Contain The Essence Of The Metal Ions, Cellulose Derivatives Flame Retardant Performance Study

Cellulose is the most abundant natural polymer in the world. But it is inflammable in the air, which is very bad for its practical application. Carboxymethyl cellulose (CMC) is one of the most important cellulose derivatives, and it is generally found in the metal ion form salt. Effect of metal ions (Na+and Ca2+) on flame retardancy of carboxymethyl cellulose and intrinsically flame-retardant mechanism were studied in this thisis. The results of this work will provide a novel thought for designing and preparing of flame-retardant polysaccharide materials.The flammability characteristics and flame retardant mechanism of cellulose, carboxymethylcellulose in the acid form (CMC-H), carboxymethylcellulose sodium (CMC-Na) and carboxymethylcellulose calcium (CMC-Ca) were studied based on TG-FTIR, XRD, LOI, CONE, SEM, FTIR and Py-GC/MS tests.The thermal stability of different samples was investigated by TG-FTIR technique. TG results revealed that the residue content was increased and stable degradation products were formed due to the existence of Na+and Ca2+. XRD results showed that the metal ions were left in the residues form carbonate.Combustion behaviors were assessed by using the limiting oxygen index (LOI) and cone calorimetry (CONE). The results indicated that CMC-Na and CMC-Ca were intrinsically flame retardant, and cellulose and CMC-H were inflammable. The incorporation metal ions enhanced the flame retardancy of CMC through working in the condensation phase.The combustion residues were also analysed by scanning electron microscopy (SEM) and digital camera. The images showed the combustion residue crust of CMC-Na formed a porous inflation carbon layer, and CMC-Ca formed a thick and consistent barrier layer. Both residue structure might improve the materials’flame retardancy of CMC.Fourier transform infrared spectroscopy (FTIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) were employed to study the residue and pyrolysis fragments of the four samples. We proposed metal ions flame retardancy mechanism in condensation phase for carboxymethyl cellulose.