orthosilicate is 10-15g:20-25g:120-150mL:25-35mL:40-50g. The post-processing step includes: after the reaction is completed, wait for the reaction system to cool to room temperature, transfer the reaction solution to a rotary evaporator at a temperature of 40-50℃, remove half of the solvent by rotary evaporation under reduced pressure, add anhydrous ethanol to adjust the solid content to 40%-60%, and obtain an amino-modified fluorosilicone resin solution.

[0012] Further, in step S2, the ratio of the amino-modified fluorosilicone resin, paraformaldehyde, 1,4-dioxane, and cashew nut shell powder solution is 6-8g:0.3-0.5g:80-100mL:18-20mL. The cashew nut shell powder solution is composed of cashew nut shell powder and 1,4-dioxane in a ratio of 1g:2mL. The post-processing step includes: after the reaction is completed, the reaction system is cooled to room temperature, and the reaction solution is transferred to a rotary evaporator at a temperature of 80-90℃ to remove the solvent by rotary evaporation, thereby obtaining cashew nut shell powder benzoxazine resin.

[0013] Further, in step S3, the weight ratio of the cashew phenol-benzoxazine resin, the naphthalene-containing epoxy resin, and the imidazole-modified silicon carbide microspheres is 80-100:30-50:10-15. The specific steps of the temperature curing are as follows: the reaction slurry is injected into a mold preheated to 120°C in an oven, cured at 120-130°C for 1.5-2.5 hours, cured at 150-160°C for 2-3 hours, cured at 190-200°C for 1-2 hours, and then demolded after natural cooling to room temperature to obtain the plastic material for fume hood cabinet surface decoration.

[0014] Furthermore, the preparation method of the naphthalene-containing epoxy resin is as follows: 1,4-dihydroxynaphthalene and epichlorohydrin are placed in a reaction vessel under nitrogen atmosphere and stirred, tetrabutylammonium bromide is added, the reaction vessel is heated to 75-85℃, sodium hydroxide aqueous solution is slowly added dropwise, the reaction is kept at the temperature for 1-2 hours, and the naphthalene-containing epoxy resin is obtained after post-treatment.

[0015] The reaction formula for preparing naphthalene-containing epoxy resin is as follows:

[0016]

[0017] Furthermore, the ratio of 1,4-dihydroxynaphthalene, epichlorohydrin, tetrabutylammonium bromide, and sodium hydroxide aqueous solution is 4-6g:6-10g:0.1-0.2g:10-12mL, and the concentration of sodium hydroxide aqueous solution is 25-30wt%. The post-processing steps include: after the reaction is completed, wait for the reaction system to cool to room temperature, add half the volume of toluene to the reaction solution, let it stand and separate the liquids, wash the organic phase with saturated sodium chloride 1-3 times, transfer it to a rotary evaporator at a temperature of 75-85℃, and evaporate until no liquid is collected to obtain naphthalene-containing epoxy resin.

[0018] Furthermore, the imidazole-modified silicon carbide microspheres are prepared by the following steps:

[0019] A1. Tannic acid and deionized water were placed in a reaction vessel and stirred. Silicon carbide microspheres were added and stirred at room temperature for 3-5 minutes. Zinc nitrate hexahydrate aqueous solution was added and ammonia was added to adjust the pH to 8±0.2. The mixture was stirred at room temperature for 25-35 minutes. Graphene oxide aqueous dispersion was added and post-processed to obtain modified silicon carbide microspheres.

[0020] A2. The modified silicon carbide microspheres and methanol were dispersed in a reaction vessel, and 2-methylimidazolium methanol solution was added. The reaction vessel was heated to 30-50℃ and stirred for 4-6 hours. The imidazolium-modified silicon carbide microspheres were obtained after post-treatment.

[0021] Further, in step A1, the ratio of tannic acid, deionized water, silicon carbide microspheres, zinc nitrate hexahydrate aqueous solution, and graphene oxide aqueous dispersion is 0.4-0.6g:100-120mL:9-11g:18-20mL:80-100mL, the concentration of zinc nitrate hexahydrate aqueous solution is 0.03-0.05 mol / L, the concentration of graphene oxide aqueous dispersion is 1-2mg / mL, and the concentration of ammonia is 1-2mol / L. The post-treatment step includes: after the reaction is completed, filtration is performed, and the filter cake is washed 2-4 times with deionized water and methanol to obtain alcohol-moistened modified silicon carbide microspheres.

