Study On Flame Retavdant Functional Cellulose Materials

Cellulose is one of the most important representatives of biopolymers, on account of its advantages such as availability in vast quantities, biodegradability and so on. However, cellulose's low flammability confines its using conditions greatly. Therefore, various flame retardants are used to produce flame retardant cellulose materials. Flame-retardant modifications on regenerated cellulose materials, especially by employing non-halogen containing, little toxic, little smoke and high effective flame retardants is one of hot research pots.NaOH /urea /thiourea aqueous solution is adopted as the solvent of cellulose, because of its easy availability and low pollution on environment. The dissolution mechanism of cellulose in NaOH /urea /thiourea aqueous solution and the influences of different concentration of NaOH, urea and thiourea are studied. The best dissolving conditions are concluded as 8% NaOH,8% urea,6% thiourea,solution precooling temperature below -10℃.In the case of environmental protection, Nano-SiO₂ is used as the flame retardant,as well as the N-P flame retardant. The flame retardant cellulose membranes are prepared by blending-method. The combustion properties of cellulose membranes are studied by Limit Oxygen Index (LOI) and the horizontal burning experiments; the thermal properties of the membranes are tested by thermogravimetric analysis (TG).The Limit Oxygen Index results indicate that, when the addition amount of Nano-SiO₂ comes to 6%, while N-P flame retardant comes to 9%, the cellulose membranes can reach the flame-retardant standard (LOI≥28); the horizontal burning experiments show that when the addition amount of Nano-SiO₂ comes to 15%, while N-P flame retardant comes to 15%, the cellulose membranes can reach the HB class , according to Plastics-Determination of burning characteristics-Horizontal and vertical test; thermogravimetric analysis indicate that the stabilities of the regenerated cellulose membranes are improved after adding flame retardants to cellulose. By comparing the mechanisms and effects of the flame retardants, Nano-SiO₂ is more efficient than the N-P flame retardant.