Quantitative Determination and Analysis of Pyrolysis Products from a Two-Zone Phenol-Formaldehyde Resin and Carbon Preform Reaction

Pyrolysis of phenol-formaldehyde (PF) resins is one of the most common processes to produce carbon-based composites. An example is carbon impregnated PF resins commonly used as ablative and friction materials for aerospace applications. Detailed kinetic understanding of the chemical interactions at high temperature between the pyrolysis products and carbon structure resulted from pyrolysis is essential but limited. In this work, pyrolysis of a resole PF resin and a carbon preform was performed in a two-zone batch reactor, with one zone holding the PF sample and the other zone holding the carbon preform. The reaction was carried out in a two-zone custom-made heating furnace. The temperature difference between the two heating zones was set to be constant (upper zone kept at higher temperature) based on heat transfer analysis. Samples in both zones were exposed to different temperatures and pyrolysis reaction was performed using a step-wise heating procedure for both heating zones. The mass loss of the samples was determined after every step, and the production of the gas-phase and liquid-phase species was quantified and analyzed using gas chromatography and mass spectrometry techniques. The experimental results provide a good source for future development of a detailed kinetic model for the pyrolysis of PF resin/carbon composites.