The retardancy effect of additives, undergoing an endothermic decomposition in the solid phase, upon flammability properties of thermally thin thermoplastics is investigated. The criterion for ignition is that of a critical mass flux of volatiles pyrolysed from the solid into the gas phase. Strong coupling between the solid and gas phases is thus neglected in this model. The kinetic parameter values are set up in such a way that easy comparison can be made between the cone calorimeter and thermogravimetric analysis (TGA).
The requirements for an additive to have maximal effect on ignition time and maximal mass loss rate are found to contrast, so that a simple heat-sink additive cannot maximise both.
M.I. Nelson, J. Brindley, and A.C. McIntosh. The Effect of Heat Sink Additives on the Ignition and Heat Release Properties of Thermally Thin Thermoplastics. Fire Safety Journal, 28(1): 67-94, February 1997.
Polymeric materials are widely used in building and construction applications and there is considerable interest in reducing their fire hazard. A major step forward in the systematic investigation of ignition properties of polymeric materials has been the increasing use of the cone calorimeter.
In this paper we model the autoignition of thermally thin thermoplastics in the cone calorimeter by three nonlinear ordinary differential equations representing the temperatures of the polymer and the gaseous reaction zone, and the mass of fuel in the gaseous reaction-zone. Although the equations are too complicated to be analysed analytically, the techniques of dynamical systems theory, including path following methods, are used to identify regimes and mechanisms for ignition. The consequences of these differences are discussed from the perspective of fire engineering.
M.I. Nelson. The Autoignition of Thermoplastics in the Cone Calorimeter: A Dynamical Systems Model In Proceedings of the 16th International Colloquium on the Dynamics of Explosions and Reactive Systems, pages 494-497. Wydawnictwo,, Akapit'' (Kraków, Poland), 1997. ISBN 83-7108-028-X. Contains material not yet published in refereed journals.
A non-linear dynamical systems model for the ignition of thermally thin thermoplastics in the cone calorimeter is investigated. The model contains equations for solid phase and gas phase processes which are coupled through heat and mass transfer. We use the model to evaluate the critical heat flux required for ignition and investigate how this depends upon the degradation kinetics of the thermoplastic. The concept of a critical surface temperature defining criticality is validated.
M.I. Nelson. A Dynamical Systems Model of Autoignition in the Cone Calorimeter. In Fire Safety Science: Proceedings of the Fifth International Symposium, pages 547-558. International Association for Fire Safety Science, 1997. ISBN 4-9900625-5-5. http://dx.doi.org/10.3801/IAFSS.FSS.5-547