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 crystallization. The peak crystallization times (τp) for all the neat PEEK and PEEK/aluminum oxide (Al2O3) composites increase with increasing crystallization temperature. Moreover, the crystallinity of the PEEK/Al2O3 composite with 7.5 wt % nano‐filler content reached the maximum value of 44.8% at 290°C, higher than that of the neat PEEK polymer. From the lower value in τp and higher value in Xc for the PEEK/Al2O3 composites, the inclusion of the nano‐alumina into the PEEK matrix favored the occurrence of heterogeneous 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, indicating that the inclusion of the nano‐filler made the crystallization 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 crystallization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Understanding the effects of nanocarbons on flexible polymer chain orientation and crystallization: Polyethylene/carbon nanochip hybrid fibrillar crystal growth

“…(a, b) Small‐angle X‐ray scattering intensity profiles for (a) PE and (b) PE/CNCF fibers. Iq as a function of q ( ) shows the development of the meridional intensity (kebabs) for the control polyethylene fibrillar crystals. (c, d) Plots of the small‐angle scattering intensity along the equatorial (i.e., extended‐chain) and meridional (i.e., folded‐chain) directions as a function of draw ratio for both the control (c) and hybrid PE/CNCF (d) fibers showing an increase in extended‐chain crystal growth at draw ratios over two.…”

“…Morphological registry and design is important for the processing of polymer nanocomposites in order to control the properties, and this may be accomplished by understanding crystallization in these systems. Nanofillers have been found to influence polymer crystallization, in particular carbon nanotubes (CNT) have been shown to template polymer crystallization and orientation . A number of mechanisms currently exist for controlling the polymer crystal structure including nucleation, solidification solution crystallization, and crystallization in the presence of nanofillers …”

Mechanical properties, morphology, and crystallization behavior of polypropylene/elastomer/talc composites

“…, the crystallization enthalpies (Δ H c ) and peak crystallization times ( τ p ) of the neat PP and its composites were determined. In addition, the absolute crystallinities ( X c ) of the neat PP and its composites can be estimated by using the heat of fusion of an infinitely thick PP crystal, : where is approximately 209.2 J/g , and W polymer is the weight fraction of the polymer matrix. These crystallization parameters, including the peak crystallization time and absolute crystallinity, are listed in Table .…”