Because flammable organic solvents are emitted during the construction process, oil-based conductive coatings generally result in potential safety problems. A high content of conductive mediums can also weaken the adhesive and protective abilities of existing conductive coatings. Therefore, an anticorrosive and conductive coating was prepared on Q235 steel substrate by spraying the multi-walled carbon nanotubes (MWCNTs)/waterborne polyurethane (WPU) dispersion with a low MWCNT content in this work. The effect of the MWCNT content on the electrical conductivity, corrosion resistance, and adhesive strength of the WPU conductive coating was investigated. It was concluded that a spatial network structure of MWCNTs-WPU was formed to make the coating structure more compact. The electrical conductivity, corrosion resistance, and adhesive strength of the WPU conductive coating first increased and then decreased as the MWCNT content increased. When the MWCNT content was only 0.2 wt % (which was far lower than that of the existing conductive coatings at 1 wt %), the coating began to conduct electricity; its resistivity was 12,675.0 Ω·m. The best combination property was the 0.3 wt % MWCNTs/WPU conductive coating. Its adhesive strength was 19.99% higher than that of pure WPU coating. Its corrosion rate was about one order of magnitude lower than that of pure WPU coating after being immersed in 3.5 wt % NaCl solution for 17 days.

Electrostatic spraying (ES) was used to prepare multi-walled carbon nanotube (MWCNT)/waterborne polyurethane (WPU) abrasion-proof, conductive coatings to improve the electrical conductivity and mechanical properties of WPU coatings. The dispersity of MWCNTs and the electrical conductivity, surface hardness, and wear resistance of the coating prepared by ES (ESC) were investigated. The ESC was further compared with coatings prepared by brushing (BrC). The results provide a theoretical basis for the preparation and application of conductive WPU coatings with excellent wear resistance. The dispersity of MWCNTs and the surface hardness and wear resistance of ESC were obviously better than those of BrC. With an increase in the MWCNT content, the surface hardness of both ESC and BrC went up. As the MWCNT content increased, the wear resistance of ESC first increased and then decreased, while the wear resistance of BrC decreased. It was evident that ESC with 0.3 wt% MWCNT was fully capable of conducting electricity, but BrC with 0.3 wt% MWCNT failed to conduct electricity. The best wear resistance was achieved for ESC with 0.3 wt% MWCNT. Its wear rate (1.18 × 10⁻¹⁰ cm³/mm N) and friction coefficient (0.28) were the lowest, which were 50.21% and 20.00% lower, respectively, than those of pure WPU ESC.

Composites with high flame-retardant behavior based on room temperature vulcanizing silicone rubber (RTV), decabromodiphenyloxide (DBDPO) and decabromodiphenylethane (DBDPE)/Sb₂O₃ as fire retardant were fabricated employing reactive solution mixing process and the method of three-roller milling. The influences of DBDPO and DBDPE/Sb₂O₃ on the morphologies, mechanical properties, flame-retardant properties, OI, insulating properties, hot properties of RTV were systematically investigated. It has been discovered that both kinds of doping agents can significantly improve the property characteristics of RTV matrix composites. Also, DBDPE/Sb₂O₃/RTV were of better comprehensive performances than DBDPO/RTV. We report final performances as follows: tear strength was 13.68 kN/m; elongation at break was 233.4%; tensile strength was 2.18 Mpa; the level of flame-retardant property was FV-0; OI was 46; Volume electric resistivity was 6.9 × 10¹⁴Ω · m; the range of decomposition temperature was 300°C to 690°C and the ending percentage of remain weight was 30.6%. The above properties were acquired on the condition of mass percent of DBDPE/Sb₂O₃ as 15 wt% for DBDPE/Sb₂O₃/RTV.

To improve the wear resistance of polyurethane (PU) coating and its adhesion to the steel substrate, a series of simple and practicable techniques were designed to mix nano-SiO ₂ with PU powder to cast a coating layer onto the steel. When the addition of nano-SiO ₂ was small, a network structure of PU-SiO ₂ was produced. It improved the wear resistance of the composite coating and its adhesion to the steel substrate. When the addition of nano-SiO ₂ was excessive, agglomerated nano-SiO ₂ particles not only affected the bond between the PU resin and the steel substrate but also became abrasive materials, intensifying the abrasion of the composite coating during friction. It resulted in lower bonding strength and poorer wear resistance of the composite coating. The wear rate and friction coefficient of 2 wt.% SiO ₂ /PU composite coating were 1.52×10 ⁻⁶ cm ³ /min N and 0.31, respectively. Its wear resistance was about 10 times as high as that of the pure PU coating. Furthermore, a simple and practicable installation was designed to test the bonding strength between the coating and the steel substrate. The bonding strength between 2 wt.% SiO ₂ /PU composite coating and the steel substrate was 7.33 MPa, which was 39% higher than that of the pure PU coating.

Five kinds of organic rectorite (OREC)-reinforced Epoxy Resin (EP) composites (OREC/EP) were prepared by using different ORECs as modifiers. The curing process of EP, the functional groups of OREC and its interlayer distance (d-spacing) are demonstrated by Fourier Transform Infrared Radiation (FTIR) and XRD (X-Ray Diffraction). The morphologies of OREC/EP composites and the dispersion of OREC in the cured EP matrix were investigated using XRD and scanning electron microscopy (SEM). The mechanical properties, thermal deformed temperature (HDT), hot-wet resistance, alkali resistance and water adsorption of the resulting OREC/EP composites were evaluated. It is found that the addition of OREC can improve the comprehensive properties of EP. The maximum mechanical properties of OREC/EP can be obtained by OREC3/EMI-2, 4/E-51 due to the high stiffness and uniform dispersion of OREC in matrixes. The most desirable properties of OREC/EP composites were obtained with impact strength of 9.5 kJ/m², bent strength of 86 KPa and HDT of 182°C, all of which is improved by 8.0%, 8.9% and 28.2% than those of pure EP, respectively.

Waterborne polyurethane (WPU) coatings hold advantages of good toughness, low cost and environmental protection. However, the low water contact angle (WCA), poor wear and corrosion resistance make them unsuitable for application in the superhydrophobic coatings such as antipollution flashover coatings for transmission lines, self-cleaning coatings for outdoor equipment and waterproof textiles. A series of superhydrophobic WPU composites (SHWPUCs) with micro-rough surface structure was prepared by electrostatic spraying nano-SiO₂ particles on WPU composites with low surface energy. It showed that as the hydrophobic system content rose the WCAs of the composites first increased and then remained stationary; however, the adhesion and corrosion resistance first increased and then decreased. An appropriate addition of the hydrophobic system content would lead to a dense coating structure, but an excessive addition could increase the interfaces in the coating and then reduce the coating performance. When the mass ratio of the WPU dispersion, polytetrafluoroethylene (PTFE) particles and modified polydimethylsiloxane was 8:0.3:0.4, 10 g/m² nano-SiO₂ particles were sprayed on the uncured coating surface to construct the SHWPUC with a WCA of 156°. Compared with pure WPU coating, its adhesion and corrosion resistance increased by 12.5% and one order of magnitude, respectively; its wear rate decreased by 88.8%.