Samples were taken every half an hour during reaction of the resole phenolic-paraformaldehyde resin reaction process

strongly cooled to block any further reaction.The relative molecular mass and distribution of the synthetic reaction process of the phenolic-paraformaldehyde resin were determined both by gel-permeation chromatography (GPC) and field desorption mass spectrometry (FD-MS).The GPC was used to analyze quantitatively the composition contents with the synthetic reaction process.The FD-MS was used to give the molecular ion peak of the every phenol unit without fragment ion peaks.The real molecular mass and the structures of every composition can be determined by FD-MS.The structural transformation during the synthetic reaction process of the phenolic-paraformaldehyde resin can be spread out clearly by combining GPC method with FD-MS method.The results show

the free phenol decreased from 70% to 7% with time.The free phenol decreased fast at the beginning with the rapid addition reaction and slowly near the end.For the two monohydroxymethylphenols (2-HMP and 4-HMP)

2-HMP had the maximum value at the beginning and then decreased with time

4-HMP increased first

had the maximum value after 120 min and then decreased quickly.The two dialcohols (2

4-DHMP and 2

6-DHMP) increased first

had the maximum value at about 210~240 min and then decreased quickly.The trialcohol (2

4

6-THMP) also increased first and then decreased

it had the maximum value after 180 min.The two-ring and the three-ring compounds increased with time.They increased slowly at the beginning and fast with the rapid condensation reaction near the end.