| The coating is widely used in marine engineering for corrosion prevention due to its simple construction,low cost,excellent effect and easy maintenance.The service process of offshore engineering equipment is affected by the external environment and the mechanical action during the operation process.The surface coating will inevitably be damaged.If it is not repaired in time,the metal substrate and some non-metallic parts will be corroded,which will affect the structural strength and reliability.Sex,not only will cause huge economic losses,but even lead to catastrophic accidents.Anti-corrosion coatings coated with self-healing are an effective way to solve this problem.At present,there are many researches on self-repair technology of coatings.However,due to the limitation of repair mechanism and principle of action,single repair technology is usually applied to self-repair of coatings,which usually has certain limitations,which limits self-repair to some extent.The repair effect of the paint and the actual repair effect.This paper comprehensively adopts the advantages of microcapsule repair technology and shape memory repair technology.With the principle of different response trigger mechanism,the effective synergy between two different mechanisms is realized by technical means to realize the repair of cracks of various sizes.Mainly carry out the following research:(1)Study on the preparation of microcapsules for coating self-repair by solution polymerization;control the size and process optimization of microcapsules by adjusting the material selection and synthesis process parameters of the core/sac wall;on this basis,by means of chemistry The method of coupling and physical blending explores the modification technology to realize the dynamic driving agent for different factors such as thermal field,magnetic field,electric field and H+,so that the microcapsule has the targeting function.Considering the factors such as the mass ratio of core wall,the type of emulsifier,the mass fraction of emulsifier and the acidification time,the optimal formulation was used to synthesize the influence of the coating rate and average particle size of the formed microcapsules.The results show that when the core wall mass ratio(2:1),the emulsifier type and the mass fraction are 0.8% of gum arabic and the stirring rate is 1500 r/min,the prepared microcapsules have better dispersibility and particle size.Small,the wall of the capsule is thin,and the surface of the microcapsule is rough,which is favorable for dispersion in the matrix.The thermal stability of the microcapsules is good.(2)The polyurethane film-forming materials with shape memory properties were synthesized by emulsion polymerization;according to the actual service environment,different soft segments/hard segments and cross-linking monomers were selected,and the soft and hard segment content and preparation process parameters were adjusted.The shape memory film suitable for different environments was realized.The effects of hard segment content on the structure and properties of shape memory polyurethane were studied by means of infrared spectroscopy,weight loss analysis,shape memory performance and nuclear magnetic resonance spectroscopy.It has been found that linear shape memory polyurethane transforms into a shape memory mechanism in the "crystal-melt" phase of the soft segment.Therefore,the soft segment has good crystallinity at room temperature,which is one of the necessary conditions for shape memory function.The hard segment microdomain formed when the hard segment content is 30~40% can effectively reach the physical cross-linking point.effect.The properties of the synthesized shape memory polyurethane were characterized by infrared spectroscopy,solid content determination and shape memory properties.The experimental results show that the shape memory performance and performance are best when the hard segment content is 30~40%.Deeply reveals the design ideas and synthetic methods of shape memory film formation.(3)The target repair microcapsules and the shape memory film-forming materials are loaded by physical blending,thereby preparing self-repairing smart paints with other pigments and fillers,and different triggering factors of different repair technologies are used to realize different The orderly expression,synergistic repair and complementary complementarity of the repair technology respectively propose two synergistic self-repair mechanisms: “first passivation-post-recovery” and “passivation simultaneous reply”;at the same time,from the two aspects of physical repair and chemical repair The repair of the size scratches can make the overall repair rate reach more than 85%,and solve the problem that the adhesion between the coating and the substrate is not strong after the repair;the induction self-heating and the specific factor response mechanism are introduced,and the applicable environmental range of the self-repair coating is expanded..In the laboratory test and the field exposure test,the performance is superior,and it has certain promotion and application value,which provides a theoretical basis for the development of the subsequent high-performance intelligent self-healing coating. |
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