Analysis on the structure-transformation of phenol-formaldehyde in high temperature with pyrolysis-gas chromatography-mass spectrometry

Phenol-formaldehyde was cured at 200℃ with a selected velocity,and then decomposed at 450,550,650,750℃ respectively.The results indicated that some methylene bonds were broken because of high activation,which deteriorated the phenol-formaldehyde structure.Some methylene groups were crosslinked with phenolic OH groups,which stabilized,at a certain extent,the phenol-formaldehyde structure in high temperature.The effect of the former on phenol-formaldehyde structure was dominate between 300 and 550℃,which was responsible for the deterioration of mechanic performance.Condense reaction between phenolic OH groups was occurred range of 650-750℃.In correspondly,structure recomposition was happened,which promoted structure-adjusting.As a result,the phenol-formaldehyde structure was transformed to amorphous carbon gradually.