[0022] Further, in step A2, the ratio of the modified silicon carbide microspheres, methanol, and 2-methylimidazole methanol solution is 8-10g:100-150mL:30-50mL, and the 2-methylimidazole methanol solution is composed of 2-methylimidazole and methanol at a ratio of 1g:10mL. The post-processing steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed 2-3 times with anhydrous ethanol, and dried in a vacuum oven at 60-80℃ to constant weight to obtain imidazole-modified silicon carbide microspheres.

[0023] The present invention also proposes a plastic material for decorating the surface of a fume hood that is resistant to strong acids and alkalis. The plastic material for decorating the surface of a fume hood that is resistant to strong acids and alkalis is prepared by a method for preparing plastic materials for decorating the surface of a fume hood that is resistant to strong acids and alkalis.

[0024] The present invention has the following beneficial effects:

[0025] 1. This invention constructs an inorganic polysiloxane framework using sol-gel technology and chemically bonds low-surface-energy perfluoroalkyl side chains with a bio-based benzoxazine structure. Simultaneously, a rigid naphthalene ring epoxy resin is introduced for synergistic modification. The extremely low surface tension of the perfluoroalkyl group imparts excellent hydrophobic and oleophobic properties to the material, significantly reducing the wetting and adhesion of corrosive media on the material surface. The synergistic support of the inorganic siloxane framework and the rigid naphthalene ring greatly enhances the mechanical modulus of the matrix. Furthermore, the internal toughening effect of the long aliphatic chains of cashew phenol effectively balances the brittleness caused by high crosslinking density. This organic-inorganic hybrid interpenetrating network structure achieves a high degree of unity between rigidity, toughness, and chemical corrosion resistance.

[0026] 2. This invention also employs a layer-by-layer assembly strategy to prepare imidazole-modified silicon carbide microspheres with a core-shell structure. Utilizing the universal interfacial adhesion and metal complexation capabilities of tannic acid, graphene oxide and ZIF-8 metal-organic framework are in situ anchored onto the surface of a highly thermally conductive silicon carbide core. The stacking of graphene oxide sheets creates a microscopic maze effect, significantly extending the diffusion path of acidic and alkaline media and organic solvents within the material. On the other hand, the porous and hydrophobic properties of the ZIF-8 framework further shield against the penetration of corrosive agents and, in conjunction with the silicon carbide microspheres, construct an efficient phonon transport channel. This not only endows the plastic material used for fume hood surface decoration with excellent barrier properties but also effectively eliminates local heat accumulation, avoiding thermal stress concentration and aging caused by localized high temperatures during experimental operations, and significantly extending the service life of the surface material in complex chemical environments.

[0027] 3. This invention also utilizes the 2-methylimidazolium ligand in the ZIF-8 layer on the filler surface as a heterogeneous nucleophilic catalytic center to achieve in-situ directional curing of the resin matrix at the filler interface. During the high-temperature molding process, the surface-enriched imidazolium groups can efficiently catalyze the thermal ring-opening polymerization of benzoxazine rings and induce the epoxy groups of naphthalene-containing epoxy resin to participate in the copolymerization reaction, promoting the direct growth of polymer chains on the filler surface through chemical bonding. This constructs a dense and defect-free interfacial cross-linking structure between the organic resin matrix and the inorganic filler. This in-situ catalytic and chemical bonding mechanism overcomes the defects of weak interfacial bonding and easy generation of micropores in traditional physical blending, reduces the capillary penetration of corrosive media along the interfacial gaps, and ensures that the material does not experience surface blistering, coating peeling, cracking, or powdering under long-term exposure to strong acid and alkali cleaning and mechanical friction. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The paraformaldehyde used in this invention was purchased from Jinan Dahui Chemical Technology Co., Ltd., with a density of 1.45 (g / mL, 20℃), and an appearance of white crystalline powder. Its CAS number is 30525-89-4.

[0030] The silicon carbide microspheres used in this invention were purchased from Wuhan Meiqilin New Materials Co., Ltd., and have a density of 3.10-3.15 g / cm³. 3 Model number MQ-885, silicon carbide purity is 99%;

[0031] The commercially available bisphenol A epoxy resin used in this invention was purchased from Cansen Chemical New Materials (Shenzhen) Co., Ltd., with the brand name NPEL-128 and a solid content of 95%.

