Experimental study on pyrolysis of black non-charring polymers in the reduced pressure environment

A series of experiments on a black non-charring polymer in the low-pressure chamber is conducted under different external heat fluxes. The surface and bottom temperatures and the mass loss of the sample are measured. A parameter $T_p$ is introduced to describe the impact of pressure on the surface temperature. There is a loose layer of the char residue left with significant pyrolysis bubbles under the low heat flux, and the bubble size decreases with pressure. The parameter $T_p$ is found to exhibit a significant decline trend with increasing pressure, and the mass loss rate of the sample decreases apparently as the pressure increases. However, under a high heat flux, the char residue is denser, and the pyrolysis bubbles are not observed. The value of $T_p$ and the mass loss rate of the sample have no obvious relationship with pressure. The average pyrolysis rate is linearly proportional to $p^a$.