Insulation materials, thermal chlorofluorocarbons

Foamed polymeric materials have several inherent features that combine to make them economically important. Any foamed material is a good heat insulator by virtue of the low conductivity of the gas, usually air, contained in the system. In a rigid foam, the gas contained in the cells may not be exchanged with air for a long time. The thermal conductivities of some common gases in W/m °C at 27°C are as follows air, 0.0262 n-pentane, 0.0144 nitrogen, 0.024 and carbon dioxide, 0.0146. Despite the low conductivity of many chlorofluorocarbons at around 0.012 W/m °C,... 

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