[0032] Example 1

[0033] This embodiment provides a method for preparing imidazole-modified silicon carbide microspheres, including the following steps:

[0034] Step I: Preparation of modified silicon carbide microspheres

[0035] Weigh 4g of tannic acid and 100mL of deionized water and place them in a reaction vessel and stir. Add 90g of silicon carbide microspheres and stir at room temperature for 3min. Add 180mL of 0.03mol / L zinc nitrate hexahydrate aqueous solution and adjust the pH to 7.8 with ammonia. Stir at room temperature for 25min. Add 800mL of 1mg / mL graphene oxide aqueous dispersion. After the reaction is complete, filter the mixture and wash the filter cake twice with deionized water and methanol to obtain alcohol-moistened modified silicon carbide microspheres.

[0036] Step II: Preparation of imidazole-modified silicon carbide microspheres

[0037] Mix 2-methylimidazole and methanol at a ratio of 1g:10mL to obtain a 2-methylimidazole methanol solution for later use.

[0038] Weigh 80g of modified silicon carbide microspheres and 1000mL of methanol and disperse them in a reaction vessel. Add 300mL of 2-methylimidazole methanol solution, heat the reaction vessel to 30℃, and stir for 4h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake twice with anhydrous ethanol, and dry it in a vacuum oven at 60℃ to constant weight to obtain imidazole modified silicon carbide microspheres.

[0039] Utilizing the universal adhesive and complexing properties of tannic acid, a tannic acid coating rich in phenolic hydroxyl groups was constructed on the surface of silicon carbide under weakly alkaline conditions. Zinc ions were anchored through coordination bonds, and graphene oxide was then assembled using hydrogen bonding and coordination interactions to construct modified silicon carbide microspheres. Subsequently, the interfacial activity was maintained by solvent displacement. Using pre-fixed zinc ions as metal central nodes and 2-methylimidazole as an organic ligand, coordination-oriented self-assembly occurred in a methanol solvothermal system, realizing the in-situ growth and coating of ZIF-8 crystals on the surface of the microspheres, and finally forming imidazole-modified silicon carbide microspheres with a core-shell structure.

[0040] By utilizing the synergistic anchoring effect of tannic acid and zinc ions, graphene oxide is assembled onto the surface of silicon carbide to construct a microscopic labyrinth barrier that blocks the penetration of corrosive media and improves heat dissipation efficiency. Combined with the in-situ growth of the ZIF-8 framework, the spatial structure of graphene oxide is locked and hydrophobicity is imparted. Using a blend system of cashew phenol-based benzoxazine resin and naphthalene-containing epoxy resin as the matrix, the 2-methylimidazolium ligand in the modified ZIF-8 layer on the silicon carbide surface is used as the in-situ curing catalytic center to directionally induce the synergistic ring-opening polymerization and etherification reaction of benzoxazine ring and epoxy group at the interface. This promotes the in-situ growth of resin polymer chains directly on the filler surface through chemical bonding, eliminating defects at the organic and inorganic phase interface and constructing a dense interfacial cross-linked structure with deep integration of matrix and filler. This significantly enhances the structural stability of the cabinet material under long-term chemical cleaning and mechanical friction environments, effectively preventing surface blistering, cracking, or peeling.

[0041] Example 2

[0042] This embodiment provides a method for preparing imidazole-modified silicon carbide microspheres, including the following steps:

[0043] Step I: Preparation of modified silicon carbide microspheres

[0044] Weigh out 5g of tannic acid and 1100mL of deionized water and place them in a reaction vessel and stir. Add 100g of silicon carbide microspheres and stir at room temperature for 4min. Add 190mL of 0.04mol / L zinc nitrate hexahydrate aqueous solution and adjust the pH to 8 with ammonia. Stir at room temperature for 30min and add 900mL of 1.5mg / mL graphene oxide aqueous dispersion. After the reaction is complete, filter the mixture and wash the filter cake three times with deionized water and methanol to obtain alcohol-moistened modified silicon carbide microspheres.

[0045] Step II: Preparation of imidazole-modified silicon carbide microspheres

[0046] Mix 2-methylimidazole and methanol at a ratio of 1g:10mL to obtain a 2-methylimidazole methanol solution for later use.

[0047] Weigh 90g of modified silicon carbide microspheres and 1250mL of methanol and disperse them in a reaction vessel. Add 400mL of 2-methylimidazole methanol solution. Heat the reaction vessel to 40℃ and stir for 5h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake three times with anhydrous ethanol, and dry it in a vacuum oven at 70℃ to constant weight to obtain imidazole-modified silicon carbide microspheres.

