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CN-122011930-A - Rod-shaped carbon nitride-polydimethylsiloxane composite coating and preparation method and application thereof

CN122011930ACN 122011930 ACN122011930 ACN 122011930ACN-122011930-A

Abstract

The invention discloses a bar-shaped carbon nitride-polydimethylsiloxane composite coating and a preparation method and application thereof, wherein the composite coating is prepared by mixing bar-shaped carbon nitride filler, polydimethylsiloxane and a curing agent, the uniform doping of the bar-shaped graphite carbon nitride filler can effectively improve the crosslinking density of the composite coating and enhance the adhesive force and tensile strength of the coating, the multifunctional nano coating with mechanical reinforcement, long-acting corrosion resistance and microbial fouling resistance can be formed on the surface of a substrate by applying the composite coating, the radius of an impedance arc after soaking for 60 days is kept at 5.17 multiplied by 10 9 Ω·cm 2 , and the composite coating has excellent antibacterial and bactericidal properties on chlorella and escherichia coli and has excellent anti-biological fouling properties.

Inventors

  • GUO FENG
  • CHEN KEYI
  • SHI WEILONG

Assignees

  • 江苏科技大学

Dates

Publication Date
20260512
Application Date
20260313

Claims (10)

  1. 1. The rodlike carbon nitride-polydimethylsiloxane composite coating is characterized by comprising a rodlike carbon nitride filler, polydimethylsiloxane and a curing agent which are mixed, wherein the mass ratio of the rodlike carbon nitride filler to the polydimethylsiloxane to the curing agent is 0.019-0.021:10:0.98-1.02.
  2. 2. The carbon nitride filler according to claim 1, wherein the rod-shaped carbon nitride is of a rod-shaped structure g-C3N4 with lamellar arrangement, the whole length is about 50-100 μm, the inside is of a compact lamellar stacked structure, the synthesis is directly obtained by a two-step method of hydrothermal treatment and calcination, melamine and water are subjected to hydrothermal reaction, the mass ratio of the water to the melamine is 15:1-1.02, and then the washed and dried hydrothermal precursor is placed in a muffle furnace for high-temperature calcination, the heating rate is 1-3 ℃ per minute, the heat preservation temperature is 520-550 ℃, and the heat preservation time is 1.5-3 h.
  3. 3. The composite coating according to claim 1, wherein the rod-shaped carbon nitride filler is in a complete rod-shaped form as a whole, and the rod-shaped carbon nitride-polydimethylsiloxane composite coating uses polydimethylsiloxane as a polymer matrix, and the rod-shaped carbon nitride filler is uniformly dispersed in the polymer matrix.
  4. 4. A method of preparing a composite coating according to claim 1, comprising the steps of: (1) Dissolving melamine in deionized water, and stirring; (2) Putting the obtained solution into a reaction kettle for hydro-thermal treatment to obtain a rod-shaped precursor; (3) Washing the precursor for multiple times, drying, and then placing the precursor into a muffle furnace for calcination to obtain a rod-shaped carbon nitride filler; (4) And dispersing the rod-shaped carbon nitride filler into the polydimethylsiloxane and the curing agent, and stirring to obtain the rod-shaped carbon nitride-polydimethylsiloxane composite coating.
  5. 5. The method according to claim 4, wherein in the step (1), the stirring time is 25 to 35 minutes, the stirring temperature is room temperature, the stirring speed is 600 to 800 r/min, and in the step (2), the hydrothermal treatment is performed at a temperature of 180 to 200 ℃ for 11 to 13 hours.
  6. 6. The method according to claim 4, wherein in the step (3), the temperature rising rate of the calcination is 1 to 3 ℃ per minute, the temperature is 520 to 550 ℃ and the temperature keeping time is 1.5 to 3 hours.
  7. 7. The method according to claim 4, wherein in the step (4), the rod-shaped carbon nitride filler, the polydimethylsiloxane and the curing agent are mixed uniformly for 10 to 30 minutes at a mass ratio of 0.019 to 0.021:9.25 to 10.75:0.95 to 1.05.
  8. 8. Use of a stick-like carbon nitride-polydimethylsiloxane composite coating as defined in claim 1 in an anti-corrosion, bacteriostatic and anti-fouling coating.
  9. 9. The application of claim 8, wherein the application is specifically that a rod-shaped carbon nitride-polydimethylsiloxane composite coating is coated on the surface of a carbon steel substrate by using a spin coater to form a composite coating with a thickness of 30-80 μm.
  10. 10. The use according to claim 9, wherein the coating is performed by first spin coating at a low speed of 1-2 min at a speed of 300-600 r/min, then spin coating at a high speed of 3-5 min at a speed of 1200-1500 r/min.

