Monitoring of Laminate Cure with Microdielectrometry.
Abstract
We report the use of microdielectrometry for monitoring the cure of the matrix resins in epoxy-glass and epoxy-graphite composites. The multi-ply laminates are cured in a press using ramped temperatures. The microdielectrometer sensor is embedded in a cavity made by cutting a hole in each of the inner plies. For a brominated-epoxy glass-reinforced prepreg ramped to final cure temperatures as high as 200 C and at pressure up to 60 psi, a reproducible pattern of cure events is observed beginning with the flow of resin onto the sensor electrodes and ending with the characteristic stabilizing of the loss factor late in cure. The apparent dielectric properties (permittivity and loss factor) show good reproductibility for identically prepared samples, but their characteristics differ from those observed in neat resin. For an MY-720 based graphite prepreg, at cure temperatures below 160 C and at pressures up to 60 psi, features in the cure data are similar to what is seen in epoxy glass. However, at pressures of 60 psi and higher cure temperatures, there is evidence that the graphite fiber can touch the sensor surface and short the electrodes, a problem that will require a revised sensor package design. Keywords include: Fiber-reinforced composite and Cure monitoring.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1984
- Accession Number
- ADA150863
Entities
People
- N. F. Sheppard Jr.
- S. D. Senturia
- W. W. Bidstrup
Organizations
- Massachusetts Institute of Technology