[0048] Example 3

[0049] This embodiment provides a method for preparing imidazole-modified silicon carbide microspheres, including the following steps:

[0050] Step I: Preparation of modified silicon carbide microspheres

[0051] Weigh 6g of tannic acid and 1200mL of deionized water and place them in a reaction vessel and stir. Add 110g of silicon carbide microspheres and stir at room temperature for 5min. Add 200mL of 0.05mol / L zinc nitrate hexahydrate aqueous solution and adjust the pH to 8.2 with ammonia. Stir at room temperature for 35min and add 1000mL of 2mg / mL graphene oxide aqueous dispersion. After the reaction is complete, filter the mixture and wash the filter cake 4 times with deionized water and methanol to obtain alcohol-moistened modified silicon carbide microspheres.

[0052] Step II: Preparation of imidazole-modified silicon carbide microspheres

[0053] Mix 2-methylimidazole and methanol at a ratio of 1g:10mL to obtain a 2-methylimidazole methanol solution for later use.

[0054] Weigh 100g of modified silicon carbide microspheres and 1500mL of methanol and disperse them in a reaction vessel. Add 500mL of 2-methylimidazole methanol solution, heat the reaction vessel to 50℃, and stir for 6h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake three times with anhydrous ethanol, and dry it in a vacuum oven at 80℃ to constant weight to obtain imidazole modified silicon carbide microspheres.

[0055] Example 4

[0056] This embodiment provides a method for preparing a naphthalene-containing epoxy resin, including the following steps:

[0057] Weigh 40g of 1,4-dihydroxynaphthalene and 60g of epichlorohydrin and place them in a reaction vessel under nitrogen atmosphere and stir. Add 1g of tetrabutylammonium bromide and heat the reaction vessel to 75℃. Slowly add 100mL of 25wt% sodium hydroxide aqueous solution and keep the reaction at this temperature for 1h. After the reaction is complete, wait for the reaction system to cool to room temperature and add half the volume of toluene of the reaction solution. Let the mixture stand and separate the liquids. Wash the organic phase once with saturated sodium chloride and transfer it to a rotary evaporator at 75℃. Evaporate until no liquid is collected to obtain naphthalene-containing epoxy resin.

[0058] Under the phase transfer catalysis of tetrabutylammonium bromide, the phenolic hydroxyl group of 1,4-dihydroxynaphthalene is deprotonated by sodium hydroxide to generate a highly active naphthox anion. This naphthox anion attacks epichlorohydrin to undergo a nucleophilic ring-opening addition reaction to generate a chlorohydrin ether intermediate. Subsequently, under alkaline conditions, an intramolecular dehydrochlorination ring-closure reaction occurs to convert the phenolic hydroxyl group into a glycidyl ether structure, thus obtaining a naphthalene-containing epoxy resin.

[0059] By introducing a rigid polycyclic naphthalene skeleton, the mechanical modulus of the plastic material matrix used for fume hood surface decoration is significantly improved. At the same time, the highly active glycidyl ether groups after conversion are used to construct a highly dense three-dimensional cross-linked network, which greatly reduces the material's permeability and endows it with excellent chemical inertness, effectively blocking the corrosion of strong acids, alkalis and organic solvents in the laboratory.

[0060] Example 5

[0061] This embodiment provides a method for preparing a naphthalene-containing epoxy resin, including the following steps:

[0062] Weigh 50g of 1,4-dihydroxynaphthalene and 80g of epichlorohydrin and place them in a reaction vessel under nitrogen atmosphere and stir. Add 1.5g of tetrabutylammonium bromide and heat the reaction vessel to 80℃. Slowly add 110mL of 27.5wt% sodium hydroxide aqueous solution and keep the reaction at this temperature for 1.5h. After the reaction is complete, wait for the reaction system to cool to room temperature and add half the volume of toluene of the reaction solution. Let it stand and separate the liquids. Wash the organic phase twice with saturated sodium chloride and transfer it to a rotary evaporator at 80℃. Evaporate until no liquid is collected to obtain naphthalene-containing epoxy resin.

