Nitrogen-based flame

Horacek, H. Grabner, W. Nitrogen based flame retardants for nitrogen-containing polymers. Makromol. Chem. Macromol. Symp. 1993, 74, 271-276. 

Phosphorus and Phosphorus/Nitrogen-Based Flame Retardants... 

For multi-analyte and/or multi-matrix methods, it is not possible to validate a method for all combinations of analyte, concentration and type of sample matrix that may be encountered in subsequent use of the method. On the other hand, the standards EN1528 andEN 12393 consist of a range of old multi-residue methods. The working principles of these methods are accepted not only in Europe, but all over the world. Most often these methods are based on extractions with acetone, acetonitrile, ethyl acetate or n-hexane. Subsequent cleanup steps are based on solvent partition steps and size exclusion or adsorption chromatography on Florisil, silica gel or alumina. Each solvent and each cleanup step has been successfully applied to hundreds of pesticides and tested in countless method validation studies. The selectivity and sensitivity of GC combined with electron capture, nitrogen-phosphorus, flame photometric or mass spectrometric detectors for a large number of pesticides are acceptable. 

Intumescent systems based on ammonium polyphosphate can produce flame retardant polypropylene. Great Lakes manufactures Reogard 1000, an intumescent phosphorus and nitrogen based, melt blendable flame retardant for polypropylene homopolymers and low ethylene PP copolymers that need V-0 ratings. It is not particularly hygroscopic and gives good electrical properties with improved heat distortion temperature. 

Nitrogen-containing FRs (without any phosphorus compounds) hold only a small share of the global FR market at present, although their popularity is growing. The main active ingredients are usually melamine cyanurate and melamine hydrobromide, although melamine phosphate is used in intumescent FR systems in combination with pentaerythritol. Melamine based flame retardants employ several modes of flame retardant action. 

The chemistry of flame-retardant additives is highly varied and is optimised not only for specific polymer chemistries, but also to address flammability effects such as flame spread, dripping, smoke release and so on. Flame-retardant chemistry includes classes of compounds such as halogenated organics, char formers, crosslinking compounds, mineral fillers, intumescent packages, phosphorus compounds, nitrogen-based compounds and even certain metal and boron compounds. 

Several approaches have been used to make polymers fire-retardant. Phosphorus-based flame retardants have been effectively used in a wide variety of polymeric materials. The efficiency of phosphorus compounds is often dramatically increased in the presence of certain nitrogen compounds. Thus, the improved flame resistance of polyesters in the presence of triphenylphosphine oxide and Nylon-6 has been attributed to the synergistic effect of phosphorus and nitrogen atoms. However, the fire-retardant additives (1) frequently influence the decomposition reaction in... 

Degradation products from both antimony-halogen based and nitrogen-phosphorus based flame retardants were studied using X-ray diffraction and atomic emission analysis. Evidence of the retardation mechanisms in use against combustion was obtained for each system and in each case emission of volatile combustion inhibitors at the degradation temperature of the polymer matrix was the critical factor. 11 refs BELARUS BELORUSSIA... 

A series of compounded flame retardants, based on finely divided insoluble ammonium polyphosphate together with char-forming nitrogenous resins, has been developed for thermoplastics (52—58). These compounds are particularly useful as iatumescent flame-retardant additives for polyolefins, ethylene—vinyl acetate, and urethane elastomers (qv). The char-forming resin can be, for example, an ethyleneurea—formaldehyde condensation polymer, a hydroxyethylisocyanurate, or a piperazine—triazine resin. 

Phosphoric Acid-Based Systems for Cellulosics. Semidurable flame-retardant treatments for cotton (qv) or wood (qv) can be attained by phosphorylation of cellulose, preferably in the presence of a nitrogenous compound. Commercial leach-resistant flame-retardant treatments for wood have been developed based on a reaction product of phosphoric acid with urea—formaldehyde and dicyandiamide resins (59,60). 

In the 1990s, two types of flame retardants are preferred for outdoor fabrics, ie, a system based on phosphoms and nitrogen such as the precondensate—NH finish and an antimony—bromine system based on decabromodiphenyl oxide [1163-19-5] and antimony(III) oxide (20,40—42). 

For the sake of brevity, the so-called cool flame techniques based upon the use of an oxidant-lean flame such as hydrogen/nitrogen-air, have not been included. 

The use of n-butylamino-derivatives of cyclophosphazenes in flame-proofing cellulose-based fabrics has been described in a patent application. The topic of fiame retardants is also covered in a recent review, where phosphazenes are important because of their relatively high phosphorus and nitrogen contents. 

The simultaneous analysis of orthophosphate, glycerol phosphates, and inositol phosphates has been achieved by spectrophotometric analysis of the molybdovanadate complexes. Also, a sensitive and selective chemiluminescent molecular emission method for the estimation of phosphorus and sulphur is described, which is based on passing solutions into a cool, reducing, nitrogen-hydrogen diffusion flame. For organic compounds it was usually necessary to prepare test solutions by an oxygen-flask combustion technique. 

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