Abstract
The paper aims to select the best conductive filler and additive which can improve the conductivity properties of polyurethane coatings. Three kinds of inorganic conductive fillers: micron-sized ITO, micron-sized conductive mica and conductive titanium dioxide, were modified by three common additives: DISPERBYK-P104S, DISPERBYK-163, DISPERBYK- 2001, respectively, to select the best additive to improve the dispersion of filler, so as to study the effects of fillers modified by the additive on the conductivity, anti-corrosion, mechanical properties and heat resistance properties of polyurethane resin coatings. The best conductive material was selected finally. Based on sedimentation test, the additive of the best dispersibility was DISPERBYK-P104S. The electrical conductivity, corrosion resistance, mechanical properties and heat resistance of the coatings were tested to judge the environmental suitability. It showed that the polyurethane resin coating with modified conductive titanium dioxide obtained the best capabilities. The resistance of the coating had the minimal value of 10.84 MΩ at room temperature, and the resistance was only 24.53 MΩ when the coating was heated at 100 ℃ for 2 h. As for water contact angle (WCA), the initial contact angle of the coating was 107°, and the WCA of the coating still reached 90° after being immersed in 3.5% NaCl solution for 400 hours. The adhesion of the coating was still above 2.1 MPa after being immersed in 3.5% NaCl solution for 800 hours. The tensile strength of the coating was 16.53 MPa, its elongation at break was 650%, which proved that the coating had good elasticity and mechanical strength. At the same time, after ablation at 300 ℃ for 3 times (15 min per time), the surface of the coating remained smooth. The test results show that when the conductive filler was conductive titanium dioxide modified by DISPERBYK-P104S, the surface resistance of polyurethane resin coating is between 0.5~25 MΩ at the temperature below 100 ℃, and the conductive coating obtains the best performances in other aspects.
Key words
electrical conductivity; inorganic filler; auxiliary; electrical resistance; tensile strength at break; elongation at break; heat resistance
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LI Hang, YU Mei-yan, ZHANG Xin-yu, HAN Xiao-mei, QI Qi, CHEN Shou-gang.
Effects of Three Different Inorganic Fillers on Application Properties of Polyurethane Conductive Coatings[J]. Surface Technology. 2019, 48(10): 148-156
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Funding
Supported by the National Natural Science Foundation of China (U1806223)