To increase the glass transition temperature (T-g) of poly(aryl ether ketone), and to decrease the melting temperature (T-m) and temperature of processing, a series of novel poly(aryl ether ketone)s with different contents of 2,7-naphthalene moieties (PANEK) was synthesized. We focused on the influence of the naphthalene contents to the copolymer's crystallization. The crystallization kinetics of the copolymers was studied isothermally and nonisothermally by differential scanning calorimetry. In the study of isothermal crystallization kinetics, the Avrami equation was used to analyze the primary process of the crystallization. The study results of the crystallization of PANEK at cooling/heating rates ranging from 5 to 60 degrees C/min under nonisothermal conditions are also reported. Both the Avrami equation and the modified Avrami-Ozawa equation were used to describe the nonisothermal crystallization kinetics of PANEK. The results show that the increase in the crystallization temperature and the content of 2,7-naphthalene moieties will make the crystallization rate decrease, while the nucleation mechanism and the crystal growth of PANEK are not influenced by the increasing of the content of 2,7-naphthalene moieties. (c) 2006 Wiley Periodicals, Inc.