Pyrolysis of Phenolic Resin by TG-MS and FTIR Analysis

The pyrolysis of phenolic-formaldehyde (PF) resin was studied by TG-MS technique. The structure changes of pyrolysis of PF resin heated to different temperatures were investigated by Fourier-transform infrared rays (FTIR). The experimental results shows that the pyrolysis of PF can be divided into three stages. Ether bonds and unreacted terminal hydroxymethyl groups of the cured resin degradate in the first stage. In the second stage, crosslinks are broken, involving formation of a thermally crosslinked intermediate structure and the breaking of methylene bridges into methyl groups. Cyclodehydration and forming char of phenolic hydroxyl occurs in the third stage. The thermal stability and char yield of resin are depended on the pyrolysis of methylene bridges.