Characterisation of cross-linking and moisture ingress detection in an epoxy/amine resin using fibre-optic sensors

Themosetting resins are being used increasingly as matrix materials in advanced fibre-reinforced composites. It is well known that the processing conditions used to manufacture the composite can have a major influence on its mechanical integrity in service. In addition, the processing parameters can also affect the ingress of moisture in thermosetting resin and composites. The feasibility of using optical fibre-based sensor systems for monitoring cross-linking reaction has been demonstrated previously. However, little work has been reported on the deployment of a single sensor to study the cross-linking kinetics and the diffusion of moisture. In the current work, four low-cost sensor designs were evaluated for in situ monitoring of the cross-linking reactions of an epoxy/amine resin system. One of these sensor designs was selected and used to investigate in detail the cross-linking kinetics. Excellent correlation was observed between the cross-linking data obtained form the sensors and conventional transmission spectroscopy. Semi-empirical models were used successfully to describe the cross-linking behaviour of the epoxy/amine resin system that was used in this study. Subsequent to monitoring the cross-linking reactions, the fibre-optic sensors were used to study the diffusion of moisture in the cross-linked resin system. Conventional gravimetric measurements were also carried out to enable the correlation with the data obtained from the fibre optic sensors. It was demonstrated that the fibre-optic sensors were capable of giving information on the “localised” diffusion of moisture in the neat-resin plaques. Three previously published models were investigated and localised diffusion of moisture in the neat-resin showed non-Fickian behaviour.

Name dc:type.qualificationname

d_ph

Level dc:type.qualificationlevel

d_ph

Grantor dc:publisher.institution

University of Birmingham

Year dc:date.issued

2010

Author dc:creator

• Mahendran, Ramani Salmalee

• TP Chemical technology
• TS Manufactures
• TK Electrical engineering. Electronics Nuclear engineering