Analysis of the nonisothermal melt and cold crystallization kinetics of poly (aryl ether ether ketone ketone) (PEEKK) was performed by using differential scanning calorimetry (DSC).The Avrami equation modified by Jeziorny could describe only the primary stage of nonisothermal crystallization of PEEKK.And,the Ozawa analysis,when applied to this polymer system,failed to describe its nonisothermal crystallization behavior.A new and convenient approach for the nonisothermal crystallization was proposed by combining the Avrami equation with the Ozawa equation.By evaluating the kinetic parameters in this approach,the crystallization behavior of PEEKK was analyzed. According to the Kissinger method,the activation energies were determined to be 189 and 328 kJ/mol for nonisothermal melt and cold crystallization,respectively.

Nanoindentation technique has been used to investigate the mechanical properties of exfoliated nylon 66 (PA66)/clay nanocomposites in present study.The hardness, elastic modulus and creep behavior of the nanocomposites have been evaluated as a function of clay concentration.It indicates that incorporation of clay nanofiller enhances the hardness and elastic modulus of the matrix.The elastic modulus data calculated from indentation load-displacement experiments are comparable with those obtained from dynamic mechanical analysis and the tensile tests.However,the creep behavior of the nanocomposites shows an unexpected increasing trend as the clay loading increases (up to 5 wt%).The lowered creep resistance with increasing clay content is mainly due to the decrease of crystal size and degree of crystallinity as a result of clay addition into PA66 matrix,as evidenced by optical microscopy and X-ray diffraction. At lower clay concentration (here ≤5 wt%),morphological changes due to addition of clay plays the dominant role in creep behavior compared with the reinforcement effect from nanoclay.

The nanoindentation behavior and morphology of the injection-molded specimens of nylon-6 (PA6)/clay nanocomposites prepared by meltcompounding have been studied in present study.The elastic and plastic properties as well as creep behavior of PA6 and its nanocomposites are comparatively evaluated as the function of clay loading by using nanoindentation technique.The anisotropic characteristics in mechanical properties are studied by indenting the injection-molded specimens in two different directions (i.e. parallel and perpendicular to the injection direction).The uneven distribution of both the clay nanofiller and the crystallinity of the polymeric matrix induced by melt-processing leads to the variation of the mechanical property of the nanocomposites in certain directions and locations within the molded specimens.The microstructural and morphological changes of PA6 upon incorporating with clay nanofiller are evidenced by transmission electron microscopy and small-angle Xray scattering, which are closely correlated with the anisotropy of the mechanical properties observed by nanoindentation.

Carbon nanotubes (CNTS) have been grown on MCM-41 supported Fe nanoparticles and the as-prepared (no further purification) CNT-silica hybrid was directly incorporated into nylon-6 (PA6) by simple melt-compounding.The urchin-shaped CNT-silica hybrid filler was observed to be homogeneously dispersed throughout the matrix by scanning electron and transmission electron microscopy.Compared with neat PA6,the tensile modulus and strength of the composite are greatly improved by about 110%,with incorporation of only 1 wt.-% CNT-silica filler.