[0063] Example 6

[0064] This embodiment provides a method for preparing a naphthalene-containing epoxy resin, including the following steps:

[0065] Weigh 60g of 1,4-dihydroxynaphthalene and 100g of epichlorohydrin and place them in a reaction vessel under nitrogen atmosphere and stir. Add 2g of tetrabutylammonium bromide and heat the reaction vessel to 85℃. Slowly add 120mL of 30wt% sodium hydroxide aqueous solution and keep the reaction at this temperature for 2h. After the reaction is complete, wait for the reaction system to cool to room temperature and add half the volume of toluene of the reaction solution. Let it stand and separate the liquids. Wash the organic phase three times with saturated sodium chloride and transfer it to a rotary evaporator at 85℃. Evaporate until no liquid is collected to obtain naphthalene-containing epoxy resin.

[0066] Example 7

[0067] This embodiment provides a method for preparing a plastic material for decorating the surface of a fume hood that is resistant to strong acids and alkalis, including the following steps:

[0068] Step 1: Prepare amino-modified fluorosilicone resin solution

[0069] Weigh out 100g of perfluorooctyltrimethoxysilane, 200g of γ-aminopropyltriethoxysilane, 1200mL of ethanol and 250mL of deionized water and place them in a reaction vessel and stir. Add 400g of tetraethyl orthosilicate dropwise. Heat the reaction vessel to reflux and keep it at that temperature for 4 hours. After the reaction is complete, wait for the reaction system to cool to room temperature and transfer the reaction solution to a rotary evaporator at 40℃. Remove half of the solvent by rotary evaporation under reduced pressure. Add anhydrous ethanol to adjust the solid content to 40% to obtain an amino-modified fluorosilicone resin solution.

[0070] Step 2: Preparation of cashew phenol-benzoxazine resin

[0071] Cashew phenol and 1,4-dioxane were mixed evenly at a ratio of 1g:2mL to obtain a cashew phenol solution for later use.

[0072] Weigh out 60g of amino-modified fluorosilicone resin, 3g of paraformaldehyde and 800mL of 1,4-dioxane and place them in a reaction vessel and stir. Add 180mL of cashew phenol solution dropwise. Heat the reaction vessel to 85℃ and keep it at that temperature for 6h. After the reaction is complete, wait for the reaction system to cool to room temperature and transfer the reaction solution to a rotary evaporator at 80℃ to remove the solvent by rotary evaporation to obtain cashew phenol-based benzoxazine resin.

[0073] Step 3: Prepare plastic materials for fume hood cabinet surface decoration

[0074] Weigh 800g of cashew phenol benzoxazine resin and 30g of naphthalene-containing epoxy resin prepared in Example 4 and place them in a reaction vessel. Heat the reaction vessel to 100°C and melt-mix for 20 min. Add 100g of imidazole-modified silicon carbide microspheres prepared in Example 1 and shear and stir at 1000 r / min for 30 min. Then degas under a vacuum of -0.09 MPa for 10 min. Pour the reaction slurry into a mold preheated to 120°C in an oven and cure at 120°C for 1.5 h, 150°C for 2 h, and 190°C for 1 h. After naturally cooling to room temperature, demold to obtain plastic material for fume hood cabinet surface decoration.

[0075] Perfluorooctyltrimethoxysilane, γ-aminopropyltriethoxysilane, and tetraethyl orthosilicate first undergo a hydrolysis reaction with water molecules to convert the alkoxy groups on the silicon atoms into highly reactive silanol groups. Subsequently, the silanol groups undergo dehydration and de-alcoholization polycondensation reactions with each other or with residual alkoxy groups to construct a polysiloxane network framework with Si-O-Si bonds as the inorganic backbone. Simultaneously, perfluorooctyl and aminopropyl groups are chemically bonded to the framework as organic side chains, yielding an amino-modified fluorosilicone resin solution rich in active amino groups and fluorocarbon segments. Subsequently, the amino modification... The amino groups in the fluorosilicone resin solution serve as the nitrogen source, undergoing a Mannich condensation ring-closing reaction with cashew phenol and paraformaldehyde to synthesize cashew phenol-based benzoxazine resin grafted onto an inorganic silicon-oxygen framework. Furthermore, imidazole-modified imidazole groups on the surface of silicon carbide microspheres are used as nucleophilic catalytic centers to catalyze the thermal ring-opening polymerization of the benzoxazine ring at high temperature, inducing the epoxy groups containing naphthalene epoxy resin to participate in co-curing. Through ring-opening addition and etherification reactions, an interpenetrating three-dimensional cross-linked network comprising rigid naphthalene rings, flexible long carbon chains, and fluorosilicone segments is constructed.

