Preparation And Characterization Of Carbamate Regenerated Cellulose Fibers And Their Flame Retardant Film Materials

Cellulose,as the inexhaustible renewable resource of nature,is close to people's life.The traditional application of cellulose preparation for chemical fibers have severely polluted the environment,and the country has already considered the reduced production capacity plan,which has limited the production of viscose fibers.Cellulose carbamate(CC)method,as a new type of green cellulose fiber production technology,not only has low energy consumption,no pollution,but also can be used to the original equipment of cellulose fiber production.Furthermore,CC method has many excellent properties like little investment and low cost,which made CC fibers became one of the attracting thing in the green cellulose fiber field.In this work,using cotton pulps and urea as raw materials,cellulose carbamates(CC)were successfully prepared by liquid-solid phase in the high-boiling aprotic and polar solvent(DMAc).Regenerated cellulose fibers were successfully spun from cellulose carbamate in a NaOH aqueous solution by wet spinning on a conventional viscose filament device.The properties of products were characterized by Fourier infrared spectrometer(FTIR),X-ray diffractometer(XRD),Thermal gravimetric analysis(TG)and Scanning electron microscopy(SEM).Among them,CC fibers demonstrated a typical cellulose ? crystal structure and a good thermal stability.However,the addition of flame retardants has greatly increased the amount of carbon residue in the cellulose films at high temperature,indicating that the flame retardant has a very strong carbon char-forming ability.Moreover,it can be see that the structure of the membrane surface had changed after combustion.A dense carbon layer was formed on the film surface and accompanied with a pronounced swelling of the bubble-like projections.The limit oxygen index test showed that the limit oxygen index of flame retardant composite material was up to 34.3%,which showed good flame retardant performance.CC fibers exhibited a bright surface and an approximately circular cross section.There was no lobulate shape and contained obvious pores and voids in the internal sections.The rheological test showed that the CC solution was presented a typical pseudo-plastic non-newtonian fluid feature.The relationship between viscosity and concentration conforms to Flory equation.Furthermore,the CC fibers showed excellent dyeing properties compared with viscose rayon and Yingli Lyocell.The above results provided theoretical and experimental basis for the industrialization of CC fibers and flame retardant cellulose films.