| Polyacrylate is one of the most widely used resins. With the rapid development of automobile, construction and packaging materials industry, demand for polyacrylate is also growing. However, polyacrylate would burn easily when encounted a fire, which mignt cause increasing security risks to people’s lives and property. Its application in various fields is greatly limited. Hence, it’s of great significance to improve the flame retardancy of polyacrylate. In this paper, a phosphorus-containing polyacrylate(PPA) emulsion was prepared and blended with a nitrogen-containing aqueous phenol resin(PMF). The effect of PMF on the flame retardancy of PPA was studied. Then, an organically modified α-zirconium phosphate(AM-ZrP) was synthesized and employed to prepare a phosphorus-containing polyacrylate /α-zirconium phosphate(PPA/AM-ZrP) nanocomposites emulsion via an in-situ emulsion polymerization. The morphology of AM-ZrP in PPA matrix and its effect on the flame retardancy of PPA/AM-ZrP were investigated The PPA/AM-ZrP composite emulsion was also blended with PMF. The synergistic effect between PMF and AM-ZrP was studied. The main contents and results are included in the following:(1) PPA emulsion was prepared through pre-emulsified sem-continuous emulsion polymerization of 2-hydroxyethyl methacrylate phosphate(PM-1500), methyl methacrylate(MMA), butyl acrylate(BA) and acrylic acid(AA). Then the PPA emulsion was blended with PMF. Effects of PMF on emulsion stability, mechanical properties, thermal stability and flame retardancy were investigated. And the flame retardant mechanism of PPA/PMF was also studied by Fourier transform infrared(FT-IR), scanning electron microscopy(SEM) and Raman spectroscopy(LRS). The results demonstrated that PMF was efficient in improving the flame retardancy of PPA. When the amount of PMF was 35.0wt%, the LOI of PPA/PMF was increased from 23.5% to 28.5%., the peak of heat release rate(pHRR) and total heat release(THR) were respectively reduced from 372.9kW/m~2 and 85.0MJ/m~2 to 166.1kW/m~2 and 62.7MJ/m~2, compared with PPA. PMF could improve the mechanical properties. The pencil hardness of PPA/PMF increased from Class B for PPA to Class HB.(2) The α-zirconium phosphate(α-ZrP) was synthesized via a refluxing method by using zirconyl chloride and phosphoric acid. An organically modified α-zirconium phosphate(AM-ZrP) was prepared by intercalating acrylamide into the layers and employed to prepare a phosphorus-containing polyacrylate/α-zirconium phosphate(PPA/AM-Zr P) nanocomposites emulsion via an in-situ emulsion polymerization. Effects of AM-ZrP on the monomer conversion, aggregation rate, average particle size, Zeta potential, mechanical properties and flame retardancy were investigated. The morphology of AM-ZrP in PPA matrix was studied by X-ray diffraction(XRD) and transmission electron microscopy(TEM). It was found that AM-ZrP was partially exfoliated and well dispersed in PPA matix. AM-Zr P could improve the flame retardancy and mechanical properties of PPA/AM-ZrP. When the amount of AM-ZrP was 0.5wt%, the LOI of PPA/AM-ZrP was increased from 23.5% to 25.0%, the pHRR was decreased from 372kW/m~2 to 338kW/m~2, compared with PPA. AM-ZrP could catalyze carbonization process, forming compact carbon layer with higher carbon content.(3) PPA/AM-ZrP was blended with PMF to prepare the PPA/AM-ZrP/PMF composite emulsion. The synergistic effect between PMF and AM-ZrP was studied. It was found that AM-ZrP had a positive synergistic effect with PMF on enhancing the flame retardancy of PPA. When the total amount of PMF and AM-ZrP was 35.0wt% and the content of AM-ZrP was 0.5wt%, PPA/AM-ZrP/PMF composite had the best flame retardancy. Compared with PPA/PMF, the LOI of PPA/AM-ZrP/PMF was increased from 28.5% for PPA to 30.5%, THR was decreased from 62.7MJ/m~2 to 49.4MJ/m~2. SEM-EDX and LRS results showed that AM-ZrP could improve the carbonization process of PMF. The carbon content and the graphitization of the char layer were increased. |
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