Dispersion monitoring of carbon nanotube modified epoxy systems

Abstract

The remarkable mechanical and electrical properties exhibited by carbon nanotubes (CNTs) have encouraged efforts to develop mass production techniques. As a result, CNTs are becoming increasingly available, and more attention from both the academic world and industry has focused on the applications of CNTs in bulk quantities. These opportunities include the use of CNTs as conductive filler in insulating polymer matrices and as reinforcement in structural materials. The use of composites made from an insulating matrix and highly conductive fillers is becoming more and more important due to their ability to electromagnetically shield and prevent electrostatic charging of electronic devices. In recent years, different models have been proposed to explain the formation of the conductive filler network. Moreover, intrinsic difficulties and unresolved issues related to the incorporation of carbon nanotubes as conductive fillers in an epoxy matrix and the interpretation of the processing behavior have not yet been resolved. In this sense, a further challenge is becoming more and more important in composite processing: cure monitoring and optimization. This paper considers the potential for real-time control of cure cycle and dispersion of a modified epoxy resin system commonly utilized in aerospace composite parts. It shows how cure cycle and dispersion control may become possible through realtime in-situ acquisition of dielectric signal from the curing resin, analysis of its main components and identification of the significant features.