Determination of Gel Point of Epoxy Thermosets via Electric Resistance Measurements

A new, nickel‐coated graphite resistance‐change‐based method for gel‐point determination for epoxy‐based thermoset resins is presented and compared with DSC and rheological methods. Gelation times determined by this new method are in very good agreement with conventional techniques; this new method is potentially simpler and less time consuming than existing ones. Conducting nickel‐coated graphite particles were used to determine the gelation time of epoxy/amine thermosets. The highest value of electric resistance was found to be a direct reflection of the gelation point. Comparison of this new method with other standard methods shows very good agreement.