Synthesis and Characterization of Polyurea Resin for Dielectric Coating Applications

Here, the polyurea coating is synthesized by reaction by introduction of urea linkages between toluene diisocyanate and polyether bifunctional amine and trifunctional amines PO - 1 and PO - 2. The isocyanate-terminated prepolymer formed further reacts with a chain extender and a short chain amine as a curing agent. These resins are synthesized by changing the molar ratio of amine to isocyanate and keeping the molar ratio of the other monomers constant. The presence of functional groups was determined using Fourier transform infrared spectroscopy. The thermal stability of the polymer was determined using thermogravimetric analysis and differential scanning calorimetry. The mechanical and electrical properties of the polymer were further tested. It has been observed that as the hard segment in the polymer increases, the electrical properties increase and the elongation decreases. As the isocyanate content increases, the increase in crosslinking leads to an improvement in the dielectric properties. The maximum dielectric strength observed was 45 kV mm -1 with an extinction coefficient of 0.068.

Whole aliphatic polyurea coatings have excellent gloss and color stability, but as stated in the introduction this stability improvement does not necessarily extend to the mechanical properties of the coating. In addition, fatty amines are more stable to air oxidation than air counterparts, but they can slowly turn yellow as time passes and some additives accelerate this effect You can do. After consultation with Ciba Specialty Chemicals, nine different UV stabilizers were evaluated, which improved retention of color and mechanical properties of typical polyurea coatings (inferred from crack resistance). The standard formulation used (without stabilizer) is shown in Table 2. Although Clearlink 1000 is often mixed with IPDA, Clearlink 1000 is used as the only curing agent to minimize the effect of ingredients on the coating. The physical properties shown are determined after 2 weeks and used in the formulation without stabilizer.

Here, the polyurea coating is synthesized by reaction by introduction of urea linkages between toluene diisocyanate and polyether bifunctional amine and trifunctional amines PO - 1 and PO - 2. The isocyanate-terminated prepolymer formed further reacts with a chain extender and a short chain amine as a curing agent. These resins are synthesized by changing the molar ratio of amine to isocyanate and keeping the molar ratio of the other monomers constant. The presence of functional groups was determined using Fourier transform infrared spectroscopy. The thermal stability of the polymer was determined using thermogravimetric analysis and differential scanning calorimetry. The mechanical and electrical properties of the polymer were further tested. It has been observed that as the hard segment in the polymer increases, the electrical properties increase and the elongation decreases. As the isocyanate content increases the crosslinking increases and the dielectric properties improve.

Mesoporous silica has been investigated as a promising material for applications requiring low thermal conductivity or low dielectric constant. In the former case, use in thermal barrier coatings is of particular interest. Previous work showed that the porous structure effectively reduces the thermal conductivity in the film by increasing phonon scattering. SiO 2 sol - gel and nanoparticle porous membrane were designed and prepared by evaporation induced self - assembly method and they were characterized by time - domain thermal reflection method. The influence of the porous structure on thermal properties was investigated by changing the film thickness from 100 nm to 1 μm, the porosity from 10% to 72%, and the pore size from 3 to 68 nm. We also compared porous networks based on sol - gel and nanoparticles. With simple synthesis method, pore size and porosity structure can be adjusted, scale up to several microns possible