Improvement of the Processability of Poly(Ether Ketone Ketone) by the Addition of a Liquid Crystalline Polymer
The addition of a thermotropic liquid crystalline, wholly aromatic copolyester, TLCP, improved the melt processability of poly(ether ketone ketone), PEKK. The tensile strength and modulus of the blends also improved with increasing TLCP, but the elongation at break decreased significantly. The blends were phase-separated, but the polymers were partially miscible as evident from shifts of the glass transition temperature (Tg) of each component towards that of the other component in the blend. Similarly, the melting points (Tm) of both components were depressed by blending. When the crystallization temperature was above Tm of the TLCP, the PEKK crystallization rate in the blend was slower than for the pure material, while crystallization was faster when the temperature was below Tm of the TLCP.