Flame Retardant

The flame retardance and thermal stability of a methyl methacrylate (MMA) copolymer reactively modified by copolymerisation of the MMA with diethyl (methacryloyloxymethyl) phosphonate (DEMMP) have been compared with those of poly (methyl methacrylate)( ...

A large number of hazardous compounds can be expected to be present in landfill leachates, many of which have not yet been identified. Thus this study screened samples from 12 Swedish municipal landfill sites for 400 parameters and compounds. More than 90 organic and metal organic compounds and 50 inorganic elements were detected, some of which seem to have not been detected before. Compounds detected include halogenated aliphatic compounds, benzene and alkylated benzenes, phenol and alkylated phenols, ethoxylates, polycyclic aromatic compounds, phthalic esters, chlorinated benzenes, chlorinated phenols, PCB, chlorinated dioxins and chlorinated furans, bromated flame-retardants, pesticides, organic tin, methyl mercury and heavy metals. The presence of this large number of hazardous compounds in landfill leachates should have a significant impact on future landfill risk assessments and the development of leachate treatment methods. We propose that future research should pay more atte...

This review covers mainly intumescent coatings, with briefer discussions of non-intumescent organic fire-resistive coatings and cementitious inorganic coatings. Emphasis is placed on the more recent developments, and the more recent patent literature is surveyed. Modeling and optimizing are covered both from basic and applied aspects. The chemistry of the production of a foamed char barrier is discussed. Enhancing the performance by adjuvants and choice of binders is shown to be possible. The important interactions of ammonium polyphosphate with other components such as titanium dioxide are described. Testing is briefly discussed, as are some shortcomings of present-day coatings, such as limited water resistance, and some opportunities for improvement.

Cotton cellulose has been treated with tetrakis(hydroxymethyl)phosphonium chloride (THPC), urea and small amounts of ammonium dihydrogen orthophosphate (ADP) to impart flame retardancy. Complexes of cell-THPC-urea-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 322kJ mol−1, the entropy of activation from 140 to 307 JK−1 mol−1 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−1, 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.

Spread of fire along electrical cables may be alleviated by using flame-retardant smoke suppressant (FRSS) additives-based PVC compositions designed for use as insulation and sheathing. These compositions offer improved resistance to ignition, flame spread and smoke generation. FRSS protection may also be achieved by the application of intumescent coatings as fire-protective layers and barriers for electrical cables and cable installations. Metal-based organic (MBO) complexes were synthesized for use as flame retardant smoke suppressants in PVC formulations. Plasticized PVC compositions were prepared and evaluated for their fire performance. Excellent smoke suppression was observed when either of the two MBOs was used. The limiting oxygen index was also found to be fairly high, particularly when the PVC samples were plasticized with a phosphate plasticizer. Flame-retardant smoke-suppressant intumescent coatings were developed for PVC-sheathed electrical cables. The coatings were applied on cables, and their fire performance was evaluated by using national and international standard procedures. The coated cables did not show any surface spread of flame on exposure and their generation of smoke was found to be very low. The coatings were found to be quite effective in reducing the burning behaviour of power cables. Significant improvement in circuit failure time was noted for coated cable specimens.