Isothermal and nonisothermal crystallization kinetics of poly(ether ether ketone)/gadolinium oxide composites

Abstract

In this study, poly(ether ether ketone) (PEEK)/gadolinium oxide (Gd₂O₃) composites were prepared by melt extrusion in combination with a Haake rheometer. Differential scanning calorimetry was used to investigate the crystallization behavior of PEEK and its corresponding composites. The microstructural features of the composites and the interfacial interactions between the filler and PEEK phases were viewed with a scanning electron microscope. Gd₂O₃ powder was blended with PEEK, and sulfonated poly(ether ether ketone) (SPEEK) was used as the compatibilizer in the PEEK/Gd₂O₃ composites. Isothermal crystallization exotherms showed that the addition of SPEEK increased the crystallization of PEEK in PEEK/Gd₂O₃ composites. However, the PEEK crystallization rates decreased with increasing Gd₂O₃ fractions, which probably resulted from the Gd₂O₃ that had no heterogeneous nucleation effects on the matrix. The modified Avrami equation and Mo’s equation were used to study the nonisothermal crystallization kinetics. The addition of Gd₂O₃ did not change the nucleation process of PEEK, but it markedly decreased the crystal growth rate.