[0076] By constructing a polysiloxane inorganic framework grafted with perfluoroalkyl groups through hydrolysis and condensation, the material is endowed with excellent low surface energy hydrophobic and oleophobic properties, effectively inhibiting the residue and penetration of chemical reagents. Then, a bio-based cashew phenol benzoxazine structure is introduced, which is used to toughen the resin matrix and ensure low curing shrinkage. Finally, with the help of modified silicon carbide microspheres to catalyze the synergistic copolymerization of naphthalene-containing epoxy resin, a highly dense organic-inorganic hybrid cross-linked network is formed, which significantly improves the surface hardness, wear resistance and corrosion resistance to extreme acid and alkali environments of the cabinet surface.

[0077] Example 8

[0078] This embodiment provides a method for preparing a plastic material for decorating the surface of a fume hood that is resistant to strong acids and alkalis, including the following steps:

[0079] Step 1: Prepare amino-modified fluorosilicone resin solution

[0080] Weigh out 125g of perfluorooctyltrimethoxysilane, 225g of γ-aminopropyltriethoxysilane, 1350mL of ethanol and 300mL of deionized water and place them in a reaction vessel and stir. Add 450g of tetraethyl orthosilicate dropwise. Heat the reaction vessel to reflux and keep it at that temperature for 5 hours. After the reaction is complete, wait for the reaction system to cool to room temperature and transfer the reaction solution to a rotary evaporator at 45℃. Remove half of the solvent by rotary evaporation under reduced pressure. Add anhydrous ethanol to adjust the solid content to 50% to obtain an amino-modified fluorosilicone resin solution.

[0081] Step 2: Preparation of cashew phenol-benzoxazine resin

[0082] Cashew phenol and 1,4-dioxane were mixed evenly at a ratio of 1g:2mL to obtain a cashew phenol solution for later use.

[0083] Weigh out 70g of amino-modified fluorosilicone resin, 4g of paraformaldehyde and 900mL of 1,4-dioxane and place them in a reaction vessel and stir. Add 190mL of cashew phenol solution dropwise. Heat the reaction vessel to 90℃ and keep it at that temperature for 7h. After the reaction is complete, wait for the reaction system to cool to room temperature and transfer the reaction solution to a rotary evaporator at 85℃ to remove the solvent by rotary evaporation to obtain cashew phenol-based benzoxazine resin.

[0084] Step 3: Prepare plastic materials for fume hood cabinet surface decoration

[0085] Weigh 900g of cashew phenol benzoxazine resin and 400g of naphthalene-containing epoxy resin prepared in Example 5 and place them in a reaction vessel. Heat the reaction vessel to 105°C and melt-mix for 25 min. Add 125g of imidazole-modified silicon carbide microspheres prepared in Example 2 and shear and stir at 1250 r / min for 35 min. Then degas under a vacuum of -0.095 MPa for 13 min. Pour the reaction slurry into a mold preheated to 120°C in an oven and cure at 125°C for 2 h, 155°C for 2.5 h, and 195°C for 1.5 h. After naturally cooling to room temperature, demold to obtain plastic material for fume hood cabinet surface decoration.

[0086] Example 9

[0087] This embodiment provides a method for preparing a plastic material for decorating the surface of a fume hood that is resistant to strong acids and alkalis, including the following steps:

[0088] Step 1: Prepare amino-modified fluorosilicone resin solution

[0089] Weigh out 150g of perfluorooctyltrimethoxysilane, 250g of γ-aminopropyltriethoxysilane, 1500mL of ethanol and 350mL of deionized water and place them in a reaction vessel and stir. Add 500g of tetraethyl orthosilicate dropwise. Heat the reaction vessel to reflux and keep it at that temperature for 6 hours. After the reaction is complete, wait for the reaction system to cool to room temperature and transfer the reaction solution to a rotary evaporator at 50℃. Remove half of the solvent by rotary evaporation under reduced pressure. Add anhydrous ethanol to adjust the solid content to 60% to obtain an amino-modified fluorosilicone resin solution.

[0090] Step 2: Preparation of cashew phenol-benzoxazine resin

[0091] Cashew phenol and 1,4-dioxane were mixed evenly at a ratio of 1g:2mL to obtain a cashew phenol solution for later use.

[0092] Weigh out 80g of amino-modified fluorosilicone resin, 5g of paraformaldehyde and 1000mL of 1,4-dioxane and place them in a reaction vessel and stir. Add 200mL of cashew phenol solution dropwise. Heat the reaction vessel to 95℃ and keep it at that temperature for 8h. After the reaction is complete, wait for the reaction system to cool to room temperature and transfer the reaction solution to a rotary evaporator at 90℃ to remove the solvent by rotary evaporation to obtain cashew phenol-based benzoxazine resin.

