Studies On Phosphazene-Derivative Antibacterial Flame-Retardant Protein Viscose Fiber

The demands of quantity and quality of flame-retardant textiles increasedramatically with the rapid development of technology and the booming consumptionlevel. In viscose fiber industry, environemental-firendly flame retardants are required, aswell as excellent wearing performance and antibacterial property. However,multi-functional product with combined features has not been reported. In this paper,flame-retardant viscose fiber was prepared by the addition of an environment-friendlyphosphazene derivative, hexaphenoxycyclotriphosphazene (HPTP). Flame-retardantprotein viscose fiber was prepared by adding animal protein solution to spinning solution.By using chitosan as antibacterial agent, Antibacterial flame-retardant protein viscosefiber was prepared for the first time. Flame retardancy, mechanical strength, wearingperformance and other properties of these viscose fibers were studied systematically.In this paper, HPTP was applied to the study of flame-retardant viscose fiber for thefirst time. Sodium phenate and hexachlorocyclotriphosphazene (HCTP) were used asreactants to synthesize HPTP. Reaction factors such as temperature, time and reactantratio were optimized using orthogonal test design, which gave a yield of76.52%. A yieldof97.3%was accomplished after PEG400was added as catalyst. Infrared spectrum and31P NMR spectrum were employed to characterize and determine the structure of theproduct. Results showed that Cl atoms were replaced completely. Differential scanningcalorimetry (DSC) and Thermogravimetry (TG) results indicated that the decompositiontemperature of HPTP is250degree centigrade higher than that of HCTP. It proved thatHPTP is a flame retardant with better heat-resistance.APG/EL-20emulsification system was selected and optimized using orthogonal testdesign to solve the bad dissolubility of HPTP before wet spinning. HPTP was blendedwith viscose spinning solution thoroughly. Fluffy structures spread uniformly wereobserved on the cross section of flame-retardant viscose fiber. The igniting property andthermal stability of the samples were evaluated by scanning electron microscope (SEM),Limited oxygen index (LOI),45degree igniting test, DSC, TG. The results indicated thathigher flame retardant percentage fiber has better flame retardancy. Viscose fiber with 16%flame retardant was evaluated as flame-retardant fiber (LOI=28.5%, ignition time>3, ignition weight loss=21.12%). The flame retardancy of the fiber remained after30times wash test. The first decomposition temperature of flame-retardant viscose fiber wasdecreased by20degree centigrade, decomposition rate was accelerated. Secondarycarbonization was more difficult than beforedecomposition rate was slower and the peakof decomposition was lagged by30~50degree centigrade. After igniting test, carbonizedlayer was formed on the surface of flame-retardant viscose fiber, the structure of fiberremained. Mechanical strength of the fiber with our emulsification system performedbetter than viscose fiber with common emulsification system.Protein solution, flame retardant and viscose spinning solution were blended for thefirst time to prepare flame-retardant protein viscose fiber. Animal protein was added5%by weight to spinning solution on the basis of16%flame retardant. The product has morecompact structure inside the fiber and evenly scattered small pores on the surface. Resultsof LOI and45degree igniting test showed that the flame-retardant protein viscose fibercan reach the flame-retardant standard both before and after30times wash test. The chiefimprovement of this product is the better orientation and mechanical strength. Moistureregain of the fiber is a little lower than that of normal viscose fiber, however, it is13.3%higher than the moisture regain of flame-retardant viscose fiber, heat retention is alsoimproved. Friction coefficient of the product is lower than that of flame-retardant viscosefiber. Bulking intensity is increased, better than that of normal viscose fiber. The productwas modified with modified amino organic silicon softener to obtain silk-like feel.Chitosan and Ag nanoparticles-chitosan antibacterial agent were used to finish theflame-retardant protein viscose fiber. After modification the antibacterial flame-retardantprotein viscose fiber showed92.4%and97.6%inhibition to mixed strain,89.3%and93.8%after30times wash teat, respectively. LOI of the product is higher than29%before and after wash test. The improvement of the flame retardanc is based on theaccumulation of N element. Dry mechanical strength of the fiber is increased while stilllower than normal viscose fiber. However, the wet mechanical strength is much improvedthan that of normal viscose fiber. Friction coefficient is increased. After modification byusing modified amino organic silicon softener, the friction coefficient is lower than that of normal viscose fiber. The final product has optimized flame retardancy, mechanicalstrength, wearing performance and antibacterial function.