Thermal Stability and Flammability of Styrene-Butadiene Rubber-Based (SBR) Ceramifiable Composites
Ceramifiable styrene-butadiene (SBR)-based composites containing low-softening-point-temperature glassy frit promoting ceramification, precipitated silica, one of four thermally stable refractory fillers (halloysite, calcined kaolin, mica or wollastonite) and a sulfur-based curing system were prepared. Kinetics of vulcanization and basic mechanical properties were analyzed and added as Supplementary Materials. Combustibility of the composites was measured by means of cone calorimetry. Their thermal properties were analyzed by means of thermogravimetry and specific heat capacity determination. Activation energy of thermal decomposition was calculated using the Flynn-Wall-Ozawa method. Finally, compression strength of the composites after ceramification was measured and their micromorphology was studied by scanning electron microscopy. The addition of a ceramification-facilitating system resulted in the lowering of combustibility and significant improvement of the thermal stability of the composites. Moreover, the compression strength of the mineral structure formed after ceramification is considerably high. The most promising refractory fillers for SBR-based ceramifiable composites are mica and halloysite.
Resistance to fire of silicone-based coatings: Fire protection of steel against cellulosic fire
The fire performance of curable silicone-based coatings containing expandable graphite, organoclay, and calcium carbonate is evaluated in cellulosic fire scenario (standard ISO834) using a lab-scale furnace test. It is shown that the use of organoclay and calcium carbonate allows achieving same insulative performance when compared with organic commercial intumescent coating. The mode of action of these silicone-based coatings is fully investigated using thermal analyses and spectroscopic analyses including X-ray photoelectron spectroscopy. It is shown that the high fire performance of intumescent silicone-based coatings is due to (1) interactions between calcium carbonate and silicone matrix increasing the thermal stability of the resin and (2) the formation of calcium silicate embedding the top of the char and permitting the formation of an additional protective ceramic layer.
Nanostructure and properties of polysiloxane‐layered silicate nanocomposites
The relationship between nanostructure and properties in polysiloxane layered silicate nanocomposites is presented. Solvent uptake (swelling) in dispersed nanocomposites was dramatically decreased as compared to conventional composites, though intercalated nanocomposites and immiscible hybrids exhibited more conventional behavior. The swelling behavior is correlated to the amount of bound polymer (bound rubber) in the nanocomposites. Thermal analysis of the bound polymer chains showed an increase and broadening of the glass-transition temperature and loss of the crystallization transition. Both modulus and solvent uptake could be related to the amount of bound polymer formed in the system. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1595–1604, 2000