Thermal and spectroscopic studies on flame‐retardant cotton cellulose modified with THPC‐urea‐ADP and its transition metal complexes

Abstract

Cotton cellulose has been treated with tetrakis(hydroxymethy1)phosphonium chloride (THPC), urea and small amounts of ammonium dihydrogen orthophosphate (ADP) to impart flame retardancy. Complexes of cell-THPCurea-ADP with transition metals such as chromium, manganese, iron, cobalt, nickel, copper and zinc have been characterized by reflectance UV-visible spectra. The samples were subjected to differential thermal analysis and thermogravimetry from ambient temperature to 700°C in air to study their thermal behaviour. From the resulting data, various kinetic parameters for different stages of thermal degradation were obtained following the method of Broido. For the decomposition of cellulose and flame-retardant celluloses, the activation energy was found to increase from 242 to 322kJmol-', the entropy of activation from 140 to 307 J K -' mol-* and the char yield from 2 5 to 31 %. The free energy of activation for decomposition of cellulose and its derivatives was almost the same, viz.148-162 kJ mol-', indicating that the basic steps in the decomposition of cellulose and its derivatives are the same. The IR spectra of the thermally degraded residues of cell-THPC-urea-ADP and its metal complexes indicate that dehydration takes place and a compound containing the carbonyl group is formed. The electron paramagnetic resonance signals indicate the formation of trapped and stable free radicals in the thermal degradation of cellulose and its derivatives.

Flame Retardant Properties of Laminated Bamboo Lumber Treated with Monoammonium Phosphate (MAP) and Boric acid/Borax (SBX) Compounds

“…Compared to the untreated samples, the MAP-SBX samples began to degrade at 171.6 C and the critical temperature of the maximum mass loss was 315.8 C, which was approximately 21.6 C to 21.9 C lower than the untreated, respectively. The function of the flame retardant in wood materials is to increase the char at the cost of flammable volatile products (Bagga et al 1990). As with the DTG curves (Fig.…”

Thermal stability of cotton cellulose modified with dysprosium complexes

“…The preparation of the samples is corresponded to references [3]. THPC (Shanghai, China) was neutralized with NaOH to give a pH value equal to 6.5 and its 45% solution was mixed with 22.5% 6th International Conference on Machinery, Materials, Environment, Biotechnology and Computer (MMEBC 2016) thiourea solution.…”

“…In previous papers [3,4], compounds of transition metals have been found to be effective smoke retarders and simultaneously increase thermal stability of samples. However, there is little information about the effects of lanthanide metal ions on smoke suspension and thermal degradation of cotton cellulose treated with flame retardants.…”

Thermal stability of cotton cellulose modified with gadolinium complexes

“…The preparation of the samples is corresponded to references [3]. THPC (Shanghai, China) was neutralized with NaOH to give a pH value equal to 6.5 and its 45% solution was mixed with 22.5% thiourea solution.…”