TGA Analysis of a Phenol-Formaldehyde Condensation Reaction

Purpose

To demonstrate the thermogravimetric analysis of condensation reaction in an open crucible. Mass losses occur due to drying and vaporization of the water formed in the reaction. 

Sample

Powdered PF molding resin containing about 20% phenol-formaldehyde resin.

Conditions

Measuring cell: TGA

Pan: Aluminum 100 μL, without lid

Sample preparation: The crucible was filled with 29.925 mg loose powder, i.e. without compacting.

TGA measurement: Heating from 30 to 220 °C at 10 K/min

Atmosphere: Purge gas: 50 mL/min nitrogen; protective gas: 20 mL/min nitrogen

Interpretation

The TGA heating curve shows a continuous loss of mass with the greatest rate of mass loss at 160 °C (DTG peak). The small peak in the DTG curve shows the maximum drying rate at about 70 °C. 

Conclusions

On heating the PF molding resin in the B-stage to processing temperature above 200 °C, the material looses about 4.5% water. The drying process is overlapped by loss of water due to the beginning of condensation reaction The two effects cannot be properly separated from one another under the experimental conditions used. 

_{TGA Analysis of a Phenol-Formaldehyde Condensation Reaction | Thermal Analysis Handbook No.HB17 | Application published in METTLER TOLEDO TA Application Handbook Thermosets, Volume 1}