Solid polymers ignition

The solid polymer (approximating to the trimer) ignites in air or chlorine. 

In addition to the effects on physical properties, an effect on ballistic properties may also be observed. If the polymer does not fill the entire space not occupied by the solids, when ignited the flame front may proceed by connected voids to yield an uncontrolled combustion condition. A porous condition can have an effect on the sensitivity to detonation as discussed in Chapter 10. The attractive forces between polymer and solids are probably the major contributing factor that causes differences in physical properties of propellant and causes one polymeric or polymer-plus-plasticizer system to be preferred over another. 

For common thermally thick combustible materials (greater than a few millimeters) the time to ignition is proportional to the product k p c (where k is the thermal conductivity, p is the density, and c is the heat capacity), which represents the thermal inertia of the sample. Thermal inertia characterizes the rate of surface temperature rise of the material when exposed to heat. Low values of thermal inertia lead to a rapid temperature rise for a given applied heat flux and hence, to a rapid ignition.4 Polymeric foams have much lower thermal conductivity and density than the corresponding solid materials, thus the surface temperature of the first heats up more rapidly than that of the latter. Foam surface may reach the ignition temperature 10 times faster than the solid polymer.5... 

Flammability is the ease with which a substance will ignite, causing fire or combustion. Combustion or burning of solid polymers is a complicated process involving physical and chemical phenomena that are only partially understood (Nelson, 2002). It is a sequence of... 

DIFLUOROETHENE or DIFLUORO-l,l-ETHENE (75-38-7) Flammable gas (flash point <—85°F/<—65°C). Violent reaction with oxidizers, barium, sodium, or potassium. Reacts with aluminum chloride. Incompatible with hydrogen chloride. May form explosive compounds with light metals and metallic azides. Capable of forming unstable peroxides may cause explosive polymerization. Undergoes thermal decomposition when exposed to flame or red-hot surfaces. May accumulate static electricity, and cause ignition of its vapors. The uninhibited monomer vapor may block vents and confined spaces by forming a solid polymer material. 

Flow or agitation of substance may generate electrostatic charges due to low conductivity. Spontaneous ignition on contact with concentrated nitric acid, strong oxidizers. The uninhibited monomer vapor may block vents and confined spaces by forming a solid polymer material. 

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