| With the continuous development and progress of resource-saving and environment-friendly society, the developing trend of coating will be high performance, high level of quality, multi-purpose and green. Waterborne coating, especially organic/inorganic waterborne composite coating has emerged to meet the demands, which has drawn more and more attention and become a research topic in recent years. It combines the good film-processing ability, strong adhesion to the substrate and excellent flexibility of organic resin with the high strength, stable performance, various functions of inorganic nano-materials so as to exhibit more excellent performance and diversified functions; it is therefore believed to possess a very broad application prospect and an important commercial value in the field of synthetic materials. Based on that fact, a series of research on the organic/inorganic waterborne composite coating were carried out in this paper, in which the acrylate polymer emulsion modified by polyurea and the mesoporous nano-SiO2 microspheres were applied as organic resin and inorganic materials respectively.In this study, polyurea pre-polymer containing urea groups(-NH-CO-NH-) was firstly synthesized by solution polymerization, with isophorone diisocyanate(IPDI) and polyether amine(D-2000) as monomer and raw material, and utilizing acetone as solvent. Then, using hydroxylethyl acrylate(HEA) as the blocking agent, acrylate-terminated polyurea oligomer(PU) was synthesized by reaction between the residual isocyanate groups(NCO) of pre-polymer system and hydroxyl group of HEA. In the process of this reaction, the change of NCO content was also determinated through di-n-butyl amine titration. The structures of acrylate-terminated polyurea oligomer(PU) were characterized by FTIR.Secondly, in the absence of the crosslinking agent PU, adding methyl methacrylate(MMA) and n-butyl acrylate(BA) as the main monomers, SDS and OP-10 as anion/nonionic compound emulsifier, and with NaHCO3 as the buffering agent, polyurea/acrylic resin waterborne composite latex(WPUA) was prepared by emulsion polymerization under the initiation of potassium persulfate(KPS). Under the same condition that the mass percentage of compound emulsifier and distilled water is respectively 3% and 120%(which accounts for the overall properties of MMA and BA), it was proved that when w(NaHCO3) was 0.65%, m(BA)/m(MMA) 0.98, w(K2S2O8) 0.5% and m(OP-10)/m(SDS) 2, the most stable polymer latex could be acquired, studied by orthogonal design. The effect of different dosage of PU on the performance of WPUA composite latex and latex film was also investigated. And the corresponding testing and characterization were carried out using FTIR, TGA, DMA, TEM, DLS, UV-Vis, electronic universal testing machine and so on. The results showed that, with the increasing dosage of PU in the polymer system, the abrasion resistance, thermal decomposition temperature, heat resistance, the elongation at break of latex film were improved, enhanced or elevated altogether, while tensile strength was decreased on the contrary. In addition, the film’s visible light transmittance reached the maximum when the dosage of PU is 8%.Lastly, the organic/inorganic waterborne composite coating was successfully prepared by blending WPUA composite latex with mesoporous nanostructured SiO2 microspheres, with the former as the main film-forming material and the latter as the heat insulation functional filler. Afterwards, the heat-insulating performance and mechanism of the prepared composite coating was then studied and simulated, followed by the investigation into its transparency and light visible light transmittance. |
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