Effects of Sepiolite Clay on Degradation and Fire Behaviour of a Bisphenol A-based Epoxy

As-received and pre-treated sepiolite/epoxy systems, characterised by an inorganic content from 2 to10 wt.%, were investigated in order to assess induced-filler effect on degradation and fire behaviour.Thermogravimetrical results show that the thermal stability of the hosting epoxy, is slightly affected bythe presence of sepiolite for both typologies; whereas, changes induced in char morphology by the pretreatedclay will significantly affect the fire behaviour of the final nanocomposite.Modelling of thermo-gravimetrical results in air atmosphere, by means of Kissinger procedure, shows anoteworthy reduction of activation energies associated with each degradation steps, especially at highestsepiolite content either by using as-received and pre-treated inorganic filler. This substantially indicatesthat the presence of sepiolite shorten the whole degradation process on the temperature scale. On theother hand, the different morphology of the char layer during the burning process can have relevantflame retardant effects acting on both condensate and vapour phase. Analysing the cone calorimetricdata, a reduction of about 27% of the peak of heat release rate for the highest sepiolite percentage is measuredand the burning total period is increased thus confirming that sepiolite when pre-treated representsa valid fire retardant inorganic filler for such a system.