"The effects of entrapped air, water, and volatile hydrocarbons from thermally-degraded carbon cement and carbon-phenolic composite on 2D carbon-carbon composite structures was investigated. Samples of 2D C-C composites with a final chemical vapor deposition coating (CVD) are compared with samples of similar composites lacking a CVD coating. Thermogravimetric analysis is used to characterize the thermal degradation of various cure cycles for C-34 carbon cement and for carbon-phenolic samples. The rupture of composite structures of these types can be correlated with the permeability of the system and the quantity of volatiles produced."