Aqueous poly(arylene ether ether ketone) suspensions
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Aqueous dispersion pre-pregging is under investigation within our laboratories for processing fiber reinforced, polymer matrix composites with environmental concern by using water instead of toxic organic solvents. This method requires that the polymers be in the form of a stable aqueous colloidal dispersion. This thesis describes the preparation of submicron diameter poly(arylene ether ether ketone) suspensions in water, and analysis of suspension stability as a function of the suspension variables. This thesis focuses on developing the procedures, and defining the parameters, for preparing stable aqueous suspensions of PEEK particles using new pyridine containing electrostatic stabilizers. Preparation of aqueous PEEK suspensions involves first adsorbing a soluble stabilizer precursor, poly(pyridine ether-co-ether ether ketimine), onto PEEK particles from a organic solvent, followed by hydrolysis of the ketimine moiety on this particle coating in conjunction with protonation of the pyridine units, forming a protonated form of poly(pyridine ether-co-ether ether ketone), which acts as an electrostatic aqueous stabilizer. Ultraviolet spectroscopy was employed to measure and compare adsorption isotherms in both THF and toluene. This high performance electrostatic stabilizer has been used successfully to stabilize aqueous suspensions of both larger particles (~ 12 micron diameter PEEK particles), as well as submicron particles. Stabilities of the suspensions were analyzed using sedimentation experiments for the larger particle size range, and using light scattering (turbidity) for the submicron sizes. The research accomplished in this thesis is currently being used to investigate the use of these dispersions for pre-pregging both continuous carbon fiber tow and pre-woven graphite fabric.
- Masters Theses