Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor

Charpentier, Paul A.

Abstract

This thesis investigates the thermomechanical properties of two commercial composites using carbon fiber reinforcement in epoxy resins for manufacturing marine based rowing racing shells. The main goal of this project was to investigate how to control the resin properties and curing temperatures to improve the final product properties including adhesion, toughness modulus and tensile strength. Moreover, an efficient curing process was required by our supporting company to be used at low temperatures to enhance the curing characteristics and to provide improved mechanical properties. Accordingly, the current research tries to improve the manufacturing curing process and build up high performance structure with enhanced properties for low weight racing hulls. Using a vacuum bagging only technique (VBO), the composite prepregs were cured by an improved ramp rate of 3˚C/min. Numerous thermomechanical devices (e.t TGA, DSC, DMA and Instron) were used to check for weigh loss and mechanical properties of the carbon fiber- epoxy resin prepregs. The results of this thesis showed that utilizing the autoclave curing technique (OoA), an epoxy matrix composite could be prepared with the thermomechanical properties of the carbon fiber prepregs improved and the curing cycle shortened. A void- free and pinhole-free composite surface was obtained with enhanced mechanical properties using a ramp rate of 3˚C/min and holding time after the curing process of 2 hours and 50 minutes with an onset curing temperature of 121˚C. Keywords Carbon fiber- epoxy resin, composite prepregs, Vacuum bagging technique (VBO), TGA, DSC, DMA, Instron, Out of Autoclave curing (OoA)

Summary for Lay Audience

This dissertation investigates the thermomechanical properties of two commercial composites using carbon fiber reinforcement in epoxy resins for manufacturing marine based rowing racing shells. The main goal was to examine how to control the resin properties and curing temperatures to improve the final product properties and illuminating the possible voids and pinholes on the surface of the composites. An efficient curing process was required by our supporting company to be used at low temperatures to enhance the curing characteristics and to provide improved mechanical properties. Using a vacuum bagging only technique (VBO), the composite prepregs were baked, which will be called curing, by an improved ramp rate of 3˚C/min. Numerous thermomechanical devices (e.t TGA, DSC, DMA and Instron) were used to check for weight loss and mechanical properties of the carbon fiber- epoxy resin prepregs. All in all, the results of this thesis showed that utilizing the autoclave curing technique (OoA), an epoxy matrix composite could be prepared with the thermomechanical properties of the carbon fiber prepregs improved and the curing cycle shortened. A void- free and pinhole-free composite surface was obtained with enhanced mechanical properties using a ramp rate of 3˚C/min and holding time after the curing process of 2 hours and 50 minutes with an onset curing temperature of 121˚C.

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