Intumescence-based components

At Bolton, we also have attempted to introduce volatile and possible vapor phase-active, phosphorus-based FR components in back-coating formulations.60 62 The selected FRs included tributyl phosphate (TBP), a monomeric cyclic phosphate Antiblaze CU (Rhodia Specialties) and the oligomeric phosphate-phosphonate Fyrol 51 (Akzo). When combined with an intumescent char-forming pentaerythritol (PER) derivative (NH1197, Chemtura) and applied as a back-coating on to cotton and polypropylene substrates, significant improvements in overall flame retardancy were observed. 

The sueeess of graphite in this applications shows that filler with plate like struetures should be considered when intumescent materials are being formulated. Reeent developments in intumescent paints show that performanee ean be improved if a layer of organic material is inserted between the layers of the plate like filler. The degradation of this material in the enclosed space increases the expansion rate and the retention of gas inside the degrading material. Based on this prinei-ple any plate like filler has the potential to be useful in an intumescent applieation. The eomposition of filler is also important. When clay was used as a filler in fire retardant applieations, it was found that some of its components interfere with the action of carbonization catalysts and detract from the overall performance of the system in terms of limiting oxygen index. ... 

In the preceding sections, various passive fire protection methods have been discussed. Practical applications have been demonstrated for CS board, VP based mortar, intumescent coating. In general, it can be concluded that passive protection methods are effective in reducing heat release, smoke, and toxic gas production, and can limit the participation of the contribution of the component to the fire. These are indeed critical issues, but for multiple-story buildings, the issue of structural fire endurance is also important. It was shown that these passive methods with certain thickness of the protective layer can prolong the structural endurance time by maximum 100% for FRP components with a flange thickness of less than 10 mm on the fire side. 

The intumescent approach has been used for about 50 years in coatings for the protection of metal and wood structures [1,2]. The introduction of intumescent systems in the bulk of polymeric materials is relatively recent [3-5]. The early developments in intumescent additives for polymers were based on experience acquired in coating applications. Indeed, the empirical approach had led to a recognition of the need for compounds capable of supplying the charred residue (a carbonific ) and of blowing it to a foamed cellular structure ( spumific ) as components of formulations showing intumescent behaviour in coatings. 

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