| Nowadays, cotton is a type of the most widely used fabric in the various fields of textileproducts. However, the cotton is flammable and its limiting oxygen index is only18. Mostrecently, with the increasing of consumption on cotton, the fire accidents caused by cottonflame are rising year by year. Therefore, a novel flame retardant with high performance andlow cost is synthesized and applied to the flame-retarded finishing of the cotton, which is notonly of theoretical interest but also are of practical importance.In this paper, two kinds of new reactive flame retardant (FR) have been synthesized byusing cyanuric chloride, sodium sulfanilate, taurine, diethanol amine, and phosphorusoxychloride as cheap raw materials. One is the FR with the aromatic ring—the nitrogen-richtriazine FR (FR-1) and the P/N synergistic intumescent FR (FR-2), and the other is the FRwith the aliphatic chain—the nitrogen-rich triazine FR (FR-3) and the P/N synergisticintumescent FR (FR-4). Based on the above-mentioned information, firstly, effects ofreaction solvent, raw material ratio, acid-binding reagent and reaction temperature on thereaction yield of these FRs have been investigated in detail, and the corresponding optimalreaction conditions are obtained; secondly, the molecular structures of the above-synthesizedFRs have been characterized by means of IR,~1H-NMR and31P-NMR spectroscopies; finally,the thermal properties of the prepared FRs have been studied using thermogravimetry analysis(TGA), indicating that these new FRs (FR-1, FR-2, FR-3, and FR-4) are good char-formingagent.In order to obtain the flame-retarded cotton with high performance, the above-preparedFRs (FR-1, FR-2, FR-3, and FR-4) have been successfully applied to the flame-retardedfinishing cotton in this paper. In view of these, the effect of the finishing temperature and the flame retardant dosage on the flame-retarded properties of the cotton have been studied byusing the limiting oxygen index (LOI) and the vertical burning testing methods,demonstrating that that addition of these new FRs can effectively improve the flame-retardedproperties of cotton. When not only the dosage of FR-1and FR-2is100g/L but also the oneof FR-3and FR-4is150g/L, the LOI of the flame-retarded finishing cotton is over26,reaching flame-resistant level. Meanwhile, the thermal properties and surface morphologies ofthe cotton before and after finishing flame-retardedly have been investigated by thethermogravimetric analysis (TGA) and the scanning electron microscopy (SEM) test. TheTGA result shows that the initial degradation temperature of the flame-retarded finishing ofthe cotton is reduced and the quantity of the carbon residue after burning is increased by morethan20%, indicating the flame-retarded finishing cotton has the high thermal stability. TheSEM test displays that the char layer of the flame-retarded cotton after inflaming stillmaintains the relatively-complete threadiness, demonstrating that the flame-retarded finishingcotton have the good flame-retarded effect.Through the LOI and TG test indicated that cotton fabrics finishing with flame retardantcontaining aromatic ring FR-1, FR-2compared with flame retardant containing aliphaticchain FR-3, FR-4have a better flame retardant performance and thermal stability.By improving the pretreatment process of cotton fabrics and dip-padding process, theafter flame time and after glow time of cotton fabrics treated with FR-2were0s, char lengthwas about0cm, reaching B1level. The LOI increased from26.9%to26.9%, reachingflame-resistant level. We also studied laundering durability of flame retardant cotton fabrics,the LOI were in22-24%, it can reaching B2level after20times laundering, indicated thatcotton fabrics after laundering show outstanding flame retardant. |
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