Self-emulsified water-borne epoxy curing agent of nonionic type was prepared using triethylene tetramine (TETA) and derivative of epoxy resin as a capping agent, which was synthesized by liquid epoxy resin (E51) and polyethylene glycol (PEG), and the curing agent possessed emulsification and curing properties at the same time. The curing agent with good property of emulsifying liquid epoxy resin could be obtained under the condition of the molar ratio of PEG : E51 : TETA as 0.8 : 1 : 3.5 at 80 C for 5 h. The mean particle size of the emulsion liquid was about 220 nm with the prepared curing agent and epoxy resin at the mass ratio of 1 : 3. The structure of the emulsion-type curing agent was confirmed by FTIR and 1 H NMR spectra, and the mechanism of cured film formation was also analyzed by SEM photographs. The cured film prepared by the emulsion-type curing agent and epoxy resin under ambient cure conditions showed good properties even at high staving temperature. This study provides useful suggestions for the application of the water-borne epoxy resins in coating industry.
In the present work, a polytetrafluoroethylene/polydimethylsiloxane (PTFE/PDMS) composite coating was fabricated using a simple brushing method. The PTFE/PDMS coating has both superhydrophobic self-cleaning property and radiation cooling function. The contact angle (CA) for water of the composite coating is 159.3°, and the sliding angle (SA) for water is 6.3°. Furthermore, the solar reflectivity of the coating in the wavelength range of 200–2500 nm is close to 92%, and the infrared emissivity in the 8–13 μm middle-infrared band is about 0.93. When the maximum daytime temperature in summer is 39 °C, the PTFE/PDMS coating could achieve an average radiation cooling temperature of 4.73 °C under direct sunlight from 10:00 a.m. to 16:00 p.m. Under the same conditions, covering the PTFE/PDMS coating on the electric vehicle seat cushion could realize the temperature drop of the seat cushion by 19.41 °C. After continuous washing and corrosion of 50,000 mL of simulated acid rain, 10 cycles of ultraviolet (UV) aging experiments, or 25 cycles of sandpaper abrasion, the superhydrophobicity and radiation cooling function of the PTFE/PDMS coating remained unchanged. In particular, the PTFE/PDMS coating lost the radiative cooling ability after the surface is contaminated. However, with the help of natural rainfall, its radiation cooling coating could recover rapidly. Therefore, the PTFE/PDMS coating developed in this work makes the radiative cooling coating more practical.
On the basis of guaranteeing the reliability of the coating, thermal-spray zinc coating has been verified by the industry to have a lifespan of more than 20 years. It is an anti-corrosion coating with excellent performance. Inorganic zinc-rich coating being a new coating technology has a certain degree of influence on its popularization and application in the field of anti-corrosion; this is due to the lack of relevant comparison data on its anti-corrosion performance and service life. It is necessary to compare and analyze the service life and corrosion resistance of the two coatings, so as to obtain the best application scenarios for the two coatings and provide a reference for the selection of the most economical coating. Based on coating reliability, 7500 h of accelerated salt-spray tests of inorganic zinc-rich coating and of the thermal-spray coating of steel structures were carried out. Electrochemical and salt-spray tests on inorganic zinc-rich coating and thermal-spray zinc coating were carried out. The micro-corrosion morphology, corrosion rate and corrosion mechanism of the two coatings and the factors affecting the corrosion rate were obtained. An interfacial corrosion-thinning and weight-loss equation was established to predict the service life of inorganic zinc-rich coating by comparing it with that of the thermal-spray zinc coating salt-spray test; they suggested that inorganic zinc-rich coating has a longer service life. The results are of practical guiding significance for the selection of a zinc coating and the rapid selection and design of a supporting scheme, and can also provide a reference for the service-life prediction of other types of coatings.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.