Description

Rod-shaped carbon nitride-polydimethylsiloxane composite coating and preparation method and application thereof Technical Field The invention relates to a composite coating, in particular to a bar-shaped carbon nitride-polydimethylsiloxane composite coating, and also relates to a preparation method and application of the composite coating. Background Worldwide, metal corrosion, as a form of persistent and widespread material degradation, results in economic losses of about 2.5 trillion dollars each year, accounting for 3-4% of total annual output. This poses a serious threat to the safety and reliability of industrial facilities, and also limits energy consumption and resource utilization efficiency for a long time. Traditional preservation techniques, represented by chromate coatings, provide relatively long lasting protection, but their powerful carcinogenicity and inherent environmental toxicity make them severely limited by the dual requirements of modern green manufacturing and sustainable development. Therefore, in the context of increased energy shortages and increased environmental pollution, the development of efficient, environmentally friendly and sustainable metal protection technologies has become an urgent priority in the field of corrosion protection. Photoelectrocatalysis cathodic protection technology is used as an innovative strategy for metal protection by using clean solar energy, and the energy band structure of a semiconductor material is utilized to generate and transmit photo-generated electrons to a metal substrate under irradiation, so that cathodic polarization is induced on the metal surface, and anodic dissolution reaction is inhibited. In this system, a central challenge is to select semiconductor materials with suitable bandgap structures and excellent charge mobility that can take advantage of their photogenerated carrier transport behavior to provide a stable, continuous supply of electrons to the metal substrate. The materials are used as functional filler to be fused into a coating matrix, so that not only are the barrier and shielding effectiveness of the coating remarkably improved, but also the active protection performance of the coating in a corrosive environment is further improved by injecting light to generate electrons through a cathode. Carbon nitride (g-C 3N4) is widely recognized as an ideal candidate for photocatalytic cathodic protection due to its non-toxic, non-metallic nature, ease of preparation, excellent chemical stability, and suitable band gap width. The labyrinth effect generated by the two-dimensional layered structure effectively delays the diffusion of corrosive media in the coating, and meanwhile, the migration of the photogenerated carrier on the metal surface further enhances the cathode polarization effect, so that the physical barrier protection and the chemical shielding are cooperatively realized. However, the bulk g-C 3N4 still faces inherent limitations such as low specific surface area, high charge recombination rate, limited active sites, etc., severely limiting its practical application performance in complex corrosion systems. The prior art adopts a morphology structure for regulating g-C 3N4 to overcome application limitations, such as ultrathin nanosheets, porous g-C 3N4, quantum dot doping and the like. However, the ultrathin nano-sheet is easy to re-stack and agglomerate between layers due to the structural characteristics, so that the actual specific surface area and the active site are reduced, the enhancement on the overall mechanical property of the coating is limited, the stacked structure of the sheet layer is easy to seriously agglomerate in the spontaneous stacking process, a large number of edges and defective active sites are shielded, the interval between the inner layers of the stacked structure is always random and difficult to control, the heterogeneous property on the structure inevitably provides local channels for the penetration of corrosive ions, the expected blocking effect is greatly weakened, the size of the quantum dot is extremely small, the dispersibility control difficulty is high, the physical blocking effect cannot be enhanced, the porous g-C 3N4 realizes the high exposed specific surface area by sacrificing the mechanical strength of the material, the excessive pores of the porous g-C 3N4 become rapid channels for the penetration of corrosive media, and the application of the porous nano-sheet cannot be realized more stably and permanently in the aspect of corrosion resistance. Therefore, there is a need to develop new composite coatings to overcome the technical problems of the prior art. Disclosure of Invention The invention aims to provide a bar-shaped carbon nitride-polydimethylsiloxane composite coating with low cost, long-acting corrosion resistance and antibacterial and antifouling capabilities, a second aim is to provide a preparation method of the composite coating, and a third aim is to provi