| Tungsten tailing is a solid waste produced from tungsten ore during the beneficiation process and its comprehensive utilization has been a hot issue in academic research.In this thesis,surface modification,decorated and coprecipitation methods were utilized to prepare tungsten tailing-based fillers for intumescent fire-retardant material field.The effects of fire resistance,smoke suppression,char formation and antiageing properties of tungsten tailing-based fillers in intumescent fireretardant coatings were investigated by fire protection,cone calorimeter analysis,thermogravimetric analysis,smoke density test,accelerated ageing test,char layer evolution and Fourier infrared spectroscopy,thus revealing the fire resistance,char formation and anti-ageing mechanisms of tungsten tailing-based fillers.The main research contents and results carried out in this thesis are as follows.(1)Tungsten tailing filler(KH-TTF)was obtained by washing,pulverizing and surface modification of tungsten tailing and applied to intumescent fire-retardant coatings.The results show when the mass fraction of KH-TTF is 3 %,the coating shows the best synergistic effects on fire retardancy and smoke suppression among the samples,which exhibits the flame spread rate of 4.3,the equilibrium backside temperature of 84.8 °C at 900 s,and the smoke density rating value of 14.2 %.Char residue analysis indicates that the incorporation of KH-TTF can promote the coating to form more cross-linking structures and aromatic structures during burning,thus producing a more dense and thermally stable intumescent char layer against heat and mass transfer,which achieves better synergistic fire retardancy and smoke suppression effects.(2)Polypyrrole-decorated tungsten tailing particles(PPY-TTF)were prepared via in situ polymerization of pyrrole in the presence of tungsten tailing particles(TTF),and compounded with intumescent flame retardant(IFR)to prepare an intumescent fire-resistant coating.The results suggest that the synthesis of PPY-TTF effectively solves the poor dispersion of tungsten tailing in the coating,which provides the theoretical foundation to improve the fire resistance and anti-ageing performance of the intumescent fire-retardant coatings.While the synergistic effect of PPYTTF in the coating depends on its content,the intumescent fire-resistant coating containing 3wt % PPY-TTF exhibits the optimal synergistic fire resistance and anti-ageing properties in the tested samples.Compared with the unmodified tungsten tailing filler,the coating containing 3wt % PPYTTF has a 10.7 % reduction in mass loss and 35.4 % reduction in flamespread rating,indicating that the presence of PPY-TTF has a better synergistic effect on improving the fire resistance and char formation of intumescent fire-retardant coatings.(3)Tungsten tailing-based hydrotalcite filler(TTF-LDH)was synthesized by coprecipitation method and then introduced into intumescent fire-retardant coatings to enhance the fire-retardant,smoke suppression and anti-ageing properties of coatings.The results reveal that the addition of TTF-LDH promotes the formation of a hard and dense char layer from the coating,blocking the transfer of combustible materials and heat between the char layer and fire,thus effectively improving the thermal stability and char-forming properties of the intumescent fire-retardant coatings.In the accelerated ageing test,TTF-LDH can provide better barrier effect of the lamellae,enhance the structural stability of the coating,and reduce the migration and decomposition of flame retardant and the blistering and chalking of the coating,thus giving the coating better structural integrity and durability of fire resistance.There are 49 figures,19 tables and 112 references in the thesis. |
