Fiber-optic epoxy composite cure sensor. II. Performance characteristics.

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Science

Background:

• Fiber-optic sensors offer a non-destructive method for monitoring composite material curing.
• Epoxy resin reaction kinetics are critical for understanding and controlling the curing process.
• Accurate monitoring of epoxy cure is essential for ensuring composite performance and structural integrity.

Purpose of the Study:

• To develop and validate a fiber-optic epoxy cure sensor.
• To model the performance characteristics of the epoxy cure sensor based on reaction kinetics.
• To demonstrate the sensor's capability in predicting gel point and monitoring cure progression.

Main Methods:

• Characterization of epoxy reaction kinetics, identifying it as a third-order autocatalytic reaction.
• Derivation of a model to predict sensor performance based on kinetic data.
• Experimental validation of the sensor's performance under isothermal curing conditions.

Main Results:

• The derived model accurately describes the epoxy cure sensor's performance.
• The sensor signal effectively predicts the gel point during isothermal composite curing.
• The sensor demonstrates reliable performance in nonstoichiometric epoxy matrices.
• The sensor can detect the end of the cure process without requiring calibration.

Conclusions:

• The fiber-optic epoxy cure sensor is a viable tool for real-time monitoring of composite curing.
• The sensor's performance is directly linked to the optical properties and reaction kinetics of the epoxy system.
• The developed sensor offers a calibration-free method for determining cure completion and monitoring the curing process.