Effect of Thermal History on the Polymorphic Behavior of Poly(Ethylene 2,6‐Naphthalate)/Clay Nanocomposites

Abstract

X‐ray diffraction method were used to investigate the structural change of poly(ethylene 2,6‐naphthalate) (PEN)/clay nanocomposites. The PEN/clay was prepared by the intercalation of PEN polymer into organically modified layered montmorillonite through the melt blending process. Both X‐ray diffraction data and transmission electron microscopy (TEM) images of PEN/clay nanocomposites indicate most of the swellable silicate layers were exfoliated and randomly dispersed into the PEN matrix. The X‐ray diffraction data also show the presence of polymorphism in PEN/clay nanocomposites. This polymorphic behavior is strongly dependent on the thermal history of PEN/clay nanocomposites from the melt and on the content of clay in PEN/clay nanocomposites. Quenching from the melt induces crystallization into the α‐crystalline form, while the addition of montmorillonite increases the growth rate of the β‐crystalline form. The effect of melt crystallization of PEN and PEN/clay nanocomposites at different crystallization temperatures on the crystalline phases is also discussed.

Keywords:

• Poly(ethylene 2,6‐naphthalate)
• Nanocomposite
• Polymorphism

Acknowledgments

The financial support provided by NSC through the project NSC92‐2622‐E‐005‐006‐CC3 was greatly appreciated.