Intumescent foams

Manufacturers Comments Structural intumescent foaming core splice Manutocturers Comments Composite bonding film with excellent ... 

Manuticturers Comments Good strength to 290 C. Moisture resistant. No volatiles during cure. Manufacturers Comments Structural intumescent foaming core-splice adhesive for use up to 230 C. Expansion ratio x2 x3 at 175 C. ... 

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... 

Li, B. and Xu, M. 2006. Effect of a novel charring-foaming agent on flame retardancy and thermal degradation of intumescent flame retardant polypropylene. Polym. Deg. Stab. 91 1380-1386. 

Due to their low dehydration temperatures and water solubilities, boric acid and sodium borates (borax pentahydrate and borax decahydrate) are mostly used as fire retardants in wood/cellulosic products such as timbers, plywood, particle board, wood fiber, paper products, and cotton products. In recent years, boric acid has also been used as fire retardant in epoxy intumescent coating, pheno-lics, urethane foam, and so on. When necessary, boric acid can be coated with silicone oil such as silicone to alleviate its water solubility in water-based coating. 

APB solution can be sprayed on paper or the paper can be dipped into the solution to yield fire-retardant products. In addition to the cellulose, it has also been used as a flame retardant in polyurethane foam and epoxy intumescent coatings. 

Fire-retarded materials functioning in the condensed phase, such as intumescent systems, form, on heating, foamed cellular charred layers on the surface, which protects the underlying material from the action of the heat flux or the flame. It is recognized that the formation of the effective char occurs via a... 

At 360°C-370°C, an important increase in the apparent initial viscosity begins that corresponds to the complete degradation of the initial material and to the carbonization of the system. The foamed material appears to be constituted by solid particles only. From 450°C-460°C, the viscosity value is more stable and increases slightly. At this temperature, a char oxidation/degradation probably starts. Complementarity, the viscosity can be analyzed versus temperature and versus time (Figure 10.10) in order to better visualize the mechanical and thermal stabilities of the protective intumescent layer and to have a better understanding of the carbonization process. 

The ceramizing capacity of polyboroxosiloxane elastomer provides a new P-free intumescent mechanism [57], The combustion of PP-polyboroxosiloxane 3 1 blend filled with 1.25% organo-modified SEP (OSEP, Pangel B40 product of Tolsa Ltd.) and 1.25% melamine borate lead to the formation of white foamed ceramic structure shown in Figure 13.15. 

Modesti, M. Lorenzetti, A. Simioni, F. Camino G. Expandable graphite as an intumescent flame retardant in polyisocyanurate-polyurethane foams. Polym. Degrad. Stab. 2002, 77, 195-202. 

Intumescent A material that foams and swells when exposed to high surface temperature or flames is said to be intumescent. 

Fillers reduce shrinkage of polymer foams. Mica and glass fiber reduce warpage and increase the heat distortion temperature. Intumescent fillers increase in volume rapidly as they degrade thermally expanding the material and blocking fire spread. 

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