Materials World Network: Dynamics in Polymer Nanocomposites Containing Hard, Soft and Mobile Nanoparticles

Polymer nanocomposites, namely mixtures of nanoparticles dispersed in a polymer matrix, have gained rapid attention for both industrial and fundamental studies since their introduction in the early 1990's. One of the first high impact applications was provided by Toyota Central Research who demonstrated that the addition of a small amount of layered silicate greatly improved the mechanical properties of nylon. In fact, the commercial use of polymer nanocomposites with improved elastic modulus, electrical conductivity, flame retardation and thermal conductivity is being explored across many economic sectors including aerospace, electronics, and sporting applications.

The main objective of this research is to provide fundamental knowledge of polymer dynamics in the presence of spherical nanoparticles using a coordinated experimental and theoretical approach. This proposed Materials World Network contains expertise in nanoparticle synthesis, nanocomposite fabrication, imaging, depth profiling, simulation, theory and neutron scattering to address how the presence of nanoparticles with sizes comparable to, and smaller than, the individual polymers impacts on dynamics. This MWN team has considerable experience in polymer nancomposites and is committed to working together to explore how polymer diffusion is correlated with structure in these fascinating and commercially-important materials.

The proposed Materials World Network is well-positioned for groundbreaking insights into the physics of polymer nanocomposites that are likely to have positive impact on the emerging industry of polymer nanocomposites. While our proposed research will focus on spherical nanoparticles, our findings will be applicable to a broader range of nanoparticles. Understanding the polymer dynamics is particularly important when designing fabrication methods for nanocomposites. When a master batch containing a high concentration of nanoparticles is melt mixed with a neat polymer, the rate of polymer diffusion is critical for establishing a homogeneous concentration. For example, one strategy for balancing the high cost of nanoparticles with their attractive properties involves coating latex particles with nanoparticles and then sintering the particles to achieve good interfacial strength. The material strength is determined by the interdiffusion of polymers across the interfacial region to form entanglements and the mechanism for this will be established by the proposed research.

Polymer nanocomposites are a promising new classes of materials. This research will benefit industries that are hoping to exploit their potential. Such industries include both traditional polymer manufacturers who will be looking towards nanocomposites to improve performance of existing products and new adopters of polymeric materials who will be hoping to replace, for example, metals with lighter weight polymer nanocomposites. We anticipate that this project will impact upon directly upon materials suppliers who wish to incorporate this important class of materials into their portfolio. A requirement for many suppliers is that the processing to be undertaken by customers matches as closely as possible that of existing materials, in order to ensure a smooth transition between material types. The knowledge gained from our work will ensure manufacturers are able to quantitatively account for the impact of incorporating nanoparticles on processing.

We will design and deliver a one-day course on polymer nanocomposites targeted at industrial scientists and engineers as part of the Sheffield Polymer Centre and the Polymer IRC two-week Polymer Course, which is taught each year. The course will provide an opportunity for an industrial researcher to discuss existing and future challenges with academics who have more regular access to new developments. We anticipate that this will lead to opportunities to engage with industrial users of the research through a variety of knowledge transfer mechanisms that we have gained experience of in recent years.