The effect of thermal degradation on the crystallisation and mechanical properties of PEEK-glass fibre composites


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Parkes, Andrew Martin (2018). The effect of thermal degradation on the crystallisation and mechanical properties of PEEK-glass fibre composites. University of Birmingham. Ph.D.

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To prevent the formation of ice on aircrafts, de-icing systems are incorporated into various structures. These can consist of multi functional composite structures. To maintain control over the production of these systems, the composite must be formed in stages. Although there is a significant body of literature describing the infusion of PEEK into fibre reinforcement, there are many inconsistencies regarding the selection of hold temperature, time and pressure. This work sought to identify a set of optimum process conditions for the infusion of PEEK into a glass fibre fabric. The key considerations were the effect of process conditions on degradation and subsequent crystallisation of PEEK.

The repeatability of DSC analysis was determined through the use of thermal cycling through a range of temperatures from above melt (350°C) to above T m 0. The number of runs obtainable, from a sample of PEEK before the effects of degradation occurred, decreased when hold temperature increased. However, a distinct change in degradation rate was observed above 380°C. Results show that multiple runs of PEEK can be obtained at 380°(, without the effects of degradation, while ensuring the removal of residual nuclei in the melt.

The process of degradation affects the chemical structure of PEEK. Through Fourier-transform infrared spectroscopy (FTIR) of PEEK the effect of degradation can be measured in the variation in the height of peak 1653cm·1 (crystalline phase) and 1648cm·1 (amorphous phase). As the amount of nuclei available for crystallisation decreases the amorphous peak will increase in ratio in comparison to the crystalline peak.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Metallurgy and Materials
Funders: None/not applicable
Subjects: T Technology > TN Mining engineering. Metallurgy


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