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Acid-base synergistic flame retardant wood pulp paper with high thermal stability

Wang, Ning, Liu, Yuansen, Xu, Changan, Liu, Yuan, Wang, Qi
Carbohydrate polymers 2017 v.178 pp. 123-130
acidity, borax, flame retardants, guanidines, lignocellulose, oxygen, phosphates, synergism, temperature, thermal stability, wood pulp
Acid-catalytic degradation caused by acid source flame retardants is the main reason for a decline in thermal stability of flame-retarded lignocellulosic materials. In the present research, a guanidine phosphate (GP)/borax (BX) flame retardant system based on acid-base synergistic interaction was designed and used in wood pulp paper (WPP) to solve this problem. Results showed that the treated WPP obtained good flame retardancy with a limiting oxygen index (LOI) value of 35.7%. As a basic flame retardant, borax could chemically combine with the acids released by guanidine phosphate, thus decreasing the acidity of the system in the initial heating stage. In this way, acid-catalytic degradation is greatly retarded on the lignocelluloses to improve thermal stability (the temperature of maximum degradation peak from 286°C to 314°C). Meanwhile, borax was also advantageous to form a denser and firmer condensed phase through reinforcement of the acid-base reaction product, borophosphates, allowing it to provide a protective barrier with higher quality.