Monitoring the dielectric cure of an epoxy-graphite prepreg

摘要

The prepreg was placed on top of a Mini-Varicon sensor with a paper filter in between. The filter allows epoxy to flow to the sensor while preventing graphite fibres from contacting the electrodes and creating a short circuit. The prepreg was then cured using the following temperature profile: - Ramp at 5 °F/min from room temperature to 260 ±5 °F - Hold at 260 °F for 90 minutes+10/-0 minutes The first prepreg sample was moni- tored at 1 Hz, 10 Hz, 100 Hz, 1.0 KHz, 10 KHz and 100 KHz at periodic intervals for the duration of its cure. Lambient Technology's CureView software acquired and stored the data, and performed post-analysis and presentation of the data. CureView can extract critical points only for data obtained at a single frequency, so multiple frequencies had to be used for the first sample to determine an optimum single frequency for the second sample. The second sample was monitored at 10 Hz only.