Materials Research Society
Warrendale, PA, United States|
Technisch Physische Dienst TNO - TH
|Source:||Proceedings of the 1999 MRS Spring Meeting - Symposium DD, 'Organic/Inorganic Hybrid Materials', 5 April 1999 through 9 April 1999, San Francisco, CA, USA, 576, 363-368|
|Materials Research Society Symposium - Proceedings|
Nanotechnology · Ceramic materials · Clay minerals · Crystal growth · Crystallization · Decomposition · Glass transition · Morphology · Polyethylenes · Thermodynamic stability · Isothermal crystallization · Nanostructured materials
In order to link the fundamental research field of polymer crystallization with the technical important field of composite materials polymer-layered silicate nanocomposites from polyethylene (PE) are prepared and their morphology and properties are investigated. The effect of an external confinement introduced by highly anisotropic silicate layers of organically modified clay minerals on crystal growth and nanocomposite properties has been studied. The prepared nanocomposites of organically modified clay minerals and PE exhibit not only a homogeneous distribution of individual silicate layers but also of tactoids. The isothermal crystallization rate of PE in the corresponding nanocomposite at 120 °C is increased in the composite material due to the action of the silicate layers. A significant effect on crystal phase has not been observed so far but from X-ray experiments, however the crystal size seems to be influenced. The thermal stability of the nanocomposites is significantly enhanced and the decomposition mechanism has been changed due to the presence of the layered silicates within the host polymer acting as a barrier for the diffusion of small molecules like oxygen. Due to the none permanent attachment of the polymer chains to the silicate surface the thermal-mechanical properties are only moderately enhanced at low temperature while the glass transition temperature remains unaffected.