Ecofriendly phosphorus-tin composite synergistic flame retardant:preparation and application in polyvinyl chloride
This article presents a synthetic method for tin phytate-coated zinc hydrox-ystannate(ZHS@Sn-Phyt)particles with different ratios,which were incorporated into soft polyvinyl chloride(PVC)as a composite synergistic flame retardant.The synthe-sized ZHS@Sn-Phyt particles were characterized by X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,and thermogravimetric analysis.The results revealed that a stable coating structure was formed in the form of Sn—O—P—O—Zn ionic bonds at the interface between the zinc hydroxystannate(ZHS)surface and the tin phytate(Sn-Phyt)coating layer.The PVC composites were evaluated through limiting oxygen index(LOI),cone calorimetry,and mechanical studies.When the mass ratio of ZHS@Sn-Phyt in the flame retardant was 1∶9,the best flame retardant properties of PVC were achieved,indicating that combining phosphorus and tin results in a better synergistic flame retardant effect.The LOI of the PVC/ZHS@Sn-Phyt composite was 1.6％higher than that of the PVC composite with only ZHS(without the Sn-Phyt coating).Moreover,the peak heat release rate and total heat release decreased by 18.9％and 31.7％,respectively.In addition,the carbon residue rate increased by 6.1％and the total smoke release of PVC/ZHS@Sn-Phyt and PVC/ZHS were similar.Both the tensile strength and the elongation at break of PVC/ZHS@Sn-Phyt were also better than those of PVC/ZHS at 26.79 MPa and 296.5％,respectively.Thus,this study provides a method for preparing efficient and green flame retardants for PVC.The phosphorus/tin-based synergistic flame retardant prepared by our method has the advan-tageous characteristics of ecofriendliness and simplicity of the preparation process.
tin phytatezinc hydroxystannatepolyvinyl chlorideflame retardantenvironmentally friendly
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维普
