As it is widely known, polymers are flexible material with a wide range of applications. However, their practical applications are sometimes limited due to a trade off in the
physical properties. It has been reported that blending traditional polymers with amounts as small as 2% vol of layered clay particles having characteristic sizes at the nanoscale can greatly
improve the host polymer properties. For instance, the reinforcement in mechanical properties can be of two orders of magnitude. Also the flammability of the host polymer can be reduced. The
layered nanocomposites have interesting electronic and magnetic properties that make them appealing for electronic applications. Since they present a high diffusion barrier toward oxygen the food
industry is interested in these materials, as they can be suitable for food packages. In traditional filled polymers containing particles with micron and macro dimensions, the particles load has to
be as high as 30 vol % since the particles can only interact over short range in distance. This work has been focused to the study of polymer nanocomposites mechanical properties and their
fundamental determinants. Layered silica-polymer nanocomposites displays, at long time, plateaus in the storage modulus characteristic of a solid-like behavior, although the content of particles is
small, [2]. The reinforcement that the layered particles provide to the host polymer are attributed to the fact that the particles are highly anisotropic having aspect ratios of 100. However,
experiments with materials containing spherical particles, isotropic, has revealed the same behavior at low frequencies suggesting that there are other interactions contributing to the macroscopic
behavior and rising the question on how the particles are really affecting the system behavior. To explore this arena, the idea of model system has been developed. Isotropic particles with modified
surface chemistry that allows control over the prominent forces is the main features of these models systems. Specifically, they will permit us to decouple the interactions at the nanoscale and
their influence on the viscoelastic properties of the system. All of this will contribute to have a deep understanding of the fundamental physics associated with the macroscopic properties allowing
the design of new materials with target properties. Also insight into the material flow behavior will ultimately enable the production at large scales.
Publisher
Cornell Center for Materials Research
Date
2005-08-17
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Additional Notes
Acknowledgements: This work was supported by the Cornell Center for Materials Research and the National Science Foundation
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