[0093] Step 3: Prepare plastic materials for fume hood cabinet surface decoration

[0094] Weigh 1000g of cashew phenol benzoxazine resin and 500g of naphthalene-containing epoxy resin prepared in Example 6 and place them in a reaction vessel. Heat the reaction vessel to 110°C and melt-mix for 30 min. Add 150g of imidazole-modified silicon carbide microspheres prepared in Example 3 and shear and stir at 1500 r / min for 40 min. Then degas under a vacuum of -0.1 MPa for 15 min. Pour the reaction slurry into a mold preheated to 120°C in an oven. Cure at 130°C for 2.5 h, at 150-160°C for 3 h, and at 200°C for 2 h. After naturally cooling to room temperature, demold to obtain plastic material for fume hood cabinet surface decoration.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 9 is that, in step (2) when preparing the cashew phenol benzoxazine resin, the use of amino-modified fluorosilicone resin was omitted.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Example 9 is that, in step (3) when preparing the plastic material for the fume hood cabinet surface decoration, an equal amount of commercially available bisphenol A epoxy resin is used instead of naphthalene-containing epoxy resin.

[0099] Comparative Example 3

[0100] The difference between this comparative example and Example 9 is that, in step (3) when preparing the plastic material for the fume hood cabinet surface decoration, modified silicon carbide microspheres are used in an equal amount to replace imidazole-modified silicon carbide microspheres.

[0101] Performance testing:

[0102] The corrosion resistance of the plastic materials for fume hood surface decoration prepared in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 11547-2008 "Determination of the resistance of plastics to liquid chemical reagents"; the flexural modulus of the plastic materials for fume hood surface decoration prepared in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 9341-2008 "Determination of the flexural properties of plastics";

[0103] Corrosion resistance: Plastic material samples (50mm×25mm×3mm) for decorative fume hood surfaces prepared in Examples 7-9 and Comparative Examples 1-3 were selected and placed in 40% concentrated sulfuric acid (strong acid) and 40% sodium hydroxide solution (strong alkali) respectively. They were immersed at room temperature (25℃) for 168h. After immersion, they were taken out, washed, and dried to constant weight. Data were recorded, and the mass retention rate and volume expansion rate after acid and alkali immersion were calculated. The appearance integrity was also judged.

[0104] Flexural modulus: Plastic material samples (80mm×10mm×4mm) for decorative fume hood surfaces prepared in Examples 7-9 and Comparative Examples 1-3 were selected. The three-point bending method was used, the test speed was 2mm / min, the test was conducted at room temperature, and the flexural modulus was recorded. The specific data are shown in Table 1.

[0105] Table 1 - Performance Test Data for Each Sample

[0106]

[0107] Data Analysis:

[0108] Comparative analysis of the data in the above tables revealed that the flexural modulus of the plastic material for fume hood surface decoration prepared by this invention is 3800 MPa. After being soaked in strong acid, the mass retention rate is 99.2%, the volume expansion rate is 0.22%, and there is no blistering, cracking, or delamination. After being soaked in strong alkali, the mass retention rate is 99.3%, the volume expansion rate is 0.29%, and there is no blistering, cracking, or delamination. All data are superior to the comparative example.

[0109] This invention first constructs a perfluoroalkyl-grafted polysiloxane inorganic framework using the sol-gel method, and then synthesizes a cashew phenol-based benzoxazine resin grafted onto this framework using the Mannich reaction. A rigid naphthalene-containing epoxy resin is synthesized as a co-curing component. A layer-by-layer assembly strategy is employed to anchor graphene oxide on a silicon carbide surface and grow ZIF-8 crystals in situ. Finally, the imidazole groups on the filler surface are used as interfacial nucleophilic catalytic centers to induce synergistic ring-opening copolymerization of benzoxazine and epoxy groups, constructing an organic-inorganic hybrid interpenetrating network with high density, low surface energy, and excellent interfacial bonding. This improves the resistance to strong acid and alkali corrosion and the flexural modulus of the plastic material used for fume hood surface decoration.

