Limiting oxygen index clays

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. ... 

The preliminary study on the flammabihty of HUP-MMT compositions was performed by the determination of limiting oxygen indexes (LOI). The flame retardance was affected by styrene content in the resin and the type of clay used (Table 9.3). An additional amount of styrene has been added to some compositions in aim to improve the casting properties on the other hand the excess styrene makes the cured compositions more flammable due to the increased content of polystyrene (LOI = 18) and decreased of HUP (LOI = 24). The cured compositions containing MMT-Na as well as organoclays with DMDTA and ADA, showed... 

---