Gel time is the time from softening to gelation of polymer materials, which is an irreversible deformation process from viscous liquid to elastic gel. Gel time is one of the most important process parameters affecting resins and prepregs. "Determination of Gel Time of Resin and Prepreg by Cone-Plate Viscometer Method" mainly uses three methods of cone-plate viscometer method, rheometer method and Electric Heating Plate method to test the gel time of resin, and test the three methods The experimental results of the two methods were compared and analyzed. This article mainly extracts the experimental process and conclusions of the cone-plate viscometer method introduced in the article. The cone-plate viscometer method uses a Thcomme AG cone-plate viscometer to measure the gel time of the epoxy resin matrix.
experimental method
Install the 100P cone-plate on the cone-plate viscometer, connect the viscometer to the computer, start the viscosity test software and viscometer power supply, adjust the viscometer test gear to the third gear, set the experimental temperature to the resin test temperature and stabilize at 30 about min.
Weighing: Weigh 0.05g of the resin matrix and place it on the viscometer test plate to cover it evenly.
Test: Press down the viscometer cone, immediately start the viscometer test and software record, the software will automatically record time, temperature and viscosity curve. When the viscosity increases rapidly and reaches the maximum value of the viscosity test, the time elapsed from the start of the test to the maximum viscosity value is the gel time of the resin matrix at this temperature. As shown below
Mark the point where the viscosity value just reaches the maximum value in the figure, and mark this point with the mouse, and the 13min34s displayed in the "Mark order" column in the lower left corner of the interface is the gel time of the tested resin.
Experimental results
in conclusion
The cone-plate viscometer method uses a small amount of sample (only 0.5g), and is especially suitable for testing the gel time of prepregs. The curve is drawn by the viscometer software, and the gel time is directly read, which effectively eliminates the artificial influence, has good reproducibility, and the coefficient of dispersion is only 0.8%. The equipment is easy to obtain, the price is low, and the test speed is fast. It is not only suitable for the production process control of resin and prepreg, but also for the performance test of resin and prepreg products. It is a test method worthy of suggestion.