[0110] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis, characterized in that, Includes the following steps: S1. Place perfluorooctyltrimethoxysilane, γ-aminopropyltriethoxysilane, ethanol and deionized water in a reaction vessel and stir. Add tetraethyl orthosilicate dropwise. Heat the reaction vessel to reflux and keep it at this temperature for 4-6 hours. After post-treatment, obtain an amino-modified fluorosilicone resin solution. S2. Place amino-modified fluorosilicone resin, paraformaldehyde and 1,4-dioxane in a reaction vessel and stir. Add cashew phenol solution dropwise. Heat the reaction vessel to 85-95℃ and keep it at the temperature for 6-8 hours. After post-treatment, cashew phenol benzoxazine resin is obtained. S3. Place cashew phenol-based benzoxazine resin and naphthalene-containing epoxy resin in a reaction vessel, heat the reaction vessel to 100-110℃, melt and mix for 20-30 minutes, add imidazole-modified silicon carbide microspheres, stir at high speed for 30-40 minutes, degas under vacuum, and heat to cure to obtain plastic material for fume hood cabinet surface decoration.

2. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 1, characterized in that, In step S1, the ratio of perfluorooctyltrimethoxysilane, γ-aminopropyltriethoxysilane, ethanol, deionized water and tetraethyl orthosilicate is 10-15g:20-25g:120-150mL:25-35mL:40-50g.

3. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 1, characterized in that, In step S2, the ratio of the amino-modified fluorosilicone resin, paraformaldehyde, 1,4-dioxane, and cashew phenol solution is 6-8g:0.3-0.5g:80-100mL:18-20mL, and the cashew phenol solution is composed of cashew phenol and 1,4-dioxane in a ratio of 1g:2mL.

4. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 1, characterized in that, In step S3, the weight ratio of the cashew phenol-benzoxazine resin, the naphthalene-containing epoxy resin, and the imidazole-modified silicon carbide microspheres is 80-100:30-50:10-15.

5. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 1, characterized in that, The preparation method of the naphthalene-containing epoxy resin is as follows: 1,4-dihydroxynaphthalene and epichlorohydrin are placed in a reaction vessel under nitrogen atmosphere and stirred. Tetrabutylammonium bromide is added, the reaction vessel is heated to 75-85℃, sodium hydroxide aqueous solution is slowly added dropwise, the reaction is kept at the temperature for 1-2 hours, and the naphthalene-containing epoxy resin is obtained after post-treatment.

6. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 5, characterized in that, The ratio of 1,4-dihydroxynaphthalene, epichlorohydrin, tetrabutylammonium bromide and sodium hydroxide aqueous solution is 4-6g:6-10g:0.1-0.2g:10-12mL, and the concentration of sodium hydroxide aqueous solution is 25-30wt%.

7. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 1, characterized in that, The imidazole-modified silicon carbide microspheres were prepared by the following steps: A1. Tannic acid and deionized water were placed in a reaction vessel and stirred. Silicon carbide microspheres were added and stirred at room temperature for 3-5 minutes. Zinc nitrate hexahydrate aqueous solution was added and ammonia was added to adjust the pH to 8±0.

2. The mixture was stirred at room temperature for 25-35 minutes. Graphene oxide aqueous dispersion was added and post-processed to obtain modified silicon carbide microspheres. A2. The modified silicon carbide microspheres and methanol were dispersed in a reaction vessel, and 2-methylimidazolium methanol solution was added. The reaction vessel was heated to 30-50℃ and stirred for 4-6 hours. The imidazolium-modified silicon carbide microspheres were obtained after post-treatment.

8. The method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 7, characterized in that, In step A1, the ratio of tannic acid, deionized water, silicon carbide microspheres, zinc nitrate hexahydrate aqueous solution, and graphene oxide aqueous dispersion is 0.4-0.6g:100-120mL:9-11g:18-20mL:80-100mL, the concentration of zinc nitrate hexahydrate aqueous solution is 0.03-0.05 mol / L, the concentration of graphene oxide aqueous dispersion is 1-2mg / mL, and the concentration of ammonia is 1-2mol / L.

9. A method for preparing a plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis according to claim 7, characterized in that, In step A2, the ratio of the modified silicon carbide microspheres, methanol, and 2-methylimidazole methanol solution is 8-10g:100-150mL:30-50mL, and the 2-methylimidazole methanol solution is composed of 2-methylimidazole and methanol in a ratio of 1g:10mL.

10. A plastic material for decorating the surface of a fume hood resistant to strong acids and alkalis, characterized in that, The acid and alkali resistant fume hood surface decoration plastic material is prepared by the preparation method of the acid and alkali resistant fume hood surface decoration plastic material as described in any one of claims 1-9.

Images