Isothermal Crystallization Behavior of Nano-Alumina Particles-Filled Poly(ether ether ketone) Composites

ABSTRACT: The isothermal crystallization behavior of nano-alumina particle-filled poly(ether ether ketone) (PEEK) composites has been investigated using differential scanning calorimeter. The results show that all the neat PEEK and nano-alumina-filled PEEK composites exhibit the double-melting behavior under isothermal crystalliza-tion. The peak crystallization times (sp) for all the neat PEEK and PEEK/aluminum oxide (Al2O3) composites increase with increasing crystallization temperature. More-over, the crystallinity of the PEEK/Al2O3 composite with 7.5 wt % nano-filler content reached the maximum value of 44.8 % at 290C, higher than that of the neat PEEK poly-mer. From the lower value in sp and higher value in Xc for the PEEK/Al2O3 composites, the inclusion of the nano-alu-mina into the PEEK matrix favored the occurrence of het-erogeneous nucleation. The Avrami exponents n of all the neat PEEK and PEEK/Al2O3 composites ranged from 2 to 3, and the n values for PEEK/Al2O3 composites were slightly higher than that of the neat PEEK polymer, indi-cating that the inclusion of the nano-filler made the crys-tallization mechanism more complex. However, the growth rate of crystallization was lowered as the nano-filler was introduced, and the decrease in growth rate reduced the grain size of the PEEK spherulites because of the lowering of molecule mobility during isothermal crys