Pyrolytic Analysis of a Charring Ablator

The aim of ablation research at Dstl is to understand the key mechanisms which contribute to the behaviour of a charring ablator. Central to understanding the mechanisms and informing the models is knowledge of the chemical products formed during the ablation process and their respective quantities. Following on from David Paynes presentation Mechanistic Analysis of a Charring Ablator at the 4th Ablation Workshop, this presentation describes the approach taken to quantify the pyrolysis products of a charring ablator and the results achieved. Pyrolytic decomposition of phenolic resin has been performed and a range of analytical techniques have been employed to initially identify, and subsequently quantify, the products: Gas chromatography mass spectrometry (GC-MS) to separate and quantify the volatile aromatic compounds. Gas chromatography thermal conductivity detection (GC-TCD) to separate and identify the permanent gases. Fourier transform infrared spectroscopy (FT-IR) to identify and quantify water and permanent gases. The products identified included water, hydrogen, methane, carbon monoxide, carbon dioxide, benzene, methylbenzenes, phenol, methylphenols and larger aromatic compounds. Quantitative data is presented demonstrating the composition of the products produced during the pyrolysis of phenolic resin