Melamine salts

Melamine can also be added to a UF-resin in the form of melamine salts like acetates, formates or oxalates [31-34]. These decompose in the aqueous resin mix at higher temperatures and enable considerable savings of melamine for the same degree of water resistance compared to traditionally prepared MUF-resins. These salts can act additionally as hardeners. 

Melamine and melamine salts (e.g., borates, phosphates) act in a similar manner promoting char formation and intumescence. 

Mechanism of Thermal Degradation of Fire-Retardant Melamine Salts... 

A thorough study of the mechanism of degradation of several fire retardant melamine salts is carried out using thermogravimetry, evolved gas analysis and spectroscopic characterisation of the products of degradation. 

The salts can be classified in three main classes salts which undergo thermal dissociation to acid and melamine salts of strong acids which catalyse melamine condensation salts of acids which react with melamine condensation products. Implications of the thermal behaviour of the salts in the mechanism of fire retardance is briefly discussed. 

COSTA ETAL. Thermal Degradation of Fin-Retardant Melamine Salts 213... 

A completely different situation may arise when melamine derivatives, e.g. melamine salts are introduced in the polymeric material, owing to the thermal behaviour of the salts which depends on the type of acid combined with melamine. We have characterised the thermal behaviour of a wide number of melamine salts and found that they may be classified into three main classes ... 

The experimental weight loss in the first and second step (4.0 and 4.5% respectively) is in agreement with that corresponding to condensation to pyrophosphate (4.0%) and polyphosphate (4.2X, n 1). Furthermore, the IR spectra of melamine phosphate and of the residues at 300 and 330 C (Figure 14 spectra A, B and C respectively) show that besides the typical bands of phosphate salts (950-1300 cm-1) which are present in the three spectra, a new absorption due to P-O-P bonds (ca. 890 cm-1) appears in the spectra of the residues. The absorptions due to melamine salt structures (e.g. 780-790 and 1450-1750 cm ) are closely similar in the three spectra of Figure 14. Fire retardants based on melamine pyrophosphate and polyphosphate are reported in the literature 51 as well as methods for preparation of these salts (25-... 

Pentaerythritol phosphate has an excellent char-forming ability owing to the presence of the pentaerythritol structure. The bis-melamine salt of the bis acid phosphate of pentaerythritol is also available commercially. This is a high melting solid that acts as an intumescent flame-retardant additive for polyolefins. Synergistic combinations with ammonium polyphosphates have also been developed primarily for urethane elastomers. Self-condensation of tris(2-chloroethyl) phosphate produces oligomeric 2-chloroethylphosphate. It has a low volatility, and is useful in resin-impregnated air filters, in flexible urethane foams and in other structural foams.11... 

The use of polyols such as pentaerythritol, mannitol, or sorbitol as classical char formers in intumescent formulations for thermoplastics is associated with migration and water solubility problems. Moreover, these additives are often not compatible with the polymeric matrix and the mechanical properties of the formulations are then very poor. Those problems can be solved (at least partially) by the synthesis of additives that concentrate the three intumescent FR elements in one material, as suggested by the pioneering work of Halpern.29 b-MAP (4) (melamine salt of 3,9-dihydroxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]-undecane-3,9-dioxide) and Melabis (5) (melamine salt of bis(l-oxo-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octan-4-ylmethanol)phosphate) were synthesized from pentaerythritol (2), melamine (3), and phosphoryl trichloride (1) (Figure 6.4). They were found to be more effective to fire retard PP than standard halogen-antimony FR. 

Liu, Y. and Wang, Q. 2006. Catalytic action of phospho-tungstic acid in the synthesis of melamine salts of pentaerythritol phosphate and their synergistic effects in flame retarded polypropylene. Polym. Deg. Stab. 91 2513-2519. 

Case (iii) above presents instead just UF oligomers and melamine salts (Formula 7), H0CH2-[(-U—CH hfu —CH j OH + CH3COO M + + UNREACTED UREA... 

Effect of Insufficient Watering and Melamine Salt of Bis(Oxymethyl) phosphonic Acid (Melaphen) on the Fatty Acid Composition... 

In this work we studied the effect of insufficient watering (IW) and melamine salt of bis(oxymethyl)-phosphonic acid (melaphen) on the fatty acid composition and the energy of 5 day etiolated pea seedling mitochondria Pisum sativum). It has been shown... 

Fattakhov, S. G. Reznik, V. S., and Konovalov, A. I. Melamine salt of bis(ox methyl)phosphoric acid (MELAPHEN) as a new generation of regulator of plant grows. Proceedings of the 13th International Conference on Chemistry of Phosphorus Compounds. Saint-Petersburg., p. 80 (2002). 

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